Android開發AsmClassVisitorFactory使用詳解

@Incubating
interface AsmClassVisitorFactory<ParametersT : InstrumentationParameters> : Serializable {
    /**
     * The parameters that will be instantiated, configured using the given config when registering
     * the visitor, and injected on instantiation.
     *
     * This field must be left unimplemented.
     */
    @get:Nested
    val parameters: Property<ParametersT>
    /**
     * Contains parameters to help instantiate the visitor objects.
     *
     * This field must be left unimplemented.
     */
    @get:Nested
    val instrumentationContext: InstrumentationContext
    /**
     * Creates a class visitor object that will visit a class with the given [classContext]. The
     * returned class visitor must delegate its calls to [nextClassVisitor].
     *
     * The given [classContext] contains static information about the classes before starting the
     * instrumentation process. Any changes in interfaces or superclasses for the class with the
     * given [classContext] or for any other class in its classpath by a previous visitor will
     * not be reflected in the [classContext] object.
     *
     * [classContext] can also be used to get the data for classes that are in the runtime classpath
     * of the class being visited.
     *
     * This method must handle asynchronous calls.
     *
     * @param classContext contains information about the class that will be instrumented by the
     *                     returned class visitor.
     * @param nextClassVisitor the [ClassVisitor] to which the created [ClassVisitor] must delegate
     *                         method calls.
     */
    fun createClassVisitor(
        classContext: ClassContext,
        nextClassVisitor: ClassVisitor
    ): ClassVisitor
    /**
     * Whether or not the factory wants to instrument the class with the given [classData].
     *
     * If returned true, [createClassVisitor] will be called and the returned class visitor will
     * visit the class.
     *
     * This method must handle asynchronous calls.
     */
    fun isInstrumentable(classData: ClassData): Boolean
}

@Incubating
interface ClassData {
    /**
     * Fully qualified name of the class.
     */
    val className: String
    /**
     * List of the annotations the class has.
     */
    val classAnnotations: List<String>
    /**
     * List of all the interfaces that this class or a superclass of this class implements.
     */
    val interfaces: List<String>
    /**
     * List of all the super classes that this class or a super class of this class extends.
     */
    val superClasses: List<String>
}

        val androidComponents = project.extensions.getByType(AndroidComponentsExtension::class.java)
        androidComponents.onVariants { variant ->
            variant.transformClassesWith(PrivacyClassVisitorFactory::class.java,
                    InstrumentationScope.ALL) {}
            variant.setAsmFramesComputationMode(FramesComputationMode.COPY_FRAMES)
        }

ClassWriter classWriter = new ClassWriter(ClassWriter.COMPUTE_MAXS);
ClassVisitor methodFilterCV = new ClassFilterVisitor(classWriter);
ClassReader cr = new ClassReader(srcClass);
cr.accept(methodFilterCV, ClassReader.SKIP_DEBUG);
return classWriter.toByteArray();

abstract class PrivacyClassVisitorFactory : AsmClassVisitorFactory<InstrumentationParameters.None> {
    override fun createClassVisitor(classContext: ClassContext, nextClassVisitor: ClassVisitor): ClassVisitor {
        return PrivacyClassNode(nextClassVisitor)
    }
    override fun isInstrumentable(classData: ClassData): Boolean {
        return true
    }
}

class PrivacyClassNode(private val nextVisitor: ClassVisitor) : ClassNode(Opcodes.ASM5) {
    override fun visitEnd() {
        super.visitEnd()
        PrivacyHelper.whiteList.let {
            val result = it.firstOrNull { whiteName ->
                name.contains(whiteName, true)
            }
            result
        }.apply {
            if (this == null) {
                //   println("filter: $name")
            }
        }
        PrivacyHelper.whiteList.firstOrNull {
            name.contains(it, true)
        }?.apply {
            val iterator: Iterator<MethodNode> = methods.iterator()
            while (iterator.hasNext()) {
                val method = iterator.next()
                method.instructions?.iterator()?.forEach {
                    if (it is MethodInsnNode) {
                        it.isPrivacy()?.apply {
                            println("privacy transform classNodeName: ${name@this}")
                            it.opcode = code
                            it.owner = owner
                            it.name = name
                            it.desc = desc
                        }
                    }
                }
            }
        }
        accept(nextVisitor)
    }
}
private fun MethodInsnNode.isPrivacy(): PrivacyAsmEntity? {
    val pair = PrivacyHelper.privacyList.firstOrNull {
        val first = it.first
        first.owner == owner && first.code == opcode && first.name == name && first.desc == desc
    }
    return pair?.second
}