build: Move subproject to root project

src/main/kotlin/app/revanced/patcher/IntegrationsConsumer.kt

@@ -0,0 +1,8 @@
+package app.revanced.patcher
+
+import java.io.File
+
+@FunctionalInterface
+interface IntegrationsConsumer {
+    fun acceptIntegrations(integrations: List<File>)
+}

src/main/kotlin/app/revanced/patcher/PackageMetadata.kt

@@ -0,0 +1,14 @@
+package app.revanced.patcher
+
+import brut.androlib.apk.ApkInfo
+
+/**
+ * Metadata about a package.
+ */
+class PackageMetadata internal constructor(internal val apkInfo: ApkInfo) {
+    lateinit var packageName: String
+        internal set
+
+    lateinit var packageVersion: String
+        internal set
+}

src/main/kotlin/app/revanced/patcher/PatchBundleLoader.kt

@@ -0,0 +1,127 @@
+@file:Suppress("unused")
+
+package app.revanced.patcher
+
+import app.revanced.patcher.patch.Patch
+import dalvik.system.DexClassLoader
+import lanchon.multidexlib2.BasicDexFileNamer
+import lanchon.multidexlib2.MultiDexIO
+import java.io.File
+import java.net.URLClassLoader
+import java.util.jar.JarFile
+import java.util.logging.Logger
+import kotlin.reflect.KClass
+
+/**
+ * A set of [Patch]es.
+ */
+typealias PatchSet = Set<Patch<*>>
+
+/**
+ * A [Patch] class.
+ */
+typealias PatchClass = KClass<out Patch<*>>
+
+/**
+ * A loader of [Patch]es from patch bundles.
+ * This will load all [Patch]es from the given patch bundles that have a name.
+ *
+ * @param getBinaryClassNames A function that returns the binary names of all classes in a patch bundle.
+ * @param classLoader The [ClassLoader] to use for loading the classes.
+ * @param patchBundles A set of patches to initialize this instance with.
+ */
+sealed class PatchBundleLoader private constructor(
+    classLoader: ClassLoader,
+    patchBundles: Array<out File>,
+    getBinaryClassNames: (patchBundle: File) -> List<String>,
+    // This constructor parameter is unfortunately necessary,
+    // so that a reference to the mutable set is present in the constructor to be able to add patches to it.
+    // because the instance itself is a PatchSet, which is immutable, that is delegated by the parameter.
+    private val patchSet: MutableSet<Patch<*>> = mutableSetOf()
+) : PatchSet by patchSet {
+    private val logger = Logger.getLogger(PatchBundleLoader::class.java.name)
+
+    init {
+        patchBundles.flatMap(getBinaryClassNames).asSequence().map {
+            classLoader.loadClass(it)
+        }.filter {
+            Patch::class.java.isAssignableFrom(it)
+        }.mapNotNull { patchClass ->
+            patchClass.getInstance(logger, silent = true)
+        }.filter {
+            it.name != null
+        }.let { patches ->
+            patchSet.addAll(patches)
+        }
+    }
+
+    internal companion object Utils {
+        /**
+         * Instantiates a [Patch]. If the class is a singleton, the INSTANCE field will be used.
+         *
+         * @param logger The [Logger] to use for logging.
+         * @param silent Whether to suppress logging.
+         * @return The instantiated [Patch] or `null` if the [Patch] could not be instantiated.
+         */
+        internal fun Class<*>.getInstance(logger: Logger, silent: Boolean = false): Patch<*>? {
+            return try {
+                getField("INSTANCE").get(null)
+            } catch (exception: NoSuchFieldException) {
+                if (!silent) logger.fine(
+                    "Patch class '${name}' has no INSTANCE field, therefor not a singleton. " +
+                            "Will try to instantiate it."
+                )
+
+                try {
+                    getDeclaredConstructor().newInstance()
+                } catch (exception: Exception) {
+                    if (!silent) logger.severe(
+                        "Patch class '${name}' is not singleton and has no suitable constructor, " +
+                                "therefor cannot be instantiated and will be ignored."
+                    )
+
+                    return null
+                }
+            } as Patch<*>
+        }
+    }
+
+    /**
+     * A [PatchBundleLoader] for JAR files.
+     *
+     * @param patchBundles The path to patch bundles of JAR format.
+     */
+    class Jar(vararg patchBundles: File) : PatchBundleLoader(
+        URLClassLoader(patchBundles.map { it.toURI().toURL() }.toTypedArray()),
+        patchBundles,
+        { patchBundle ->
+            JarFile(patchBundle).entries().toList().filter { it.name.endsWith(".class") }
+                .map { it.name.replace('/', '.').replace(".class", "") }
+        }
+    )
+
+    /**
+     * A [PatchBundleLoader] for [Dex] files.
+     *
+     * @param patchBundles The path to patch bundles of DEX format.
+     * @param optimizedDexDirectory The directory to store optimized DEX files in.
+     * This parameter is deprecated and has no effect since API level 26.
+     */
+    class Dex(vararg patchBundles: File, optimizedDexDirectory: File? = null) : PatchBundleLoader(
+        DexClassLoader(
+            patchBundles.joinToString(File.pathSeparator) { it.absolutePath }, optimizedDexDirectory?.absolutePath,
+            null,
+            PatchBundleLoader::class.java.classLoader
+        ),
+        patchBundles,
+        { patchBundle ->
+            MultiDexIO.readDexFile(true, patchBundle, BasicDexFileNamer(), null, null).classes
+                .map { classDef ->
+                    classDef.type.substring(1, classDef.length - 1)
+                }
+        }
+    ) {
+        @Deprecated("This constructor is deprecated. Use the constructor with the second parameter instead.")
+        constructor(vararg patchBundles: File) : this(*patchBundles, optimizedDexDirectory = null)
+    }
+}

src/main/kotlin/app/revanced/patcher/PatchExecutorFunction.kt

@@ -0,0 +1,8 @@
+package app.revanced.patcher
+
+import app.revanced.patcher.patch.PatchResult
+import kotlinx.coroutines.flow.Flow
+import java.util.function.Function
+
+@FunctionalInterface
+interface PatchExecutorFunction : Function<Boolean, Flow<PatchResult>>

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

@@ -0,0 +1,265 @@
+package app.revanced.patcher
+
+import app.revanced.patcher.PatchBundleLoader.Utils.getInstance
+import app.revanced.patcher.data.ResourceContext
+import app.revanced.patcher.fingerprint.method.impl.MethodFingerprint
+import app.revanced.patcher.fingerprint.method.impl.MethodFingerprint.Companion.resolveUsingLookupMap
+import app.revanced.patcher.patch.*
+import kotlinx.coroutines.flow.flow
+import java.io.Closeable
+import java.io.File
+import java.util.function.Supplier
+import java.util.logging.Logger
+
+/**
+ * ReVanced Patcher.
+ *
+ * @param options The options for the patcher.
+ */
+class Patcher(
+    private val options: PatcherOptions
+) : PatchExecutorFunction, PatchesConsumer, IntegrationsConsumer, Supplier<PatcherResult>, Closeable {
+    private val logger = Logger.getLogger(Patcher::class.java.name)
+
+    /**
+     * The context of ReVanced [Patcher].
+     * This holds the current state of the patcher.
+     */
+    val context = PatcherContext(options)
+
+    init {
+        context.resourceContext.decodeResources(ResourceContext.ResourceDecodingMode.MANIFEST_ONLY)
+    }
+
+    // TODO: Fix circular dependency detection.
+    // /**
+    //  * Add [Patch]es to ReVanced [Patcher].
+    //  * It is not guaranteed that all supplied [Patch]es will be accepted, if an exception is thrown.
+    //  *
+    //  * @param patches The [Patch]es to add.
+    //  * @throws PatcherException.CircularDependencyException If a circular dependency is detected.
+    // */
+    /**
+     * Add [Patch]es to ReVanced [Patcher].
+     *
+     * @param patches The [Patch]es to add.
+    */
+    @Suppress("NAME_SHADOWING")
+    override fun acceptPatches(patches: List<Patch<*>>) {
+        /**
+         * Add dependencies of a [Patch] recursively to [PatcherContext.allPatches].
+         * If a [Patch] is already in [PatcherContext.allPatches], it will not be added again.
+         */
+        fun PatchClass.putDependenciesRecursively() {
+            if (context.allPatches.contains(this)) return
+
+            val dependency = this.java.getInstance(logger)!!
+            context.allPatches[this] = dependency
+
+            dependency.dependencies?.forEach { it.putDependenciesRecursively() }
+        }
+
+        // Add all patches and their dependencies to the context.
+        for (patch in patches) context.executablePatches.putIfAbsent(patch::class, patch) ?: run {
+            context.allPatches[patch::class] = patch
+
+            patch.dependencies?.forEach { it.putDependenciesRecursively() }
+        }
+
+        /* TODO: Fix circular dependency detection.
+        val graph = mutableMapOf<PatchClass, MutableList<PatchClass>>()
+        fun PatchClass.visit() {
+            if (this in graph) return
+
+            val group = graph.getOrPut(this) { mutableListOf(this) }
+
+            val dependencies = context.allPatches[this]!!.manifest.dependencies ?: return
+            dependencies.forEach { dependency ->
+                if (group == graph[dependency])
+                    throw PatcherException.CircularDependencyException(context.allPatches[this]!!.manifest.name)
+
+                graph[dependency] = group.apply { add(dependency) }
+                dependency.visit()
+            }
+        }
+        */
+
+        /**
+         * Returns true if at least one patch or its dependencies matches the given predicate.
+         *
+         * @param predicate The predicate to match.
+         */
+        fun Patch<*>.anyRecursively(predicate: (Patch<*>) -> Boolean): Boolean =
+            predicate(this) || dependencies?.any { dependency ->
+                context.allPatches[dependency]!!.anyRecursively(predicate)
+            } ?: false
+
+        context.allPatches.values.let { patches ->
+            // Determine, if resource patching is required.
+            for (patch in patches)
+                if (patch.anyRecursively { patch is ResourcePatch }) {
+                    options.resourceDecodingMode = ResourceContext.ResourceDecodingMode.FULL
+                    break
+                }
+
+            // Determine, if merging integrations is required.
+            for (patch in patches)
+                if (patch.anyRecursively { it.requiresIntegrations }) {
+                    context.bytecodeContext.integrations.merge = true
+                    break
+                }
+        }
+    }
+
+    /**
+     * Add integrations to the [Patcher].
+     *
+     * @param integrations The integrations to add. Must be a DEX file or container of DEX files.
+     */
+    override fun acceptIntegrations(integrations: List<File>) {
+        context.bytecodeContext.integrations.addAll(integrations)
+    }
+
+    /**
+     * Execute [Patch]es that were added to ReVanced [Patcher].
+     *
+     * @param returnOnError If true, ReVanced [Patcher] will return immediately if a [Patch] fails.
+     * @return A pair of the name of the [Patch] and its [PatchResult].
+     */
+    override fun apply(returnOnError: Boolean) = flow {
+
+        /**
+         * Execute a [Patch] and its dependencies recursively.
+         *
+         * @param patch The [Patch] to execute.
+         * @param executedPatches A map to prevent [Patch]es from being executed twice due to dependencies.
+         * @return The result of executing the [Patch].
+         */
+        fun executePatch(
+            patch: Patch<*>,
+            executedPatches: LinkedHashMap<Patch<*>, PatchResult>
+        ): PatchResult {
+            val patchName = patch.name ?: patch.toString()
+
+            executedPatches[patch]?.let { patchResult ->
+                patchResult.exception ?: return patchResult
+
+                // Return a new result with an exception indicating that the patch was not executed previously,
+                // because it is a dependency of another patch that failed.
+                return PatchResult(patch, PatchException("'$patchName' did not succeed previously"))
+            }
+
+            // Recursively execute all dependency patches.
+            patch.dependencies?.forEach { dependencyClass ->
+                val dependency = context.allPatches[dependencyClass]!!
+                val result = executePatch(dependency, executedPatches)
+
+                result.exception?.let {
+                    return PatchResult(
+                        patch,
+                        PatchException(
+                            "'$patchName' depends on '${dependency.name ?: dependency}' " +
+                                    "that raised an exception:\n${it.stackTraceToString()}"
+                        )
+                    )
+                }
+            }
+
+            return try {
+                // TODO: Implement this in a more polymorphic way.
+                when (patch) {
+                    is BytecodePatch -> {
+                        patch.fingerprints.resolveUsingLookupMap(context.bytecodeContext)
+                        patch.execute(context.bytecodeContext)
+                    }
+                    is ResourcePatch -> {
+                        patch.execute(context.resourceContext)
+                    }
+                }
+
+                PatchResult(patch)
+            } catch (exception: PatchException) {
+                PatchResult(patch, exception)
+            } catch (exception: Exception) {
+                PatchResult(patch, PatchException(exception))
+            }.also { executedPatches[patch] = it }
+        }
+
+        if (context.bytecodeContext.integrations.merge) context.bytecodeContext.integrations.flush()
+
+        MethodFingerprint.initializeFingerprintResolutionLookupMaps(context.bytecodeContext)
+
+        // Prevent from decoding the app manifest twice if it is not needed.
+        if (options.resourceDecodingMode == ResourceContext.ResourceDecodingMode.FULL)
+            context.resourceContext.decodeResources(ResourceContext.ResourceDecodingMode.FULL)
+
+        logger.info("Executing patches")
+
+        val executedPatches = LinkedHashMap<Patch<*>, PatchResult>() // Key is name.
+
+        context.executablePatches.values.sortedBy { it.name }.forEach { patch ->
+            val patchResult = executePatch(patch, executedPatches)
+
+            // If the patch failed, emit the result, even if it is closeable.
+            // Results of executed patches that are closeable will be emitted later.
+            patchResult.exception?.let {
+                // Propagate exception to caller instead of wrapping it in a new exception.
+                emit(patchResult)
+
+                if (returnOnError) return@flow
+            } ?: run {
+                if (patch is Closeable) return@run
+
+                emit(patchResult)
+            }
+        }
+
+        executedPatches.values
+            .filter { it.exception == null }
+            .filter { it.patch is Closeable }.asReversed().forEach { executedPatch ->
+                val patch = executedPatch.patch
+
+                val result = try {
+                    (patch as Closeable).close()
+
+                    executedPatch
+                } catch (exception: PatchException) {
+                    PatchResult(patch, exception)
+                } catch (exception: Exception) {
+                    PatchResult(patch, PatchException(exception))
+                }
+
+                result.exception?.let {
+                    emit(
+                        PatchResult(
+                            patch,
+                            PatchException(
+                                "'${patch.name}' raised an exception while being closed: ${it.stackTraceToString()}",
+                                result.exception
+                            )
+                        )
+                    )
+
+                    if (returnOnError) return@flow
+                } ?: run {
+                    patch.name ?: return@run
+
+                    emit(result)
+                }
+            }
+    }
+
+    override fun close() = MethodFingerprint.clearFingerprintResolutionLookupMaps()
+
+    /**
+     * Compile and save the patched APK file.
+     *
+     * @return The [PatcherResult] containing the patched input files.
+     */
+    override fun get() = PatcherResult(
+        context.bytecodeContext.get(),
+        context.resourceContext.get(),
+        context.packageMetadata.apkInfo.doNotCompress?.toList()
+    )
+}
+

