refactor: do initial refactoring attempt

BREAKING CHANGE: This removes the previously available `Path` option

.gitattributes

@@ -0,0 +1,9 @@
+#
+# https://help.github.com/articles/dealing-with-line-endings/
+#
+# Linux start script should use lf
+/gradlew        text eol=lf
+
+# These are Windows script files and should use crlf
+*.bat           text eol=crlf
+

.github/ISSUE_TEMPLATE/bug-issue.yml

@@ -0,0 +1,72 @@
+name: 🐞 Bug report
+description: Report a very clearly broken issue.
+title: 'bug: <title>'
+labels: [bug]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        # ReVanced bug report
+
+        Important to note that your issue may have already been reported before. Please check for existing issues [here](https://github.com/revanced/revanced-patcher/labels/bug).
+
+  - type: dropdown
+    attributes:
+      label: Type
+      options:
+        - Crash
+        - Cosmetic
+        - Other
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Bug description
+      description: How did you find the bug? Any additional details that might help?
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Steps to reproduce
+      description: Add the steps to reproduce this bug including your environment.
+      placeholder: Step 1. Download some files. Step 2. ...
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Relevant log output
+      description: Please copy and paste any relevant log output. This will be automatically formatted into code, so no need for backticks.
+      render: shell
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Screenshots or videos
+      description: Add screenshots or videos that show the bug here.
+      placeholder: Drag and drop the screenshots/videos into this box.
+    validations:
+      required: false
+  - type: textarea
+    attributes:
+      label: Solution
+      description: If applicable, add a possible solution.
+    validations:
+      required: false
+  - type: textarea
+    attributes:
+      label: Additional context
+      description: Add additional context here.
+    validations:
+      required: false
+  - type: checkboxes
+    id: acknowledgements
+    attributes:
+      label: Acknowledgements
+      description: Your issue will be closed if you haven't done these steps.
+      options:
+        - label: I have searched the existing issues and this is a new and no duplicate or related to another open issue.
+          required: true
+        - label: I have written a short but informative title.
+          required: true
+        - label: I filled out all of the requested information in this issue properly.
+          required: true

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,8 @@
+blank_issues_enabled: false
+contact_links:
+  - name: 📃 Documentation
+    url: https://github.com/revanced/revanced-documentation/
+    about: Don't know how or where to start? Check out our documentation!
+  - name: 🗨 Discussions
+    url: https://github.com/revanced/revanced-suggestions/discussions
+    about: Got something you think should change or be added? Search for or start a new discussion!

.github/ISSUE_TEMPLATE/feature-issue.yml

@@ -0,0 +1,58 @@
+name: ⭐ Feature request
+description: Create a detailed feature request.
+title: 'feat: <title>'
+labels: [feature-request]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        # ReVanced feature request
+        
+        Do not submit requests for patches here. Please submit them [here](https://github.com/orgs/revanced/discussions/categories/patches) instead.
+        Important to note that your feature request may have already been made before. Please check for existing feature requests [here](https://github.com/revanced/revanced-patcher/labels/feature-request).
+
+  - type: dropdown
+    attributes:
+      label: Type
+      options:
+        - Functionality
+        - Cosmetic
+        - Other
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Issue
+      description: What is the current problem. Why does it require a feature request?
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Feature
+      description: Describe your feature in detail. How does it solve the issue?
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Motivation
+      description: Why should your feature should be considered?
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Additional context
+      description: Add additional context here.
+    validations:
+      required: false
+  - type: checkboxes
+    id: acknowledgements
+    attributes:
+      label: Acknowledgements
+      description: Your issue will be closed if you haven't done these steps.
+      options:
+        - label: I have searched the existing issues and this is a new and no duplicate or related to another open issue.
+          required: true
+        - label: I have written a short but informative title.
+          required: true
+        - label: I filled out all of the requested information in this issue properly.
+          required: true

.github/config.yml

@@ -0,0 +1,2 @@
+firstPRMergeComment: >
+  Thank you for contributing to ReVanced. Join us on [Discord](https://revanced.app/discord) if you want to receive a contributor role.

.github/workflows/pull_request.yml

@@ -0,0 +1,25 @@
+name: PR to main
+
+on:
+  push:
+    branches:
+      - dev
+  workflow_dispatch:
+
+env:
+  MESSAGE: merge branch `${{ github.head_ref || github.ref_name }}` to `main`
+
+jobs:
+  pull-request:
+    name: Open pull request
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+      - name: Open pull request
+        uses: repo-sync/pull-request@v2
+        with:
+          destination_branch: 'main'
+          pr_title: 'chore: ${{ env.MESSAGE }}'
+          pr_body: 'This pull request will ${{ env.MESSAGE }}.'
+          pr_draft: true

.github/workflows/release.yml

@@ -0,0 +1,45 @@
+name: Release
+
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - main
+      - dev
+  pull_request:
+    branches:
+      - main
+      - dev
+
+jobs:
+  release:
+    name: Release
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          # Make sure the release step uses its own credentials:
+          # https://github.com/cycjimmy/semantic-release-action#private-packages
+          persist-credentials: false
+          fetch-depth: 0
+      - name: Cache
+        uses: actions/cache@v3
+        with:
+          path: |
+            ${{ runner.home }}/.gradle/caches
+            ${{ runner.home }}/.gradle/wrapper
+            .gradle
+            build
+            node_modules
+          key: ${{ runner.os }}-gradle-npm-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties', 'package-lock.json') }}
+      - name: Build with Gradle
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: ./gradlew clean --no-daemon
+      - name: Setup semantic-release
+        run: npm install
+      - name: Release
+        env:
+          GITHUB_TOKEN: ${{ secrets.REPOSITORY_PUSH_ACCESS }}
+        run: npm exec semantic-release

.gitignore

@@ -74,6 +74,7 @@ cmake-build-*/
 
 # IntelliJ
 out/
+.idea/
 
 # mpeltonen/sbt-idea plugin
 .idea_modules/
@@ -115,3 +116,9 @@ gradle-app.setting
 
 # Avoid ignoring test resources
 !src/test/resources/*
+
+# Dependency directories
+node_modules/
+
+# Gradle props, to avoid sharing the gpr key
+gradle.properties

.idea/.gitignore

@@ -1,8 +0,0 @@
-# Default ignored files
-/shelf/
-/workspace.xml
-# Editor-based HTTP Client requests
-/httpRequests/
-# Datasource local storage ignored files
-/dataSources/
-/dataSources.local.xml

.idea/codeStyles/Project.xml

@@ -1,10 +0,0 @@
-<component name="ProjectCodeStyleConfiguration">
-  <code_scheme name="Project" version="173">
-    <JetCodeStyleSettings>
-      <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
-    </JetCodeStyleSettings>
-    <codeStyleSettings language="kotlin">
-      <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
-    </codeStyleSettings>
-  </code_scheme>
-</component>

.idea/codeStyles/codeStyleConfig.xml

@@ -1,5 +0,0 @@
-<component name="ProjectCodeStyleConfiguration">
-  <state>
-    <option name="USE_PER_PROJECT_SETTINGS" value="true" />
-  </state>
-</component>

.idea/discord.xml

@@ -1,7 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="DiscordProjectSettings">
-    <option name="show" value="PROJECT_FILES" />
-    <option name="description" value="" />
-  </component>
-</project>

.idea/misc.xml

@@ -1,10 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="ExternalStorageConfigurationManager" enabled="true" />
-  <component name="FrameworkDetectionExcludesConfiguration">
-    <file type="web" url="file://$PROJECT_DIR$" />
-  </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_17" default="true" project-jdk-name="azul-17" project-jdk-type="JavaSDK">
-    <output url="file://$PROJECT_DIR$/out" />
-  </component>
-</project>

.idea/vcs.xml

@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="VcsDirectoryMappings">
-    <mapping directory="$PROJECT_DIR$" vcs="Git" />
-  </component>
-</project>

.releaserc

@@ -0,0 +1,37 @@
+{
+  "branches": [
+    "main",
+    {
+      "name": "dev",
+      "prerelease": true
+    }
+  ],
+  "plugins": [
+    "@semantic-release/commit-analyzer",
+    "@semantic-release/release-notes-generator",
+    "@semantic-release/changelog",
+    "gradle-semantic-release-plugin",
+    [
+      "@semantic-release/git",
+      {
+        "assets": [
+          "CHANGELOG.md",
+          "gradle.properties"
+        ]
+      }
+    ],
+    [
+      "@saithodev/semantic-release-backmerge",
+      {
+        backmergeBranches: [{"from": "main", "to": "dev"}],
+        clearWorkspace: true
+      }
+    ],
+    [
+        "@semantic-release/github",
+        {
+            successComment: false
+        }
+    ]
+  ]
+}

README.md

@@ -1 +1,3 @@
-# Patcher
+# 💉 ReVanced Patcher
+
+ReVanced Patcher used to patch Android applications.

arsclib-utils/.gitignore

@@ -0,0 +1,42 @@
+.gradle
+build/
+!gradle/wrapper/gradle-wrapper.jar
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### IntelliJ IDEA ###
+.idea/modules.xml
+.idea/jarRepositories.xml
+.idea/compiler.xml
+.idea/libraries/
+*.iws
+*.iml
+*.ipr
+out/
+!**/src/main/**/out/
+!**/src/test/**/out/
+
+### Eclipse ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+bin/
+!**/src/main/**/bin/
+!**/src/test/**/bin/
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+
+### VS Code ###
+.vscode/
+
+### Mac OS ###
+.DS_Store

arsclib-utils/build.gradle.kts

@@ -0,0 +1,18 @@
+plugins {
+    kotlin("jvm")
+    `maven-publish`
+}
+
+group = "app.revanced"
+
+dependencies {
+    implementation("io.github.reandroid:ARSCLib:1.1.7")
+}
+
+java {
+    withSourcesJar()
+}
+
+kotlin {
+    jvmToolchain(11)
+}

arsclib-utils/src/main/kotlin/app/revanced/arsc/ApkResourceException.kt

@@ -0,0 +1,72 @@
+package app.revanced.arsc
+
+/**
+ * An exception thrown when there is an error with APK resources.
+ *
+ * @param message The exception message.
+ * @param throwable The corresponding [Throwable].
+ */
+sealed class ApkResourceException(message: String, throwable: Throwable? = null) : Exception(message, throwable) {
+    /**
+     * An exception when locking resources.
+     *
+     * @param message The exception message.
+     * @param throwable The corresponding [Throwable].
+     */
+    class Locked(message: String, throwable: Throwable? = null) : ApkResourceException(message, throwable)
+
+    /**
+     * An exception when writing resources.
+     *
+     * @param message The exception message.
+     * @param throwable The corresponding [Throwable].
+     */
+     class Write(message: String, throwable: Throwable? = null) : ApkResourceException(message, throwable)
+
+    /**
+     * An exception when reading resources.
+     *
+     * @param message The exception message.
+     * @param throwable The corresponding [Throwable].
+     */
+    class Read(message: String, throwable: Throwable? = null) : ApkResourceException(message, throwable)
+    /**
+     * An exception when decoding resources.
+     *
+     * @param message The exception message.
+     * @param throwable The corresponding [Throwable].
+     */
+    class Decode(message: String, throwable: Throwable? = null) : ApkResourceException(message, throwable)
+
+    /**
+     * An exception when encoding resources.
+     *
+     * @param message The exception message.
+     * @param throwable The corresponding [Throwable].
+     */
+    class Encode(message: String, throwable: Throwable? = null) : ApkResourceException(message, throwable)
+
+    /**
+     * An exception thrown when a reference could not be resolved.
+     *
+     * @param reference The invalid reference.
+     * @param throwable The corresponding [Throwable].
+     */
+    class InvalidReference(reference: String, throwable: Throwable? = null) :
+        ApkResourceException("Failed to resolve: $reference", throwable) {
+
+        /**
+         * An exception thrown when a reference could not be resolved.
+         *
+         * @param type The type of the reference.
+         * @param name The name of the reference.
+         * @param throwable The corresponding [Throwable].
+         */
+        constructor(type: String, name: String, throwable: Throwable? = null) : this("@$type/$name", throwable)
+    }
+
+    /**
+     * An exception thrown when the Apk file not have a resource table, but was expected to have one.
+     */
+    class MissingResourceTable : ApkResourceException("Apk does not have a resource table.")
+}

arsclib-utils/src/main/kotlin/app/revanced/arsc/archive/Archive.kt

@@ -0,0 +1,28 @@
+@file:Suppress("MemberVisibilityCanBePrivate")
+
+package app.revanced.arsc.archive
+
+import app.revanced.arsc.resource.ResourceContainer
+import com.reandroid.apk.ApkModule
+import com.reandroid.apk.DexFileInputSource
+import com.reandroid.archive.InputSource
+import java.io.File
+import java.io.Flushable
+
+/**
+ * A class for reading/writing files in an [ApkModule].
+ *
+ * @param module The [ApkModule] to operate on.
+ */
+class Archive(internal val module: ApkModule) : Flushable {
+    val mainPackageResources = ResourceContainer(this, module.tableBlock)
+
+    fun save(output: File) {
+        flush()
+        module.writeApk(output)
+    }
+    fun readDexFiles(): MutableList<DexFileInputSource> = module.listDexFiles()
+    fun write(inputSource: InputSource) = module.apkArchive.add(inputSource) // Overwrites existing files.
+    fun read(name: String): InputSource? = module.apkArchive.getInputSource(name)
+    override fun flush() = mainPackageResources.flush()
+}

arsclib-utils/src/main/kotlin/app/revanced/arsc/logging/Logger.kt

@@ -0,0 +1,7 @@
+package app.revanced.arsc.logging
+interface Logger {
+    fun error(msg: String)
+    fun warn(msg: String)
+    fun info(msg: String)
+    fun trace(msg: String)
+}

arsclib-utils/src/main/kotlin/app/revanced/arsc/resource/Resource.kt

@@ -0,0 +1,166 @@
+package app.revanced.arsc.resource
+
+import app.revanced.arsc.ApkResourceException
+import com.reandroid.arsc.coder.EncodeResult
+import com.reandroid.arsc.coder.ValueDecoder
+import com.reandroid.arsc.value.Entry
+import com.reandroid.arsc.value.ValueType
+import com.reandroid.arsc.value.array.ArrayBag
+import com.reandroid.arsc.value.array.ArrayBagItem
+import com.reandroid.arsc.value.plurals.PluralsBag
+import com.reandroid.arsc.value.plurals.PluralsBagItem
+import com.reandroid.arsc.value.plurals.PluralsQuantity
+import com.reandroid.arsc.value.style.StyleBag
+import com.reandroid.arsc.value.style.StyleBagItem
+
+/**
+ * A resource value.
+ */
+sealed class Resource {
+    internal abstract fun write(entry: Entry, resources: ResourceContainer)
+}
+
+internal val Resource.isComplex get() = when (this) {
+    is Scalar -> false
+    is Complex -> true
+}
+
+/**
+ * A simple resource.
+ */
+open class Scalar internal constructor(private val valueType: ValueType, private val value: Int) : Resource() {
+    protected open fun data(resources: ResourceContainer) = value
+
+    override fun write(entry: Entry, resources: ResourceContainer) {
+        entry.setValueAsRaw(valueType, data(resources))
+    }
+
+    internal open fun toArrayItem(resources: ResourceContainer) = ArrayBagItem.create(valueType, data(resources))
+    internal open fun toStyleItem(resources: ResourceContainer) = StyleBagItem.create(valueType, data(resources))
+}
+
+/**
+ * A marker class for complex resources.
+ */
+sealed class Complex : Resource()
+
+private fun encoded(encodeResult: EncodeResult?) = encodeResult?.let { Scalar(it.valueType, it.value) }
+    ?: throw ApkResourceException.Encode("Failed to encode value")
+
+/**
+ * Encode a color.
+ *
+ * @param hex The hex value of the color.
+ * @return The encoded [Resource].
+ */
+fun color(hex: String) = encoded(ValueDecoder.encodeColor(hex))
+
+/**
+ * Encode a dimension or fraction.
+ *
+ * @param value The dimension value such as 24dp.
+ * @return The encoded [Resource].
+ */
+fun dimension(value: String) = encoded(ValueDecoder.encodeDimensionOrFraction(value))
+
+/**
+ * Encode a boolean resource.
+ *
+ * @param value The boolean.
+ * @return The encoded [Resource].
+ */
+fun boolean(value: Boolean) = Scalar(ValueType.INT_BOOLEAN, if (value) -Int.MAX_VALUE else 0)
+
+/**
+ * Encode a float.
+ *
+ * @param n The number to encode.
+ * @return The encoded [Resource].
+ */
+fun float(n: Float) = Scalar(ValueType.FLOAT, n.toBits())
+
+/**
+ * Create an integer [Resource].
+ *
+ * @param n The number to encode.
+ * @return The integer [Resource].
+ */
+fun integer(n: Int) = Scalar(ValueType.INT_DEC, n)
+
+/**
+ * Create a reference [Resource].
+ *
+ * @param resourceId The target resource.
+ * @return The reference resource.
+ */
+fun reference(resourceId: Int) = Scalar(ValueType.REFERENCE, resourceId)
+
+/**
+ * Resolve and create a reference [Resource].
+ *
+ * @see reference
+ * @param ref The reference string to resolve.
+ * @param resourceTable The resource table to resolve the reference with.
+ * @return The reference resource.
+ */
+fun reference(resourceTable: ResourceTable, ref: String) = reference(resourceTable.resolve(ref))
+
+/**
+ * An array [Resource].
+ *
+ * @param elements The elements of the array.
+ */
+class Array(private val elements: Collection<Scalar>) : Complex() {
+    override fun write(entry: Entry, resources: ResourceContainer) {
+        ArrayBag.create(entry).addAll(elements.map { it.toArrayItem(resources) })
+    }
+}
+
+/**
+ * A style resource.
+ *
+ * @param elements The attributes to override.
+ * @param parent A reference to the parent style.
+ */
+class Style(private val elements: Map<String, Scalar>, private val parent: String? = null) : Complex() {
+    override fun write(entry: Entry, resources: ResourceContainer) {
+        val resTable = resources.resourceTable
+        val style = StyleBag.create(entry)
+        parent?.let {
+            style.parentId = resTable.resolve(parent)
+        }
+
+        style.putAll(
+            elements.asIterable().associate {
+                StyleBag.resolve(resTable.encodeMaterials, it.key) to it.value.toStyleItem(resources)
+            })
+    }
+}
+
+/**
+ * A quantity string [Resource].
+ *
+ * @param elements A map of the quantity to the corresponding string.
+ */
+class Plurals(private val elements: Map<String, String>) : Complex() {
+    override fun write(entry: Entry, resources: ResourceContainer) {
+        val plurals = PluralsBag.create(entry)
+
+        plurals.putAll(elements.asIterable().associate { (k, v) ->
+            PluralsQuantity.value(k) to PluralsBagItem.string(resources.getOrCreateString(v))
+        })
+    }
+}
+
+/**
+ * A string [Resource].
+ *
+ * @param value The string value.
+ */
+class StringResource(val value: String) : Scalar(ValueType.STRING, 0) {
+    private fun tableString(resources: ResourceContainer) = resources.getOrCreateString(value)
+
+    override fun data(resources: ResourceContainer) = tableString(resources).index
+    override fun toArrayItem(resources: ResourceContainer) = ArrayBagItem.string(tableString(resources))
+    override fun toStyleItem(resources: ResourceContainer) = StyleBagItem.string(tableString(resources))
+}

arsclib-utils/src/main/kotlin/app/revanced/arsc/resource/ResourceContainer.kt

@@ -0,0 +1,167 @@
+package app.revanced.arsc.resource
+
+import app.revanced.arsc.ApkResourceException
+import app.revanced.arsc.archive.Archive
+import com.reandroid.apk.xmlencoder.EncodeUtil
+import com.reandroid.arsc.chunk.TableBlock
+import com.reandroid.arsc.chunk.xml.ResXmlDocument
+import com.reandroid.arsc.value.Entry
+import com.reandroid.arsc.value.ResConfig
+import java.io.Closeable
+import java.io.File
+import java.io.Flushable
+
+class ResourceContainer(private val archive: Archive, internal val tableBlock: TableBlock) : Flushable {
+    private val packageBlock = tableBlock.pickOne() // Pick the main package block.
+    internal lateinit var resourceTable: ResourceTable // TODO: Set this.
+
+    private val lockedResourceFileNames = mutableSetOf<String>()
+
+    private fun lock(resourceFile: ResourceFile) {
+        if (resourceFile.name in lockedResourceFileNames) {
+            throw ApkResourceException.Locked("Resource file ${resourceFile.name} is already locked.")
+        }
+
+        lockedResourceFileNames.add(resourceFile.name)
+    }
+
+    private fun unlock(resourceFile: ResourceFile) {
+        lockedResourceFileNames.remove(resourceFile.name)
+    }
+
+
+    fun <T : ResourceFile> openResource(name: String): ResourceFileEditor<T> {
+        val inputSource = archive.read(name)
+            ?: throw ApkResourceException.Read("Resource file $name not found.")
+
+        val resourceFile = when {
+            ResXmlDocument.isResXmlBlock(inputSource.openStream()) -> {
+                val xmlDocument = archive.module
+                    .loadResXmlDocument(inputSource)
+                    .decodeToXml(resourceTable.entryStore, packageBlock.id)
+
+                ResourceFile.XmlResourceFile(name, xmlDocument)
+            }
+
+            else -> {
+                val bytes = inputSource.openStream().use { it.readAllBytes() }
+
+                ResourceFile.BinaryResourceFile(name, bytes)
+            }
+        }
+
+        try {
+            @Suppress("UNCHECKED_CAST")
+            return ResourceFileEditor(resourceFile as T).also {
+                lockedResourceFileNames.add(name)
+            }
+        } catch (e: ClassCastException) {
+            throw ApkResourceException.Decode("Resource file $name is not ${resourceFile::class}.", e)
+        }
+    }
+
+    inner class ResourceFileEditor<T : ResourceFile> internal constructor(
+        private val resourceFile: T,
+    ) : Closeable {
+        fun use(block: (T) -> Unit) = block(resourceFile)
+        override fun close() {
+            lockedResourceFileNames.remove(resourceFile.name)
+        }
+    }
+
+    override fun flush() {
+        TODO("Not yet implemented")
+    }
+
+    /**
+     * Open a resource file, creating it if the file does not exist.
+     *
+     * @param path The resource file path.
+     * @return The corresponding [ResourceFiles],
+     */
+    fun openFile(path: String) = ResourceFiles(createHandle(path), archive)
+
+    private fun getPackageBlock() = packageBlock ?: throw ApkResourceException.MissingResourceTable
+
+    internal fun getOrCreateString(value: String) =
+        tableBlock?.stringPool?.getOrCreate(value) ?: throw ApkResourceException.MissingResourceTable
+
+    private fun Entry.set(resource: Resource) {
+        val existingEntryNameReference = specReference
+
+        // Sets this.specReference if the entry is not yet initialized.
+        // Sets this.specReference to 0 if the resource type of the existing entry changes.
+        ensureComplex(resource.isComplex)
+
+        if (existingEntryNameReference != 0) {
+            // Preserve the entry name by restoring the previous spec block reference (if present).
+            specReference = existingEntryNameReference
+        }
+
+        resource.write(this, this@ResourceContainer)
+        resourceTable.registerChanged(this)
+    }
+
+    /**
+     * Retrieve an [Entry] from the resource table.
+     *
+     * @param type The resource type.
+     * @param name The resource name.
+     * @param qualifiers The variant to use.
+     */
+    private fun getEntry(type: String, name: String, qualifiers: String?): Entry? {
+        val resourceId = try {
+            resourceTable.resolve("@$type/$name")
+        } catch (_: ApkResourceException.InvalidReference) {
+            return null
+        }
+
+        val config = ResConfig.parse(qualifiers)
+        return tableBlock?.resolveReference(resourceId)?.singleOrNull { it.resConfig == config }
+    }
+
+    /**
+     * Create a [ResourceFiles.Handle] that can be used to open a [ResourceFiles].
+     * This may involve looking it up in the resource table to find the actual location in the archive.
+     *
+     * @param path The path of the resource.
+     */
+    private fun createHandle(path: String): ResourceFiles.Handle {
+        if (path.startsWith("res/values")) throw ApkResourceException.Decode("Decoding the resource table as a file is not supported")
+
+        var onClose = {}
+        var archivePath = path
+
+        if (tableBlock != null && path.startsWith("res/") && path.count { it == '/' } == 2) {
+            val file = File(path)
+
+            val qualifiers = EncodeUtil.getQualifiersFromResFile(file)
+            val type = EncodeUtil.getTypeNameFromResFile(file)
+            val name = file.nameWithoutExtension
+
+            // The resource file names that the app developers used may have been minified, so we have to resolve it with the resource table.
+            // Example: res/drawable-hdpi/icon.png -> res/4a.png
+            getEntry(type, name, qualifiers)?.resValue?.valueAsString?.let {
+                archivePath = it
+            } ?: run {
+                // An entry for this specific resource file was not found in the resource table, so we have to register it after we save.
+                onClose = { setResource(type, name, StringResource(archivePath), qualifiers) }
+            }
+        }
+
+        return ResourceFiles.Handle(path, archivePath, onClose)
+    }
+
+    fun setResource(type: String, entryName: String, resource: Resource, qualifiers: String? = null) =
+        getPackageBlock().getOrCreate(qualifiers, type, entryName).also { it.set(resource) }.resourceId
+
+    fun setResources(type: String, resources: Map<String, Resource>, configuration: String? = null) {
+        getPackageBlock().getOrCreateSpecTypePair(type).getOrCreateTypeBlock(configuration).apply {
+            resources.forEach { (entryName, resource) -> getOrCreateEntry(entryName).set(resource) }
+        }
+    }
+
+    override fun flush() {
+        packageBlock?.name = archive
+    }
+}