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

@@ -0,0 +1,41 @@
+package app.revanced.patcher
+
+import app.revanced.patcher.data.BytecodeContext
+import app.revanced.patcher.data.ResourceContext
+import app.revanced.patcher.patch.Patch
+import brut.androlib.apk.ApkInfo
+import brut.directory.ExtFile
+
+/**
+ * A context for ReVanced [Patcher].
+ *
+ * @param options The [PatcherOptions] used to create this context.
+ */
+class PatcherContext internal constructor(options: PatcherOptions) {
+    /**
+     * [PackageMetadata] of the supplied [PatcherOptions.inputFile].
+     */
+    val packageMetadata = PackageMetadata(ApkInfo(ExtFile(options.inputFile)))
+
+    /**
+     * The map of [Patch]es associated by their [PatchClass].
+     */
+    internal val executablePatches = mutableMapOf<PatchClass, Patch<*>>()
+
+    /**
+     * The map of all [Patch]es and their dependencies associated by their [PatchClass].
+     */
+    internal val allPatches = mutableMapOf<PatchClass, Patch<*>>()
+
+    /**
+     * The [ResourceContext] of this [PatcherContext].
+     * This holds the current state of the resources.
+     */
+    internal val resourceContext = ResourceContext(this, options)
+
+    /**
+     * The [BytecodeContext] of this [PatcherContext].
+     * This holds the current state of the bytecode.
+     */
+    internal val bytecodeContext = BytecodeContext(options)
+}

src/main/kotlin/app/revanced/patcher/PatcherException.kt

@@ -0,0 +1,16 @@
+package app.revanced.patcher
+
+/**
+ * An exception thrown by ReVanced [Patcher].
+ *
+ * @param errorMessage The exception message.
+ * @param cause The corresponding [Throwable].
+ */
+sealed class PatcherException(errorMessage: String?, cause: Throwable?) : Exception(errorMessage, cause) {
+    constructor(errorMessage: String) : this(errorMessage, null)
+
+
+    class CircularDependencyException internal constructor(dependant: String) : PatcherException(
+        "Patch '$dependant' causes a circular dependency"
+    )
+}

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

@@ -0,0 +1,72 @@
+package app.revanced.patcher
+
+import app.revanced.patcher.data.ResourceContext
+import brut.androlib.Config
+import java.io.File
+import java.util.logging.Logger
+
+/**
+ * Options for ReVanced [Patcher].
+ * @param inputFile The input file to patch.
+ * @param resourceCachePath The path to the directory to use for caching resources.
+ * @param aaptBinaryPath The path to a custom aapt binary.
+ * @param frameworkFileDirectory The path to the directory to cache the framework file in.
+ * @param multithreadingDexFileWriter Whether to use multiple threads for writing dex files.
+ * This can impact memory usage.
+ */
+data class PatcherOptions(
+    internal val inputFile: File,
+    internal val resourceCachePath: File = File("revanced-resource-cache"),
+    internal val aaptBinaryPath: String? = null,
+    internal val frameworkFileDirectory: String? = null,
+    internal val multithreadingDexFileWriter: Boolean = false,
+) {
+    private val logger = Logger.getLogger(PatcherOptions::class.java.name)
+
+    /**
+     * The mode to use for resource decoding.
+     * @see ResourceContext.ResourceDecodingMode
+     */
+    internal var resourceDecodingMode = ResourceContext.ResourceDecodingMode.MANIFEST_ONLY
+
+    /**
+     * The configuration to use for resource decoding and compiling.
+     */
+    internal val resourceConfig = Config.getDefaultConfig().apply {
+        useAapt2 = true
+        aaptPath = aaptBinaryPath ?: ""
+        frameworkDirectory = frameworkFileDirectory
+    }
+
+    /**
+     * Options for ReVanced [Patcher].
+     * @param inputFile The input file to patch.
+     * @param resourceCachePath The path to the directory to use for caching resources.
+     * @param aaptBinaryPath The path to a custom aapt binary.
+     * @param frameworkFileDirectory The path to the directory to cache the framework file in.
+     */
+    @Deprecated("Use the constructor with the multithreadingDexFileWriter parameter instead")
+    constructor(
+        inputFile: File,
+        resourceCachePath: File = File("revanced-resource-cache"),
+        aaptBinaryPath: String? = null,
+        frameworkFileDirectory: String? = null,
+    ) : this(
+        inputFile,
+        resourceCachePath,
+        aaptBinaryPath,
+        frameworkFileDirectory,
+        false,
+    )
+
+    fun recreateResourceCacheDirectory() = resourceCachePath.also {
+        if (it.exists()) {
+            logger.info("Deleting existing resource cache directory")
+
+            if (!it.deleteRecursively())
+                logger.severe("Failed to delete existing resource cache directory")
+        }
+
+        it.mkdirs()
+    }
+}

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

@@ -0,0 +1,23 @@
+package app.revanced.patcher
+
+import java.io.File
+import java.io.InputStream
+
+/**
+ * The result of a patcher.
+ * @param dexFiles The patched dex files.
+ * @param resourceFile File containing resources that need to be extracted into the APK.
+ * @param doNotCompress List of relative paths of files to exclude from compressing.
+ */
+data class PatcherResult(
+    val dexFiles: List<PatchedDexFile>,
+    val resourceFile: File?,
+    val doNotCompress: List<String>? = null
+) {
+    /**
+     * Wrapper for dex files.
+     * @param name The original name of the dex file.
+     * @param stream The dex file as [InputStream].
+     */
+    class PatchedDexFile(val name: String, val stream: InputStream)
+}

src/main/kotlin/app/revanced/patcher/PatchesConsumer.kt

@@ -0,0 +1,8 @@
+package app.revanced.patcher
+
+import app.revanced.patcher.patch.Patch
+
+@FunctionalInterface
+interface PatchesConsumer {
+    fun acceptPatches(patches: List<Patch<*>>)
+}

src/main/kotlin/app/revanced/patcher/data/BytecodeContext.kt

@@ -0,0 +1,168 @@
+package app.revanced.patcher.data
+
+import app.revanced.patcher.PatcherContext
+import app.revanced.patcher.PatcherOptions
+import app.revanced.patcher.PatcherResult
+import app.revanced.patcher.patch.Patch
+import app.revanced.patcher.util.ClassMerger.merge
+import app.revanced.patcher.util.ProxyClassList
+import app.revanced.patcher.util.method.MethodWalker
+import app.revanced.patcher.util.proxy.ClassProxy
+import com.android.tools.smali.dexlib2.Opcodes
+import com.android.tools.smali.dexlib2.iface.ClassDef
+import com.android.tools.smali.dexlib2.iface.DexFile
+import com.android.tools.smali.dexlib2.iface.Method
+import lanchon.multidexlib2.BasicDexFileNamer
+import lanchon.multidexlib2.DexIO
+import lanchon.multidexlib2.MultiDexIO
+import java.io.File
+import java.io.FileFilter
+import java.io.Flushable
+import java.util.logging.Logger
+
+/**
+ * A context for bytecode.
+ * This holds the current state of the bytecode.
+ *
+ * @param options The [PatcherOptions] used to create this context.
+ */
+class BytecodeContext internal constructor(private val options: PatcherOptions) :
+    Context<List<PatcherResult.PatchedDexFile>> {
+    private val logger = Logger.getLogger(BytecodeContext::class.java.name)
+
+    /**
+     * [Opcodes] of the supplied [PatcherOptions.inputFile].
+     */
+    internal lateinit var opcodes: Opcodes
+
+    /**
+     * The list of classes.
+     */
+    val classes by lazy {
+        ProxyClassList(
+            MultiDexIO.readDexFile(
+                true, options.inputFile, BasicDexFileNamer(), null, null
+            ).also { opcodes = it.opcodes }.classes.toMutableSet()
+        )
+    }
+
+    /**
+     * The [Integrations] of this [PatcherContext].
+     */
+    internal val integrations = Integrations()
+
+    /**
+     * 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 findClass(className: String) = findClass { 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 findClass(predicate: (ClassDef) -> Boolean) =
+        // if we already proxied the class matching the predicate...
+        classes.proxies.firstOrNull { predicate(it.immutableClass) } ?:
+        // else resolve the class to a proxy and return it, if the predicate is matching a class
+        classes.find(predicate)?.let { proxy(it) }
+
+    /**
+     * Proxy a class.
+     * This will allow the class to be modified.
+     *
+     * @param classDef The class to proxy.
+     * @return A proxy for the class.
+     */
+    fun proxy(classDef: ClassDef) = this.classes.proxies.find { it.immutableClass.type == classDef.type } ?: let {
+        ClassProxy(classDef).also { this.classes.add(it) }
+    }
+
+    /**
+     * Create a [MethodWalker] instance for the current [BytecodeContext].
+     *
+     * @param startMethod The method to start at.
+     * @return A [MethodWalker] instance.
+     */
+    fun toMethodWalker(startMethod: Method) = MethodWalker(this, startMethod)
+
+    /**
+     * Compile bytecode from the [BytecodeContext].
+     *
+     * @return The compiled bytecode.
+     */
+    override fun get(): List<PatcherResult.PatchedDexFile> {
+        logger.info("Compiling patched dex files")
+
+        val patchedDexFileResults = options.resourceCachePath.resolve("dex").also {
+            it.deleteRecursively() // Make sure the directory is empty.
+            it.mkdirs()
+        }.apply {
+            MultiDexIO.writeDexFile(
+                true,
+                if (options.multithreadingDexFileWriter) -1 else 1,
+                this,
+                BasicDexFileNamer(),
+                object : DexFile {
+                    override fun getClasses() = this@BytecodeContext.classes.also(ProxyClassList::replaceClasses)
+                    override fun getOpcodes() = this@BytecodeContext.opcodes
+                },
+                DexIO.DEFAULT_MAX_DEX_POOL_SIZE
+            ) { _, entryName, _ -> logger.info("Compiled $entryName") }
+        }.listFiles(FileFilter { it.isFile })!!.map { PatcherResult.PatchedDexFile(it.name, it.inputStream()) }
+
+        System.gc()
+
+        return patchedDexFileResults
+    }
+
+    /**
+     * The integrations of a [PatcherContext].
+     */
+    internal inner class Integrations : MutableList<File> by mutableListOf(), Flushable {
+        /**
+         * Whether to merge integrations.
+         * Set to true, if the field requiresIntegrations of any supplied [Patch] is true.
+         */
+        var merge = false
+
+        /**
+         * Merge integrations into the [BytecodeContext] and flush all [Integrations].
+         */
+        override fun flush() {
+            if (!merge) return
+
+            logger.info("Merging integrations")
+
+            val classMap = classes.associateBy { it.type }
+
+            this@Integrations.forEach { integrations ->
+                MultiDexIO.readDexFile(
+                    true,
+                    integrations, BasicDexFileNamer(),
+                    null,
+                    null
+                ).classes.forEach classDef@{ classDef ->
+                    val existingClass = classMap[classDef.type] ?: run {
+                        logger.fine("Adding $classDef")
+                        classes.add(classDef)
+                        return@classDef
+                    }
+
+                    logger.fine("$classDef exists. Adding missing methods and fields.")
+
+                    existingClass.merge(classDef, this@BytecodeContext).let { mergedClass ->
+                        // If the class was merged, replace the original class with the merged class.
+                        if (mergedClass === existingClass) return@let
+                        classes.apply { remove(existingClass); add(mergedClass) }
+                    }
+                }
+            }
+            clear()
+        }
+    }
+}

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

@@ -0,0 +1,9 @@
+package app.revanced.patcher.data
+
+import java.util.function.Supplier
+
+/**
+ * A common interface for contexts such as [ResourceContext] and [BytecodeContext].
+ */
+
+sealed interface Context<T> : Supplier<T>

src/main/kotlin/app/revanced/patcher/data/ResourceContext.kt

@@ -0,0 +1,170 @@
+package app.revanced.patcher.data
+
+import app.revanced.patcher.PatcherContext
+import app.revanced.patcher.PatcherOptions
+import app.revanced.patcher.util.DomFileEditor
+import brut.androlib.AaptInvoker
+import brut.androlib.ApkDecoder
+import brut.androlib.apk.UsesFramework
+import brut.androlib.res.Framework
+import brut.androlib.res.ResourcesDecoder
+import brut.androlib.res.decoder.AndroidManifestResourceParser
+import brut.androlib.res.decoder.XmlPullStreamDecoder
+import brut.androlib.res.xml.ResXmlPatcher
+import brut.directory.ExtFile
+import java.io.File
+import java.io.InputStream
+import java.io.OutputStream
+import java.nio.file.Files
+import java.util.logging.Logger
+
+/**
+ * A context for resources.
+ * This holds the current state of the resources.
+ *
+ * @param context The [PatcherContext] to create the context for.
+ */
+class ResourceContext internal constructor(
+    private val context: PatcherContext,
+    private val options: PatcherOptions
+) : Context<File?>, Iterable<File> {
+    private val logger = Logger.getLogger(ResourceContext::class.java.name)
+
+    val xmlEditor = XmlFileHolder()
+
+    /**
+     * Decode resources for the patcher.
+     *
+     * @param mode The [ResourceDecodingMode] to use when decoding.
+     */
+    internal fun decodeResources(mode: ResourceDecodingMode) = with(context.packageMetadata.apkInfo) {
+        // Needed to decode resources.
+        val resourcesDecoder = ResourcesDecoder(options.resourceConfig, this)
+
+        when (mode) {
+            ResourceDecodingMode.FULL -> {
+                val outDir = options.recreateResourceCacheDirectory()
+
+                logger.info("Decoding resources")
+
+                resourcesDecoder.decodeResources(outDir)
+                resourcesDecoder.decodeManifest(outDir)
+
+                // Needed to record uncompressed files.
+                val apkDecoder = ApkDecoder(options.resourceConfig, this)
+                apkDecoder.recordUncompressedFiles(resourcesDecoder.resFileMapping)
+
+                usesFramework = UsesFramework().apply {
+                    ids = resourcesDecoder.resTable.listFramePackages().map { it.id }
+                }
+            }
+
+            ResourceDecodingMode.MANIFEST_ONLY -> {
+                logger.info("Decoding app manifest")
+
+                // Decode manually instead of using resourceDecoder.decodeManifest
+                // because it does not support decoding to an OutputStream.
+                XmlPullStreamDecoder(
+                    AndroidManifestResourceParser(resourcesDecoder.resTable),
+                    resourcesDecoder.resXmlSerializer
+                ).decodeManifest(
+                    apkFile.directory.getFileInput("AndroidManifest.xml"),
+                    // Older Android versions do not support OutputStream.nullOutputStream()
+                    object : OutputStream() {
+                        override fun write(b: Int) { /* do nothing */
+                        }
+                    }
+                )
+
+                // Get the package name and version from the manifest using the XmlPullStreamDecoder.
+                // XmlPullStreamDecoder.decodeManifest() sets metadata.apkInfo.
+                context.packageMetadata.let { metadata ->
+                    metadata.packageName = resourcesDecoder.resTable.packageRenamed
+                    versionInfo.let {
+                        metadata.packageVersion = it.versionName ?: it.versionCode
+                    }
+
+                    /*
+                     The ResTable if flagged as sparse if the main package is not loaded, which is the case here,
+                     because ResourcesDecoder.decodeResources loads the main package
+                     and not XmlPullStreamDecoder.decodeManifest.
+                     See ARSCDecoder.readTableType for more info.
+
+                     Set this to false again to prevent the ResTable from being flagged as sparse falsely.
+                     */
+                    metadata.apkInfo.sparseResources = false
+                }
+            }
+        }
+
+    }
+
+    operator fun get(path: String) = options.resourceCachePath.resolve(path)
+
+    override fun iterator() = options.resourceCachePath.walkTopDown().iterator()
+
+
+    /**
+     * Compile resources from the [ResourceContext].
+     *
+     * @return The compiled resources.
+     */
+    override fun get(): File? {
+        var resourceFile: File? = null
+
+        if (options.resourceDecodingMode == ResourceDecodingMode.FULL) {
+            logger.info("Compiling modified resources")
+
+            val cacheDirectory = ExtFile(options.resourceCachePath)
+            val aaptFile = cacheDirectory.resolve("aapt_temp_file").also {
+                Files.deleteIfExists(it.toPath())
+            }.also { resourceFile = it }
+
+            try {
+                AaptInvoker(
+                    options.resourceConfig, context.packageMetadata.apkInfo
+                ).invokeAapt(aaptFile,
+                    cacheDirectory.resolve("AndroidManifest.xml").also {
+                        ResXmlPatcher.fixingPublicAttrsInProviderAttributes(it)
+                    },
+                    cacheDirectory.resolve("res"),
+                    null,
+                    null,
+                    context.packageMetadata.apkInfo.usesFramework.let { usesFramework ->
+                        usesFramework.ids.map { id ->
+                            Framework(options.resourceConfig).getFrameworkApk(id, usesFramework.tag)
+                        }.toTypedArray()
+                    })
+            } finally {
+                cacheDirectory.close()
+            }
+        }
+
+        return resourceFile
+    }
+
+    /**
+     * The type of decoding the resources.
+     */
+    internal enum class ResourceDecodingMode {
+        /**
+         * Decode all resources.
+         */
+        FULL,
+
+        /**
+         * Decode the manifest file only.
+         */
+        MANIFEST_ONLY,
+    }
+
+    inner class XmlFileHolder {
+        operator fun get(inputStream: InputStream) =
+            DomFileEditor(inputStream)
+
+        operator fun get(path: String): DomFileEditor {
+            return DomFileEditor(this@ResourceContext[path])
+        }
+
+    }
+}

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())
+    }
+}

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 com.android.tools.smali.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

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

@@ -0,0 +1,330 @@
+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 com.android.tools.smali.dexlib2.builder.BuilderInstruction
+import com.android.tools.smali.dexlib2.builder.BuilderOffsetInstruction
+import com.android.tools.smali.dexlib2.builder.Label
+import com.android.tools.smali.dexlib2.builder.MutableMethodImplementation
+import com.android.tools.smali.dexlib2.builder.instruction.*
+import com.android.tools.smali.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.
+     */
+    fun <T> MutableMethod.getInstruction(index: Int): T = implementation!!.getInstruction<T>(index)
+
+    /**
+     * Get the instructions of a method.
+     * @return The instructions.
+     */
+    fun MutableMethod.getInstructions(): MutableList<BuilderInstruction> = implementation!!.instructions
+}

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

@@ -0,0 +1,14 @@
+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 {
+    // TODO: Make this a property.
+    /**
+     * The [FuzzyPatternScanMethod] annotation of a [MethodFingerprint].
+     */
+    val MethodFingerprint.fuzzyPatternScanMethod
+        get() = javaClass.findAnnotationRecursively(FuzzyPatternScanMethod::class)
+}

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

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
+)

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.data.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 com.android.tools.smali.dexlib2.AccessFlags
+import com.android.tools.smali.dexlib2.Opcode
+import com.android.tools.smali.dexlib2.iface.ClassDef
+import com.android.tools.smali.dexlib2.iface.Method
+import com.android.tools.smali.dexlib2.iface.instruction.Instruction
+import com.android.tools.smali.dexlib2.iface.instruction.ReferenceInstruction
+import com.android.tools.smali.dexlib2.iface.reference.StringReference
+import com.android.tools.smali.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()) clearFingerprintResolutionLookupMaps()
+
+            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 Set<MethodFingerprint>.resolveUsingLookupMap(context: BytecodeContext) {
+            if (methods.isEmpty()) throw PatchException("lookup map not initialized")
+
+            forEach { fingerprint ->
+                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.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,
+            )
+        }
+    }
+}