arsclib-utils/src/main/kotlin/app/revanced/arsc/resource/ResourceFiles.kt

@@ -0,0 +1,91 @@
+package app.revanced.arsc.resource
+
+import app.revanced.arsc.ApkResourceException
+import app.revanced.arsc.archive.Archive
+import com.reandroid.archive.InputSource
+import com.reandroid.xml.XMLDocument
+import com.reandroid.xml.XMLException
+import java.io.*
+
+
+abstract class ResourceFile(val name: String) {
+    internal var realName: String? = null
+
+    class XmlResourceFile(name: String, val document: XMLDocument) : ResourceFile(name)
+    class BinaryResourceFile(name: String, var bytes: ByteArray) : ResourceFile(name)
+}
+
+
+class ResourceFiles private constructor(
+) : Closeable {
+
+    /**
+     * Instantiate a [ResourceFiles].
+     *
+     * @param handle The [Handle] associated with this file.
+     * @param archive The [Archive] that the file resides in.
+     */
+    internal constructor(handle: Handle, archive: Archive) : this(
+        handle,
+        archive,
+        try {
+            archive.read(handle.archivePath)
+        } catch (e: XMLException) {
+            throw ApkResourceException.Decode("Failed to decode XML while reading ${handle.virtualPath}", e)
+        } catch (e: IOException) {
+            throw ApkResourceException.Decode("Could not read ${handle.virtualPath}", e)
+        }
+    )
+
+    companion object {
+        const val DEFAULT_BUFFER_SIZE = 1024
+    }
+
+    var contents = readResult?.data ?: ByteArray(0)
+        set(value) {
+            pendingWrite = true
+            field = value
+        }
+
+    val exists = readResult != null
+
+    override fun toString() = handle.virtualPath
+
+    override fun close() {
+        if (pendingWrite) {
+            val path = handle.archivePath
+
+            if (isXmlResource) archive.writeXml(
+                path,
+                try {
+                    XMLDocument.load(inputStream())
+                } catch (e: XMLException) {
+                    throw ApkResourceException.Encode("Failed to parse XML while writing ${handle.virtualPath}", e)
+                }
+
+            ) else archive.writeRaw(path, contents)
+        }
+
+        handle.onClose()
+
+
+        archive.unlock(this)
+    }
+
+    fun inputStream(): InputStream = ByteArrayInputStream(contents)
+
+    fun outputStream(bufferSize: Int = DEFAULT_BUFFER_SIZE): OutputStream =
+        object : ByteArrayOutputStream(bufferSize) {
+            override fun close() {
+                this@ResourceFiles.contents = if (buf.size > count) buf.copyOf(count) else buf
+                super.close()
+            }
+        }
+
+    /**
+     * @param virtualPath The resource file path. Example: /res/drawable-hdpi/icon.png.
+     * @param archivePath The actual file path in the archive. Example: res/4a.png.
+     * @param onClose An action to perform when the file associated with this handle is closed
+     */
+    internal data class Handle(val virtualPath: String, val archivePath: String, val onClose: () -> Unit)
+}

arsclib-utils/src/main/kotlin/app/revanced/arsc/resource/ResourceTable.kt

@@ -0,0 +1,100 @@
+package app.revanced.arsc.resource
+
+import app.revanced.arsc.ApkResourceException
+import com.reandroid.apk.xmlencoder.EncodeException
+import com.reandroid.apk.xmlencoder.EncodeMaterials
+import com.reandroid.arsc.util.FrameworkTable
+import com.reandroid.arsc.value.Entry
+import com.reandroid.common.TableEntryStore
+
+/**
+ * A high-level API for resolving resources in the resource table, which spans the entire ApkBundle.
+ */
+class ResourceTable(base: ResourceContainer, all: Sequence<ResourceContainer>) {
+    private val packageName = base.tableBlock!!.name
+
+    /**
+     * A [TableEntryStore] used to decode XML.
+     */
+    internal val entryStore = TableEntryStore()
+
+    /**
+     * The [EncodeMaterials] to use for resolving resources and encoding XML.
+     */
+    internal val encodeMaterials: EncodeMaterials = object : EncodeMaterials() {
+        /*
+        Our implementation is more efficient because it does not have to loop through every single entry group
+        when the resource id cannot be found in the TableIdentifier, which does not update when you create a new resource.
+        It also looks at the entire table instead of just the current package.
+        */
+        override fun resolveLocalResourceId(type: String, name: String) = resolveLocal(type, name)
+    }
+
+    /**
+     * The resource mappings which are generated when the ApkBundle is created.
+     */
+    private val tableIdentifier = encodeMaterials.tableIdentifier
+
+    /**
+     * A table of all the resources that have been changed or added.
+     */
+    private val modifiedResources = HashMap<String, HashMap<String, Int>>()
+
+
+    /**
+     * Resolve a resource id for the specified resource.
+     * Cannot resolve resources from the android framework.
+     *
+     * @param type The type of the resource.
+     * @param name The name of the resource.
+     * @return The id of the resource.
+     */
+    fun resolveLocal(type: String, name: String) =
+        modifiedResources[type]?.get(name)
+            ?: tableIdentifier.get(packageName, type, name)?.resourceId
+            ?: throw ApkResourceException.InvalidReference(
+                type,
+                name
+            )
+
+    /**
+     * Resolve a resource id for the specified resource.
+     *
+     * @param reference The resource reference string.
+     * @return The id of the resource.
+     */
+    fun resolve(reference: String) = try {
+        encodeMaterials.resolveReference(reference)
+    } catch (e: EncodeException) {
+        throw ApkResourceException.InvalidReference(reference, e)
+    }
+
+    /**
+     * Notify the [ResourceTable] that an [Entry] has been created or modified.
+     */
+    internal fun registerChanged(entry: Entry) {
+        modifiedResources.getOrPut(entry.typeName, ::HashMap)[entry.name] = entry.resourceId
+    }
+
+    init {
+        all.forEach {
+            it.tableBlock?.let { table ->
+                entryStore.add(table)
+                tableIdentifier.load(table)
+            }
+
+            it.resourceTable = this
+        }
+
+        base.also {
+            encodeMaterials.currentPackage = it.tableBlock
+
+            it.tableBlock!!.frameWorks.forEach { fw ->
+                if (fw is FrameworkTable) {
+                    entryStore.add(fw)
+                    encodeMaterials.addFramework(fw)
+                }
+            }
+        }
+    }
+}

arsclib-utils/src/main/kotlin/app/revanced/arsc/xml/LazyXMLEncodeSource.kt

@@ -0,0 +1,56 @@
+package app.revanced.arsc.xml
+
+import app.revanced.arsc.resource.ResourceContainer
+import app.revanced.arsc.resource.boolean
+import com.reandroid.apk.xmlencoder.EncodeException
+import com.reandroid.apk.xmlencoder.XMLEncodeSource
+import com.reandroid.arsc.chunk.xml.ResXmlDocument
+import com.reandroid.xml.XMLDocument
+import com.reandroid.xml.XMLElement
+import com.reandroid.xml.source.XMLDocumentSource
+
+/**
+ * Archive input source to lazily encode an [XMLDocument] after it has been modified.
+ *
+ * @param name The file name of this input source.
+ * @param document The [XMLDocument] to encode.
+ * @param resources The [ResourceContainer] to use for encoding.
+ */
+internal class LazyXMLEncodeSource(
+    name: String,
+    val document: XMLDocument,
+    private val resources: ResourceContainer
+) : XMLEncodeSource(resources.resourceTable.encodeMaterials, XMLDocumentSource(name, document)) {
+    private var encoded = false
+
+    override fun getResXmlBlock(): ResXmlDocument {
+        if (encoded) return super.getResXmlBlock()
+
+        XMLEncodeSource(resources.resourceTable.encodeMaterials, XMLDocumentSource(name, document))
+        
+        fun XMLElement.registerIds() {
+            listAttributes().forEach { attr ->
+                if (!attr.value.startsWith("@+id/")) return@forEach
+
+                val name = attr.value.split('/').last()
+                resources.setResource("id", name, boolean(false))
+                attr.value = "@id/$name"
+            }
+
+            listChildElements().forEach { it.registerIds() }
+        }
+
+        // Handle all @+id/id_name references in the document.
+        document.documentElement.registerIds()
+
+        encoded = true
+
+        // This will call XMLEncodeSource.getResXmlBlock(),
+        // which will encode the document if it has not already been encoded.
+        try {
+            return super.getResXmlBlock()
+        } catch (e: EncodeException) {
+            throw EncodeException("Failed to encode $name", e)
+        }
+    }
+}

build.gradle.kts

@@ -1,46 +1,3 @@
 plugins {
-    kotlin("jvm") version "1.6.10"
-    `maven-publish`
-}
-
-group = "net.revanced"
-
-repositories {
-    mavenCentral()
-}
-
-dependencies {
-    implementation(kotlin("stdlib"))
-    implementation("org.ow2.asm:asm:9.2")
-    implementation("org.ow2.asm:asm-util:9.2")
-    implementation("org.ow2.asm:asm-tree:9.2")
-    implementation("org.ow2.asm:asm-commons:9.2")
-    implementation("io.github.microutils:kotlin-logging:2.1.21")
-    testImplementation("ch.qos.logback:logback-classic:1.2.11") // use your own logger!
-    testImplementation(kotlin("test"))
-}
-
-tasks.test {
-    useJUnitPlatform()
-    testLogging {
-        events("PASSED", "SKIPPED", "FAILED")
-    }
-}
-
-publishing {
-    repositories {
-        maven {
-            name = "GitHubPackages"
-            url = uri("https://maven.pkg.github.com/ReVancedTeam/revanced-patcher")
-            credentials {
-                username = System.getenv("GITHUB_ACTOR")
-                password = System.getenv("GITHUB_TOKEN")
-            }
-        }
-    }
-    publications {
-        register<MavenPublication>("gpr") {
-            from(components["java"])
-        }
-    }
+    kotlin("jvm") version "1.8.20" apply false
 }

gradle.properties

@@ -1,2 +1,4 @@
-kotlin.code.style=official
-version=1.0.0
+org.gradle.parallel=true
+org.gradle.caching=true
+kotlin.code.style = official
+version = 11.0.4

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.2-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

gradlew

@@ -1,7 +1,7 @@
-#!/usr/bin/env sh
+#!/bin/sh
 
 #
-# Copyright 2015 the original author or authors.
+# Copyright © 2015-2021 the original authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -17,67 +17,98 @@
 #
 
 ##############################################################################
-##
-##  Gradle start up script for UN*X
-##
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
 ##############################################################################
 
 # Attempt to set APP_HOME
+
 # Resolve links: $0 may be a link
-PRG="$0"
-# Need this for relative symlinks.
-while [ -h "$PRG" ] ; do
-    ls=`ls -ld "$PRG"`
-    link=`expr "$ls" : '.*-> \(.*\)$'`
-    if expr "$link" : '/.*' > /dev/null; then
-        PRG="$link"
-    else
-        PRG=`dirname "$PRG"`"/$link"
-    fi
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
 done
-SAVED="`pwd`"
-cd "`dirname \"$PRG\"`/" >/dev/null
-APP_HOME="`pwd -P`"
-cd "$SAVED" >/dev/null
 
-APP_NAME="Gradle"
-APP_BASE_NAME=`basename "$0"`
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
-MAX_FD="maximum"
+MAX_FD=maximum
 
 warn () {
     echo "$*"
-}
+} >&2
 
 die () {
     echo
     echo "$*"
     echo
     exit 1
-}
+} >&2
 
 # OS specific support (must be 'true' or 'false').
 cygwin=false
 msys=false
 darwin=false
 nonstop=false
-case "`uname`" in
-  CYGWIN* )
-    cygwin=true
-    ;;
-  Darwin* )
-    darwin=true
-    ;;
-  MSYS* | MINGW* )
-    msys=true
-    ;;
-  NONSTOP* )
-    nonstop=true
-    ;;
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -87,9 +118,9 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 if [ -n "$JAVA_HOME" ] ; then
     if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
         # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD="$JAVA_HOME/jre/sh/java"
+        JAVACMD=$JAVA_HOME/jre/sh/java
     else
-        JAVACMD="$JAVA_HOME/bin/java"
+        JAVACMD=$JAVA_HOME/bin/java
     fi
     if [ ! -x "$JAVACMD" ] ; then
         die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
@@ -98,88 +129,120 @@ Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
     fi
 else
-    JAVACMD="java"
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
+    fi
 fi
 
 # Increase the maximum file descriptors if we can.
-if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
-    MAX_FD_LIMIT=`ulimit -H -n`
-    if [ $? -eq 0 ] ; then
-        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
-            MAX_FD="$MAX_FD_LIMIT"
-        fi
-        ulimit -n $MAX_FD
-        if [ $? -ne 0 ] ; then
-            warn "Could not set maximum file descriptor limit: $MAX_FD"
-        fi
-    else
-        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
-    fi
-fi
-
-# For Darwin, add options to specify how the application appears in the dock
-if $darwin; then
-    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
-fi
-
-# For Cygwin or MSYS, switch paths to Windows format before running java
-if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
-    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
-    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
-
-    JAVACMD=`cygpath --unix "$JAVACMD"`
-
-    # We build the pattern for arguments to be converted via cygpath
-    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
-    SEP=""
-    for dir in $ROOTDIRSRAW ; do
-        ROOTDIRS="$ROOTDIRS$SEP$dir"
-        SEP="|"
-    done
-    OURCYGPATTERN="(^($ROOTDIRS))"
-    # Add a user-defined pattern to the cygpath arguments
-    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
-        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
-    fi
-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    i=0
-    for arg in "$@" ; do
-        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
-        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
-
-        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
-            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
-        else
-            eval `echo args$i`="\"$arg\""
-        fi
-        i=`expr $i + 1`
-    done
-    case $i in
-        0) set -- ;;
-        1) set -- "$args0" ;;
-        2) set -- "$args0" "$args1" ;;
-        3) set -- "$args0" "$args1" "$args2" ;;
-        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
-        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
-        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
-        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
-        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
-        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
     esac
 fi
 
-# Escape application args
-save () {
-    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
-    echo " "
-}
-APP_ARGS=`save "$@"`
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
 
-# Collect all arguments for the java command, following the shell quoting and substitution rules
-eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
 
 exec "$JAVACMD" "$@"

gradlew.bat

@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -40,7 +41,7 @@ if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
+if %ERRORLEVEL% equ 0 goto execute
 
 echo.
 echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
@@ -75,13 +76,15 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal

package.json

@@ -0,0 +1,9 @@
+{
+  "devDependencies": {
+    "@saithodev/semantic-release-backmerge": "^3.1.0",
+    "@semantic-release/changelog": "^6.0.2",
+    "@semantic-release/git": "^10.0.1",
+    "gradle-semantic-release-plugin": "^1.7.6",
+    "semantic-release": "^20.1.0"
+  }
+}

revanced-patcher/build.gradle.kts

@@ -0,0 +1,61 @@
+plugins {
+    kotlin("jvm")
+    `maven-publish`
+}
+
+group = "app.revanced"
+
+dependencies {
+    implementation("xpp3:xpp3:1.1.4c")
+    implementation("app.revanced:smali:2.5.3-a3836654")
+    implementation("app.revanced:multidexlib2:2.5.3-a3836654")
+    implementation("io.github.reandroid:ARSCLib:1.1.7")
+    implementation(project(":arsclib-utils"))
+
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.7.1")
+    implementation("org.jetbrains.kotlin:kotlin-reflect:1.8.20-RC")
+    testImplementation("org.jetbrains.kotlin:kotlin-test:1.8.20-RC")
+
+    compileOnly("com.google.android:android:4.1.1.4")
+}
+
+tasks {
+    test {
+        useJUnitPlatform()
+        testLogging {
+            events("PASSED", "SKIPPED", "FAILED")
+        }
+    }
+    processResources {
+        expand("projectVersion" to project.version)
+    }
+}
+
+java {
+    withSourcesJar()
+}
+
+kotlin {
+    jvmToolchain(11)
+}
+
+publishing {
+    repositories {
+        if (System.getenv("GITHUB_ACTOR") != null)
+            maven {
+                name = "GitHubPackages"
+                url = uri("https://maven.pkg.github.com/revanced/revanced-patcher")
+                credentials {
+                    username = System.getenv("GITHUB_ACTOR")
+                    password = System.getenv("GITHUB_TOKEN")
+                }
+            }
+        else
+            mavenLocal()
+    }
+    publications {
+        register<MavenPublication>("gpr") {
+            from(components["java"])
+        }
+    }
+}

revanced-patcher/settings.gradle.kts

@@ -0,0 +1 @@
+rootProject.name = "revanced-patcher"

revanced-patcher/src/main/kotlin/app/revanced/patcher/Context.kt

@@ -0,0 +1,113 @@
+package app.revanced.patcher
+
+import app.revanced.arsc.resource.ResourceContainer
+import app.revanced.patcher.apk.Apk
+import app.revanced.patcher.apk.ApkBundle
+import app.revanced.arsc.resource.ResourceFiles
+import app.revanced.patcher.util.method.MethodWalker
+import org.jf.dexlib2.iface.Method
+import org.w3c.dom.Document
+import java.io.Closeable
+import java.io.InputStream
+import java.io.StringWriter
+import javax.xml.parsers.DocumentBuilderFactory
+import javax.xml.transform.TransformerFactory
+import javax.xml.transform.dom.DOMSource
+import javax.xml.transform.stream.StreamResult
+
+/**
+ * A common class to constrain [Context] to [BytecodeContext] and [ResourceContext].
+ * @param apkBundle The [ApkBundle] for this context.
+ */
+sealed class Context(val apkBundle: ApkBundle)
+
+/**
+ * A context for the bytecode of an [Apk.Base] file.
+ *
+ * @param apkBundle The [ApkBundle] for this context.
+ */
+class BytecodeContext internal constructor(apkBundle: ApkBundle) : Context(apkBundle) {
+    /**
+     * The list of classes.
+     */
+    val classes = apkBundle.base.bytecodeData.classes
+
+    /**
+     * Create a [MethodWalker] instance for the current [BytecodeContext].
+     *
+     * @param startMethod The method to start at.
+     * @return A [MethodWalker] instance.
+     */
+    fun traceMethodCalls(startMethod: Method) = MethodWalker(this, startMethod)
+}
+
+/**
+ * A context for [Apk] file resources.
+ *
+ * @param apkBundle the [ApkBundle] for this context.
+ */
+class ResourceContext internal constructor(apkBundle: ApkBundle) : Context(apkBundle) {
+
+    /**
+     * Open an [DomFileEditor] for a given DOM file.
+     *
+     * @param inputStream The input stream to read the DOM file from.
+     * @return A [DomFileEditor] instance.
+     */
+    fun openXmlFile(inputStream: InputStream) = DomFileEditor(inputStream)
+}
+
+
+/**
+ * Open a [DomFileEditor] for a resource file in the archive.
+ *
+ * @see [ResourceContainer.openFile]
+ * @param path The resource file path.
+ * @return A [DomFileEditor].
+ */
+fun ResourceContainer.openXmlFile(path: String) = DomFileEditor(openFile(path))
+
+/**
+ * Wrapper for a file that can be edited as a dom document.
+ *
+ * @param inputStream the input stream to read the xml file from.
+ * @param onSave A callback that will be called when the editor is closed to save the file.
+ */
+class DomFileEditor internal constructor(
+    private val inputStream: InputStream,
+    private val onSave: ((String) -> Unit)? = null
+) : Closeable {
+    private var closed: Boolean = false
+
+    /**
+     * The document of the xml file.
+     */
+    val file: Document = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(inputStream)
+        .also(Document::normalize)
+
+    internal constructor(file: ResourceFiles) : this(
+        file.inputStream(),
+        {
+            file.contents = it.toByteArray()
+            file.close()
+        }
+    )
+
+    /**
+     * Closes the editor and writes back to the file.
+     */
+    override fun close() {
+        if (closed) return
+
+        inputStream.close()
+
+        onSave?.let { callback ->
+            // Save the updated file.
+            val writer = StringWriter()
+            TransformerFactory.newInstance().newTransformer().transform(DOMSource(file), StreamResult(writer))
+            callback(writer.toString())
+        }
+
+        closed = true
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/Patcher.kt