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

@@ -0,0 +1,9 @@
+package app.revanced.patcher.logging
+
+@Deprecated("This will be removed in a future release")
+interface Logger {
+    fun error(msg: String) {}
+    fun warn(msg: String) {}
+    fun info(msg: String) {}
+    fun trace(msg: String) {}
+}

src/main/kotlin/app/revanced/patcher/logging/impl/NopLogger.kt

@@ -0,0 +1,6 @@
+package app.revanced.patcher.logging.impl
+
+import app.revanced.patcher.logging.Logger
+
+@Deprecated("This will be removed in a future release")
+object NopLogger : Logger

src/main/kotlin/app/revanced/patcher/patch/BytecodePatch.kt

@@ -0,0 +1,13 @@
+package app.revanced.patcher.patch
+
+import app.revanced.patcher.data.BytecodeContext
+import app.revanced.patcher.fingerprint.method.impl.MethodFingerprint
+
+/**
+ * A ReVanced [Patch] that works on [BytecodeContext].
+ *
+ * @param fingerprints A list of [MethodFingerprint]s which will be resolved before the patch is executed.
+ */
+abstract class BytecodePatch(
+    internal val fingerprints : Set<MethodFingerprint> = emptySet(),
+) : Patch<BytecodeContext>()

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

@@ -0,0 +1,106 @@
+@file:Suppress("MemberVisibilityCanBePrivate")
+
+package app.revanced.patcher.patch
+
+import app.revanced.patcher.PatchClass
+import app.revanced.patcher.Patcher
+import app.revanced.patcher.data.Context
+import app.revanced.patcher.patch.options.PatchOptions
+import java.io.Closeable
+import kotlin.reflect.full.findAnnotation
+
+/**
+ * A ReVanced patch.
+ * If an implementation of [Patch] also implements [Closeable]
+ * it will be closed in reverse execution order of patches executed by ReVanced [Patcher].
+ *
+ * @param T The [Context] type this patch will work on.
+ */
+sealed class Patch<out T : Context<*>> {
+    /**
+     * The name of the patch.
+     */
+    var name: String? = null
+        private set
+
+    /**
+     * The description of the patch.
+     */
+    var description: String? = null
+        private set
+
+    /**
+     * The packages the patch is compatible with.
+     */
+    var compatiblePackages: Set<CompatiblePackage>? = null
+        private set
+
+    /**
+     * Other patches this patch depends on.
+     */
+    var dependencies: Set<PatchClass>? = null
+        private set
+
+    /**
+     * Weather or not the patch should be used.
+     */
+    var use = true
+        private set
+
+
+    // TODO: Remove this property, once integrations are coupled with patches.
+    /**
+     * Weather or not the patch requires integrations.
+     */
+    var requiresIntegrations = false
+        private set
+
+    /**
+     * The options of the patch associated by the options key.
+     */
+    val options = PatchOptions()
+
+    init {
+        this::class.findAnnotation<app.revanced.patcher.patch.annotation.Patch>()?.let { annotation ->
+            name = annotation.name.ifEmpty { null }
+            description = annotation.description.ifEmpty { null }
+            compatiblePackages = annotation.compatiblePackages
+                .map { CompatiblePackage(it.name, it.versions.toSet()) }.toSet()
+            dependencies = annotation.dependencies.toSet().ifEmpty { null }
+            use = annotation.use
+            requiresIntegrations = annotation.requiresIntegrations
+        }
+    }
+
+    /**
+     * The execution function of the patch.
+     *
+     * @param context The [Context] the patch will work on.
+     * @return The result of executing the patch.
+     */
+    abstract fun execute(context: @UnsafeVariance T)
+
+    override fun hashCode() = name.hashCode()
+
+    override fun toString() = name ?: this::class.simpleName ?: "Unnamed patch"
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (javaClass != other?.javaClass) return false
+
+        other as Patch<*>
+
+        return name == other.name
+    }
+
+    /**
+     * A package a [Patch] is compatible with.
+     *
+     * @param name The name of the package.
+     * @param versions The versions of the package.
+     */
+    class CompatiblePackage(
+        val name: String,
+        val versions: Set<String>? = null,
+    )
+}

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)
+}

src/main/kotlin/app/revanced/patcher/patch/PatchResult.kt

@@ -0,0 +1,9 @@
+package app.revanced.patcher.patch
+
+/**
+ * A result of executing a [Patch].
+ *
+ * @param patch The [Patch] that was executed.
+ * @param exception The [PatchException] thrown, if any.
+ */
+class PatchResult internal constructor(val patch: Patch<*>, val exception: PatchException? = null)

src/main/kotlin/app/revanced/patcher/patch/ResourcePatch.kt

@@ -0,0 +1,8 @@
+package app.revanced.patcher.patch
+
+import app.revanced.patcher.data.ResourceContext
+
+/**
+ * A ReVanced [Patch] that works on [ResourceContext].
+ */
+abstract class ResourcePatch : Patch<ResourceContext>()

src/main/kotlin/app/revanced/patcher/patch/annotation/PatchAnnotations.kt

@@ -0,0 +1,37 @@
+package app.revanced.patcher.patch.annotation
+
+import java.lang.annotation.Inherited
+import kotlin.reflect.KClass
+
+/**
+ * Annotation for [app.revanced.patcher.patch.Patch] classes.
+ *
+ * @param name The name of the patch. If empty, the patch will be unnamed.
+ * @param description The description of the patch. If empty, no description will be used.
+ * @param dependencies The patches this patch depends on.
+ * @param compatiblePackages The packages this patch is compatible with.
+ * @param use Whether this patch should be used.
+ * @param requiresIntegrations Whether this patch requires integrations.
+ */
+@Target(AnnotationTarget.CLASS)
+@Inherited
+annotation class Patch(
+    val name: String = "",
+    val description: String = "",
+    val dependencies: Array<KClass<out app.revanced.patcher.patch.Patch<*>>> = [],
+    val compatiblePackages: Array<CompatiblePackage> = [],
+    val use: Boolean = true,
+    // TODO: Remove this property, once integrations are coupled with patches.
+    val requiresIntegrations: Boolean = false,
+)
+
+/**
+ * A package that a [app.revanced.patcher.patch.Patch] is compatible with.
+ *
+ * @param name The name of the package.
+ * @param versions The versions of the package.
+ */
+annotation class CompatiblePackage(
+    val name: String,
+    val versions: Array<String> = [],
+)

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

@@ -0,0 +1,40 @@
+package app.revanced.patcher.patch.options
+
+import app.revanced.patcher.patch.Patch
+import kotlin.reflect.KProperty
+
+/**
+ * A [Patch] option.
+ * @param key The identifier.
+ * @param default The default value.
+ * @param title The title.
+ * @param description A description.
+ * @param required Whether the option is required.
+ * @param validate The function to validate values of the option.
+ * @param T The value type of the option.
+ */
+abstract class PatchOption<T>(
+    val key: String,
+    default: T?,
+    val title: String?,
+    val description: String?,
+    val required: Boolean,
+    val validate: (T?) -> Boolean
+) {
+    /**
+     * The value of the [PatchOption].
+     */
+    var value: T? = default
+        set(value) {
+            if (required && value == null) throw PatchOptionException.ValueRequiredException(this)
+            if (!validate(value)) throw PatchOptionException.ValueValidationException(value, this)
+
+            field = value
+        }
+
+    operator fun getValue(thisRef: Any?, property: KProperty<*>) = value
+
+    operator fun setValue(thisRef: Any?, property: KProperty<*>, value: T?) {
+        this.value = value
+    }
+}

src/main/kotlin/app/revanced/patcher/patch/options/PatchOptionException.kt

@@ -0,0 +1,41 @@
+package app.revanced.patcher.patch.options
+
+/**
+ * An exception thrown when using [PatchOption]s.
+ *
+ * @param errorMessage The exception message.
+ */
+sealed class PatchOptionException(errorMessage: String) : Exception(errorMessage, null) {
+    /**
+     * An exception thrown when a [PatchOption] is set to an invalid value.
+     *
+     * @param invalidType The type of the value that was passed.
+     * @param expectedType The type of the value that was expected.
+     */
+    class InvalidValueTypeException(invalidType: String, expectedType: String) :
+        PatchOptionException("Type $expectedType was expected but received type $invalidType")
+
+    /**
+     * An exception thrown when a value did not satisfy the value conditions specified by the [PatchOption].
+     *
+     * @param value The value that failed validation.
+     */
+    class ValueValidationException(value: Any?, option: PatchOption<*>) :
+        PatchOptionException("The option value \"$value\" failed validation for ${option.key}")
+
+    /**
+     * An exception thrown when a value is required but null was passed.
+     *
+     * @param option The [PatchOption] that requires a value.
+     */
+    class ValueRequiredException(option: PatchOption<*>) :
+        PatchOptionException("The option ${option.key} requires a value, but null was passed")
+
+    /**
+     * An exception thrown when a [PatchOption] is not found.
+     *
+     * @param key The key of the [PatchOption].
+     */
+    class PatchOptionNotFoundException(key: String)
+        : PatchOptionException("No option with key $key")
+}

src/main/kotlin/app/revanced/patcher/patch/options/PatchOptions.kt

@@ -0,0 +1,45 @@
+package app.revanced.patcher.patch.options
+
+
+/**
+ * A map of [PatchOption]s associated by their keys.
+ *
+ * @param options The [PatchOption]s to initialize with.
+ */
+class PatchOptions internal constructor(
+    private val options: MutableMap<String, PatchOption<*>> = mutableMapOf()
+) : MutableMap<String, PatchOption<*>> by options {
+    /**
+     * Register a [PatchOption]. Acts like [MutableMap.put].
+     * @param value The [PatchOption] to register.
+     */
+    fun register(value: PatchOption<*>) {
+        options[value.key] = value
+    }
+
+    /**
+     * Set an option's value.
+     * @param key The identifier.
+     * @param value The value.
+     * @throws PatchOptionException.PatchOptionNotFoundException If the option does not exist.
+     */
+    operator fun <T : Any> set(key: String, value: T?) {
+        val option = this[key]
+
+        try {
+            @Suppress("UNCHECKED_CAST")
+            (option as PatchOption<T>).value = value
+        } catch (e: ClassCastException) {
+            throw PatchOptionException.InvalidValueTypeException(
+                value?.let { it::class.java.name } ?: "null",
+                option.value?.let { it::class.java.name } ?: "null",
+            )
+        }
+    }
+
+    /**
+     * Get an option.
+     */
+    override operator fun get(key: String) =
+        options[key] ?: throw PatchOptionException.PatchOptionNotFoundException(key)
+}

src/main/kotlin/app/revanced/patcher/patch/options/types/BooleanPatchOption.kt

@@ -0,0 +1,48 @@
+package app.revanced.patcher.patch.options.types
+
+import app.revanced.patcher.patch.Patch
+import app.revanced.patcher.patch.options.PatchOption
+
+/**
+ * A [PatchOption] representing a [Boolean].
+ *
+ * @param key The identifier.
+ * @param default The default value.
+ * @param title The title.
+ * @param description A description.
+ * @param required Whether the option is required.
+ *
+ * @see PatchOption
+ */
+class BooleanPatchOption private constructor(
+    key: String,
+    default: Boolean?,
+    title: String?,
+    description: String?,
+    required: Boolean,
+    validator: (Boolean?) -> Boolean
+) : PatchOption<Boolean>(key, default, title, description, required, validator) {
+    companion object {
+        /**
+         * Create a new [BooleanPatchOption] and add it to the current [Patch].
+         *
+         * @param key The identifier.
+         * @param default The default value.
+         * @param title The title.
+         * @param description A description.
+         * @param required Whether the option is required.
+         * @return The created [BooleanPatchOption].
+         *
+         * @see BooleanPatchOption
+         * @see PatchOption
+         */
+        fun <T : Patch<*>> T.booleanPatchOption(
+            key: String,
+            default: Boolean? = null,
+            title: String? = null,
+            description: String? = null,
+            required: Boolean = false,
+            validator: (Boolean?) -> Boolean = { true }
+        ) = BooleanPatchOption(key, default, title, description, required, validator).also  { options.register(it) }
+    }
+}