@@ -0,0 +1,222 @@
+package app.revanced.patcher
+
+import app.revanced.patcher.apk.Apk
+import app.revanced.patcher.extensions.PatchExtensions.dependencies
+import app.revanced.patcher.extensions.PatchExtensions.patchName
+import app.revanced.patcher.extensions.PatchExtensions.requiresIntegrations
+import app.revanced.patcher.fingerprint.method.impl.MethodFingerprint
+import app.revanced.patcher.fingerprint.method.impl.MethodFingerprint.Companion.resolveUsingLookupMap
+import app.revanced.patcher.patch.*
+import app.revanced.patcher.util.VersionReader
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flow
+import lanchon.multidexlib2.BasicDexFileNamer
+import java.io.Closeable
+import java.io.File
+import java.util.function.Function
+
+typealias ExecutedPatchResults = Flow<Pair<String, PatchException?>>
+
+/**
+ * The ReVanced Patcher.
+ * @param options The options for the patcher.
+ * @param patches The patches to use.
+ * @param integrations The integrations to merge if necessary. Must be dex files or dex file container such as ZIP, APK or DEX files.
+ */
+class Patcher(private val options: PatcherOptions, patches: Iterable<PatchClass>, integrations: Iterable<File>) :
+    Function<Boolean, ExecutedPatchResults> {
+    private val context = PatcherContext(options, patches.toList(), integrations)
+    private val logger = options.logger
+
+    companion object {
+        /**
+         * The version of the ReVanced Patcher.
+         */
+        @JvmStatic
+        val version = VersionReader.read()
+
+        @Suppress("SpellCheckingInspection")
+        internal val dexFileNamer = BasicDexFileNamer()
+    }
+
+    init {
+        /**
+         * Returns true if at least one patches or its dependencies matches the given predicate.
+         */
+        fun PatchClass.anyRecursively(predicate: (PatchClass) -> Boolean): Boolean =
+            predicate(this) || dependencies?.any { it.java.anyRecursively(predicate) } == true
+
+        // Determine if merging integrations is required.
+        for (patch in context.patches) {
+            if (patch.anyRecursively { it.requiresIntegrations }) {
+                context.integrations.merge = true
+                break
+            }
+        }
+    }
+
+    /**
+     * Execute the patcher.
+     *
+     * @param stopOnError If true, the patches will stop on the first error.
+     * @return A pair of the name of the [Patch] and a [PatchException] if it failed.
+     */
+    override fun apply(stopOnError: Boolean) = flow {
+        /**
+         * Execute a [Patch] and its dependencies recursively.
+         *
+         * @param patchClass The [Patch] to execute.
+         * @param executedPatches A map of [Patch]es paired to a boolean indicating their success, to prevent infinite recursion.
+         */
+        suspend fun executePatch(
+            patchClass: PatchClass,
+            executedPatches: HashMap<String, ExecutedPatch>
+        ) {
+            val patchName = patchClass.patchName
+
+            // If the patch has already executed silently skip it.
+            if (executedPatches.contains(patchName)) {
+                if (!executedPatches[patchName]!!.success)
+                    throw PatchException("'$patchName' did not succeed previously")
+
+                logger.trace("Skipping '$patchName' because it has already been executed")
+
+                return
+            }
+
+            // Recursively execute all dependency patches.
+            patchClass.dependencies?.forEach { dependencyClass ->
+                val dependency = dependencyClass.java
+
+                try {
+                    executePatch(dependency, executedPatches)
+                } catch (throwable: Throwable) {
+                    throw PatchException(
+                        "'$patchName' depends on '${dependency.patchName}' " +
+                                "but the following exception was raised: ${throwable.cause?.stackTraceToString() ?: throwable.message}",
+                        throwable
+                    )
+                }
+            }
+
+            val isResourcePatch = ResourcePatch::class.java.isAssignableFrom(patchClass)
+            val patchInstance = patchClass.getDeclaredConstructor().newInstance()
+
+            // TODO: implement this in a more polymorphic way.
+            val patchContext = if (isResourcePatch) {
+                context.resourceContext
+            } else {
+                context.bytecodeContext.apply {
+                    val bytecodePatch = patchInstance as BytecodePatch
+                    bytecodePatch.fingerprints?.resolveUsingLookupMap(context.bytecodeContext)
+                }
+            }
+
+            logger.trace("Executing '$patchName' of type: ${if (isResourcePatch) "resource" else "bytecode"}")
+
+            var success = false
+            try {
+                patchInstance.execute(patchContext)
+
+                success = true
+            } catch (patchException: PatchException) {
+                throw patchException
+            } catch (throwable: Throwable) {
+                throw PatchException("Unhandled patch exception: ${throwable.message}", throwable)
+            } finally {
+                executedPatches[patchName] = ExecutedPatch(patchInstance, success)
+            }
+        }
+
+        if (context.integrations.merge) context.integrations.merge(logger)
+
+        logger.trace("Initialize lookup maps for method MethodFingerprint resolution")
+
+        MethodFingerprint.initializeFingerprintResolutionLookupMaps(context.bytecodeContext)
+
+        logger.info("Executing patches")
+
+        // Key is patch name.
+        LinkedHashMap<String, ExecutedPatch>().apply {
+            context.patches.forEach { patch ->
+                var exception: PatchException? = null
+
+                try {
+                    executePatch(patch, this)
+                } catch (patchException: PatchException) {
+                    exception = patchException
+                }
+
+                // TODO: only emit if the patch is not a closeable.
+                //  If it is a closeable, this should be done when closing the patch.
+                emit(patch.patchName to exception)
+
+                if (stopOnError && exception != null) return@flow
+            }
+        }.let {
+            it.values
+                .filter(ExecutedPatch::success)
+                .map(ExecutedPatch::patchInstance)
+                .filterIsInstance(Closeable::class.java)
+                .asReversed().forEach { patch ->
+                    try {
+                        patch.close()
+                    } catch (throwable: Throwable) {
+                        val patchException =
+                            if (throwable is PatchException) throwable
+                            else PatchException(throwable)
+
+                        val patchName = (patch as Patch<Context>).javaClass.patchName
+
+                        logger.error("Failed to close '$patchName': ${patchException.stackTraceToString()}")
+
+                        emit(patchName to patchException)
+
+                        // This is not failsafe. If a patch throws an exception while closing,
+                        // the other patches that depend on it may fail.
+                        if (stopOnError) return@flow
+                    }
+                }
+        }
+
+        MethodFingerprint.clearFingerprintResolutionLookupMaps()
+    }
+
+    /**
+     * Finish patching all [Apk]s.
+     *
+     * @return The [PatcherResult] of the [Patcher].
+     */
+    fun finish(): PatcherResult {
+        val patchResults = buildList {
+            logger.info("Processing patched apks")
+            options.apkBundle.cleanup(options).forEach { result ->
+                if (result.exception != null) {
+                    logger.error("Got exception while processing ${result.apk}: ${result.exception.stackTraceToString()}")
+                    return@forEach
+                }
+
+                val patch = result.let {
+                    when (it.apk) {
+                        is Apk.Base -> PatcherResult.Patch.Base(it.apk)
+                        is Apk.Split -> PatcherResult.Patch.Split(it.apk)
+                    }
+                }
+
+                add(patch)
+
+                logger.info("Patched ${result.apk}")
+            }
+        }
+
+        return PatcherResult(patchResults)
+    }
+}
+
+/**
+ * A result of executing a [Patch].
+ *
+ * @param patchInstance The instance of the [Patch] that was executed.
+ * @param success The result of the [Patch].
+ */
+internal data class ExecutedPatch(val patchInstance: Patch<Context>, val success: Boolean)

revanced-patcher/src/main/kotlin/app/revanced/patcher/PatcherContext.kt

@@ -0,0 +1,55 @@
+package app.revanced.patcher
+
+import app.revanced.patcher.logging.Logger
+import app.revanced.patcher.patch.PatchClass
+import app.revanced.patcher.util.ClassMerger.merge
+import lanchon.multidexlib2.MultiDexIO
+import java.io.File
+
+class PatcherContext(
+    options: PatcherOptions,
+    internal val patches: List<PatchClass>,
+    integrations: Iterable<File>
+) {
+    internal val integrations = Integrations(this, integrations)
+    internal val bytecodeContext = BytecodeContext(options.apkBundle)
+    internal val resourceContext = ResourceContext(options.apkBundle)
+
+    internal class Integrations(val context: PatcherContext, private val dexContainers: Iterable<File>) {
+        var merge = false
+
+        /**
+         * Merge integrations.
+         * @param logger A logger.
+         */
+        fun merge(logger: Logger) {
+            context.bytecodeContext.classes.apply {
+                for (integrations in dexContainers) {
+                    logger.info("Merging $integrations")
+
+                    for (classDef in MultiDexIO.readDexFile(true, integrations, Patcher.dexFileNamer, null, null).classes) {
+                        val type = classDef.type
+
+                        val existingClassIndex = this.indexOfFirst { it.type == type }
+                        if (existingClassIndex == -1) {
+                            logger.trace("Merging type $type")
+                            add(classDef)
+                            continue
+                        }
+
+
+                        logger.trace("Type $type exists. Adding missing methods and fields.")
+
+                        get(existingClassIndex).apply {
+                            merge(classDef, context.bytecodeContext, logger).let { mergedClass ->
+                                if (mergedClass !== this) // referential equality check
+                                    set(existingClassIndex, mergedClass)
+                            }
+                        }
+
+                    }
+                }
+            }
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/PatcherOptions.kt

@@ -0,0 +1,14 @@
+package app.revanced.patcher
+
+import app.revanced.patcher.apk.ApkBundle
+import app.revanced.patcher.logging.Logger
+
+/**
+ * Options for the [Patcher].
+ * @param apkBundle The [ApkBundle].
+ * @param logger Custom logger implementation for the [Patcher].
+ */
+class PatcherOptions(
+    internal val apkBundle: ApkBundle,
+    internal val logger: Logger = Logger.Nop
+)

revanced-patcher/src/main/kotlin/app/revanced/patcher/PatcherResult.kt

@@ -0,0 +1,33 @@
+package app.revanced.patcher
+
+import app.revanced.patcher.apk.Apk
+import java.io.File
+
+/**
+ * The result of a patcher.
+ * @param apkFiles The patched [Apk] files.
+ */
+data class PatcherResult(val apkFiles: List<Patch>) {
+
+    /**
+     * The result of a patch.
+     *
+     * @param apk The patched [Apk] file.
+     */
+    sealed class Patch(val apk: Apk) {
+
+        /**
+         * The result of a patch of an [Apk.Split] file.
+         *
+         * @param apk The patched [Apk.Split] file.
+         */
+        class Split(apk: Apk.Split) : Patch(apk)
+
+        /**
+         * The result of a patch of an [Apk.Split] file.
+         *
+         * @param apk The patched [Apk.Base] file.
+         */
+        class Base(apk: Apk.Base) : Patch(apk)
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/annotation/CompatibilityAnnotation.kt

@@ -0,0 +1,23 @@
+package app.revanced.patcher.annotation
+
+import app.revanced.patcher.patch.Patch
+
+/**
+ * Annotation to constrain a [Patch] to compatible packages.
+ * @param compatiblePackages A list of packages a [Patch] is compatible with.
+ */
+@Target(AnnotationTarget.CLASS)
+annotation class Compatibility(
+    val compatiblePackages: Array<Package>,
+)
+
+/**
+ * Annotation to represent packages a patch can be compatible with.
+ * @param name The package identifier name.
+ * @param versions The versions of the package the [Patch] is compatible with.
+ */
+@Target()
+annotation class Package(
+    val name: String,
+    val versions: Array<String> = [],
+)

revanced-patcher/src/main/kotlin/app/revanced/patcher/annotation/MetadataAnnotation.kt

@@ -0,0 +1,32 @@
+package app.revanced.patcher.annotation
+
+import app.revanced.patcher.patch.Patch
+
+/**
+ * Annotation to name a [Patch].
+ * @param name A suggestive name for the [Patch].
+ */
+@Target(AnnotationTarget.CLASS)
+annotation class Name(
+    val name: String,
+)
+
+/**
+ * Annotation to describe a [Patch].
+ * @param description A description for the [Patch].
+ */
+@Target(AnnotationTarget.CLASS)
+annotation class Description(
+    val description: String,
+)
+
+
+/**
+ * Annotation to version a [Patch].
+ * @param version The version of a [Patch].
+ */
+@Target(AnnotationTarget.CLASS)
+@Deprecated("This annotation is deprecated and will be removed in the future.")
+annotation class Version(
+    val version: String,
+)

revanced-patcher/src/main/kotlin/app/revanced/patcher/apk/Apk.kt

@@ -0,0 +1,285 @@
+@file:Suppress("MemberVisibilityCanBePrivate")
+
+package app.revanced.patcher.apk
+
+import app.revanced.arsc.ApkResourceException
+import app.revanced.arsc.archive.Archive
+import app.revanced.patcher.Patcher
+import app.revanced.patcher.PatcherOptions
+import app.revanced.patcher.logging.asArscLogger
+import app.revanced.patcher.util.ProxyBackedClassList
+import com.reandroid.apk.ApkModule
+import com.reandroid.apk.xmlencoder.EncodeException
+import com.reandroid.archive.InputSource
+import com.reandroid.arsc.chunk.xml.AndroidManifestBlock
+import com.reandroid.arsc.value.ResConfig
+import lanchon.multidexlib2.*
+import org.jf.dexlib2.Opcodes
+import org.jf.dexlib2.dexbacked.DexBackedDexFile
+import org.jf.dexlib2.iface.DexFile
+import org.jf.dexlib2.iface.MultiDexContainer
+import org.jf.dexlib2.writer.io.MemoryDataStore
+import java.io.File
+
+/**
+ * An [Apk] file.
+ */
+sealed class Apk private constructor(module: ApkModule) {
+    /**
+     * A wrapper around the zip archive of this [Apk].
+     *
+     * @see Archive
+     */
+    private val archive = Archive(module)
+
+    /**
+     * The metadata of the [Apk].
+     */
+    val packageMetadata = PackageMetadata(module.androidManifestBlock)
+
+    /**
+     * Refresh updated resources and close any open files.
+     *
+     * @param options The [PatcherOptions] of the [Patcher].
+     */
+    internal open fun cleanup(options: PatcherOptions) {
+        try {
+            archive.cleanup(options.logger.asArscLogger())
+        } catch (e: EncodeException) {
+            throw ApkResourceException.Encode(e.message!!, e)
+        }
+
+        archive.mainPackageResources.refreshPackageName()
+    }
+
+    /**
+     * Write the [Apk] to a file.
+     *
+     * @param output The target file.
+     */
+    fun write(output: File) = archive.save(output)
+
+    companion object {
+        const val MANIFEST_FILE_NAME = "AndroidManifest.xml"
+
+        /**
+         * Determine the [Module] and [Type] of an [ApkModule].
+         *
+         * @return A [Pair] containing the [Module] and [Type] of the [ApkModule].
+         */
+        fun ApkModule.identify(): Pair<Module, Type> {
+            val manifestElement = androidManifestBlock.manifestElement
+            return when {
+                isBaseModule -> Module.Main to Type.Base
+                // The module is a base apk for a dynamic feature module if the "isFeatureModule" attribute is set to true.
+                manifestElement.searchAttributeByName("isFeatureModule")?.valueAsBoolean == true -> Module.DynamicFeature(
+                    split
+                ) to Type.Base
+
+                else -> {
+                    val module = manifestElement.searchAttributeByName("configForSplit")
+                    ?.let { Module.DynamicFeature(it.valueAsString) } ?: Module.Main
+
+                    // Examples:
+                    // config.xhdpi
+                    // df_my_feature.config.en
+                    val config = this.split.split(".").last()
+
+                    val type = when {
+                        // Language splits have a two-letter country code.
+                        config.length == 2 -> Type.Language(config)
+                        // Library splits use the target CPU architecture.
+                        Split.Library.architectures.contains(config) -> Type.Library(config)
+                        // Asset splits use the density.
+                        ResConfig.Density.valueOf(config) != null -> Type.Asset(config)
+                        else -> throw IllegalArgumentException("Invalid split config: $config")
+                    }
+
+                    module to type
+                }
+            }
+        }
+    }
+
+    internal inner class BytecodeData {
+        private val opcodes: Opcodes
+
+        /**
+         * The classes and proxied classes of the [Base] apk file.
+         */
+        val classes: ProxyBackedClassList
+
+        init {
+            MultiDexContainerBackedDexFile(object : MultiDexContainer<DexBackedDexFile> {
+                // Load all dex files from the apk module and create a dex entry for each of them.
+                private val entries = archive.readDexFiles().associateBy { it.name }
+                    .mapValues { (name, inputSource) ->
+                        BasicDexEntry(
+                            this,
+                            name,
+                            RawDexIO.readRawDexFile(inputSource.openStream(), inputSource.length, null)
+                        )
+                    }
+
+                override fun getDexEntryNames() = entries.keys.toList()
+                override fun getEntry(entryName: String) = entries[entryName]
+            }).let {
+                opcodes = it.opcodes
+                classes = ProxyBackedClassList(it.classes)
+            }
+        }
+
+        /**
+         * Write [classes] to the archive.
+         */
+        internal fun writeDexFiles() {
+            // Create patched dex files.
+            mutableMapOf<String, MemoryDataStore>().also {
+                val newDexFile = object : DexFile {
+                    override fun getClasses() =
+                        this@BytecodeData.classes.also(ProxyBackedClassList::applyProxies).toSet()
+                    override fun getOpcodes() = this@BytecodeData.opcodes
+                }
+
+                // Write modified dex files.
+                MultiDexIO.writeDexFile(
+                    true, -1, // Core count.
+                    it, Patcher.dexFileNamer, newDexFile, DexIO.DEFAULT_MAX_DEX_POOL_SIZE, null
+                )
+            }.forEach { (name, store) ->
+                val dexFileInputSource = object : InputSource(name) {
+                    override fun openStream() = store.readAt(0)
+                }
+
+                archive.write(dexFileInputSource)
+            }
+        }
+    }
+
+    /**
+     * Metadata about an [Apk] file.
+     *
+     * @param packageName The package name of the [Apk] file.
+     * @param packageVersion The package version of the [Apk] file.
+     */
+    data class PackageMetadata(val packageName: String?, val packageVersion: String?) {
+        internal constructor(manifestBlock: AndroidManifestBlock) : this(
+            manifestBlock.packageName,
+            manifestBlock.versionName
+        )
+    }
+
+    /**
+     * An [Apk] of type [Split].
+     *
+     * @param config The device configuration associated with this [Split], such as arm64_v8a, en or xhdpi.
+     * @see Apk
+     */
+    sealed class Split(val config: String, module: ApkModule) : Apk(module) {
+        override fun toString() = "split_config.$config.apk"
+
+        /**
+         * The split apk file which contains libraries.
+         *
+         * @see Split
+         */
+        class Library internal constructor(config: String, module: ApkModule) : Split(config, module) {
+            companion object {
+                /**
+                 * A set of all architectures supported by android.
+                 */
+                val architectures = setOf("armeabi_v7a", "arm64_v8a", "x86", "x86_64")
+            }
+        }
+
+        /**
+         * The split apk file which contains language strings.
+         *
+         * @see Split
+         */
+        class Language internal constructor(config: String, module: ApkModule) : Split(config, module)
+
+        /**
+         * The split apk file which contains assets.
+         *
+         * @see Split
+         */
+        class Asset internal constructor(config: String, module: ApkModule) : Split(config, module)
+    }
+
+    /**
+     * The base [Apk] file..
+     *
+     * @see Apk
+     */
+    class Base internal constructor(module: ApkModule) : Apk(module) {
+        /**
+         * Data of the [Base] apk file.
+         */
+        internal val bytecodeData = BytecodeData()
+
+        override fun toString() = "base.apk"
+
+        override fun cleanup(options: PatcherOptions) {
+            super.cleanup(options)
+
+            options.logger.info("Writing patched dex files")
+            bytecodeData.writeDexFiles()
+        }
+    }
+
+    /**
+     * The module that the [ApkModule] belongs to.
+     */
+    sealed class Module {
+        /**
+         * The default [Module] that is always installed by software repositories.
+         */
+        object Main : Module()
+
+        /**
+         * A [Module] that can be installed later by software repositories when requested by the application.
+         *
+         * @param name The name of the feature.
+         */
+        data class DynamicFeature(val name: String) : Module()
+    }
+
+    /**
+     * The type of the [ApkModule].
+     */
+    sealed class Type {
+        /**
+         * The main Apk of a [Module].
+         */
+        object Base : Type()
+
+        /**
+         * A superclass for all split configuration types.
+         *
+         * @param target The target device configuration.
+         */
+        sealed class SplitConfig(val target: String) : Type()
+
+        /**
+         * The [Type] of an apk containing native libraries.
+         *
+         * @param architecture The target CPU architecture.
+         */
+        data class Library(val architecture: String) : SplitConfig(architecture)
+
+        /**
+         * The [Type] for an Apk containing language resources.
+         *
+         * @param language The target language code.
+         */
+        data class Language(val language: String) : SplitConfig(language)
+
+        /**
+         * The [Type] for an Apk containing assets.
+         *
+         * @param pixelDensity The target screen density.
+         */
+        data class Asset(val pixelDensity: String) : SplitConfig(pixelDensity)
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/apk/ApkBundle.kt