src/main/kotlin/app/revanced/patcher/patch/options/types/FloatPatchOption.kt

@@ -0,0 +1,48 @@
+package app.revanced.patcher.patch.options.types
+
+import app.revanced.patcher.patch.Patch
+import app.revanced.patcher.patch.options.PatchOption
+
+/**
+ * A [PatchOption] representing a [Float].
+ *
+ * @param key The identifier.
+ * @param default The default value.
+ * @param title The title.
+ * @param description A description.
+ * @param required Whether the option is required.
+ *
+ * @see PatchOption
+ */
+class FloatPatchOption private constructor(
+    key: String,
+    default: Float?,
+    title: String?,
+    description: String?,
+    required: Boolean,
+    validator: (Float?) -> Boolean
+) : PatchOption<Float>(key, default, title, description, required, validator) {
+    companion object {
+        /**
+         * Create a new [FloatPatchOption] and add it to the current [Patch].
+         *
+         * @param key The identifier.
+         * @param default The default value.
+         * @param title The title.
+         * @param description A description.
+         * @param required Whether the option is required.
+         * @return The created [FloatPatchOption].
+         *
+         * @see FloatPatchOption
+         * @see PatchOption
+         */
+        fun <T : Patch<*>> T.floatPatchOption(
+            key: String,
+            default: Float? = null,
+            title: String? = null,
+            description: String? = null,
+            required: Boolean = false,
+            validator: (Float?) -> Boolean = { true }
+        ) = FloatPatchOption(key, default, title, description, required, validator).also  { options.register(it) }
+    }
+}

src/main/kotlin/app/revanced/patcher/patch/options/types/IntPatchOption.kt

@@ -0,0 +1,48 @@
+package app.revanced.patcher.patch.options.types
+
+import app.revanced.patcher.patch.Patch
+import app.revanced.patcher.patch.options.PatchOption
+
+/**
+ * A [PatchOption] representing an [Integer].
+ *
+ * @param key The identifier.
+ * @param default The default value.
+ * @param title The title.
+ * @param description A description.
+ * @param required Whether the option is required.
+ *
+ * @see PatchOption
+ */
+class IntPatchOption private constructor(
+    key: String,
+    default: Int?,
+    title: String?,
+    description: String?,
+    required: Boolean,
+    validator: (Int?) -> Boolean
+) : PatchOption<Int>(key, default, title, description, required, validator) {
+    companion object {
+        /**
+         * Create a new [IntPatchOption] and add it to the current [Patch].
+         *
+         * @param key The identifier.
+         * @param default The default value.
+         * @param title The title.
+         * @param description A description.
+         * @param required Whether the option is required.
+         * @return The created [IntPatchOption].
+         *
+         * @see IntPatchOption
+         * @see PatchOption
+         */
+        fun <T : Patch<*>> T.intPatchOption(
+            key: String,
+            default: Int? = null,
+            title: String? = null,
+            description: String? = null,
+            required: Boolean = false,
+            validator: (Int?) -> Boolean = { true }
+        ) = IntPatchOption(key, default, title, description, required, validator).also  { options.register(it) }
+    }
+}

src/main/kotlin/app/revanced/patcher/patch/options/types/LongPatchOption.kt

@@ -0,0 +1,48 @@
+package app.revanced.patcher.patch.options.types
+
+import app.revanced.patcher.patch.Patch
+import app.revanced.patcher.patch.options.PatchOption
+
+/**
+ * A [PatchOption] representing a [Long].
+ *
+ * @param key The identifier.
+ * @param default The default value.
+ * @param title The title.
+ * @param description A description.
+ * @param required Whether the option is required.
+ *
+ * @see PatchOption
+ */
+class LongPatchOption private constructor(
+    key: String,
+    default: Long?,
+    title: String?,
+    description: String?,
+    required: Boolean,
+    validator: (Long?) -> Boolean
+) : PatchOption<Long>(key, default, title, description, required, validator) {
+    companion object {
+        /**
+         * Create a new [LongPatchOption] and add it to the current [Patch].
+         *
+         * @param key The identifier.
+         * @param default The default value.
+         * @param title The title.
+         * @param description A description.
+         * @param required Whether the option is required.
+         * @return The created [LongPatchOption].
+         *
+         * @see LongPatchOption
+         * @see PatchOption
+         */
+        fun <T : Patch<*>> T.longPatchOption(
+            key: String,
+            default: Long? = null,
+            title: String? = null,
+            description: String? = null,
+            required: Boolean = false,
+            validator: (Long?) -> Boolean = { true }
+        ) = LongPatchOption(key, default, title, description, required, validator).also { options.register(it) }
+    }
+}

src/main/kotlin/app/revanced/patcher/patch/options/types/StringPatchOption.kt

@@ -0,0 +1,48 @@
+package app.revanced.patcher.patch.options.types
+
+import app.revanced.patcher.patch.Patch
+import app.revanced.patcher.patch.options.PatchOption
+
+/**
+ * A [PatchOption] representing a [String].
+ *
+ * @param key The identifier.
+ * @param default The default value.
+ * @param title The title.
+ * @param description A description.
+ * @param required Whether the option is required.
+ *
+ * @see PatchOption
+ */
+class StringPatchOption private constructor(
+    key: String,
+    default: String?,
+    title: String?,
+    description: String?,
+    required: Boolean,
+    validator: (String?) -> Boolean
+) : PatchOption<String>(key, default, title, description, required, validator) {
+    companion object {
+        /**
+         * Create a new [StringPatchOption] and add it to the current [Patch].
+         *
+         * @param key The identifier.
+         * @param default The default value.
+         * @param title The title.
+         * @param description A description.
+         * @param required Whether the option is required.
+         * @return The created [StringPatchOption].
+         *
+         * @see StringPatchOption
+         * @see PatchOption
+         */
+        fun <T : Patch<*>> T.stringPatchOption(
+            key: String,
+            default: String? = null,
+            title: String? = null,
+            description: String? = null,
+            required: Boolean = false,
+            validator: (String?) -> Boolean = { true }
+        ) = StringPatchOption(key, default, title, description, required, validator).also  { options.register(it) }
+    }
+}

src/main/kotlin/app/revanced/patcher/patch/options/types/array/BooleanArrayPatchOption.kt

@@ -0,0 +1,48 @@
+package app.revanced.patcher.patch.options.types.array
+
+import app.revanced.patcher.patch.Patch
+import app.revanced.patcher.patch.options.PatchOption
+
+/**
+ * A [PatchOption] representing a [Boolean] array.
+ *
+ * @param key The identifier.
+ * @param default The default value.
+ * @param title The title.
+ * @param description A description.
+ * @param required Whether the option is required.
+ *
+ * @see PatchOption
+ */
+class BooleanArrayPatchOption private constructor(
+    key: String,
+    default: Array<Boolean>?,
+    title: String?,
+    description: String?,
+    required: Boolean,
+    validator: (Array<Boolean>?) -> Boolean
+) : PatchOption<Array<Boolean>>(key, default, title, description, required, validator) {
+    companion object {
+        /**
+         * Create a new [BooleanArrayPatchOption] and add it to the current [Patch].
+         *
+         * @param key The identifier.
+         * @param default The default value.
+         * @param title The title.
+         * @param description A description.
+         * @param required Whether the option is required.
+         * @return The created [BooleanArrayPatchOption].
+         *
+         * @see BooleanArrayPatchOption
+         * @see PatchOption
+         */
+        fun <T : Patch<*>> T.booleanArrayPatchOption(
+            key: String,
+            default: Array<Boolean>? = null,
+            title: String? = null,
+            description: String? = null,
+            required: Boolean = false,
+            validator: (Array<Boolean>?) -> Boolean = { true }
+        ) = BooleanArrayPatchOption(key, default, title, description, required, validator).also  { options.register(it) }
+    }
+}

src/main/kotlin/app/revanced/patcher/patch/options/types/array/FloatArrayPatchOption.kt

@@ -0,0 +1,48 @@
+package app.revanced.patcher.patch.options.types.array
+
+import app.revanced.patcher.patch.Patch
+import app.revanced.patcher.patch.options.PatchOption
+
+/**
+ * A [PatchOption] representing a [Float] array.
+ *
+ * @param key The identifier.
+ * @param default The default value.
+ * @param title The title.
+ * @param description A description.
+ * @param required Whether the option is required.
+ *
+ * @see PatchOption
+ */
+class FloatArrayPatchOption private constructor(
+    key: String,
+    default: Array<Float>?,
+    title: String?,
+    description: String?,
+    required: Boolean,
+    validator: (Array<Float>?) -> Boolean
+) : PatchOption<Array<Float>>(key, default, title, description, required, validator) {
+    companion object {
+        /**
+         * Create a new [FloatArrayPatchOption] and add it to the current [Patch].
+         *
+         * @param key The identifier.
+         * @param default The default value.
+         * @param title The title.
+         * @param description A description.
+         * @param required Whether the option is required.
+         * @return The created [FloatArrayPatchOption].
+         *
+         * @see FloatArrayPatchOption
+         * @see PatchOption
+         */
+        fun <T : Patch<*>> T.floatArrayPatchOption(
+            key: String,
+            default: Array<Float>? = null,
+            title: String? = null,
+            description: String? = null,
+            required: Boolean = false,
+            validator: (Array<Float>?) -> Boolean = { true }
+        ) = FloatArrayPatchOption(key, default, title, description, required, validator).also  { options.register(it) }
+    }
+}

src/main/kotlin/app/revanced/patcher/patch/options/types/array/IntArrayPatchOption.kt

@@ -0,0 +1,48 @@
+package app.revanced.patcher.patch.options.types.array
+
+import app.revanced.patcher.patch.Patch
+import app.revanced.patcher.patch.options.PatchOption
+
+/**
+ * A [PatchOption] representing an [Integer] array.
+ *
+ * @param key The identifier.
+ * @param default The default value.
+ * @param title The title.
+ * @param description A description.
+ * @param required Whether the option is required.
+ *
+ * @see PatchOption
+ */
+class IntArrayPatchOption private constructor(
+    key: String,
+    default: Array<Int>?,
+    title: String?,
+    description: String?,
+    required: Boolean,
+    validator: (Array<Int>?) -> Boolean
+) : PatchOption<Array<Int>>(key, default, title, description, required, validator) {
+    companion object {
+        /**
+         * Create a new [IntArrayPatchOption] and add it to the current [Patch].
+         *
+         * @param key The identifier.
+         * @param default The default value.
+         * @param title The title.
+         * @param description A description.
+         * @param required Whether the option is required.
+         * @return The created [IntArrayPatchOption].
+         *
+         * @see IntArrayPatchOption
+         * @see PatchOption
+         */
+        fun <T : Patch<*>> T.intArrayPatchOption(
+            key: String,
+            default: Array<Int>? = null,
+            title: String? = null,
+            description: String? = null,
+            required: Boolean = false,
+            validator: (Array<Int>?) -> Boolean = { true }
+        ) = IntArrayPatchOption(key, default, title, description, required, validator).also { options.register(it) }
+    }
+}

src/main/kotlin/app/revanced/patcher/patch/options/types/array/LongArrayPatchOption.kt