@@ -0,0 +1,105 @@
+@file:Suppress("MemberVisibilityCanBePrivate")
+
+package app.revanced.patcher.apk
+
+import app.revanced.arsc.ApkResourceException
+import app.revanced.arsc.resource.ResourceTable
+import app.revanced.patcher.Patcher
+import app.revanced.patcher.PatcherOptions
+import app.revanced.patcher.apk.Apk.Companion.identify
+import com.reandroid.apk.ApkModule
+import java.io.File
+
+/**
+ * An [Apk] file of type [Apk.Split].
+ *
+ * @param files A list of apk files to load.
+ */
+class ApkBundle(files: List<File>) : Sequence<Apk> {
+    /**
+     * The [Apk.Base] of this [ApkBundle].
+     */
+    val base: Apk.Base
+
+    /**
+     * A map containing all the [Apk.Split]s in this bundle associated by their configuration.
+     */
+    val splits: Map<String, Apk.Split>?
+
+    init {
+        var baseApk: Apk.Base? = null
+
+        splits = buildMap {
+            files.forEach {
+                val apk = ApkModule.loadApkFile(it)
+                val (module, type) = apk.identify()
+                if (module is Apk.Module.DynamicFeature) {
+                    return@forEach // Dynamic feature modules are not supported yet.
+                }
+
+                when (type) {
+                    Apk.Type.Base -> {
+                        if (baseApk != null) {
+                            throw IllegalArgumentException("Cannot have more than one base apk")
+                        }
+                        baseApk = Apk.Base(apk)
+                    }
+
+                    is Apk.Type.SplitConfig -> {
+                        val target = type.target
+                        if (this.contains(target)) {
+                            throw IllegalArgumentException("Duplicate split: $target")
+                        }
+
+                        val constructor = when (type) {
+                            is Apk.Type.Asset -> Apk.Split::Asset
+                            is Apk.Type.Library -> Apk.Split::Library
+                            is Apk.Type.Language -> Apk.Split::Language
+                        }
+
+                        this[target] = constructor(target, apk)
+                    }
+                }
+            }
+        }.takeIf { it.isNotEmpty() }
+
+        base = baseApk ?: throw IllegalArgumentException("Base apk not found")
+    }
+
+    /**
+     * The [ResourceTable] of this [ApkBundle].
+     */
+    val resources = ResourceTable(base.resources, map { it.resources })
+
+    override fun iterator() = sequence {
+        yield(base)
+        splits?.values?.let {
+            yieldAll(it)
+        }
+    }.iterator()
+
+    /**
+     * Refresh all updated resources in an [ApkBundle].
+     *
+     * @param options The [PatcherOptions] of the [Patcher].
+     * @return A sequence of the [Apk] files which are being refreshed.
+     */
+    internal fun cleanup(options: PatcherOptions) = map {
+        var exception: ApkResourceException? = null
+        try {
+            it.cleanup(options)
+        } catch (e: ApkResourceException) {
+            exception = e
+        }
+
+        SplitApkResult(it, exception)
+    }
+
+    /**
+     * The result of writing an [Apk] file.
+     *
+     * @param apk The corresponding [Apk] file.
+     * @param exception The optional [ApkResourceException] when an exception occurred.
+     */
+    data class SplitApkResult(val apk: Apk, val exception: ApkResourceException? = null)
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/extensions/AnnotationExtensions.kt

@@ -0,0 +1,33 @@
+package app.revanced.patcher.extensions
+
+import kotlin.reflect.KClass
+
+internal object AnnotationExtensions {
+    /**
+     * Recursively find a given annotation on a class.
+     *
+     * @param targetAnnotation The annotation to find.
+     * @return The annotation.
+     */
+    fun <T : Annotation> Class<*>.findAnnotationRecursively(targetAnnotation: KClass<T>): T? {
+        fun <T : Annotation> Class<*>.findAnnotationRecursively(
+            targetAnnotation: Class<T>, traversed: MutableSet<Annotation>
+        ): T? {
+            val found = this.annotations.firstOrNull { it.annotationClass.java.name == targetAnnotation.name }
+
+            @Suppress("UNCHECKED_CAST") if (found != null) return found as T
+
+            for (annotation in this.annotations) {
+                if (traversed.contains(annotation)) continue
+                traversed.add(annotation)
+
+                return (annotation.annotationClass.java.findAnnotationRecursively(targetAnnotation, traversed))
+                    ?: continue
+            }
+
+            return null
+        }
+
+        return this.findAnnotationRecursively(targetAnnotation.java, mutableSetOf())
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/extensions/Extensions.kt

@@ -0,0 +1,33 @@
+package app.revanced.patcher.extensions
+
+import app.revanced.patcher.util.proxy.mutableTypes.MutableMethod
+import org.jf.dexlib2.AccessFlags
+
+/**
+ * Create a label for the instruction at given index.
+ *
+ * @param index The index to create the label for the instruction at.
+ * @return The label.
+ */
+fun MutableMethod.newLabel(index: Int) = implementation!!.newLabelForIndex(index)
+
+/**
+ * Perform a bitwise OR operation between two [AccessFlags].
+ *
+ * @param other The other [AccessFlags] to perform the operation with.
+ */
+infix fun AccessFlags.or(other: AccessFlags) = value or other.value
+
+/**
+ * Perform a bitwise OR operation between an [AccessFlags] and an [Int].
+ *
+ * @param other The [Int] to perform the operation with.
+ */
+infix fun Int.or(other: AccessFlags) = this or other.value
+
+/**
+ * Perform a bitwise OR operation between an [Int] and an [AccessFlags].
+ *
+ * @param other The [AccessFlags] to perform the operation with.
+ */
+infix fun AccessFlags.or(other: Int) = value or other

revanced-patcher/src/main/kotlin/app/revanced/patcher/extensions/InstructionExtensions.kt

@@ -0,0 +1,326 @@
+package app.revanced.patcher.extensions
+
+import app.revanced.patcher.util.proxy.mutableTypes.MutableMethod
+import app.revanced.patcher.util.smali.ExternalLabel
+import app.revanced.patcher.util.smali.toInstruction
+import app.revanced.patcher.util.smali.toInstructions
+import org.jf.dexlib2.builder.BuilderInstruction
+import org.jf.dexlib2.builder.BuilderOffsetInstruction
+import org.jf.dexlib2.builder.Label
+import org.jf.dexlib2.builder.MutableMethodImplementation
+import org.jf.dexlib2.builder.instruction.*
+import org.jf.dexlib2.iface.instruction.Instruction
+
+object InstructionExtensions {
+
+    /**
+     * Add instructions to a method at the given index.
+     *
+     * @param index The index to add the instructions at.
+     * @param instructions The instructions to add.
+     */
+    fun MutableMethodImplementation.addInstructions(
+        index: Int,
+        instructions: List<BuilderInstruction>
+    ) =
+        instructions.asReversed().forEach { addInstruction(index, it) }
+
+    /**
+     * Add instructions to a method.
+     * The instructions will be added at the end of the method.
+     *
+     * @param instructions The instructions to add.
+     */
+    fun MutableMethodImplementation.addInstructions(instructions: List<BuilderInstruction>) =
+        instructions.forEach { this.addInstruction(it) }
+
+    /**
+     * Remove instructions from a method at the given index.
+     *
+     * @param index The index to remove the instructions at.
+     * @param count The amount of instructions to remove.
+     */
+    fun MutableMethodImplementation.removeInstructions(index: Int, count: Int) = repeat(count) {
+        removeInstruction(index)
+    }
+
+    /**
+     * Remove the first instructions from a method.
+     *
+     * @param count The amount of instructions to remove.
+     */
+    fun MutableMethodImplementation.removeInstructions(count: Int) = removeInstructions(0, count)
+
+    /**
+     * Replace instructions at the given index with the given instructions.
+     * The amount of instructions to replace is the amount of instructions in the given list.
+     *
+     * @param index The index to replace the instructions at.
+     * @param instructions The instructions to replace the instructions with.
+     */
+    fun MutableMethodImplementation.replaceInstructions(index: Int, instructions: List<BuilderInstruction>) {
+        // Remove the instructions at the given index.
+        removeInstructions(index, instructions.size)
+
+        // Add the instructions at the given index.
+        addInstructions(index, instructions)
+    }
+
+    /**
+     * Add an instruction to a method at the given index.
+     *
+     * @param index The index to add the instruction at.
+     * @param instruction The instruction to add.
+     */
+    fun MutableMethod.addInstruction(index: Int, instruction: BuilderInstruction) =
+        implementation!!.addInstruction(index, instruction)
+
+    /**
+     * Add an instruction to a method.
+     *
+     * @param instruction The instructions to add.
+     */
+    fun MutableMethod.addInstruction(instruction: BuilderInstruction) =
+        implementation!!.addInstruction(instruction)
+
+    /**
+     * Add an instruction to a method at the given index.
+     *
+     * @param index The index to add the instruction at.
+     * @param smaliInstructions The instruction to add.
+     */
+    fun MutableMethod.addInstruction(index: Int, smaliInstructions: String) =
+        implementation!!.addInstruction(index, smaliInstructions.toInstruction(this))
+
+    /**
+     * Add an instruction to a method.
+     *
+     * @param smaliInstructions The instruction to add.
+     */
+    fun MutableMethod.addInstruction(smaliInstructions: String) =
+        implementation!!.addInstruction(smaliInstructions.toInstruction(this))
+
+
+    /**
+     * Add instructions to a method at the given index.
+     *
+     * @param index The index to add the instructions at.
+     * @param instructions The instructions to add.
+     */
+    fun MutableMethod.addInstructions(index: Int, instructions: List<BuilderInstruction>) =
+        implementation!!.addInstructions(index, instructions)
+
+    /**
+     * Add instructions to a method.
+     *
+     * @param instructions The instructions to add.
+     */
+    fun MutableMethod.addInstructions(instructions: List<BuilderInstruction>) =
+        implementation!!.addInstructions(instructions)
+
+    /**
+     * Add instructions to a method.
+     *
+     * @param smaliInstructions The instructions to add.
+     */
+    fun MutableMethod.addInstructions(index: Int, smaliInstructions: String) =
+        implementation!!.addInstructions(index, smaliInstructions.toInstructions(this))
+
+    /**
+     * Add instructions to a method.
+     *
+     * @param smaliInstructions The instructions to add.
+     */
+    fun MutableMethod.addInstructions(smaliInstructions: String) =
+        implementation!!.addInstructions(smaliInstructions.toInstructions(this))
+
+    /**
+     * Add instructions to a method at the given index.
+     *
+     * @param index The index to add the instructions at.
+     * @param smaliInstructions The instructions to add.
+     * @param externalLabels A list of [ExternalLabel] for instructions outside of [smaliInstructions].
+     */
+// Special function for adding instructions with external labels.
+    fun MutableMethod.addInstructionsWithLabels(
+        index: Int,
+        smaliInstructions: String,
+        vararg externalLabels: ExternalLabel
+    ) {
+        // Create reference dummy instructions for the instructions.
+        val nopSmali = StringBuilder(smaliInstructions).also { builder ->
+            externalLabels.forEach { (name, _) ->
+                builder.append("\n:$name\nnop")
+            }
+        }.toString()
+
+        // Compile the instructions with the dummy labels
+        val compiledInstructions = nopSmali.toInstructions(this)
+
+        // Add the compiled list of instructions to the method.
+        addInstructions(
+            index,
+            compiledInstructions.subList(0, compiledInstructions.size - externalLabels.size)
+        )
+
+        implementation!!.apply {
+            this@apply.instructions.subList(index, index + compiledInstructions.size - externalLabels.size)
+                .forEachIndexed { compiledInstructionIndex, compiledInstruction ->
+                    // If the compiled instruction is not an offset instruction, skip it.
+                    if (compiledInstruction !is BuilderOffsetInstruction) return@forEachIndexed
+
+                    /**
+                     * Creates a new label for the instruction
+                     * and replaces it with the label of the [compiledInstruction] at [compiledInstructionIndex].
+                     */
+                    fun Instruction.makeNewLabel() {
+                        fun replaceOffset(
+                            i: BuilderOffsetInstruction, label: Label
+                        ): BuilderOffsetInstruction {
+                            return when (i) {
+                                is BuilderInstruction10t -> BuilderInstruction10t(i.opcode, label)
+                                is BuilderInstruction20t -> BuilderInstruction20t(i.opcode, label)
+                                is BuilderInstruction21t -> BuilderInstruction21t(i.opcode, i.registerA, label)
+                                is BuilderInstruction22t -> BuilderInstruction22t(
+                                    i.opcode,
+                                    i.registerA,
+                                    i.registerB,
+                                    label
+                                )
+                                is BuilderInstruction30t -> BuilderInstruction30t(i.opcode, label)
+                                is BuilderInstruction31t -> BuilderInstruction31t(i.opcode, i.registerA, label)
+                                else -> throw IllegalStateException(
+                                    "A non-offset instruction was given, this should never happen!"
+                                )
+                            }
+                        }
+
+                        // Create the final label.
+                        val label = newLabelForIndex(this@apply.instructions.indexOf(this))
+
+                        // Create the final instruction with the new label.
+                        val newInstruction = replaceOffset(
+                            compiledInstruction, label
+                        )
+
+                        // Replace the instruction pointing to the dummy label
+                        // with the new instruction pointing to the real instruction.
+                        replaceInstruction(index + compiledInstructionIndex, newInstruction)
+                    }
+
+                    // If the compiled instruction targets its own instruction,
+                    // which means it points to some of its own, simply an offset has to be applied.
+                    val labelIndex = compiledInstruction.target.location.index
+                    if (labelIndex < compiledInstructions.size - externalLabels.size) {
+                        // Get the targets index (insertion index + the index of the dummy instruction).
+                        this.instructions[index + labelIndex].makeNewLabel()
+                        return@forEachIndexed
+                    }
+
+                    // Since the compiled instruction points to a dummy instruction,
+                    // we can find the real instruction which it was created for by calculation.
+
+                    // Get the index of the instruction in the externalLabels list
+                    // which the dummy instruction was created for.
+                    // This works because we created the dummy instructions in the same order as the externalLabels list.
+                    val (_, instruction) = externalLabels[(compiledInstructions.size - 1) - labelIndex]
+                    instruction.makeNewLabel()
+                }
+        }
+    }
+
+    /**
+     * Remove an instruction at the given index.
+     *
+     * @param index The index to remove the instruction at.
+     */
+    fun MutableMethod.removeInstruction(index: Int) =
+        implementation!!.removeInstruction(index)
+
+    /**
+     * Remove instructions at the given index.
+     *
+     * @param index The index to remove the instructions at.
+     * @param count The amount of instructions to remove.
+     */
+    fun MutableMethod.removeInstructions(index: Int, count: Int) =
+        implementation!!.removeInstructions(index, count)
+
+    /**
+     * Remove instructions at the given index.
+     *
+     * @param count The amount of instructions to remove.
+     */
+    fun MutableMethod.removeInstructions(count: Int) =
+        implementation!!.removeInstructions(count)
+
+    /**
+     * Replace an instruction at the given index.
+     *
+     * @param index The index to replace the instruction at.
+     * @param instruction The instruction to replace the instruction with.
+     */
+    fun MutableMethod.replaceInstruction(index: Int, instruction: BuilderInstruction) =
+        implementation!!.replaceInstruction(index, instruction)
+
+    /**
+     * Replace an instruction at the given index.
+     *
+     * @param index The index to replace the instruction at.
+     * @param smaliInstruction The smali instruction to replace the instruction with.
+     */
+    fun MutableMethod.replaceInstruction(index: Int, smaliInstruction: String) =
+        implementation!!.replaceInstruction(index, smaliInstruction.toInstruction(this))
+
+    /**
+     * Replace instructions at the given index.
+     *
+     * @param index The index to replace the instructions at.
+     * @param instructions The instructions to replace the instructions with.
+     */
+    fun MutableMethod.replaceInstructions(index: Int, instructions: List<BuilderInstruction>) =
+        implementation!!.replaceInstructions(index, instructions)
+
+    /**
+     * Replace instructions at the given index.
+     *
+     * @param index The index to replace the instructions at.
+     * @param smaliInstructions The smali instructions to replace the instructions with.
+     */
+    fun MutableMethod.replaceInstructions(index: Int, smaliInstructions: String) =
+        implementation!!.replaceInstructions(index, smaliInstructions.toInstructions(this))
+
+    /**
+     * Get an instruction at the given index.
+     *
+     * @param index The index to get the instruction at.
+     * @return The instruction.
+     */
+    fun MutableMethodImplementation.getInstruction(index: Int): BuilderInstruction = instructions[index]
+
+    /**
+     * Get an instruction at the given index.
+     *
+     * @param index The index to get the instruction at.
+     * @param T The type of instruction to return.
+     * @return The instruction.
+     */
+    @Suppress("UNCHECKED_CAST")
+    fun <T> MutableMethodImplementation.getInstruction(index: Int): T = getInstruction(index) as T
+
+    /**
+     * Get an instruction at the given index.
+     * @param index The index to get the instruction at.
+     * @return The instruction.
+     */
+    fun MutableMethod.getInstruction(index: Int): BuilderInstruction = implementation!!.getInstruction(index)
+
+    /**
+     * Get an instruction at the given index.
+     * @param index The index to get the instruction at.
+     * @param T The type of instruction to return.
+     * @return The instruction.
+     */
+    @Suppress("UNCHECKED_CAST")
+    fun <T> MutableMethod.getInstruction(index: Int): T = implementation!!.getInstruction<T>(index)
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/extensions/MethodFingerprintExtensions.kt

@@ -0,0 +1,20 @@
+package app.revanced.patcher.extensions
+
+import app.revanced.patcher.extensions.AnnotationExtensions.findAnnotationRecursively
+import app.revanced.patcher.fingerprint.method.annotation.FuzzyPatternScanMethod
+import app.revanced.patcher.fingerprint.method.impl.MethodFingerprint
+
+object MethodFingerprintExtensions {
+
+    /**
+     * The name of a [MethodFingerprint].
+     */
+    val MethodFingerprint.name: String
+        get() = this.javaClass.simpleName
+
+    /**
+     * The [FuzzyPatternScanMethod] annotation of a [MethodFingerprint].
+     */
+    val MethodFingerprint.fuzzyPatternScanMethod
+        get() = javaClass.findAnnotationRecursively(FuzzyPatternScanMethod::class)
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/extensions/PatchExtensions.kt

@@ -0,0 +1,72 @@
+package app.revanced.patcher.extensions
+
+import app.revanced.patcher.annotation.Compatibility
+import app.revanced.patcher.annotation.Description
+import app.revanced.patcher.annotation.Name
+import app.revanced.patcher.annotation.Version
+import app.revanced.patcher.extensions.AnnotationExtensions.findAnnotationRecursively
+import app.revanced.patcher.patch.OptionsContainer
+import app.revanced.patcher.patch.Patch
+import app.revanced.patcher.patch.PatchClass
+import app.revanced.patcher.patch.PatchOptions
+import app.revanced.patcher.patch.annotations.DependsOn
+import app.revanced.patcher.patch.annotations.RequiresIntegrations
+import kotlin.reflect.KVisibility
+import kotlin.reflect.full.companionObject
+import kotlin.reflect.full.companionObjectInstance
+
+object PatchExtensions {
+    /**
+     * The name of a [Patch].
+     */
+    val PatchClass.patchName: String
+        get() = findAnnotationRecursively(Name::class)?.name ?: this.simpleName
+
+    /**
+     * The version of a [Patch].
+     */
+    @Deprecated("This property is deprecated and will be removed in the future.")
+    val PatchClass.version
+        get() = findAnnotationRecursively(Version::class)?.version
+
+    /**
+     * Weather or not a [Patch] should be included.
+     */
+    val PatchClass.include
+        get() = findAnnotationRecursively(app.revanced.patcher.patch.annotations.Patch::class)!!.include
+
+    /**
+     * The description of a [Patch].
+     */
+    val PatchClass.description
+        get() = findAnnotationRecursively(Description::class)?.description
+
+    /**
+     * The dependencies of a [Patch].
+     */
+    val PatchClass.dependencies
+        get() = findAnnotationRecursively(DependsOn::class)?.dependencies
+
+    /**
+     * The packages a [Patch] is compatible with.
+     */
+    val PatchClass.compatiblePackages
+        get() = findAnnotationRecursively(Compatibility::class)?.compatiblePackages
+
+    /**
+     * Weather or not a [Patch] requires integrations.
+     */
+    internal val PatchClass.requiresIntegrations
+        get() = findAnnotationRecursively(RequiresIntegrations::class) != null
+
+    /**
+     * The options of a [Patch].
+     */
+    val PatchClass.options: PatchOptions?
+        get() = kotlin.companionObject?.let { cl ->
+            if (cl.visibility != KVisibility.PUBLIC) return null
+            kotlin.companionObjectInstance?.let {
+                (it as? OptionsContainer)?.options
+            }
+        }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/fingerprint/Fingerprint.kt

@@ -0,0 +1,9 @@
+package app.revanced.patcher.fingerprint
+
+import app.revanced.patcher.fingerprint.method.impl.MethodFingerprint
+
+/**
+ * A ReVanced fingerprint.
+ * Can be a [MethodFingerprint].
+ */
+interface Fingerprint

revanced-patcher/src/main/kotlin/app/revanced/patcher/fingerprint/method/annotation/MethodFingerprintMetadata.kt

@@ -0,0 +1,12 @@
+package app.revanced.patcher.fingerprint.method.annotation
+
+import app.revanced.patcher.fingerprint.method.impl.MethodFingerprint
+
+/**
+ * Annotations to scan a pattern [MethodFingerprint] with fuzzy algorithm.
+ * @param threshold if [threshold] or more of the opcodes do not match, skip.
+ */
+@Target(AnnotationTarget.CLASS)
+annotation class FuzzyPatternScanMethod(
+    val threshold: Int = 1
+)

revanced-patcher/src/main/kotlin/app/revanced/patcher/fingerprint/method/impl/MethodFingerprint.kt

@@ -0,0 +1,513 @@
+package app.revanced.patcher.fingerprint.method.impl
+
+import app.revanced.patcher.BytecodeContext
+import app.revanced.patcher.extensions.MethodFingerprintExtensions.fuzzyPatternScanMethod
+import app.revanced.patcher.fingerprint.Fingerprint
+import app.revanced.patcher.fingerprint.method.annotation.FuzzyPatternScanMethod
+import app.revanced.patcher.patch.PatchException
+import app.revanced.patcher.util.proxy.ClassProxy
+import org.jf.dexlib2.AccessFlags
+import org.jf.dexlib2.Opcode
+import org.jf.dexlib2.iface.ClassDef
+import org.jf.dexlib2.iface.Method
+import org.jf.dexlib2.iface.instruction.Instruction
+import org.jf.dexlib2.iface.instruction.ReferenceInstruction
+import org.jf.dexlib2.iface.reference.StringReference
+import org.jf.dexlib2.util.MethodUtil
+import java.util.*
+
+private typealias StringMatch = MethodFingerprintResult.MethodFingerprintScanResult.StringsScanResult.StringMatch
+private typealias StringsScanResult = MethodFingerprintResult.MethodFingerprintScanResult.StringsScanResult
+private typealias MethodClassPair = Pair<Method, ClassDef>
+
+/**
+ * A fingerprint to resolve methods.
+ *
+ * @param returnType The method's return type compared using [String.startsWith].
+ * @param accessFlags The method's exact access flags using values of [AccessFlags].
+ * @param parameters The parameters of the method. Partial matches allowed and follow the same rules as [returnType].
+ * @param opcodes An opcode pattern of the method's instructions. Wildcard or unknown opcodes can be specified by `null`.
+ * @param strings A list of the method's strings compared each using [String.contains].
+ * @param customFingerprint A custom condition for this fingerprint.
+ */
+abstract class MethodFingerprint(
+    internal val returnType: String? = null,
+    internal val accessFlags: Int? = null,
+    internal val parameters: Iterable<String>? = null,
+    internal val opcodes: Iterable<Opcode?>? = null,
+    internal val strings: Iterable<String>? = null,
+    internal val customFingerprint: ((methodDef: Method, classDef: ClassDef) -> Boolean)? = null
+) : Fingerprint {
+    /**
+     * The result of the [MethodFingerprint].
+     */
+    var result: MethodFingerprintResult? = null
+
+    companion object {
+        /**
+         * A list of methods and the class they were found in.
+         */
+        private val methods = mutableListOf<MethodClassPair>()
+
+        /**
+         * Lookup map for methods keyed to the methods access flags, return type and parameter.
+         */
+        private val methodSignatureLookupMap = mutableMapOf<String, MutableList<MethodClassPair>>()
+
+        /**
+         * Lookup map for methods keyed to the strings contained in the method.
+         */
+        private val methodStringsLookupMap = mutableMapOf<String, MutableList<MethodClassPair>>()
+
+        /**
+         * Appends a string based on the parameter reference types of this method.
+         */
+        private fun StringBuilder.appendParameters(parameters: Iterable<CharSequence>) {
+            // Maximum parameters to use in the signature key.
+            // Some apps have methods with an incredible number of parameters (over 100 parameters have been seen).
+            // To keep the signature map from becoming needlessly bloated,
+            // group together in the same map entry all methods with the same access/return and 5 or more parameters.
+            // The value of 5 was chosen based on local performance testing and is not set in stone.
+            val maxSignatureParameters = 5
+            // Must append a unique value before the parameters to distinguish this key includes the parameters.
+            // If this is not appended, then methods with no parameters
+            // will collide with different keys that specify access/return but omit the parameters.
+            append("p:")
+            parameters.forEachIndexed { index, parameter ->
+                if (index >= maxSignatureParameters) return
+                append(parameter.first())
+            }
+        }
+
+        /**
+         * Initializes lookup maps for [MethodFingerprint] resolution
+         * using attributes of methods such as the method signature or strings.
+         *
+         * @param context The [BytecodeContext] containing the classes to initialize the lookup maps with.
+         */
+        internal fun initializeFingerprintResolutionLookupMaps(context: BytecodeContext) {
+            fun MutableMap<String, MutableList<MethodClassPair>>.add(
+                key: String,
+                methodClassPair: MethodClassPair
+            ) {
+                var methodClassPairs = this[key]
+
+                methodClassPairs ?: run {
+                    methodClassPairs = LinkedList<MethodClassPair>().also { this[key] = it }
+                }
+
+                methodClassPairs!!.add(methodClassPair)
+            }
+
+            if (methods.isNotEmpty()) throw PatchException("Map already initialized")
+
+            context.classes.forEach { classDef ->
+                classDef.methods.forEach { method ->
+                    val methodClassPair = method to classDef
+
+                    // For fingerprints with no access or return type specified.
+                    methods += methodClassPair
+
+                    val accessFlagsReturnKey = method.accessFlags.toString() + method.returnType.first()
+
+                    // Add <access><returnType> as the key.
+                    methodSignatureLookupMap.add(accessFlagsReturnKey, methodClassPair)
+
+                    // Add <access><returnType>[parameters] as the key.
+                    methodSignatureLookupMap.add(
+                        buildString {
+                            append(accessFlagsReturnKey)
+                            appendParameters(method.parameterTypes)
+                        },
+                        methodClassPair
+                    )
+
+                    // Add strings contained in the method as the key.
+                    method.implementation?.instructions?.forEach instructions@{ instruction ->
+                        if (instruction.opcode != Opcode.CONST_STRING && instruction.opcode != Opcode.CONST_STRING_JUMBO)
+                            return@instructions
+
+                        val string = ((instruction as ReferenceInstruction).reference as StringReference).string
+
+                        methodStringsLookupMap.add(string, methodClassPair)
+                    }
+
+                    // In the future, the class type could be added to the lookup map.
+                    // This would require MethodFingerprint to be changed to include the class type.
+                }
+            }
+        }
+
+        /**
+         * Clears the internal lookup maps created in [initializeFingerprintResolutionLookupMaps]
+         */
+        internal fun clearFingerprintResolutionLookupMaps() {
+            methods.clear()
+            methodSignatureLookupMap.clear()
+            methodStringsLookupMap.clear()
+        }
+
+        /**
+         * Resolve a list of [MethodFingerprint] using the lookup map built by [initializeFingerprintResolutionLookupMaps].
+         *
+         * [MethodFingerprint] resolution is fast, but if many are present they can consume a noticeable
+         * amount of time because they are resolved in sequence.
+         *
+         * For apps with many fingerprints, resolving performance can be improved by:
+         * - Slowest: Specify [opcodes] and nothing else.
+         * - Fast: Specify [accessFlags], [returnType].
+         * - Faster: Specify [accessFlags], [returnType] and [parameters].
+         * - Fastest: Specify [strings], with at least one string being an exact (non-partial) match.
+         */
+        internal fun Iterable<MethodFingerprint>.resolveUsingLookupMap(context: BytecodeContext) {
+            if (methods.isEmpty()) throw PatchException("lookup map not initialized")
+
+            for (fingerprint in this) {
+                fingerprint.resolveUsingLookupMap(context)
+            }
+        }
+
+        /**
+         * Resolve a [MethodFingerprint] using the lookup map built by [initializeFingerprintResolutionLookupMaps].
+         *
+         * [MethodFingerprint] resolution is fast, but if many are present they can consume a noticeable
+         * amount of time because they are resolved in sequence.
+         *
+         * For apps with many fingerprints, resolving performance can be improved by:
+         * - Slowest: Specify [opcodes] and nothing else.
+         * - Fast: Specify [accessFlags], [returnType].
+         * - Faster: Specify [accessFlags], [returnType] and [parameters].
+         * - Fastest: Specify [strings], with at least one string being an exact (non-partial) match.
+         */
+        internal fun MethodFingerprint.resolveUsingLookupMap(context: BytecodeContext): Boolean {
+            /**
+             * Lookup [MethodClassPair]s that match the methods strings present in a [MethodFingerprint].
+             *
+             * @return A list of [MethodClassPair]s that match the methods strings present in a [MethodFingerprint].
+             */
+            fun MethodFingerprint.methodStringsLookup(): List<MethodClassPair>? {
+                strings?.forEach {
+                    val methods = methodStringsLookupMap[it]
+                    if (methods != null) return methods
+                }
+                return null
+            }
+
+            /**
+             * Lookup [MethodClassPair]s that match the method signature present in a [MethodFingerprint].
+             *
+             * @return A list of [MethodClassPair]s that match the method signature present in a [MethodFingerprint].
+             */
+            fun MethodFingerprint.methodSignatureLookup(): List<MethodClassPair> {
+                if (accessFlags == null) return methods
+
+                var returnTypeValue = returnType
+                if (returnTypeValue == null) {
+                    if (AccessFlags.CONSTRUCTOR.isSet(accessFlags)) {
+                        // Constructors always have void return type
+                        returnTypeValue = "V"
+                    } else {
+                        return methods
+                    }
+                }
+
+                val key = buildString {
+                    append(accessFlags)
+                    append(returnTypeValue.first())
+                    if (parameters != null) appendParameters(parameters)
+                }
+                return methodSignatureLookupMap[key] ?: return emptyList()
+            }
+
+            /**
+             * Resolve a [MethodFingerprint] using a list of [MethodClassPair].
+             *
+             * @return True if the resolution was successful, false otherwise.
+             */
+            fun MethodFingerprint.resolveUsingMethodClassPair(classMethods: Iterable<MethodClassPair>): Boolean {
+                classMethods.forEach { classAndMethod ->
+                    if (resolve(context, classAndMethod.first, classAndMethod.second)) return true
+                }
+                return false
+            }
+
+            val methodsWithSameStrings = methodStringsLookup()
+            if (methodsWithSameStrings != null) if (resolveUsingMethodClassPair(methodsWithSameStrings)) return true
+
+            // No strings declared or none matched (partial matches are allowed).
+            // Use signature matching.
+            return resolveUsingMethodClassPair(methodSignatureLookup())
+        }
+
+        /**
+         * Resolve a list of [MethodFingerprint] against a list of [ClassDef].
+         *
+         * @param classes The classes on which to resolve the [MethodFingerprint] in.
+         * @param context The [BytecodeContext] to host proxies.
+         * @return True if the resolution was successful, false otherwise.
+         */
+        fun Iterable<MethodFingerprint>.resolve(context: BytecodeContext, classes: Iterable<ClassDef>) {
+            for (fingerprint in this) // For each fingerprint...
+                classes@ for (classDef in classes) // ...search through all classes for the MethodFingerprint
+                    if (fingerprint.resolve(context, classDef))
+                        break@classes // ...if the resolution succeeded, continue with the next MethodFingerprint.
+        }
+
+        /**
+         * Resolve a [MethodFingerprint] against a [ClassDef].
+         *
+         * @param forClass The class on which to resolve the [MethodFingerprint] in.
+         * @param context The [BytecodeContext] to host proxies.
+         * @return True if the resolution was successful, false otherwise.
+         */
+        fun MethodFingerprint.resolve(context: BytecodeContext, forClass: ClassDef): Boolean {
+            for (method in forClass.methods)
+                if (this.resolve(context, method, forClass))
+                    return true
+            return false
+        }
+
+        /**
+         * Resolve a [MethodFingerprint] against a [Method].
+         *
+         * @param method The class on which to resolve the [MethodFingerprint] in.
+         * @param forClass The class on which to resolve the [MethodFingerprint].
+         * @param context The [BytecodeContext] to host proxies.
+         * @return True if the resolution was successful or if the fingerprint is already resolved, false otherwise.
+         */
+        fun MethodFingerprint.resolve(context: BytecodeContext, method: Method, forClass: ClassDef): Boolean {
+            val methodFingerprint = this
+
+            if (methodFingerprint.result != null) return true
+
+            if (methodFingerprint.returnType != null && !method.returnType.startsWith(methodFingerprint.returnType))
+                return false
+
+            if (methodFingerprint.accessFlags != null && methodFingerprint.accessFlags != method.accessFlags)
+                return false
+
+
+            fun parametersEqual(
+                parameters1: Iterable<CharSequence>, parameters2: Iterable<CharSequence>
+            ): Boolean {
+                if (parameters1.count() != parameters2.count()) return false
+                val iterator1 = parameters1.iterator()
+                parameters2.forEach {
+                    if (!it.startsWith(iterator1.next())) return false
+                }
+                return true
+            }
+
+            if (methodFingerprint.parameters != null && !parametersEqual(
+                    methodFingerprint.parameters, // TODO: parseParameters()
+                    method.parameterTypes
+                )
+            ) return false
+
+            @Suppress("UNNECESSARY_NOT_NULL_ASSERTION")
+            if (methodFingerprint.customFingerprint != null && !methodFingerprint.customFingerprint!!(method, forClass))
+                return false
+
+            val stringsScanResult: StringsScanResult? =
+                if (methodFingerprint.strings != null) {
+                    StringsScanResult(
+                        buildList {
+                            val implementation = method.implementation ?: return false
+
+                            val stringsList = methodFingerprint.strings.toMutableList()
+
+                            implementation.instructions.forEachIndexed { instructionIndex, instruction ->
+                                if (
+                                    instruction.opcode != Opcode.CONST_STRING &&
+                                    instruction.opcode != Opcode.CONST_STRING_JUMBO
+                                ) return@forEachIndexed
+
+                                val string = ((instruction as ReferenceInstruction).reference as StringReference).string
+                                val index = stringsList.indexOfFirst(string::contains)
+                                if (index == -1) return@forEachIndexed
+
+                                add(
+                                    StringMatch(
+                                        string,
+                                        instructionIndex
+                                    )
+                                )
+                                stringsList.removeAt(index)
+                            }
+
+                            if (stringsList.isNotEmpty()) return false
+                        }
+                    )
+                } else null
+
+            val patternScanResult = if (methodFingerprint.opcodes != null) {
+                method.implementation?.instructions ?: return false
+
+                fun Method.patternScan(
+                    fingerprint: MethodFingerprint
+                ): MethodFingerprintResult.MethodFingerprintScanResult.PatternScanResult? {
+                    val instructions = this.implementation!!.instructions
+                    val fingerprintFuzzyPatternScanThreshold = fingerprint.fuzzyPatternScanMethod?.threshold ?: 0
+
+                    val pattern = fingerprint.opcodes!!
+                    val instructionLength = instructions.count()
+                    val patternLength = pattern.count()
+
+                    for (index in 0 until instructionLength) {
+                        var patternIndex = 0
+                        var threshold = fingerprintFuzzyPatternScanThreshold
+
+                        while (index + patternIndex < instructionLength) {
+                            val originalOpcode = instructions.elementAt(index + patternIndex).opcode
+                            val patternOpcode = pattern.elementAt(patternIndex)
+
+                            if (patternOpcode != null && patternOpcode.ordinal != originalOpcode.ordinal) {
+                                // Reaching maximum threshold (0) means,
+                                // the pattern does not match to the current instructions.
+                                if (threshold-- == 0) break
+                            }
+
+                            if (patternIndex < patternLength - 1) {
+                                // If the entire pattern has not been scanned yet
+                                // continue the scan.
+                                patternIndex++
+                                continue
+                            }
+                            // The pattern is valid, generate warnings if fuzzyPatternScanMethod is FuzzyPatternScanMethod
+                            val result =
+                                MethodFingerprintResult.MethodFingerprintScanResult.PatternScanResult(
+                                    index,
+                                    index + patternIndex
+                                )
+                            if (fingerprint.fuzzyPatternScanMethod !is FuzzyPatternScanMethod) return result
+                            result.warnings = result.createWarnings(pattern, instructions)
+
+                            return result
+                        }
+                    }
+
+                    return null
+                }
+
+                method.patternScan(methodFingerprint) ?: return false
+            } else null
+
+            methodFingerprint.result = MethodFingerprintResult(
+                method,
+                forClass,
+                MethodFingerprintResult.MethodFingerprintScanResult(
+                    patternScanResult,
+                    stringsScanResult
+                ),
+                context
+            )
+
+            return true
+        }
+
+        private fun MethodFingerprintResult.MethodFingerprintScanResult.PatternScanResult.createWarnings(
+            pattern: Iterable<Opcode?>, instructions: Iterable<Instruction>
+        ) = buildList {
+            for ((patternIndex, instructionIndex) in (this@createWarnings.startIndex until this@createWarnings.endIndex).withIndex()) {
+                val originalOpcode = instructions.elementAt(instructionIndex).opcode
+                val patternOpcode = pattern.elementAt(patternIndex)
+
+                if (patternOpcode == null || patternOpcode.ordinal == originalOpcode.ordinal) continue
+
+                this.add(
+                    MethodFingerprintResult.MethodFingerprintScanResult.PatternScanResult.Warning(
+                        originalOpcode,
+                        patternOpcode,
+                        instructionIndex,
+                        patternIndex
+                    )
+                )
+            }
+        }
+    }
+}
+
+/**
+ * Represents the result of a [MethodFingerprintResult].
+ *
+ * @param method The matching method.
+ * @param classDef The [ClassDef] that contains the matching [method].
+ * @param scanResult The result of scanning for the [MethodFingerprint].
+ * @param context The [BytecodeContext] this [MethodFingerprintResult] is attached to, to create proxies.
+ */
+data class MethodFingerprintResult(
+    val method: Method,
+    val classDef: ClassDef,
+    val scanResult: MethodFingerprintScanResult,
+    internal val context: BytecodeContext
+) {
+    /**
+     * Returns a mutable clone of [classDef]
+     *
+     * Please note, this method allocates a [ClassProxy].
+     * Use [classDef] where possible.
+     */
+    @Suppress("MemberVisibilityCanBePrivate")
+    val mutableClass by lazy { context.classes.proxy(classDef).mutableClass }
+
+    /**
+     * Returns a mutable clone of [method]
+     *
+     * Please note, this method allocates a [ClassProxy].
+     * Use [method] where possible.
+     */
+    val mutableMethod by lazy {
+        mutableClass.methods.first {
+            MethodUtil.methodSignaturesMatch(it, this.method)
+        }
+    }
+
+    /**
+     * The result of scanning on the [MethodFingerprint].
+     * @param patternScanResult The result of the pattern scan.
+     * @param stringsScanResult The result of the string scan.
+     */
+    data class MethodFingerprintScanResult(
+        val patternScanResult: PatternScanResult?,
+        val stringsScanResult: StringsScanResult?
+    ) {
+        /**
+         * The result of scanning strings on the [MethodFingerprint].
+         * @param matches The list of strings that were matched.
+         */
+        data class StringsScanResult(val matches: List<StringMatch>) {
+            /**
+             * Represents a match for a string at an index.
+             * @param string The string that was matched.
+             * @param index The index of the string.
+             */
+            data class StringMatch(val string: String, val index: Int)
+        }
+
+        /**
+         * The result of a pattern scan.
+         * @param startIndex The start index of the instructions where to which this pattern matches.
+         * @param endIndex The end index of the instructions where to which this pattern matches.
+         * @param warnings A list of warnings considering this [PatternScanResult].
+         */
+        data class PatternScanResult(
+            val startIndex: Int,
+            val endIndex: Int,
+            var warnings: List<Warning>? = null
+        ) {
+            /**
+             * Represents warnings of the pattern scan.
+             * @param correctOpcode The opcode the instruction list has.
+             * @param wrongOpcode The opcode the pattern list of the signature currently has.
+             * @param instructionIndex The index of the opcode relative to the instruction list.
+             * @param patternIndex The index of the opcode relative to the pattern list from the signature.
+             */
+            data class Warning(
+                val correctOpcode: Opcode,
+                val wrongOpcode: Opcode,
+                val instructionIndex: Int,
+                val patternIndex: Int,
+            )
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/logging/Logger.kt

@@ -0,0 +1,20 @@
+package app.revanced.patcher.logging
+
+interface Logger {
+    fun error(msg: String) {}
+    fun warn(msg: String) {}
+    fun info(msg: String) {}
+    fun trace(msg: String) {}
+
+    object Nop : Logger
+}
+
+/**
+ * Turn a Patcher [Logger] into an [app.revanced.arsc.logging.Logger].
+ */
+internal fun Logger.asArscLogger() = object : app.revanced.arsc.logging.Logger {
+    override fun error(msg: String) = this@asArscLogger.error(msg)
+    override fun warn(msg: String) = this@asArscLogger.warn(msg)
+    override fun info(msg: String) = this@asArscLogger.info(msg)
+    override fun trace(msg: String) = this@asArscLogger.error(msg)
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/patch/OptionsContainer.kt

@@ -0,0 +1,18 @@
+package app.revanced.patcher.patch
+
+/**
+ * A container for patch options.
+ */
+abstract class OptionsContainer {
+    /**
+     * A list of [PatchOption]s.
+     * @see PatchOptions
+     */
+    @Suppress("MemberVisibilityCanBePrivate")
+    val options = PatchOptions()
+
+    protected fun <T> option(opt: PatchOption<T>): PatchOption<T> {
+        options.register(opt)
+        return opt
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/patch/Patch.kt

@@ -0,0 +1,42 @@
+package app.revanced.patcher.patch
+
+import app.revanced.patcher.BytecodeContext
+import app.revanced.patcher.Context
+import app.revanced.patcher.ResourceContext
+import app.revanced.patcher.fingerprint.method.impl.MethodFingerprint
+import java.io.Closeable
+
+/**
+ * A ReVanced patch.
+ *
+ * If it implements [Closeable], it will be closed after all patches have been executed.
+ * Closing will be done in reverse execution order.
+ */
+sealed interface Patch<out T : Context> {
+    /**
+     * The main function of the [Patch] which the patcher will call.
+     *
+     * @param context The [Context] the patch will work on.
+     */
+    suspend fun execute(context: @UnsafeVariance T)
+}
+
+/**
+ * Resource patch for the Patcher.
+ */
+interface ResourcePatch : Patch<ResourceContext>
+
+/**
+ * Bytecode patch for the Patcher.
+ *
+ * @param fingerprints A list of [MethodFingerprint] this patch relies on.
+ */
+abstract class BytecodePatch(
+    internal val fingerprints: Iterable<MethodFingerprint>? = null
+) : Patch<BytecodeContext>
+
+// TODO: populate this everywhere where the alias is not used yet
+/**
+ * The class type of [Patch].
+ */
+typealias PatchClass = Class<out Patch<Context>>

revanced-patcher/src/main/kotlin/app/revanced/patcher/patch/PatchException.kt

@@ -0,0 +1,12 @@
+package app.revanced.patcher.patch
+
+/**
+ * An exception thrown when patching.
+ *
+ * @param errorMessage The exception message.
+ * @param cause The corresponding [Throwable].
+ */
+class PatchException(errorMessage: String?, cause: Throwable?) : Exception(errorMessage, cause) {
+    constructor(errorMessage: String) : this(errorMessage, null)
+    constructor(cause: Throwable) : this(cause.message, cause)
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/patch/PatchOption.kt