@@ -0,0 +1,48 @@
+package app.revanced.patcher.patch.options.types.array
+
+import app.revanced.patcher.patch.Patch
+import app.revanced.patcher.patch.options.PatchOption
+
+/**
+ * A [PatchOption] representing a [Long] array.
+ *
+ * @param key The identifier.
+ * @param default The default value.
+ * @param title The title.
+ * @param description A description.
+ * @param required Whether the option is required.
+ *
+ * @see PatchOption
+ */
+class LongArrayPatchOption private constructor(
+    key: String,
+    default: Array<Long>?,
+    title: String?,
+    description: String?,
+    required: Boolean,
+    validator: (Array<Long>?) -> Boolean
+) : PatchOption<Array<Long>>(key, default, title, description, required, validator) {
+    companion object {
+        /**
+         * Create a new [LongArrayPatchOption] and add it to the current [Patch].
+         *
+         * @param key The identifier.
+         * @param default The default value.
+         * @param title The title.
+         * @param description A description.
+         * @param required Whether the option is required.
+         * @return The created [LongArrayPatchOption].
+         *
+         * @see LongArrayPatchOption
+         * @see PatchOption
+         */
+        fun <T : Patch<*>> T.longArrayPatchOption(
+            key: String,
+            default: Array<Long>? = null,
+            title: String? = null,
+            description: String? = null,
+            required: Boolean = false,
+            validator: (Array<Long>?) -> Boolean = { true }
+        ) = LongArrayPatchOption(key, default, title, description, required, validator).also  { options.register(it) }
+    }
+}

src/main/kotlin/app/revanced/patcher/patch/options/types/array/StringArrayPatchOption.kt

@@ -0,0 +1,48 @@
+package app.revanced.patcher.patch.options.types.array
+
+import app.revanced.patcher.patch.Patch
+import app.revanced.patcher.patch.options.PatchOption
+
+/**
+ * A [PatchOption] representing a [String] array.
+ *
+ * @param key The identifier.
+ * @param default The default value.
+ * @param title The title.
+ * @param description A description.
+ * @param required Whether the option is required.
+ *
+ * @see PatchOption
+ */
+class StringArrayPatchOption private constructor(
+    key: String,
+    default: Array<String>?,
+    title: String?,
+    description: String?,
+    required: Boolean,
+    validator: (Array<String>?) -> Boolean
+) : PatchOption<Array<String>>(key, default, title, description, required, validator) {
+    companion object {
+        /**
+         * Create a new [StringArrayPatchOption] and add it to the current [Patch].
+         *
+         * @param key The identifier.
+         * @param default The default value.
+         * @param title The title.
+         * @param description A description.
+         * @param required Whether the option is required.
+         * @return The created [StringArrayPatchOption].
+         *
+         * @see StringArrayPatchOption
+         * @see PatchOption
+         */
+        fun <T : Patch<*>> T.stringArrayPatchOption(
+            key: String,
+            default: Array<String>? = null,
+            title: String? = null,
+            description: String? = null,
+            required: Boolean = false,
+            validator: (Array<String>?) -> Boolean = { true }
+        ) = StringArrayPatchOption(key, default, title, description, required, validator).also { options.register(it) }
+    }
+}

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

@@ -0,0 +1,222 @@
+package app.revanced.patcher.util
+
+import app.revanced.patcher.data.BytecodeContext
+import app.revanced.patcher.extensions.or
+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.ClassMerger.Utils.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 com.android.tools.smali.dexlib2.AccessFlags
+import com.android.tools.smali.dexlib2.iface.ClassDef
+import com.android.tools.smali.dexlib2.util.MethodUtil
+import java.util.logging.Logger
+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 {
+    private val logger = Logger.getLogger(ClassMerger::class.java.name)
+
+    /**
+     * Merge a class with [otherClass].
+     *
+     * @param otherClass The class to merge with
+     * @param context The context to traverse the class hierarchy in.
+     * @return The merged class or the original class if no merge was needed.
+     */
+    fun ClassDef.merge(otherClass: ClassDef, context: BytecodeContext) = this
+        //.fixFieldAccess(otherClass)
+        //.fixMethodAccess(otherClass)
+        .addMissingFields(otherClass)
+        .addMissingMethods(otherClass)
+        .publicize(otherClass, context)
+
+    /**
+     * Add methods which are missing but existing in [fromClass].
+     *
+     * @param fromClass The class to add missing methods from.
+     */
+    private fun ClassDef.addMissingMethods(fromClass: ClassDef): ClassDef {
+        val missingMethods = fromClass.methods.let { fromMethods ->
+            methods.filterNot { method ->
+                fromMethods.any { fromMethod ->
+                    MethodUtil.methodSignaturesMatch(fromMethod, method)
+                }
+            }
+        }
+
+        if (missingMethods.isEmpty()) return this
+
+        logger.fine("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.
+     */
+    private fun ClassDef.addMissingFields(fromClass: ClassDef): ClassDef {
+        val missingFields = fields.filterNotAny(fromClass.fields) { field, fromField ->
+            fromField.name == field.name
+        }
+
+        if (missingFields.isEmpty()) return this
+
+        logger.fine("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.
+     */
+    private fun ClassDef.publicize(reference: ClassDef, context: BytecodeContext) =
+        if (reference.accessFlags.isPublic() && !accessFlags.isPublic())
+            this.asMutableClass().apply {
+                context.traverseClassHierarchy(this) {
+                    if (accessFlags.isPublic()) return@traverseClassHierarchy
+
+                    logger.fine("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.
+     */
+    private fun ClassDef.fixFieldAccess(reference: ClassDef): 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.fine("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.
+     */
+    private fun ClassDef.fixMethodAccess(reference: ClassDef): 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.fine("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 {
+        /**
+         * traverse the class hierarchy starting from the given root class
+         *
+         * @param targetClass the class to start traversing the class hierarchy from
+         * @param callback function that is called for every class in the hierarchy
+         */
+        fun BytecodeContext.traverseClassHierarchy(targetClass: MutableClass, callback: MutableClass.() -> Unit) {
+            callback(targetClass)
+            this.findClass(targetClass.superclass ?: return)?.mutableClass?.let {
+                traverseClassHierarchy(it, callback)
+            }
+        }
+
+        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 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 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)
+            }
+        }
+    }
+}

src/main/kotlin/app/revanced/patcher/util/DomFileEditor.kt

@@ -0,0 +1,87 @@
+package app.revanced.patcher.util
+
+import org.w3c.dom.Document
+import java.io.Closeable
+import java.io.File
+import java.io.InputStream
+import java.io.OutputStream
+import javax.xml.parsers.DocumentBuilderFactory
+import javax.xml.transform.TransformerFactory
+import javax.xml.transform.dom.DOMSource
+import javax.xml.transform.stream.StreamResult
+
+/**
+ * Wrapper for a file that can be edited as a dom document.
+ *
+ * This constructor does not check for locks to the file when writing.
+ * Use the secondary constructor.
+ *
+ * @param inputStream the input stream to read the xml file from.
+ * @param outputStream the output stream to write the xml file to. If null, the file will be read only.
+ *
+ */
+class DomFileEditor internal constructor(
+    private val inputStream: InputStream,
+    private val outputStream: Lazy<OutputStream>? = null,
+) : Closeable {
+    // path to the xml file to unlock the resource when closing the editor
+    private var filePath: String? = null
+    private var closed: Boolean = false
+
+    /**
+     * The document of the xml file
+     */
+    val file: Document = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(inputStream)
+        .also(Document::normalize)
+
+
+    // lazily open an output stream
+    // this is required because when constructing a DomFileEditor the output stream is created along with the input stream, which is not allowed
+    // the workaround is to lazily create the output stream. This way it would be used after the input stream is closed, which happens in the constructor
+    constructor(file: File) : this(file.inputStream(), lazy { file.outputStream() }) {
+        // increase the lock
+        locks.merge(file.path, 1, Integer::sum)
+        filePath = file.path
+    }
+
+    /**
+     * Closes the editor. Write backs and decreases the lock count.
+     *
+     * Will not write back to the file if the file is still locked.
+     */
+    override fun close() {
+        if (closed) return
+
+        inputStream.close()
+
+        // if the output stream is not null, do not close it
+        outputStream?.let {
+            // prevent writing to same file, if it is being locked
+            // isLocked will be false if the editor was created through a stream
+            val isLocked = filePath?.let { path ->
+                val isLocked = locks[path]!! > 1
+                // decrease the lock count if the editor was opened for a file
+                locks.merge(path, -1, Integer::sum)
+                isLocked
+            } ?: false
+
+            // if unlocked, write back to the file
+            if (!isLocked) {
+                it.value.use { stream ->
+                    val result = StreamResult(stream)
+                    TransformerFactory.newInstance().newTransformer().transform(DOMSource(file), result)
+                }
+
+                it.value.close()
+                return
+            }
+        }
+
+        closed = true
+    }
+
+    private companion object {
+        // map of concurrent open files
+        val locks = mutableMapOf<String, Int>()
+    }
+}

src/main/kotlin/app/revanced/patcher/util/ProxyClassList.kt

@@ -0,0 +1,33 @@
+package app.revanced.patcher.util
+
+import app.revanced.patcher.util.proxy.ClassProxy
+import com.android.tools.smali.dexlib2.iface.ClassDef
+
+/**
+ * A class that represents a set of classes and proxies.
+ *
+ * @param classes The classes to be backed by proxies.
+ */
+class ProxyClassList internal constructor(classes: MutableSet<ClassDef>) : MutableSet<ClassDef> by classes {
+    internal val proxies = mutableListOf<ClassProxy>()
+
+    /**
+     * Add a [ClassProxy].
+     */
+    fun add(classProxy: ClassProxy) = proxies.add(classProxy)
+
+    /**
+     * Replace all classes with their mutated versions.
+     */
+    internal fun replaceClasses() = proxies.removeIf { proxy ->
+        // If the proxy is unused, return false to keep it in the proxies list.
+            if (!proxy.resolved) return@removeIf false
+
+        // If it has been used, replace the original class with the mutable class.
+        remove(proxy.immutableClass)
+        add(proxy.mutableClass)
+
+        // Return true to remove the proxy from the proxies list.
+            return@removeIf true
+        }
+}

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

@@ -0,0 +1,56 @@
+package app.revanced.patcher.util.method
+
+import app.revanced.patcher.data.BytecodeContext
+import app.revanced.patcher.util.proxy.mutableTypes.MutableMethod
+import com.android.tools.smali.dexlib2.iface.Method
+import com.android.tools.smali.dexlib2.iface.instruction.ReferenceInstruction
+import com.android.tools.smali.dexlib2.iface.reference.MethodReference
+import com.android.tools.smali.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.findClass(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)
+}

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 com.android.tools.smali.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)
+    }
+}

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 com.android.tools.smali.dexlib2.base.BaseAnnotation
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.BaseAnnotationElement
+import com.android.tools.smali.dexlib2.iface.AnnotationElement
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.reference.BaseTypeReference
+import com.android.tools.smali.dexlib2.iface.ClassDef
+import com.android.tools.smali.dexlib2.util.FieldUtil
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.HiddenApiRestriction
+import com.android.tools.smali.dexlib2.base.reference.BaseFieldReference
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.HiddenApiRestriction
+import com.android.tools.smali.dexlib2.base.reference.BaseMethodReference
+import com.android.tools.smali.dexlib2.builder.MutableMethodImplementation
+import com.android.tools.smali.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
+
+    // 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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.BaseMethodParameter
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.value.BaseAnnotationEncodedValue
+import com.android.tools.smali.dexlib2.iface.AnnotationElement
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.value.BaseArrayEncodedValue
+import com.android.tools.smali.dexlib2.iface.value.ArrayEncodedValue
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.value.BaseBooleanEncodedValue
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.value.BaseByteEncodedValue
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.value.BaseCharEncodedValue
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.value.BaseDoubleEncodedValue
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.ValueType
+import com.android.tools.smali.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
+            }
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.value.BaseEnumEncodedValue
+import com.android.tools.smali.dexlib2.iface.reference.FieldReference
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.ValueType
+import com.android.tools.smali.dexlib2.base.value.BaseFieldEncodedValue
+import com.android.tools.smali.dexlib2.iface.reference.FieldReference
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.value.BaseFloatEncodedValue
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.value.BaseIntEncodedValue
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.value.BaseLongEncodedValue
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.value.BaseMethodEncodedValue
+import com.android.tools.smali.dexlib2.iface.reference.MethodReference
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.value.BaseMethodHandleEncodedValue
+import com.android.tools.smali.dexlib2.iface.reference.MethodHandleReference
+import com.android.tools.smali.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)
+        }
+    }
+
+
+}