@@ -0,0 +1,230 @@
+@file:Suppress("CanBeParameter", "MemberVisibilityCanBePrivate", "UNCHECKED_CAST")
+
+package app.revanced.patcher.patch
+
+import kotlin.reflect.KProperty
+
+class NoSuchOptionException(val option: String) : Exception("No such option: $option")
+class IllegalValueException(val value: Any?) : Exception("Illegal value: $value")
+class InvalidTypeException(val got: String, val expected: String) :
+    Exception("Invalid option value type: $got, expected $expected")
+
+object RequirementNotMetException : Exception("null was passed into an option that requires a value")
+
+/**
+ * A registry for an array of [PatchOption]s.
+ * @param options An array of [PatchOption]s.
+ */
+class PatchOptions(vararg options: PatchOption<*>) : Iterable<PatchOption<*>> {
+    private val register = mutableMapOf<String, PatchOption<*>>()
+
+    init {
+        options.forEach { register(it) }
+    }
+
+    internal fun register(option: PatchOption<*>) {
+        if (register.containsKey(option.key)) {
+            throw IllegalStateException("Multiple options found with the same key")
+        }
+        register[option.key] = option
+    }
+
+    /**
+     * Get a [PatchOption] by its key.
+     * @param key The key of the [PatchOption].
+     */
+    @JvmName("getUntyped")
+    operator fun get(key: String) = register[key] ?: throw NoSuchOptionException(key)
+
+    /**
+     * Get a [PatchOption] by its key.
+     * @param key The key of the [PatchOption].
+     */
+    inline operator fun <reified T> get(key: String): PatchOption<T> {
+        val opt = get(key)
+        if (opt.value !is T) throw InvalidTypeException(
+            opt.value?.let { it::class.java.canonicalName } ?: "null",
+            T::class.java.canonicalName
+        )
+        return opt as PatchOption<T>
+    }
+
+    /**
+     * Set the value of a [PatchOption].
+     * @param key The key of the [PatchOption].
+     * @param value The value you want it to be.
+     * Please note that using the wrong value type results in a runtime error.
+     */
+    inline operator fun <reified T> set(key: String, value: T) {
+        val opt = get<T>(key)
+        if (opt.value !is T) throw InvalidTypeException(
+            T::class.java.canonicalName,
+            opt.value?.let { it::class.java.canonicalName } ?: "null"
+        )
+        opt.value = value
+    }
+
+    /**
+     * Sets the value of a [PatchOption] to `null`.
+     * @param key The key of the [PatchOption].
+     */
+    fun nullify(key: String) {
+        get(key).value = null
+    }
+
+    override fun iterator() = register.values.iterator()
+}
+
+/**
+ * A [Patch] option.
+ * @param key Unique identifier of the option. Example: _`settings.microg.enabled`_
+ * @param default The default value of the option.
+ * @param title A human-readable title of the option. Example: _MicroG Settings_
+ * @param description A human-readable description of the option. Example: _Settings integration for MicroG._
+ * @param required Whether the option is required.
+ */
+@Suppress("MemberVisibilityCanBePrivate")
+sealed class PatchOption<T>(
+    val key: String,
+    default: T?,
+    val title: String,
+    val description: String,
+    val required: Boolean,
+    val validator: (T?) -> Boolean
+) {
+    var value: T? = default
+        get() {
+            if (field == null && required) {
+                throw RequirementNotMetException
+            }
+            return field
+        }
+        set(value) {
+            if (value == null && required) {
+                throw RequirementNotMetException
+            }
+            if (!validator(value)) {
+                throw IllegalValueException(value)
+            }
+            field = value
+        }
+
+    /**
+     * Gets the value of the option.
+     * Please note that using the wrong value type results in a runtime error.
+     */
+    @JvmName("getValueTyped")
+    inline operator fun <reified V> getValue(thisRef: Nothing?, property: KProperty<*>): V? {
+        if (value !is V?) throw InvalidTypeException(
+            V::class.java.canonicalName,
+            value?.let { it::class.java.canonicalName } ?: "null"
+        )
+        return value as? V?
+    }
+
+    operator fun getValue(thisRef: Any?, property: KProperty<*>) = value
+
+    /**
+     * Gets the value of the option.
+     * Please note that using the wrong value type results in a runtime error.
+     */
+    @JvmName("setValueTyped")
+    inline operator fun <reified V> setValue(thisRef: Nothing?, property: KProperty<*>, new: V) {
+        if (value !is V) throw InvalidTypeException(
+            V::class.java.canonicalName,
+            value?.let { it::class.java.canonicalName } ?: "null"
+        )
+        value = new as T
+    }
+
+    operator fun setValue(thisRef: Any?, property: KProperty<*>, new: T?) {
+        value = new
+    }
+
+    /**
+     * A [PatchOption] representing a [String].
+     * @see PatchOption
+     */
+    class StringOption(
+        key: String,
+        default: String?,
+        title: String,
+        description: String,
+        required: Boolean = false,
+        validator: (String?) -> Boolean = { true }
+    ) : PatchOption<String>(
+        key, default, title, description, required, validator
+    )
+
+    /**
+     * A [PatchOption] representing a [Boolean].
+     * @see PatchOption
+     */
+    class BooleanOption(
+        key: String,
+        default: Boolean?,
+        title: String,
+        description: String,
+        required: Boolean = false,
+        validator: (Boolean?) -> Boolean = { true }
+    ) : PatchOption<Boolean>(
+        key, default, title, description, required, validator
+    )
+
+    /**
+     * A [PatchOption] with a list of allowed options.
+     * @param options A list of allowed options for the [ListOption].
+     * @see PatchOption
+     */
+    sealed class ListOption<E>(
+        key: String,
+        default: E?,
+        val options: Iterable<E>,
+        title: String,
+        description: String,
+        required: Boolean = false,
+        validator: (E?) -> Boolean = { true }
+    ) : PatchOption<E>(
+        key, default, title, description, required, {
+            (it?.let { it in options } ?: true) && validator(it)
+        }
+    ) {
+        init {
+            if (default != null && default !in options) {
+                throw IllegalStateException("Default option must be an allowed option")
+            }
+        }
+    }
+
+    /**
+     * A [ListOption] of type [String].
+     * @see ListOption
+     */
+    class StringListOption(
+        key: String,
+        default: String?,
+        options: Iterable<String>,
+        title: String,
+        description: String,
+        required: Boolean = false,
+        validator: (String?) -> Boolean = { true }
+    ) : ListOption<String>(
+        key, default, options, title, description, required, validator
+    )
+
+    /**
+     * A [ListOption] of type [Int].
+     * @see ListOption
+     */
+    class IntListOption(
+        key: String,
+        default: Int?,
+        options: Iterable<Int>,
+        title: String,
+        description: String,
+        required: Boolean = false,
+        validator: (Int?) -> Boolean = { true }
+    ) : ListOption<Int>(
+        key, default, options, title, description, required, validator
+    )
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/patch/annotations/PatchAnnotation.kt

@@ -0,0 +1,27 @@
+package app.revanced.patcher.patch.annotations
+
+import app.revanced.patcher.Context
+import app.revanced.patcher.patch.Patch
+import kotlin.reflect.KClass
+
+/**
+ * Annotation to mark a class as a patch.
+ * @param include If false, the patch should be treated as optional by default.
+ */
+@Target(AnnotationTarget.CLASS)
+annotation class Patch(val include: Boolean = true)
+
+/**
+ * Annotation for dependencies of [Patch]es.
+ */
+@Target(AnnotationTarget.CLASS)
+annotation class DependsOn(
+    val dependencies: Array<KClass<out Patch<Context>>> = [] // TODO: This should be a list of PatchClass instead
+)
+
+
+/**
+ * Annotation to mark [Patch]es which depend on integrations.
+ */
+@Target(AnnotationTarget.CLASS)
+annotation class RequiresIntegrations // TODO: Remove this annotation and replace it with a proper system

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/ClassMerger.kt

@@ -0,0 +1,214 @@
+package app.revanced.patcher.util
+
+import app.revanced.patcher.BytecodeContext
+import app.revanced.patcher.extensions.or
+import app.revanced.patcher.logging.Logger
+import app.revanced.patcher.util.ClassMerger.Utils.asMutableClass
+import app.revanced.patcher.util.ClassMerger.Utils.filterAny
+import app.revanced.patcher.util.ClassMerger.Utils.filterNotAny
+import app.revanced.patcher.util.ClassMerger.Utils.isPublic
+import app.revanced.patcher.util.ClassMerger.Utils.toPublic
+import app.revanced.patcher.util.TypeUtil.traverseClassHierarchy
+import app.revanced.patcher.util.proxy.mutableTypes.MutableClass
+import app.revanced.patcher.util.proxy.mutableTypes.MutableClass.Companion.toMutable
+import app.revanced.patcher.util.proxy.mutableTypes.MutableField
+import app.revanced.patcher.util.proxy.mutableTypes.MutableField.Companion.toMutable
+import app.revanced.patcher.util.proxy.mutableTypes.MutableMethod
+import app.revanced.patcher.util.proxy.mutableTypes.MutableMethod.Companion.toMutable
+import org.jf.dexlib2.AccessFlags
+import org.jf.dexlib2.iface.ClassDef
+import org.jf.dexlib2.util.MethodUtil
+import kotlin.reflect.KFunction2
+
+/**
+ * Experimental class to merge a [ClassDef] with another.
+ * Note: This will not consider method implementations or if the class is missing a superclass or interfaces.
+ */
+internal object ClassMerger {
+    /**
+     * Merge a class with [otherClass].
+     *
+     * @param otherClass The class to merge with
+     * @param context The context to traverse the class hierarchy in.
+     * @param logger A logger.
+     */
+    fun ClassDef.merge(otherClass: ClassDef, context: BytecodeContext, logger: Logger? = null) = this
+        //.fixFieldAccess(otherClass, logger)
+        //.fixMethodAccess(otherClass, logger)
+        .addMissingFields(otherClass, logger)
+        .addMissingMethods(otherClass, logger)
+        .publicize(otherClass, context, logger)
+
+    /**
+     * Add methods which are missing but existing in [fromClass].
+     *
+     * @param fromClass The class to add missing methods from.
+     * @param logger A logger.
+     */
+    private fun ClassDef.addMissingMethods(fromClass: ClassDef, logger: Logger? = null): ClassDef {
+        val missingMethods = fromClass.methods.let { fromMethods ->
+            methods.filterNot { method ->
+                fromMethods.any { fromMethod ->
+                    MethodUtil.methodSignaturesMatch(fromMethod, method)
+                }
+            }
+        }
+
+        if (missingMethods.isEmpty()) return this
+
+        logger?.trace("Found ${missingMethods.size} missing methods")
+
+        return asMutableClass().apply {
+            methods.addAll(missingMethods.map { it.toMutable() })
+        }
+    }
+
+    /**
+     * Add fields which are missing but existing in [fromClass].
+     *
+     * @param fromClass The class to add missing fields from.
+     * @param logger A logger.
+     */
+    private fun ClassDef.addMissingFields(fromClass: ClassDef, logger: Logger? = null): ClassDef {
+        val missingFields = fields.filterNotAny(fromClass.fields) { field, fromField ->
+            fromField.name == field.name
+        }
+
+        if (missingFields.isEmpty()) return this
+
+        logger?.trace("Found ${missingFields.size} missing fields")
+
+        return asMutableClass().apply {
+            fields.addAll(missingFields.map { it.toMutable() })
+        }
+    }
+
+    /**
+     * Make a class and its super class public recursively.
+     * @param reference The class to check the [AccessFlags] of.
+     * @param context The context to traverse the class hierarchy in.
+     * @param logger A logger.
+     */
+    private fun ClassDef.publicize(reference: ClassDef, context: BytecodeContext, logger: Logger? = null) =
+        if (reference.accessFlags.isPublic() && !accessFlags.isPublic())
+            this.asMutableClass().apply {
+                context.traverseClassHierarchy(this) {
+                    if (accessFlags.isPublic()) return@traverseClassHierarchy
+
+                    logger?.trace("Publicizing ${this.type}")
+
+                    accessFlags = accessFlags.toPublic()
+                }
+            }
+        else this
+
+    /**
+     * Publicize fields if they are public in [reference].
+     *
+     * @param reference The class to check the [AccessFlags] of the fields in.
+     * @param logger A logger.
+     */
+    private fun ClassDef.fixFieldAccess(reference: ClassDef, logger: Logger? = null): ClassDef {
+        val brokenFields = fields.filterAny(reference.fields) { field, referenceField ->
+            if (field.name != referenceField.name) return@filterAny false
+
+            referenceField.accessFlags.isPublic() && !field.accessFlags.isPublic()
+        }
+
+        if (brokenFields.isEmpty()) return this
+
+        logger?.trace("Found ${brokenFields.size} broken fields")
+
+        /**
+         * Make a field public.
+         */
+        fun MutableField.publicize() {
+            accessFlags = accessFlags.toPublic()
+        }
+
+        return asMutableClass().apply {
+            fields.filter { brokenFields.contains(it) }.forEach(MutableField::publicize)
+        }
+    }
+
+    /**
+     * Publicize methods if they are public in [reference].
+     *
+     * @param reference The class to check the [AccessFlags] of the methods in.
+     * @param logger A logger.
+     */
+    private fun ClassDef.fixMethodAccess(reference: ClassDef, logger: Logger? = null): ClassDef {
+        val brokenMethods = methods.filterAny(reference.methods) { method, referenceMethod ->
+            if (!MethodUtil.methodSignaturesMatch(method, referenceMethod)) return@filterAny false
+
+            referenceMethod.accessFlags.isPublic() && !method.accessFlags.isPublic()
+        }
+
+        if (brokenMethods.isEmpty()) return this
+
+        logger?.trace("Found ${brokenMethods.size} methods")
+
+        /**
+         * Make a method public.
+         */
+        fun MutableMethod.publicize() {
+            accessFlags = accessFlags.toPublic()
+        }
+
+        return asMutableClass().apply {
+            methods.filter { brokenMethods.contains(it) }.forEach(MutableMethod::publicize)
+        }
+    }
+
+    private object Utils {
+        fun ClassDef.asMutableClass() = if (this is MutableClass) this else this.toMutable()
+
+        /**
+         * Check if the [AccessFlags.PUBLIC] flag is set.
+         *
+         * @return True, if the flag is set.
+         */
+        fun Int.isPublic() = AccessFlags.PUBLIC.isSet(this)
+
+        /**
+         * Make [AccessFlags] public.
+         *
+         * @return The new [AccessFlags].
+         */
+        fun Int.toPublic() = this.or(AccessFlags.PUBLIC).and(AccessFlags.PRIVATE.value.inv())
+
+        /**
+         * Filter [this] on [needles] matching the given [predicate].
+         *
+         * @param this The hay to filter for [needles].
+         * @param needles The needles to filter [this] with.
+         * @param predicate The filter.
+         * @return The [this] filtered on [needles] matching the given [predicate].
+         */
+        fun <HayType, NeedleType> Iterable<HayType>.filterAny(
+            needles: Iterable<NeedleType>, predicate: (HayType, NeedleType) -> Boolean
+        ) = Iterable<HayType>::filter.any(this, needles, predicate)
+
+        /**
+         * Filter [this] on [needles] not matching the given [predicate].
+         *
+         * @param this The hay to filter for [needles].
+         * @param needles The needles to filter [this] with.
+         * @param predicate The filter.
+         * @return The [this] filtered on [needles] not matching the given [predicate].
+         */
+        fun <HayType, NeedleType> Iterable<HayType>.filterNotAny(
+            needles: Iterable<NeedleType>, predicate: (HayType, NeedleType) -> Boolean
+        ) = Iterable<HayType>::filterNot.any(this, needles, predicate)
+
+        fun <HayType, NeedleType> KFunction2<Iterable<HayType>, (HayType) -> Boolean, List<HayType>>.any(
+            haystack: Iterable<HayType>,
+            needles: Iterable<NeedleType>,
+            predicate: (HayType, NeedleType) -> Boolean
+        ) = this(haystack) { hay ->
+            needles.any { needle ->
+                predicate(hay, needle)
+            }
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/ListBackedSet.kt

@@ -0,0 +1,15 @@
+package app.revanced.patcher.util
+
+internal class ListBackedSet<E>(private val list: MutableList<E>) : MutableSet<E> {
+    override val size get() = list.size
+    override fun add(element: E) = list.add(element)
+    override fun addAll(elements: Collection<E>) = list.addAll(elements)
+    override fun clear() = list.clear()
+    override fun iterator() = list.listIterator()
+    override fun remove(element: E) = list.remove(element)
+    override fun removeAll(elements: Collection<E>) = list.removeAll(elements)
+    override fun retainAll(elements: Collection<E>) = list.retainAll(elements)
+    override fun contains(element: E) = list.contains(element)
+    override fun containsAll(elements: Collection<E>) = list.containsAll(elements)
+    override fun isEmpty() = list.isEmpty()
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/ProxyBackedClassList.kt

@@ -0,0 +1,89 @@
+package app.revanced.patcher.util
+
+import app.revanced.patcher.util.proxy.ClassProxy
+import org.jf.dexlib2.iface.ClassDef
+
+/**
+ * A class that represents a list of classes and proxies.
+ *
+ * @param classes The classes to be backed by proxies.
+ */
+class ProxyBackedClassList(classes: Set<ClassDef>) : Iterable<ClassDef> {
+    // A list for pending proxied classes to be added to the current ProxyBackedClassList instance.
+    private val proxiedClasses = mutableListOf<ClassProxy>()
+    private val mutableClasses = classes.toMutableList()
+
+    /**
+     * Replace the [mutableClasses]es with their proxies.
+     */
+    internal fun applyProxies() {
+        proxiedClasses.removeIf { proxy ->
+            // If the proxy is unused, keep it in the proxiedClasses list.
+            if (!proxy.resolved) return@removeIf false
+
+            with(mutableClasses) {
+                remove(proxy.immutableClass)
+                add(proxy.mutableClass)
+            }
+
+            return@removeIf true
+        }
+    }
+
+    /**
+     * Replace a [ClassDef] at a given [index].
+     *
+     * @param index The index of the class to be replaced.
+     * @param classDef The new class to replace the old one.
+     */
+    operator fun set(index: Int, classDef: ClassDef) {
+        mutableClasses[index] = classDef
+    }
+
+    /**
+     * Get a [ClassDef] at a given [index].
+     *
+     * @param index The index of the class.
+     */
+    operator fun get(index: Int) = mutableClasses[index]
+
+    /**
+     * Iterator for the classes in [ProxyBackedClassList].
+     *
+     * @return The iterator for the classes.
+     */
+    override fun iterator() = mutableClasses.iterator()
+
+    /**
+     * Proxy a [ClassDef].
+     *
+     * Note: This creates a [ClassProxy] of the [ClassDef], if not already present.
+     *
+     * @return A proxy for the given class.
+     */
+    fun proxy(classDef: ClassDef) = proxiedClasses
+        .find { it.immutableClass.type == classDef.type } ?: ClassProxy(classDef).also(proxiedClasses::add)
+
+    /**
+     * Add a [ClassDef].
+     */
+    fun add(classDef: ClassDef) = mutableClasses.add(classDef)
+
+    /**
+     * Find a class by a given class name.
+     *
+     * @param className The name of the class.
+     * @return A proxy for the first class that matches the class name.
+     */
+    fun findClassProxied(className: String) = findClassProxied { it.type.contains(className) }
+
+    /**
+     * Find a class by a given predicate.
+     *
+     * @param predicate A predicate to match the class.
+     * @return A proxy for the first class that matches the predicate.
+     */
+    fun findClassProxied(predicate: (ClassDef) -> Boolean) = this.find(predicate)?.let(::proxy)
+
+    val size get() = mutableClasses.size
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/TypeUtil.kt

@@ -0,0 +1,19 @@
+package app.revanced.patcher.util
+
+import app.revanced.patcher.BytecodeContext
+import app.revanced.patcher.util.proxy.mutableTypes.MutableClass
+
+object TypeUtil {
+    /**
+     * Traverse the class hierarchy starting from the given root class.
+     *
+     * @param targetClass The class to start traversing the class hierarchy from.
+     * @param callback The function that is called for every class in the hierarchy.
+     */
+    fun BytecodeContext.traverseClassHierarchy(targetClass: MutableClass, callback: MutableClass.() -> Unit) {
+        callback(targetClass)
+        this.classes.findClassProxied(targetClass.superclass ?: return)?.mutableClass?.let {
+            traverseClassHierarchy(it, callback)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/VersionReader.kt

@@ -0,0 +1,19 @@
+package app.revanced.patcher.util
+
+import java.util.*
+
+@Deprecated("This class serves no purpose anymore")
+internal object VersionReader {
+    @JvmStatic
+    private val properties = Properties().apply {
+        load(
+            VersionReader::class.java.getResourceAsStream("/app/revanced/patcher/version.properties")
+                ?: throw IllegalStateException("Could not load version.properties")
+        )
+    }
+
+    @JvmStatic
+    fun read(): String {
+        return properties.getProperty("version") ?: throw IllegalStateException("Version not found")
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/method/MethodWalker.kt

@@ -0,0 +1,56 @@
+package app.revanced.patcher.util.method
+
+import app.revanced.patcher.BytecodeContext
+import app.revanced.patcher.util.proxy.mutableTypes.MutableMethod
+import org.jf.dexlib2.iface.Method
+import org.jf.dexlib2.iface.instruction.ReferenceInstruction
+import org.jf.dexlib2.iface.reference.MethodReference
+import org.jf.dexlib2.util.MethodUtil
+
+/**
+ * Find a method from another method via instruction offsets.
+ * @param bytecodeContext The context to use when resolving the next method reference.
+ * @param currentMethod The method to start from.
+ */
+class MethodWalker internal constructor(
+    private val bytecodeContext: BytecodeContext,
+    private var currentMethod: Method
+) {
+    /**
+     * Get the method which was walked last.
+     *
+     * It is possible to cast this method to a [MutableMethod], if the method has been walked mutably.
+     *
+     * @return The method which was walked last.
+     */
+    fun getMethod(): Method {
+        return currentMethod
+    }
+
+    /**
+     * Walk to a method defined at the offset in the instruction list of the current method.
+     *
+     * The current method will be mutable.
+     *
+     * @param offset The offset of the instruction. This instruction must be of format 35c.
+     * @param walkMutable If this is true, the class of the method will be resolved mutably.
+     * @return The same [MethodWalker] instance with the method at [offset].
+     */
+    fun nextMethod(offset: Int, walkMutable: Boolean = false): MethodWalker {
+        currentMethod.implementation?.instructions?.let { instructions ->
+            val instruction = instructions.elementAt(offset)
+
+            val newMethod = (instruction as ReferenceInstruction).reference as MethodReference
+            val proxy = bytecodeContext.classes.findClassProxied(newMethod.definingClass)!!
+
+            val methods = if (walkMutable) proxy.mutableClass.methods else proxy.immutableClass.methods
+            currentMethod = methods.first {
+                return@first MethodUtil.methodSignaturesMatch(it, newMethod)
+            }
+            return this
+        }
+        throw MethodNotFoundException("This method can not be walked at offset $offset inside the method ${currentMethod.name}")
+    }
+
+    internal class MethodNotFoundException(exception: String) : Exception(exception)
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/patch/PatchBundle.kt

@@ -0,0 +1,59 @@
+@file:Suppress("unused")
+
+package app.revanced.patcher.util.patch
+
+import app.revanced.patcher.extensions.AnnotationExtensions.findAnnotationRecursively
+import app.revanced.patcher.patch.Patch
+import app.revanced.patcher.patch.PatchClass
+import dalvik.system.PathClassLoader
+import org.jf.dexlib2.DexFileFactory
+import java.io.File
+import java.net.URLClassLoader
+import java.util.jar.JarFile
+import kotlin.streams.toList
+
+/**
+ * A patch bundle.
+ *
+ * @param fromClasses The classes to get [Patch]es from.
+ */
+sealed class PatchBundle private constructor(fromClasses: Iterable<Class<*>>) : Iterable<PatchClass> {
+    private val patches = fromClasses.filter {
+        if (it.isAnnotation) return@filter false
+
+        it.findAnnotationRecursively(app.revanced.patcher.patch.annotations.Patch::class) != null
+    }.map {
+        @Suppress("UNCHECKED_CAST")
+        it as PatchClass
+    }
+
+    override fun iterator() = patches.iterator()
+
+    /**
+     * A patch bundle of type [Jar].
+     *
+     * @param patchBundlePath The path to a patch bundle.
+     */
+    class Jar(private val patchBundlePath: File) : PatchBundle(
+        with(URLClassLoader(arrayOf(patchBundlePath.toURI().toURL()), PatchBundle::class.java.classLoader)) {
+            JarFile(patchBundlePath).stream().filter { it.name.endsWith(".class") }.map {
+                loadClass(
+                    it.realName.replace('/', '.').replace(".class", "")
+                )
+            }.toList()
+        }
+    )
+
+    /**
+     * A patch bundle of type [Dex] format.
+     *
+     * @param patchBundlePath The path to a patch bundle of dex format.
+     */
+    class Dex(private val patchBundlePath: File) : PatchBundle(
+        with(PathClassLoader(patchBundlePath.absolutePath, null, PatchBundle::class.java.classLoader)) {
+            DexFileFactory.loadDexFile(patchBundlePath, null).classes.map { classDef ->
+                classDef.type.substring(1, classDef.length - 1).replace('/', '.')
+            }.map { loadClass(it) }
+        }
+    )
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/ClassProxy.kt

@@ -0,0 +1,33 @@
+package app.revanced.patcher.util.proxy
+
+import app.revanced.patcher.util.proxy.mutableTypes.MutableClass
+import org.jf.dexlib2.iface.ClassDef
+
+/**
+ * A proxy class for a [ClassDef].
+ *
+ * A class proxy simply holds a reference to the original class
+ * and allocates a mutable clone for the original class if needed.
+ * @param immutableClass The class to proxy.
+ */
+class ClassProxy internal constructor(
+    val immutableClass: ClassDef,
+) {
+    /**
+     * Weather the proxy was actually used.
+     */
+    internal var resolved = false
+
+    /**
+     * The mutable clone of the original class.
+     *
+     * Note: This is only allocated if the proxy is actually used.
+     */
+    val mutableClass by lazy {
+        resolved = true
+        if (immutableClass is MutableClass) {
+            immutableClass
+        } else
+            MutableClass(immutableClass)
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/MutableAnnotation.kt

@@ -0,0 +1,29 @@
+package app.revanced.patcher.util.proxy.mutableTypes
+
+import app.revanced.patcher.util.proxy.mutableTypes.MutableAnnotationElement.Companion.toMutable
+import org.jf.dexlib2.base.BaseAnnotation
+import org.jf.dexlib2.iface.Annotation
+
+class MutableAnnotation(annotation: Annotation) : BaseAnnotation() {
+    private val visibility = annotation.visibility
+    private val type = annotation.type
+    private val _elements by lazy { annotation.elements.map { element -> element.toMutable() }.toMutableSet() }
+
+    override fun getType(): String {
+        return type
+    }
+
+    override fun getElements(): MutableSet<MutableAnnotationElement> {
+        return _elements
+    }
+
+    override fun getVisibility(): Int {
+        return visibility
+    }
+
+    companion object {
+        fun Annotation.toMutable(): MutableAnnotation {
+            return MutableAnnotation(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/MutableAnnotationElement.kt

@@ -0,0 +1,34 @@
+package app.revanced.patcher.util.proxy.mutableTypes
+
+import app.revanced.patcher.util.proxy.mutableTypes.encodedValue.MutableEncodedValue
+import app.revanced.patcher.util.proxy.mutableTypes.encodedValue.MutableEncodedValue.Companion.toMutable
+import org.jf.dexlib2.base.BaseAnnotationElement
+import org.jf.dexlib2.iface.AnnotationElement
+import org.jf.dexlib2.iface.value.EncodedValue
+
+class MutableAnnotationElement(annotationElement: AnnotationElement) : BaseAnnotationElement() {
+    private var name = annotationElement.name
+    private var value = annotationElement.value.toMutable()
+
+    fun setName(name: String) {
+        this.name = name
+    }
+
+    fun setValue(value: MutableEncodedValue) {
+        this.value = value
+    }
+
+    override fun getName(): String {
+        return name
+    }
+
+    override fun getValue(): EncodedValue {
+        return value
+    }
+
+    companion object {
+        fun AnnotationElement.toMutable(): MutableAnnotationElement {
+            return MutableAnnotationElement(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/MutableClass.kt

@@ -0,0 +1,103 @@
+package app.revanced.patcher.util.proxy.mutableTypes
+
+import app.revanced.patcher.util.proxy.mutableTypes.MutableAnnotation.Companion.toMutable
+import app.revanced.patcher.util.proxy.mutableTypes.MutableField.Companion.toMutable
+import app.revanced.patcher.util.proxy.mutableTypes.MutableMethod.Companion.toMutable
+import com.google.common.collect.Iterables
+import org.jf.dexlib2.base.reference.BaseTypeReference
+import org.jf.dexlib2.iface.ClassDef
+import org.jf.dexlib2.util.FieldUtil
+import org.jf.dexlib2.util.MethodUtil
+
+class MutableClass(classDef: ClassDef) : ClassDef, BaseTypeReference() {
+    // Class
+    private var type = classDef.type
+    private var sourceFile = classDef.sourceFile
+    private var accessFlags = classDef.accessFlags
+    private var superclass = classDef.superclass
+
+    private val _interfaces by lazy { classDef.interfaces.toMutableList() }
+    private val _annotations by lazy {
+        classDef.annotations.map { annotation -> annotation.toMutable() }.toMutableSet()
+    }
+
+    // Methods
+    private val _methods by lazy { classDef.methods.map { method -> method.toMutable() }.toMutableSet() }
+    private val _directMethods by lazy { Iterables.filter(_methods, MethodUtil.METHOD_IS_DIRECT).toMutableSet() }
+    private val _virtualMethods by lazy { Iterables.filter(_methods, MethodUtil.METHOD_IS_VIRTUAL).toMutableSet() }
+
+    // Fields
+    private val _fields by lazy { classDef.fields.map { field -> field.toMutable() }.toMutableSet() }
+    private val _staticFields by lazy { Iterables.filter(_fields, FieldUtil.FIELD_IS_STATIC).toMutableSet() }
+    private val _instanceFields by lazy { Iterables.filter(_fields, FieldUtil.FIELD_IS_INSTANCE).toMutableSet() }
+
+    fun setType(type: String) {
+        this.type = type
+    }
+
+    fun setSourceFile(sourceFile: String?) {
+        this.sourceFile = sourceFile
+    }
+
+    fun setAccessFlags(accessFlags: Int) {
+        this.accessFlags = accessFlags
+    }
+
+    fun setSuperClass(superclass: String?) {
+        this.superclass = superclass
+    }
+
+    override fun getType(): String {
+        return type
+    }
+
+    override fun getAccessFlags(): Int {
+        return accessFlags
+    }
+
+    override fun getSourceFile(): String? {
+        return sourceFile
+    }
+
+    override fun getSuperclass(): String? {
+        return superclass
+    }
+
+    override fun getInterfaces(): MutableList<String> {
+        return _interfaces
+    }
+
+    override fun getAnnotations(): MutableSet<MutableAnnotation> {
+        return _annotations
+    }
+
+    override fun getStaticFields(): MutableSet<MutableField> {
+        return _staticFields
+    }
+
+    override fun getInstanceFields(): MutableSet<MutableField> {
+        return _instanceFields
+    }
+
+    override fun getFields(): MutableSet<MutableField> {
+        return _fields
+    }
+
+    override fun getDirectMethods(): MutableSet<MutableMethod> {
+        return _directMethods
+    }
+
+    override fun getVirtualMethods(): MutableSet<MutableMethod> {
+        return _virtualMethods
+    }
+
+    override fun getMethods(): MutableSet<MutableMethod> {
+        return _methods
+    }
+
+    companion object {
+        fun ClassDef.toMutable(): MutableClass {
+            return MutableClass(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/MutableField.kt

@@ -0,0 +1,73 @@
+package app.revanced.patcher.util.proxy.mutableTypes
+
+import app.revanced.patcher.util.proxy.mutableTypes.MutableAnnotation.Companion.toMutable
+import app.revanced.patcher.util.proxy.mutableTypes.encodedValue.MutableEncodedValue
+import app.revanced.patcher.util.proxy.mutableTypes.encodedValue.MutableEncodedValue.Companion.toMutable
+import org.jf.dexlib2.HiddenApiRestriction
+import org.jf.dexlib2.base.reference.BaseFieldReference
+import org.jf.dexlib2.iface.Field
+
+class MutableField(field: Field) : Field, BaseFieldReference() {
+    private var definingClass = field.definingClass
+    private var name = field.name
+    private var type = field.type
+    private var accessFlags = field.accessFlags
+
+    private var initialValue = field.initialValue?.toMutable()
+    private val _annotations by lazy { field.annotations.map { annotation -> annotation.toMutable() }.toMutableSet() }
+    private val _hiddenApiRestrictions by lazy { field.hiddenApiRestrictions }
+
+    fun setDefiningClass(definingClass: String) {
+        this.definingClass = definingClass
+    }
+
+    fun setName(name: String) {
+        this.name = name
+    }
+
+    fun setType(type: String) {
+        this.type = type
+    }
+
+    fun setAccessFlags(accessFlags: Int) {
+        this.accessFlags = accessFlags
+    }
+
+    fun setInitialValue(initialValue: MutableEncodedValue?) {
+        this.initialValue = initialValue
+    }
+
+    override fun getDefiningClass(): String {
+        return this.definingClass
+    }
+
+    override fun getName(): String {
+        return this.name
+    }
+
+    override fun getType(): String {
+        return this.type
+    }
+
+    override fun getAnnotations(): MutableSet<MutableAnnotation> {
+        return this._annotations
+    }
+
+    override fun getAccessFlags(): Int {
+        return this.accessFlags
+    }
+
+    override fun getHiddenApiRestrictions(): MutableSet<HiddenApiRestriction> {
+        return this._hiddenApiRestrictions
+    }
+
+    override fun getInitialValue(): MutableEncodedValue? {
+        return this.initialValue
+    }
+
+    companion object {
+        fun Field.toMutable(): MutableField {
+            return MutableField(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/MutableMethod.kt

@@ -0,0 +1,80 @@
+package app.revanced.patcher.util.proxy.mutableTypes
+
+import app.revanced.patcher.util.proxy.mutableTypes.MutableAnnotation.Companion.toMutable
+import app.revanced.patcher.util.proxy.mutableTypes.MutableMethodParameter.Companion.toMutable
+import org.jf.dexlib2.HiddenApiRestriction
+import org.jf.dexlib2.base.reference.BaseMethodReference
+import org.jf.dexlib2.builder.MutableMethodImplementation
+import org.jf.dexlib2.iface.Method
+
+class MutableMethod(method: Method) : Method, BaseMethodReference() {
+    private var definingClass = method.definingClass
+    private var name = method.name
+    private var accessFlags = method.accessFlags
+    private var returnType = method.returnType
+
+    // TODO: Create own mutable MethodImplementation (due to not being able to change members like register count).
+    private val _implementation by lazy { method.implementation?.let { MutableMethodImplementation(it) } }
+    private val _annotations by lazy { method.annotations.map { annotation -> annotation.toMutable() }.toMutableSet() }
+    private val _parameters by lazy { method.parameters.map { parameter -> parameter.toMutable() }.toMutableList() }
+    private val _parameterTypes by lazy { method.parameterTypes.toMutableList() }
+    private val _hiddenApiRestrictions by lazy { method.hiddenApiRestrictions }
+
+    fun setDefiningClass(definingClass: String) {
+        this.definingClass = definingClass
+    }
+
+    fun setName(name: String) {
+        this.name = name
+    }
+
+    fun setAccessFlags(accessFlags: Int) {
+        this.accessFlags = accessFlags
+    }
+
+    fun setReturnType(returnType: String) {
+        this.returnType = returnType
+    }
+
+    override fun getDefiningClass(): String {
+        return definingClass
+    }
+
+    override fun getName(): String {
+        return name
+    }
+
+    override fun getParameterTypes(): MutableList<CharSequence> {
+        return _parameterTypes
+    }
+
+    override fun getReturnType(): String {
+        return returnType
+    }
+
+    override fun getAnnotations(): MutableSet<MutableAnnotation> {
+        return _annotations
+    }
+
+    override fun getAccessFlags(): Int {
+        return accessFlags
+    }
+
+    override fun getHiddenApiRestrictions(): MutableSet<HiddenApiRestriction> {
+        return _hiddenApiRestrictions
+    }
+
+    override fun getParameters(): MutableList<MutableMethodParameter> {
+        return _parameters
+    }
+
+    override fun getImplementation(): MutableMethodImplementation? {
+        return _implementation
+    }
+
+    companion object {
+        fun Method.toMutable(): MutableMethod {
+            return MutableMethod(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/MutableMethodParameter.kt

@@ -0,0 +1,37 @@
+package app.revanced.patcher.util.proxy.mutableTypes
+
+import app.revanced.patcher.util.proxy.mutableTypes.MutableAnnotation.Companion.toMutable
+import org.jf.dexlib2.base.BaseMethodParameter
+import org.jf.dexlib2.iface.MethodParameter
+
+// TODO: Finish overriding all members if necessary.
+class MutableMethodParameter(parameter: MethodParameter) : MethodParameter, BaseMethodParameter() {
+    private var type = parameter.type
+    private var name = parameter.name
+    private var signature = parameter.signature
+    private val _annotations by lazy {
+        parameter.annotations.map { annotation -> annotation.toMutable() }.toMutableSet()
+    }
+
+    override fun getType(): String {
+        return type
+    }
+
+    override fun getName(): String? {
+        return name
+    }
+
+    override fun getSignature(): String? {
+        return signature
+    }
+
+    override fun getAnnotations(): MutableSet<MutableAnnotation> {
+        return _annotations
+    }
+
+    companion object {
+        fun MethodParameter.toMutable(): MutableMethodParameter {
+            return MutableMethodParameter(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableAnnotationEncodedValue.kt

@@ -0,0 +1,33 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import app.revanced.patcher.util.proxy.mutableTypes.MutableAnnotationElement.Companion.toMutable
+import org.jf.dexlib2.base.value.BaseAnnotationEncodedValue
+import org.jf.dexlib2.iface.AnnotationElement
+import org.jf.dexlib2.iface.value.AnnotationEncodedValue
+
+class MutableAnnotationEncodedValue(annotationEncodedValue: AnnotationEncodedValue) : BaseAnnotationEncodedValue(),
+    MutableEncodedValue {
+    private var type = annotationEncodedValue.type
+
+    private val _elements by lazy {
+        annotationEncodedValue.elements.map { annotationElement -> annotationElement.toMutable() }.toMutableSet()
+    }
+
+    override fun getType(): String {
+        return this.type
+    }
+
+    fun setType(type: String) {
+        this.type = type
+    }
+
+    override fun getElements(): MutableSet<out AnnotationElement> {
+        return _elements
+    }
+
+    companion object {
+        fun AnnotationEncodedValue.toMutable(): MutableAnnotationEncodedValue {
+            return MutableAnnotationEncodedValue(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableArrayEncodedValue.kt

@@ -0,0 +1,22 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import app.revanced.patcher.util.proxy.mutableTypes.encodedValue.MutableEncodedValue.Companion.toMutable
+import org.jf.dexlib2.base.value.BaseArrayEncodedValue
+import org.jf.dexlib2.iface.value.ArrayEncodedValue
+import org.jf.dexlib2.iface.value.EncodedValue
+
+class MutableArrayEncodedValue(arrayEncodedValue: ArrayEncodedValue) : BaseArrayEncodedValue(), MutableEncodedValue {
+    private val _value by lazy {
+        arrayEncodedValue.value.map { encodedValue -> encodedValue.toMutable() }.toMutableList()
+    }
+
+    override fun getValue(): MutableList<out EncodedValue> {
+        return _value
+    }
+
+    companion object {
+        fun ArrayEncodedValue.toMutable(): MutableArrayEncodedValue {
+            return MutableArrayEncodedValue(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableBooleanEncodedValue.kt

@@ -0,0 +1,23 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.base.value.BaseBooleanEncodedValue
+import org.jf.dexlib2.iface.value.BooleanEncodedValue
+
+class MutableBooleanEncodedValue(booleanEncodedValue: BooleanEncodedValue) : BaseBooleanEncodedValue(),
+    MutableEncodedValue {
+    private var value = booleanEncodedValue.value
+
+    override fun getValue(): Boolean {
+        return this.value
+    }
+
+    fun setValue(value: Boolean) {
+        this.value = value
+    }
+
+    companion object {
+        fun BooleanEncodedValue.toMutable(): MutableBooleanEncodedValue {
+            return MutableBooleanEncodedValue(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableByteEncodedValue.kt

@@ -0,0 +1,22 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.base.value.BaseByteEncodedValue
+import org.jf.dexlib2.iface.value.ByteEncodedValue
+
+class MutableByteEncodedValue(byteEncodedValue: ByteEncodedValue) : BaseByteEncodedValue(), MutableEncodedValue {
+    private var value = byteEncodedValue.value
+
+    override fun getValue(): Byte {
+        return this.value
+    }
+
+    fun setValue(value: Byte) {
+        this.value = value
+    }
+
+    companion object {
+        fun ByteEncodedValue.toMutable(): MutableByteEncodedValue {
+            return MutableByteEncodedValue(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableCharEncodedValue.kt

@@ -0,0 +1,22 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.base.value.BaseCharEncodedValue
+import org.jf.dexlib2.iface.value.CharEncodedValue
+
+class MutableCharEncodedValue(charEncodedValue: CharEncodedValue) : BaseCharEncodedValue(), MutableEncodedValue {
+    private var value = charEncodedValue.value
+
+    override fun getValue(): Char {
+        return this.value
+    }
+
+    fun setValue(value: Char) {
+        this.value = value
+    }
+
+    companion object {
+        fun CharEncodedValue.toMutable(): MutableCharEncodedValue {
+            return MutableCharEncodedValue(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableDoubleEncodedValue.kt

@@ -0,0 +1,23 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.base.value.BaseDoubleEncodedValue
+import org.jf.dexlib2.iface.value.DoubleEncodedValue
+
+class MutableDoubleEncodedValue(doubleEncodedValue: DoubleEncodedValue) : BaseDoubleEncodedValue(),
+    MutableEncodedValue {
+    private var value = doubleEncodedValue.value
+
+    override fun getValue(): Double {
+        return this.value
+    }
+
+    fun setValue(value: Double) {
+        this.value = value
+    }
+
+    companion object {
+        fun DoubleEncodedValue.toMutable(): MutableDoubleEncodedValue {
+            return MutableDoubleEncodedValue(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableEncodedValue.kt

@@ -0,0 +1,32 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.ValueType
+import org.jf.dexlib2.iface.value.*
+
+interface MutableEncodedValue : EncodedValue {
+    companion object {
+        fun EncodedValue.toMutable(): MutableEncodedValue {
+            return when (this.valueType) {
+                ValueType.TYPE -> MutableTypeEncodedValue(this as TypeEncodedValue)
+                ValueType.FIELD -> MutableFieldEncodedValue(this as FieldEncodedValue)
+                ValueType.METHOD -> MutableMethodEncodedValue(this as MethodEncodedValue)
+                ValueType.ENUM -> MutableEnumEncodedValue(this as EnumEncodedValue)
+                ValueType.ARRAY -> MutableArrayEncodedValue(this as ArrayEncodedValue)
+                ValueType.ANNOTATION -> MutableAnnotationEncodedValue(this as AnnotationEncodedValue)
+                ValueType.BYTE -> MutableByteEncodedValue(this as ByteEncodedValue)
+                ValueType.SHORT -> MutableShortEncodedValue(this as ShortEncodedValue)
+                ValueType.CHAR -> MutableCharEncodedValue(this as CharEncodedValue)
+                ValueType.INT -> MutableIntEncodedValue(this as IntEncodedValue)
+                ValueType.LONG -> MutableLongEncodedValue(this as LongEncodedValue)
+                ValueType.FLOAT -> MutableFloatEncodedValue(this as FloatEncodedValue)
+                ValueType.DOUBLE -> MutableDoubleEncodedValue(this as DoubleEncodedValue)
+                ValueType.METHOD_TYPE -> MutableMethodTypeEncodedValue(this as MethodTypeEncodedValue)
+                ValueType.METHOD_HANDLE -> MutableMethodHandleEncodedValue(this as MethodHandleEncodedValue)
+                ValueType.STRING -> MutableStringEncodedValue(this as StringEncodedValue)
+                ValueType.BOOLEAN -> MutableBooleanEncodedValue(this as BooleanEncodedValue)
+                ValueType.NULL -> MutableNullEncodedValue()
+                else -> this as MutableEncodedValue
+            }
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableEnumEncodedValue.kt

@@ -0,0 +1,23 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.base.value.BaseEnumEncodedValue
+import org.jf.dexlib2.iface.reference.FieldReference
+import org.jf.dexlib2.iface.value.EnumEncodedValue
+
+class MutableEnumEncodedValue(enumEncodedValue: EnumEncodedValue) : BaseEnumEncodedValue(), MutableEncodedValue {
+    private var value = enumEncodedValue.value
+
+    override fun getValue(): FieldReference {
+        return this.value
+    }
+
+    fun setValue(value: FieldReference) {
+        this.value = value
+    }
+
+    companion object {
+        fun EnumEncodedValue.toMutable(): MutableEnumEncodedValue {
+            return MutableEnumEncodedValue(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableFieldEncodedValue.kt

@@ -0,0 +1,28 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.ValueType
+import org.jf.dexlib2.base.value.BaseFieldEncodedValue
+import org.jf.dexlib2.iface.reference.FieldReference
+import org.jf.dexlib2.iface.value.FieldEncodedValue
+
+class MutableFieldEncodedValue(fieldEncodedValue: FieldEncodedValue) : BaseFieldEncodedValue(), MutableEncodedValue {
+    private var value = fieldEncodedValue.value
+
+    override fun getValueType(): Int {
+        return ValueType.FIELD
+    }
+
+    override fun getValue(): FieldReference {
+        return this.value
+    }
+
+    fun setValue(value: FieldReference) {
+        this.value = value
+    }
+
+    companion object {
+        fun FieldEncodedValue.toMutable(): MutableFieldEncodedValue {
+            return MutableFieldEncodedValue(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableFloatEncodedValue.kt