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 com.android.tools.smali.dexlib2.base.value.BaseMethodTypeEncodedValue
+import com.android.tools.smali.dexlib2.iface.reference.MethodProtoReference
+import com.android.tools.smali.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)
+        }
+    }
+
+
+}

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 com.android.tools.smali.dexlib2.base.value.BaseNullEncodedValue
+import com.android.tools.smali.dexlib2.iface.value.ByteEncodedValue
+
+class MutableNullEncodedValue : BaseNullEncodedValue(), MutableEncodedValue {
+    companion object {
+        fun ByteEncodedValue.toMutable(): MutableByteEncodedValue {
+            return MutableByteEncodedValue(this)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.value.BaseShortEncodedValue
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.value.BaseStringEncodedValue
+import com.android.tools.smali.dexlib2.iface.value.ByteEncodedValue
+import com.android.tools.smali.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)
+        }
+    }
+}

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 com.android.tools.smali.dexlib2.base.value.BaseTypeEncodedValue
+import com.android.tools.smali.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)
+        }
+    }
+}

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

@@ -0,0 +1,10 @@
+package app.revanced.patcher.util.smali
+
+import com.android.tools.smali.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)

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

@@ -0,0 +1,85 @@
+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 com.android.tools.smali.dexlib2.AccessFlags
+import com.android.tools.smali.dexlib2.Opcodes
+import com.android.tools.smali.dexlib2.builder.BuilderInstruction
+import com.android.tools.smali.dexlib2.writer.builder.DexBuilder
+import com.android.tools.smali.smali.LexerErrorInterface
+import com.android.tools.smali.smali.smaliFlexLexer
+import com.android.tools.smali.smali.smaliParser
+import com.android.tools.smali.smali.smaliTreeWalker
+import java.io.InputStreamReader
+import java.util.Locale
+
+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(Locale.ENGLISH,
+                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()

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

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

src/test/kotlin/app/revanced/patcher/extensions/InstructionExtensionsTest.kt

@@ -0,0 +1,233 @@
+package app.revanced.patcher.extensions
+
+import app.revanced.patcher.extensions.InstructionExtensions.addInstruction
+import app.revanced.patcher.extensions.InstructionExtensions.addInstructions
+import app.revanced.patcher.extensions.InstructionExtensions.addInstructionsWithLabels
+import app.revanced.patcher.extensions.InstructionExtensions.getInstruction
+import app.revanced.patcher.extensions.InstructionExtensions.removeInstruction
+import app.revanced.patcher.extensions.InstructionExtensions.removeInstructions
+import app.revanced.patcher.extensions.InstructionExtensions.replaceInstruction
+import app.revanced.patcher.extensions.InstructionExtensions.replaceInstructions
+import app.revanced.patcher.util.proxy.mutableTypes.MutableMethod
+import app.revanced.patcher.util.proxy.mutableTypes.MutableMethod.Companion.toMutable
+import app.revanced.patcher.util.smali.ExternalLabel
+import com.android.tools.smali.dexlib2.AccessFlags
+import com.android.tools.smali.dexlib2.Opcode
+import com.android.tools.smali.dexlib2.builder.BuilderOffsetInstruction
+import com.android.tools.smali.dexlib2.builder.MutableMethodImplementation
+import com.android.tools.smali.dexlib2.builder.instruction.BuilderInstruction21s
+import com.android.tools.smali.dexlib2.iface.instruction.OneRegisterInstruction
+import com.android.tools.smali.dexlib2.immutable.ImmutableMethod
+import org.junit.jupiter.api.BeforeEach
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+private object InstructionExtensionsTest {
+    private lateinit var testMethod: MutableMethod
+    private lateinit var testMethodImplementation: MutableMethodImplementation
+
+    @BeforeEach
+    fun createTestMethod() = ImmutableMethod(
+        "TestClass;",
+        "testMethod",
+        null,
+        "V",
+        AccessFlags.PUBLIC.value,
+        null,
+        null,
+        MutableMethodImplementation(16).also { testMethodImplementation = it }.apply {
+            repeat(10) { i -> this.addInstruction(TestInstruction(i)) }
+        },
+    ).let { testMethod = it.toMutable() }
+
+    @Test
+    fun addInstructionsToImplementationIndexed() = applyToImplementation {
+        addInstructions(5, getTestInstructions(5..6)).also {
+            assertRegisterIs(5, 5)
+            assertRegisterIs(6, 6)
+
+            assertRegisterIs(5, 7)
+        }
+    }
+
+    @Test
+    fun addInstructionsToImplementation() = applyToImplementation {
+        addInstructions(getTestInstructions(10..11)).also {
+            assertRegisterIs(10, 10)
+            assertRegisterIs(11, 11)
+        }
+    }
+
+    @Test
+    fun removeInstructionsFromImplementationIndexed() = applyToImplementation {
+        removeInstructions(5, 5).also { assertRegisterIs(4, 4) }
+    }
+
+    @Test
+    fun removeInstructionsFromImplementation() = applyToImplementation {
+        removeInstructions(0).also { assertRegisterIs(9, 9) }
+        removeInstructions(1).also { assertRegisterIs(1, 0) }
+        removeInstructions(2).also { assertRegisterIs(3, 0) }
+    }
+
+    @Test
+    fun replaceInstructionsInImplementationIndexed() = applyToImplementation {
+        replaceInstructions(5, getTestInstructions(0..1)).also {
+            assertRegisterIs(0, 5)
+            assertRegisterIs(1, 6)
+            assertRegisterIs(7, 7)
+        }
+    }
+
+    @Test
+    fun addInstructionToMethodIndexed() = applyToMethod {
+        addInstruction(5, TestInstruction(0)).also { assertRegisterIs(0, 5) }
+    }
+
+    @Test
+    fun addInstructionToMethod() = applyToMethod {
+        addInstruction(TestInstruction(0)).also { assertRegisterIs(0, 10) }
+    }
+
+    @Test
+    fun addSmaliInstructionToMethodIndexed() = applyToMethod {
+        addInstruction(5, getTestSmaliInstruction(0)).also { assertRegisterIs(0, 5) }
+    }
+
+    @Test
+    fun addSmaliInstructionToMethod() = applyToMethod {
+        addInstruction(getTestSmaliInstruction(0)).also { assertRegisterIs(0, 10) }
+    }
+
+    @Test
+    fun addInstructionsToMethodIndexed() = applyToMethod {
+        addInstructions(5, getTestInstructions(0..1)).also {
+            assertRegisterIs(0, 5)
+            assertRegisterIs(1, 6)
+
+            assertRegisterIs(5, 7)
+        }
+    }
+
+    @Test
+    fun addInstructionsToMethod() = applyToMethod {
+        addInstructions(getTestInstructions(0..1)).also {
+            assertRegisterIs(0, 10)
+            assertRegisterIs(1, 11)
+
+            assertRegisterIs(9, 9)
+        }
+    }
+
+    @Test
+    fun addSmaliInstructionsToMethodIndexed() = applyToMethod {
+        addInstructionsWithLabels(5, getTestSmaliInstructions(0..1)).also {
+            assertRegisterIs(0, 5)
+            assertRegisterIs(1, 6)
+
+            assertRegisterIs(5, 7)
+        }
+    }
+
+    @Test
+    fun addSmaliInstructionsToMethod() = applyToMethod {
+        addInstructions(getTestSmaliInstructions(0..1)).also {
+            assertRegisterIs(0, 10)
+            assertRegisterIs(1, 11)
+
+            assertRegisterIs(9, 9)
+        }
+    }
+
+    @Test
+    fun addSmaliInstructionsWithExternalLabelToMethodIndexed() = applyToMethod {
+        val label = ExternalLabel("testLabel", getInstruction(5))
+
+        addInstructionsWithLabels(
+            5,
+            getTestSmaliInstructions(0..1).plus("\n").plus("goto :${label.name}"),
+            label
+        ).also {
+            assertRegisterIs(0, 5)
+            assertRegisterIs(1, 6)
+            assertRegisterIs(5, 8)
+
+            val gotoTarget = getInstruction<BuilderOffsetInstruction>(7)
+                .target.location.instruction as OneRegisterInstruction
+
+            assertEquals(5, gotoTarget.registerA)
+        }
+    }
+
+    @Test
+    fun removeInstructionFromMethodIndexed() = applyToMethod {
+        removeInstruction(5).also {
+            assertRegisterIs(4, 4)
+            assertRegisterIs(6, 5)
+        }
+    }
+
+    @Test
+    fun removeInstructionsFromMethodIndexed() = applyToMethod {
+        removeInstructions(5, 5).also { assertRegisterIs(4, 4) }
+    }
+
+    @Test
+    fun removeInstructionsFromMethod() = applyToMethod {
+        removeInstructions(0).also { assertRegisterIs(9, 9) }
+        removeInstructions(1).also { assertRegisterIs(1, 0) }
+        removeInstructions(2).also { assertRegisterIs(3, 0) }
+    }
+
+    @Test
+    fun replaceInstructionInMethodIndexed() = applyToMethod {
+        replaceInstruction(5, TestInstruction(0)).also { assertRegisterIs(0, 5) }
+    }
+
+    @Test
+    fun replaceInstructionsInMethodIndexed() = applyToMethod {
+        replaceInstructions(5, getTestInstructions(0..1)).also {
+            assertRegisterIs(0, 5)
+            assertRegisterIs(1, 6)
+            assertRegisterIs(7, 7)
+        }
+    }
+
+    @Test
+    fun replaceSmaliInstructionsInMethodIndexed() = applyToMethod {
+        replaceInstructions(5, getTestSmaliInstructions(0..1)).also {
+            assertRegisterIs(0, 5)
+            assertRegisterIs(1, 6)
+            assertRegisterIs(7, 7)
+        }
+    }
+
+    // region Helper methods
+
+    private fun applyToImplementation(block: MutableMethodImplementation.() -> Unit) {
+        testMethodImplementation.apply(block)
+    }
+
+    private fun applyToMethod(block: MutableMethod.() -> Unit) {
+        testMethod.apply(block)
+    }
+
+    private fun MutableMethodImplementation.assertRegisterIs(register: Int, atIndex: Int) = assertEquals(
+        register, getInstruction<OneRegisterInstruction>(atIndex).registerA
+    )
+
+    private fun MutableMethod.assertRegisterIs(register: Int, atIndex: Int) =
+        implementation!!.assertRegisterIs(register, atIndex)
+
+    private fun getTestInstructions(range: IntRange) = range.map { TestInstruction(it) }
+
+    private fun getTestSmaliInstruction(register: Int) = "const/16 v$register, 0"
+
+    private fun getTestSmaliInstructions(range: IntRange) = range.joinToString("\n") {
+        getTestSmaliInstruction(it)
+    }
+
+    // endregion
+
+    private class TestInstruction(register: Int) : BuilderInstruction21s(Opcode.CONST_16, register, 0)
+}