@@ -0,0 +1,22 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.base.value.BaseFloatEncodedValue
+import org.jf.dexlib2.iface.value.FloatEncodedValue
+
+class MutableFloatEncodedValue(floatEncodedValue: FloatEncodedValue) : BaseFloatEncodedValue(), MutableEncodedValue {
+    private var value = floatEncodedValue.value
+
+    override fun getValue(): Float {
+        return this.value
+    }
+
+    fun setValue(value: Float) {
+        this.value = value
+    }
+
+    companion object {
+        fun FloatEncodedValue.toMutable(): MutableFloatEncodedValue {
+            return MutableFloatEncodedValue(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableIntEncodedValue.kt

@@ -0,0 +1,22 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.base.value.BaseIntEncodedValue
+import org.jf.dexlib2.iface.value.IntEncodedValue
+
+class MutableIntEncodedValue(intEncodedValue: IntEncodedValue) : BaseIntEncodedValue(), MutableEncodedValue {
+    private var value = intEncodedValue.value
+
+    override fun getValue(): Int {
+        return this.value
+    }
+
+    fun setValue(value: Int) {
+        this.value = value
+    }
+
+    companion object {
+        fun IntEncodedValue.toMutable(): MutableIntEncodedValue {
+            return MutableIntEncodedValue(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableLongEncodedValue.kt

@@ -0,0 +1,22 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.base.value.BaseLongEncodedValue
+import org.jf.dexlib2.iface.value.LongEncodedValue
+
+class MutableLongEncodedValue(longEncodedValue: LongEncodedValue) : BaseLongEncodedValue(), MutableEncodedValue {
+    private var value = longEncodedValue.value
+
+    override fun getValue(): Long {
+        return this.value
+    }
+
+    fun setValue(value: Long) {
+        this.value = value
+    }
+
+    companion object {
+        fun LongEncodedValue.toMutable(): MutableLongEncodedValue {
+            return MutableLongEncodedValue(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableMethodEncodedValue.kt

@@ -0,0 +1,24 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.base.value.BaseMethodEncodedValue
+import org.jf.dexlib2.iface.reference.MethodReference
+import org.jf.dexlib2.iface.value.MethodEncodedValue
+
+class MutableMethodEncodedValue(methodEncodedValue: MethodEncodedValue) : BaseMethodEncodedValue(),
+    MutableEncodedValue {
+    private var value = methodEncodedValue.value
+
+    override fun getValue(): MethodReference {
+        return this.value
+    }
+
+    fun setValue(value: MethodReference) {
+        this.value = value
+    }
+
+    companion object {
+        fun MethodEncodedValue.toMutable(): MutableMethodEncodedValue {
+            return MutableMethodEncodedValue(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableMethodHandleEncodedValue.kt

@@ -0,0 +1,27 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.base.value.BaseMethodHandleEncodedValue
+import org.jf.dexlib2.iface.reference.MethodHandleReference
+import org.jf.dexlib2.iface.value.MethodHandleEncodedValue
+
+class MutableMethodHandleEncodedValue(methodHandleEncodedValue: MethodHandleEncodedValue) :
+    BaseMethodHandleEncodedValue(),
+    MutableEncodedValue {
+    private var value = methodHandleEncodedValue.value
+
+    override fun getValue(): MethodHandleReference {
+        return this.value
+    }
+
+    fun setValue(value: MethodHandleReference) {
+        this.value = value
+    }
+
+    companion object {
+        fun MethodHandleEncodedValue.toMutable(): MutableMethodHandleEncodedValue {
+            return MutableMethodHandleEncodedValue(this)
+        }
+    }
+
+
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableMethodTypeEncodedValue.kt

@@ -0,0 +1,26 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.base.value.BaseMethodTypeEncodedValue
+import org.jf.dexlib2.iface.reference.MethodProtoReference
+import org.jf.dexlib2.iface.value.MethodTypeEncodedValue
+
+class MutableMethodTypeEncodedValue(methodTypeEncodedValue: MethodTypeEncodedValue) : BaseMethodTypeEncodedValue(),
+    MutableEncodedValue {
+    private var value = methodTypeEncodedValue.value
+
+    override fun getValue(): MethodProtoReference {
+        return this.value
+    }
+
+    fun setValue(value: MethodProtoReference) {
+        this.value = value
+    }
+
+    companion object {
+        fun MethodTypeEncodedValue.toMutable(): MutableMethodTypeEncodedValue {
+            return MutableMethodTypeEncodedValue(this)
+        }
+    }
+
+
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableNullEncodedValue.kt

@@ -0,0 +1,12 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.base.value.BaseNullEncodedValue
+import org.jf.dexlib2.iface.value.ByteEncodedValue
+
+class MutableNullEncodedValue : BaseNullEncodedValue(), MutableEncodedValue {
+    companion object {
+        fun ByteEncodedValue.toMutable(): MutableByteEncodedValue {
+            return MutableByteEncodedValue(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableShortEncodedValue.kt

@@ -0,0 +1,22 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.base.value.BaseShortEncodedValue
+import org.jf.dexlib2.iface.value.ShortEncodedValue
+
+class MutableShortEncodedValue(shortEncodedValue: ShortEncodedValue) : BaseShortEncodedValue(), MutableEncodedValue {
+    private var value = shortEncodedValue.value
+
+    override fun getValue(): Short {
+        return this.value
+    }
+
+    fun setValue(value: Short) {
+        this.value = value
+    }
+
+    companion object {
+        fun ShortEncodedValue.toMutable(): MutableShortEncodedValue {
+            return MutableShortEncodedValue(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableStringEncodedValue.kt

@@ -0,0 +1,24 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.base.value.BaseStringEncodedValue
+import org.jf.dexlib2.iface.value.ByteEncodedValue
+import org.jf.dexlib2.iface.value.StringEncodedValue
+
+class MutableStringEncodedValue(stringEncodedValue: StringEncodedValue) : BaseStringEncodedValue(),
+    MutableEncodedValue {
+    private var value = stringEncodedValue.value
+
+    override fun getValue(): String {
+        return this.value
+    }
+
+    fun setValue(value: String) {
+        this.value = value
+    }
+
+    companion object {
+        fun ByteEncodedValue.toMutable(): MutableByteEncodedValue {
+            return MutableByteEncodedValue(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/proxy/mutableTypes/encodedValue/MutableTypeEncodedValue.kt

@@ -0,0 +1,22 @@
+package app.revanced.patcher.util.proxy.mutableTypes.encodedValue
+
+import org.jf.dexlib2.base.value.BaseTypeEncodedValue
+import org.jf.dexlib2.iface.value.TypeEncodedValue
+
+class MutableTypeEncodedValue(typeEncodedValue: TypeEncodedValue) : BaseTypeEncodedValue(), MutableEncodedValue {
+    private var value = typeEncodedValue.value
+
+    override fun getValue(): String {
+        return this.value
+    }
+
+    fun setValue(value: String) {
+        this.value = value
+    }
+
+    companion object {
+        fun TypeEncodedValue.toMutable(): MutableTypeEncodedValue {
+            return MutableTypeEncodedValue(this)
+        }
+    }
+}

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/smali/ExternalLabel.kt

@@ -0,0 +1,10 @@
+package app.revanced.patcher.util.smali
+
+import org.jf.dexlib2.iface.instruction.Instruction
+
+/**
+ * A class that represents a label for an instruction.
+ * @param name The label name.
+ * @param instruction The instruction that this label is for.
+ */
+data class ExternalLabel(internal val name: String, internal val instruction: Instruction)

revanced-patcher/src/main/kotlin/app/revanced/patcher/util/smali/InlineSmaliCompiler.kt

@@ -0,0 +1,84 @@
+package app.revanced.patcher.util.smali
+
+import app.revanced.patcher.util.proxy.mutableTypes.MutableMethod
+import org.antlr.runtime.CommonTokenStream
+import org.antlr.runtime.TokenSource
+import org.antlr.runtime.tree.CommonTreeNodeStream
+import org.jf.dexlib2.AccessFlags
+import org.jf.dexlib2.Opcodes
+import org.jf.dexlib2.builder.BuilderInstruction
+import org.jf.dexlib2.writer.builder.DexBuilder
+import org.jf.smali.LexerErrorInterface
+import org.jf.smali.smaliFlexLexer
+import org.jf.smali.smaliParser
+import org.jf.smali.smaliTreeWalker
+import java.io.InputStreamReader
+
+private const val METHOD_TEMPLATE = """
+    .class LInlineCompiler;
+    .super Ljava/lang/Object;
+    .method %s dummyMethod(%s)V
+        .registers %d
+        %s
+    .end method
+"""
+
+class InlineSmaliCompiler {
+    companion object {
+        /**
+         * Compiles a string of Smali code to a list of instructions.
+         * Special registers (such as p0, p1) will only work correctly
+         * if the parameters and registers of the method are passed.
+         */
+        fun compile(
+            instructions: String, parameters: String, registers: Int, forStaticMethod: Boolean
+        ): List<BuilderInstruction> {
+            val input = METHOD_TEMPLATE.format(
+                if (forStaticMethod) {
+                    "static"
+                } else {
+                    ""
+                }, parameters, registers, instructions
+            )
+            val reader = InputStreamReader(input.byteInputStream())
+            val lexer: LexerErrorInterface = smaliFlexLexer(reader, 15)
+            val tokens = CommonTokenStream(lexer as TokenSource)
+            val parser = smaliParser(tokens)
+            val result = parser.smali_file()
+            if (parser.numberOfSyntaxErrors > 0 || lexer.numberOfSyntaxErrors > 0) {
+                throw IllegalStateException(
+                    "Encountered ${parser.numberOfSyntaxErrors} parser syntax errors and ${lexer.numberOfSyntaxErrors} lexer syntax errors!"
+                )
+            }
+            val treeStream = CommonTreeNodeStream(result.tree)
+            treeStream.tokenStream = tokens
+            val dexGen = smaliTreeWalker(treeStream)
+            dexGen.setDexBuilder(DexBuilder(Opcodes.getDefault()))
+            val classDef = dexGen.smali_file()
+            return classDef.methods.first().implementation!!.instructions.map { it as BuilderInstruction }
+        }
+    }
+}
+
+/**
+ * Compile lines of Smali code to a list of instructions.
+ *
+ * Note: Adding compiled instructions to an existing method with
+ * offset instructions WITHOUT specifying a parent method will not work.
+ * @param method The method to compile the instructions against.
+ * @returns A list of instructions.
+ */
+fun String.toInstructions(method: MutableMethod? = null): List<BuilderInstruction> {
+    return InlineSmaliCompiler.compile(this,
+        method?.parameters?.joinToString("") { it } ?: "",
+        method?.implementation?.registerCount ?: 1,
+        method?.let { AccessFlags.STATIC.isSet(it.accessFlags) } ?: true
+    )
+}
+
+/**
+ * Compile a line of Smali code to an instruction.
+ * @param templateMethod The method to compile the instructions against.
+ * @return The instruction.
+ */
+fun String.toInstruction(templateMethod: MutableMethod? = null) = this.toInstructions(templateMethod).first()

revanced-patcher/src/main/resources/app/revanced/patcher/version.properties

@@ -0,0 +1 @@
+version=${projectVersion}

revanced-patcher/src/test/kotlin/app/revanced/patcher/issues/Issue98.kt

@@ -0,0 +1,18 @@
+package app.revanced.patcher.issues
+
+import app.revanced.patcher.patch.PatchOption
+import org.junit.jupiter.api.Test
+import kotlin.test.assertNull
+
+internal class Issue98 {
+    companion object {
+        var key1: String? by PatchOption.StringOption(
+            "key1", null, "title", "description"
+        )
+    }
+
+    @Test
+    fun `should infer nullable type correctly`() {
+        assertNull(key1)
+    }
+}

revanced-patcher/src/test/kotlin/app/revanced/patcher/patch/PatchOptionsTest.kt

@@ -0,0 +1,107 @@
+package app.revanced.patcher.patch
+
+import app.revanced.patcher.usage.bytecode.ExampleBytecodePatch
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertThrows
+import kotlin.test.assertNotEquals
+
+internal class PatchOptionsTest {
+    private val options = ExampleBytecodePatch.options
+
+    @Test
+    fun `should not throw an exception`() {
+        for (option in options) {
+            when (option) {
+                is PatchOption.StringOption -> {
+                    option.value = "Hello World"
+                }
+
+                is PatchOption.BooleanOption -> {
+                    option.value = false
+                }
+
+                is PatchOption.StringListOption -> {
+                    option.value = option.options.first()
+                    for (choice in option.options) {
+                        println(choice)
+                    }
+                }
+
+                is PatchOption.IntListOption -> {
+                    option.value = option.options.first()
+                    for (choice in option.options) {
+                        println(choice)
+                    }
+                }
+            }
+        }
+        val option = options.get<String>("key1")
+        // or: val option: String? by options["key1"]
+        // then you won't need `.value` every time
+        println(option.value)
+        options["key1"] = "Hello, world!"
+        println(option.value)
+    }
+
+    @Test
+    fun `should return a different value when changed`() {
+        var value: String? by options["key1"]
+        val current = value + "" // force a copy
+        value = "Hello, world!"
+        assertNotEquals(current, value)
+    }
+
+    @Test
+    fun `should be able to set value to null`() {
+        // Sadly, doing:
+        // > options["key2"] = null
+        // is not possible because Kotlin
+        // cannot reify the type "Nothing?".
+        // So we have to do this instead:
+        options["key2"] = null as Any?
+        // This is a cleaner replacement for the above:
+        options.nullify("key2")
+    }
+
+    @Test
+    fun `should fail because the option does not exist`() {
+        assertThrows<NoSuchOptionException> {
+            options["this option does not exist"] = 123
+        }
+    }
+
+    @Test
+    fun `should fail because of invalid value type when setting an option`() {
+        assertThrows<InvalidTypeException> {
+            options["key1"] = 123
+        }
+    }
+
+    @Test
+    fun `should fail because of invalid value type when getting an option`() {
+        assertThrows<InvalidTypeException> {
+            options.get<Int>("key1")
+        }
+    }
+
+    @Test
+    fun `should fail because of an illegal value`() {
+        assertThrows<IllegalValueException> {
+            options["key3"] = "this value is not an allowed option"
+        }
+    }
+
+    @Test
+    fun `should fail because the requirement is not met`() {
+        assertThrows<RequirementNotMetException> {
+            options.nullify("key1")
+        }
+    }
+
+    @Test
+    fun `should fail because getting a non-initialized option is illegal`() {
+        assertThrows<RequirementNotMetException> {
+            println(options["key5"].value)
+        }
+    }
+}

revanced-patcher/src/test/kotlin/app/revanced/patcher/usage/bytecode/ExampleBytecodeCompatibility.kt

@@ -0,0 +1,13 @@
+package app.revanced.patcher.usage.bytecode
+
+import app.revanced.patcher.annotation.Compatibility
+import app.revanced.patcher.annotation.Package
+
+@Compatibility(
+    [Package(
+        "com.example.examplePackage", arrayOf("0.0.1", "0.0.2")
+    )]
+)
+@Target(AnnotationTarget.CLASS)
+internal annotation class ExampleBytecodeCompatibility
+

revanced-patcher/src/test/kotlin/app/revanced/patcher/usage/bytecode/ExampleBytecodePatch.kt

@@ -0,0 +1,192 @@
+package app.revanced.patcher.usage.bytecode
+
+import app.revanced.patcher.BytecodeContext
+import app.revanced.patcher.annotation.Description
+import app.revanced.patcher.annotation.Name
+import app.revanced.patcher.annotation.Version
+import app.revanced.patcher.extensions.InstructionExtensions.addInstructionsWithLabels
+import app.revanced.patcher.extensions.InstructionExtensions.replaceInstruction
+import app.revanced.patcher.extensions.or
+import app.revanced.patcher.patch.BytecodePatch
+import app.revanced.patcher.patch.OptionsContainer
+import app.revanced.patcher.patch.PatchOption
+import app.revanced.patcher.patch.annotations.DependsOn
+import app.revanced.patcher.patch.annotations.Patch
+import app.revanced.patcher.usage.resource.annotation.ExampleResourceCompatibility
+import app.revanced.patcher.usage.resource.patch.ExampleResourcePatch
+import app.revanced.patcher.util.proxy.mutableTypes.MutableField.Companion.toMutable
+import app.revanced.patcher.util.proxy.mutableTypes.MutableMethod.Companion.toMutable
+import com.google.common.collect.ImmutableList
+import org.jf.dexlib2.AccessFlags
+import org.jf.dexlib2.Format
+import org.jf.dexlib2.Opcode
+import org.jf.dexlib2.builder.MutableMethodImplementation
+import org.jf.dexlib2.builder.instruction.BuilderInstruction11x
+import org.jf.dexlib2.builder.instruction.BuilderInstruction21c
+import org.jf.dexlib2.iface.instruction.formats.Instruction21c
+import org.jf.dexlib2.immutable.ImmutableField
+import org.jf.dexlib2.immutable.ImmutableMethod
+import org.jf.dexlib2.immutable.ImmutableMethodImplementation
+import org.jf.dexlib2.immutable.reference.ImmutableFieldReference
+import org.jf.dexlib2.immutable.reference.ImmutableStringReference
+import org.jf.dexlib2.immutable.value.ImmutableFieldEncodedValue
+import org.jf.dexlib2.util.Preconditions
+
+@Patch
+@Name("example-bytecode-patch")
+@Description("Example demonstration of a bytecode patch.")
+@ExampleResourceCompatibility
+@Version("0.0.1")
+@DependsOn([ExampleResourcePatch::class])
+class ExampleBytecodePatch : BytecodePatch(listOf(ExampleFingerprint)) {
+    // This function will be executed by the patcher.
+    // You can treat it as a constructor
+    override suspend fun execute(context: BytecodeContext) {
+        // Get the resolved method by its fingerprint from the resolver cache
+        val result = ExampleFingerprint.result!!
+
+        // Patch options
+        println(key1)
+        key2 = false
+
+        // Get the implementation for the resolved method
+        val method = result.mutableMethod
+        val implementation = method.implementation!!
+
+        // Let's modify it, so it prints "Hello, ReVanced! Editing bytecode."
+        // Get the start index of our opcode pattern.
+        // This will be the index of the instruction with the opcode CONST_STRING.
+        val startIndex = result.scanResult.patternScanResult!!.startIndex
+
+        implementation.replaceStringAt(startIndex, "Hello, ReVanced! Editing bytecode.")
+
+        // Get the class in which the method matching our fingerprint is defined in.
+        val mainClass = context.classes.findClassProxied {
+            it.type == result.classDef.type
+        }!!.mutableClass
+
+        // Add a new method returning a string
+        mainClass.methods.add(
+            ImmutableMethod(
+                result.classDef.type,
+                "returnHello",
+                null,
+                "Ljava/lang/String;",
+                AccessFlags.PRIVATE or AccessFlags.STATIC,
+                null,
+                null,
+                ImmutableMethodImplementation(
+                    1,
+                    ImmutableList.of(
+                        BuilderInstruction21c(
+                            Opcode.CONST_STRING,
+                            0,
+                            ImmutableStringReference("Hello, ReVanced! Adding bytecode.")
+                        ),
+                        BuilderInstruction11x(Opcode.RETURN_OBJECT, 0)
+                    ),
+                    null,
+                    null
+                )
+            ).toMutable()
+        )
+
+        // Add a field in the main class
+        // We will use this field in our method below to call println on
+        // The field holds the Ljava/io/PrintStream->out; field
+        mainClass.fields.add(
+            ImmutableField(
+                mainClass.type,
+                "dummyField",
+                "Ljava/io/PrintStream;",
+                AccessFlags.PRIVATE or AccessFlags.STATIC,
+                ImmutableFieldEncodedValue(
+                    ImmutableFieldReference(
+                        "Ljava/lang/System;",
+                        "out",
+                        "Ljava/io/PrintStream;"
+                    )
+                ),
+                null,
+                null
+            ).toMutable()
+        )
+
+        // store the fields initial value into the first virtual register
+        method.replaceInstruction(0, "sget-object v0, LTestClass;->dummyField:Ljava/io/PrintStream;")
+
+        // Now let's create a new call to our method and print the return value!
+        // You can also use the smali compiler to create instructions.
+        // For this sake of example I reuse the TestClass field dummyField inside the virtual register 0.
+        //
+        // Control flow instructions are not supported as of now.
+        method.addInstructionsWithLabels(
+            startIndex + 2,
+            """
+                invoke-static { }, LTestClass;->returnHello()Ljava/lang/String;
+                move-result-object v1
+                invoke-virtual { v0, v1 }, Ljava/io/PrintStream;->println(Ljava/lang/String;)V
+                """
+        )
+    }
+
+    /**
+     * Replace the string for an instruction at the given index with a new one.
+     * @param index The index of the instruction to replace the string for
+     * @param string The replacing string
+     */
+    private fun MutableMethodImplementation.replaceStringAt(index: Int, string: String) {
+        val instruction = this.instructions[index]
+
+        // Utility method of dexlib2
+        Preconditions.checkFormat(instruction.opcode, Format.Format21c)
+
+        // Cast this to an instruction of the format 21c
+        // The instruction format can be found in the docs at
+        // https://source.android.com/devices/tech/dalvik/dalvik-bytecode
+        val strInstruction = instruction as Instruction21c
+
+        // In our case we want an instruction with the opcode CONST_STRING
+        // The format is 21c, so we create a new BuilderInstruction21c
+        // This instruction will hold the string reference constant in the virtual register of the original instruction
+        // For that a reference to the string is needed. It can be created with an ImmutableStringReference.
+        // At last, use the method replaceInstruction to replace it at the given index startIndex.
+        this.replaceInstruction(
+            index,
+            BuilderInstruction21c(
+                Opcode.CONST_STRING,
+                strInstruction.registerA,
+                ImmutableStringReference(string)
+            )
+        )
+    }
+
+    @Suppress("unused")
+    companion object : OptionsContainer() {
+        private var key1 by option(
+            PatchOption.StringOption(
+                "key1", "default", "title", "description", true
+            )
+        )
+        private var key2 by option(
+            PatchOption.BooleanOption(
+                "key2", true, "title", "description" // required defaults to false
+            )
+        )
+        private var key3 by option(
+            PatchOption.StringListOption(
+                "key3", "TEST", listOf("TEST", "TEST1", "TEST2"), "title", "description"
+            )
+        )
+        private var key4 by option(
+            PatchOption.IntListOption(
+                "key4", 1, listOf(1, 2, 3), "title", "description"
+            )
+        )
+        private var key5 by option(
+            PatchOption.StringOption(
+                "key5", null, "title", "description", true
+            )
+        )
+    }
+}