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

@@ -0,0 +1,59 @@
+package app.revanced.patcher.patch.options
+
+import app.revanced.patcher.data.BytecodeContext
+import app.revanced.patcher.patch.BytecodePatch
+import app.revanced.patcher.patch.options.types.BooleanPatchOption.Companion.booleanPatchOption
+import app.revanced.patcher.patch.options.types.StringPatchOption.Companion.stringPatchOption
+import app.revanced.patcher.patch.options.types.array.StringArrayPatchOption.Companion.stringArrayPatchOption
+import org.junit.jupiter.api.assertDoesNotThrow
+import org.junit.jupiter.api.assertThrows
+import kotlin.test.Test
+
+internal class PatchOptionsTest {
+    @Test
+    fun `should not fail because default value is unvalidated`() {
+        assertDoesNotThrow {
+            OptionsTestPatch.options["required"].value
+        }
+    }
+
+    @Test
+    fun `should throw due to incorrect type`() {
+        assertThrows<PatchOptionException.InvalidValueTypeException> {
+            OptionsTestPatch.options["bool"] = 0
+        }
+    }
+
+    @Test
+    fun `should be nullable`() {
+        OptionsTestPatch.options["bool"] = null
+    }
+
+    @Test
+    fun `option should not be found`() {
+        assertThrows<PatchOptionException.PatchOptionNotFoundException> {
+            OptionsTestPatch.options["this option does not exist"] = 1
+        }
+    }
+
+    @Test
+    fun `should be able to add options manually`() {
+        assertThrows<PatchOptionException.InvalidValueTypeException> {
+            OptionsTestPatch.options["array"] = OptionsTestPatch.stringArrayOption
+        }
+        assertDoesNotThrow {
+            OptionsTestPatch.options.register(OptionsTestPatch.stringArrayOption)
+        }
+    }
+
+    private object OptionsTestPatch : BytecodePatch() {
+        private var stringOption by stringPatchOption("string", "default")
+        private var booleanOption by booleanPatchOption("bool", true)
+        private var requiredStringOption by stringPatchOption("required", "default", required = true)
+        private var nullDefaultRequiredOption by stringPatchOption("null", null, required = true)
+
+        val stringArrayOption = stringArrayPatchOption("array", arrayOf("1", "2"))
+
+        override fun execute(context: BytecodeContext) {}
+    }
+}

src/test/kotlin/app/revanced/patcher/patch/usage/ExampleBytecodePatch.kt

@@ -0,0 +1,146 @@
+package app.revanced.patcher.patch.usage
+
+import app.revanced.patcher.data.BytecodeContext
+import app.revanced.patcher.extensions.InstructionExtensions.addInstructionsWithLabels
+import app.revanced.patcher.extensions.InstructionExtensions.getInstruction
+import app.revanced.patcher.extensions.InstructionExtensions.replaceInstruction
+import app.revanced.patcher.extensions.or
+import app.revanced.patcher.patch.BytecodePatch
+import app.revanced.patcher.patch.PatchException
+import app.revanced.patcher.patch.annotation.CompatiblePackage
+import app.revanced.patcher.patch.annotation.Patch
+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 com.android.tools.smali.dexlib2.AccessFlags
+import com.android.tools.smali.dexlib2.Format
+import com.android.tools.smali.dexlib2.Opcode
+import com.android.tools.smali.dexlib2.builder.instruction.BuilderInstruction11x
+import com.android.tools.smali.dexlib2.builder.instruction.BuilderInstruction21c
+import com.android.tools.smali.dexlib2.iface.instruction.formats.Instruction21c
+import com.android.tools.smali.dexlib2.immutable.ImmutableField
+import com.android.tools.smali.dexlib2.immutable.ImmutableMethod
+import com.android.tools.smali.dexlib2.immutable.ImmutableMethodImplementation
+import com.android.tools.smali.dexlib2.immutable.reference.ImmutableFieldReference
+import com.android.tools.smali.dexlib2.immutable.reference.ImmutableStringReference
+import com.android.tools.smali.dexlib2.immutable.value.ImmutableFieldEncodedValue
+import com.android.tools.smali.dexlib2.util.Preconditions
+import com.google.common.collect.ImmutableList
+
+@Suppress("unused")
+@Patch(
+    name = "Example bytecode patch",
+    description = "Example demonstration of a bytecode patch.",
+    dependencies = [ExampleResourcePatch::class],
+    compatiblePackages = [CompatiblePackage("com.example.examplePackage", arrayOf("0.0.1", "0.0.2"))]
+)
+object ExampleBytecodePatch : BytecodePatch(setOf(ExampleFingerprint)) {
+    // Entry point of a patch. Supplied fingerprints are resolved at this point.
+    override fun execute(context: BytecodeContext) {
+        ExampleFingerprint.result?.let { result ->
+            // 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
+
+            result.mutableMethod.apply {
+                replaceStringAt(startIndex, "Hello, ReVanced! Editing bytecode.")
+
+                // Store the fields initial value into the first virtual register.
+                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.
+                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
+                    """
+                )
+            }
+
+            // Find the class in which the method matching our fingerprint is defined in.
+            context.findClass(result.classDef.type)!!.mutableClass.apply {
+                // Add a new method that returns a string.
+                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.
+                fields.add(
+                    ImmutableField(
+                        type,
+                        "dummyField",
+                        "Ljava/io/PrintStream;",
+                        AccessFlags.PRIVATE or AccessFlags.STATIC,
+                        ImmutableFieldEncodedValue(
+                            ImmutableFieldReference(
+                                "Ljava/lang/System;",
+                                "out",
+                                "Ljava/io/PrintStream;"
+                            )
+                        ),
+                        null,
+                        null
+                    ).toMutable()
+                )
+            }
+        } ?: throw PatchException("Fingerprint failed to resolve.")
+    }
+
+    /**
+     * Replace an existing instruction with a new one containing a reference to a new string.
+     * @param index The index of the instruction to replace.
+     * @param string The replacement string.
+     */
+    private fun MutableMethod.replaceStringAt(index: Int, string: String) {
+        val instruction = getInstruction(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.
+        replaceInstruction(
+            index,
+            "const-string ${strInstruction.registerA}, ${ImmutableStringReference(string)}"
+        )
+    }
+}
+

src/test/kotlin/app/revanced/patcher/patch/usage/ExampleFingerprint.kt

@@ -0,0 +1,20 @@
+package app.revanced.patcher.patch.usage
+import app.revanced.patcher.extensions.or
+import app.revanced.patcher.fingerprint.method.annotation.FuzzyPatternScanMethod
+import app.revanced.patcher.fingerprint.method.impl.MethodFingerprint
+import com.android.tools.smali.dexlib2.AccessFlags
+import com.android.tools.smali.dexlib2.Opcode
+
+@FuzzyPatternScanMethod(2)
+object ExampleFingerprint : MethodFingerprint(
+    "V",
+    AccessFlags.PUBLIC or AccessFlags.STATIC,
+    listOf("[L"),
+    listOf(
+        Opcode.SGET_OBJECT,
+        null,                 // Matching unknown opcodes.
+        Opcode.INVOKE_STATIC, // This is intentionally wrong to test fuzzy matching.
+        Opcode.RETURN_VOID
+    ),
+    null
+)

src/test/kotlin/app/revanced/patcher/patch/usage/ExampleResourcePatch.kt

@@ -0,0 +1,22 @@
+package app.revanced.patcher.patch.usage
+
+import app.revanced.patcher.data.ResourceContext
+import app.revanced.patcher.patch.ResourcePatch
+import org.w3c.dom.Element
+
+
+class ExampleResourcePatch : ResourcePatch() {
+    override fun execute(context: ResourceContext) {
+        context.xmlEditor["AndroidManifest.xml"].use { editor ->
+            val element = editor // regular DomFileEditor
+                .file
+                .getElementsByTagName("application")
+                .item(0) as Element
+            element
+                .setAttribute(
+                    "exampleAttribute",
+                    "exampleValue"
+                )
+        }
+    }
+}

src/test/kotlin/app/revanced/patcher/util/smali/InlineSmaliCompilerTest.kt

@@ -0,0 +1,105 @@
+package app.revanced.patcher.util.smali
+
+import app.revanced.patcher.extensions.InstructionExtensions.addInstructions
+import app.revanced.patcher.extensions.InstructionExtensions.addInstructionsWithLabels
+import app.revanced.patcher.extensions.InstructionExtensions.getInstruction
+import app.revanced.patcher.extensions.newLabel
+import app.revanced.patcher.util.proxy.mutableTypes.MutableMethod.Companion.toMutable
+import com.android.tools.smali.dexlib2.AccessFlags
+import com.android.tools.smali.dexlib2.Opcode
+import com.android.tools.smali.dexlib2.builder.BuilderInstruction
+import com.android.tools.smali.dexlib2.builder.MutableMethodImplementation
+import com.android.tools.smali.dexlib2.builder.instruction.BuilderInstruction21c
+import com.android.tools.smali.dexlib2.builder.instruction.BuilderInstruction21t
+import com.android.tools.smali.dexlib2.immutable.ImmutableMethod
+import com.android.tools.smali.dexlib2.immutable.reference.ImmutableStringReference
+import java.util.*
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+internal class InlineSmaliCompilerTest {
+    @Test
+    fun `compiler should output valid instruction`() {
+        val want = BuilderInstruction21c(Opcode.CONST_STRING, 0, ImmutableStringReference("Test")) as BuilderInstruction
+        val have = "const-string v0, \"Test\"".toInstruction()
+        instructionEquals(want, have)
+    }
+
+    @Test
+    fun `compiler should support branching with own branches`() {
+        val method = createMethod()
+        val insnAmount = 8
+        val insnIndex = insnAmount - 2
+        val targetIndex = insnIndex - 1
+
+        method.addInstructions(arrayOfNulls<String>(insnAmount).also {
+            Arrays.fill(it, "const/4 v0, 0x0")
+        }.joinToString("\n"))
+        method.addInstructionsWithLabels(
+            targetIndex,
+            """
+                :test
+                const/4 v0, 0x1
+                if-eqz v0, :test
+            """
+        )
+
+        val insn = method.getInstruction<BuilderInstruction21t>(insnIndex)
+        assertEquals(targetIndex, insn.target.location.index)
+    }
+
+    @Test
+    fun `compiler should support branching to outside branches`() {
+        val method = createMethod()
+        val insnIndex = 3
+        val labelIndex = 1
+
+        method.addInstructions(
+            """
+                const/4 v0, 0x1
+                const/4 v0, 0x0
+            """
+        )
+
+        assertEquals(labelIndex, method.newLabel(labelIndex).location.index)
+
+        method.addInstructionsWithLabels(
+            method.implementation!!.instructions.size,
+            """
+                const/4 v0, 0x1
+                if-eqz v0, :test
+                return-void
+            """,
+            ExternalLabel("test", method.getInstruction(1))
+        )
+
+        val insn = method.getInstruction<BuilderInstruction21t>(insnIndex)
+        assertTrue(insn.target.isPlaced, "Label was not placed")
+        assertEquals(labelIndex, insn.target.location.index)
+    }
+
+    companion object {
+        private fun createMethod(
+            name: String = "dummy",
+            returnType: String = "V",
+            accessFlags: Int = AccessFlags.STATIC.value,
+            registerCount: Int = 1,
+        ) = ImmutableMethod(
+            "Ldummy;",
+            name,
+            emptyList(), // parameters
+            returnType,
+            accessFlags,
+            emptySet(),
+            emptySet(),
+            MutableMethodImplementation(registerCount)
+        ).toMutable()
+
+        private fun instructionEquals(want: BuilderInstruction, have: BuilderInstruction) {
+            assertEquals(want.opcode, have.opcode)
+            assertEquals(want.format, have.format)
+            assertEquals(want.codeUnits, have.codeUnits)
+        }
+    }
+}