Android 插桩（gradle + asm）统计方法耗时

最近学习插桩就尝试了一下用插桩的方式做一个统计Activity生命周期方法耗时的小demo

本文所用技术要点
1、自定义gradle插件
2、asm插桩

要点讲解

自定义插件
新建一个module（library），gradle文件如下：

apply plugin: 'groovy'
apply plugin: 'maven'

repositories {
    mavenCentral()
    jcenter()
}

dependencies {
    //gradle sdk
    implementation gradleApi()
    //groovy sdk
    implementation localGroovy()

    implementation 'com.android.tools.build:gradle:3.1.3'
}

group='com.benz.ams'
version='1.0.0'

uploadArchives {
    repositories {
        mavenDeployer {
            repository(url: uri('./plugin'))
        }
    }
}

创建groovy文件

class AmsPlugin extends Transform implements Plugin<Project> {

    static File tempFile

    @Override
    void apply(Project project) {
        //registerTransform
        initDir(project);
        def android = project.extensions.getByType(AppExtension)
        android.registerTransform(this)
    }

    @Override
    String getName() {
        return "AmsPlugin"
    }

    @Override
    Set<QualifiedContent.ContentType> getInputTypes() {
        return TransformManager.CONTENT_CLASS
    }

    @Override
    Set<? super QualifiedContent.Scope> getScopes() {
        return TransformManager.SCOPE_FULL_PROJECT
    }

    @Override
    boolean isIncremental() {
        return false
    }

    static void initDir(Project project) {
        if (!project.buildDir.exists()) {
            project.buildDir.mkdirs()
        }
        tempFile = new File(project.buildDir, "ams")
        if (!tempFile.exists()) {
            tempFile.mkdir()
        }
    }

    @Override
    void transform(TransformInvocation transformInvocation) {
        println '--------------- AmsPlugin visit start --------------- '
        def startTime = System.currentTimeMillis()
        Collection<TransformInput> inputs = transformInvocation.inputs
        TransformOutputProvider outputProvider = transformInvocation.outputProvider
        //删除之前的输出
        if (outputProvider != null)
            outputProvider.deleteAll()
        //遍历inputs
        inputs.each { TransformInput input ->
            //遍历directoryInputs
            input.directoryInputs.each { DirectoryInput directoryInput ->
                handleDirectoryInput(directoryInput, outputProvider)
            }

            //遍历jarInputs
            input.jarInputs.each { JarInput jarInput ->
                handleJarInputs(jarInput, outputProvider)
            }
        }
        def cost = (System.currentTimeMillis() - startTime) / 1000
        println '--------------- AmsPlugin visit end --------------- '
        println "AmsPlugin cost : $cost s"
    }

    /**
     * 处理文件目录下的class文件
     */
    static void handleDirectoryInput(DirectoryInput directoryInput, TransformOutputProvider outputProvider) {
        //是否是目录
        if (directoryInput.file.isDirectory()) {
            //列出目录所有文件（包含子文件夹，子文件夹内文件）
            directoryInput.file.eachFileRecurse { File file ->
                def name = file.name
                if (checkClassFile(name)) {
                    println '----------- deal with "class" file <' + name + '> -----------'
                    ClassReader classReader = new ClassReader(file.bytes)
                    ClassWriter classWriter = new ClassWriter(classReader, ClassWriter.COMPUTE_MAXS)
                    ClassVisitor cv = new AmsClassVisitor(classWriter)
                    classReader.accept(cv, EXPAND_FRAMES)
                    byte[] code = classWriter.toByteArray()
                    FileOutputStream fos = new FileOutputStream(
                            file.parentFile.absolutePath + File.separator + name)
                    fos.write(code)
                    fos.close()
                    saveModifiedClassForCheck(file);
                }
            }
        }
        //处理完输入文件之后，要把输出给下一个任务
        def dest = outputProvider.getContentLocation(directoryInput.name,
                directoryInput.contentTypes, directoryInput.scopes,
                Format.DIRECTORY)
        FileUtils.copyDirectory(directoryInput.file, dest)
    }

    /**
     * 处理Jar中的class文件
     */
    static void handleJarInputs(JarInput jarInput, TransformOutputProvider outputProvider) {
        if (jarInput.file.getAbsolutePath().endsWith(".jar")) {
            //重名名输出文件,因为可能同名,会覆盖
            def jarName = jarInput.name
            def md5Name = DigestUtils.md5Hex(jarInput.file.getAbsolutePath())
            if (jarName.endsWith(".jar")) {
                jarName = jarName.substring(0, jarName.length() - 4)
            }
            JarFile jarFile = new JarFile(jarInput.file)
            Enumeration enumeration = jarFile.entries()
            File tmpFile = new File(jarInput.file.getParent() + File.separator + "classes_temp.jar")
            //避免上次的缓存被重复插入
            if (tmpFile.exists()) {
                tmpFile.delete()
            }
            JarOutputStream jarOutputStream = new JarOutputStream(new FileOutputStream(tmpFile))
            //用于保存
            while (enumeration.hasMoreElements()) {
                JarEntry jarEntry = (JarEntry) enumeration.nextElement()
                String entryName = jarEntry.getName()
                ZipEntry zipEntry = new ZipEntry(entryName)
                InputStream inputStream = jarFile.getInputStream(jarEntry)
                //插桩class
                if (checkClassFile(entryName)) {
                    //class文件处理
                    println '----------- deal with "jar" class file <' + entryName + '> -----------'
                    jarOutputStream.putNextEntry(zipEntry)
                    ClassReader classReader = new ClassReader(IOUtils.toByteArray(inputStream))
                    ClassWriter classWriter = new ClassWriter(classReader, ClassWriter.COMPUTE_MAXS)
                    ClassVisitor cv = new AmsClassVisitor(classWriter)
                    classReader.accept(cv, EXPAND_FRAMES)
                    byte[] code = classWriter.toByteArray()
                    jarOutputStream.write(code)
                } else {
                    jarOutputStream.putNextEntry(zipEntry)
                    jarOutputStream.write(IOUtils.toByteArray(inputStream))
                }
                jarOutputStream.closeEntry()
            }
            //结束
            jarOutputStream.close()
            jarFile.close()
            def dest = outputProvider.getContentLocation(jarName + md5Name,
                    jarInput.contentTypes, jarInput.scopes, Format.JAR)
            FileUtils.copyFile(tmpFile, dest)
            tmpFile.delete()
        }
    }

    /*
    保存插桩后的文件到临时目录 方便查看是否插桩正确
     */
    static void saveModifiedClassForCheck(File tempClass) {
        File dir = tempFile;
        File checkJarFile = new File(dir, tempClass.getName().replace("/", "_"));
        if (checkJarFile.exists()) {
            checkJarFile.delete();
        }
        FileUtils.copyFile(tempClass, checkJarFile);
    }

    /**
     * 检查class文件是否需要处理
     * @param fileName
     * @return
     */
    static boolean checkClassFile(String name) {
        //只处理需要的class文件
        return (name.endsWith(".class") && !name.startsWith("R\$")
                && !"R.class".equals(name) && !"BuildConfig.class".equals(name)
                && name.contains("Activity") && !name.contains("android/"))
    }

}

插桩关键代码
创建ClassVisitor和MethodVisitor

public class AmsClassVisitor extends ClassVisitor implements Opcodes {

    private static final String[] methodNames = {"onCreate", "onStart", "onResume", "onPause", "onStop", "onDestroy"};

    private String mClassName;
    private ArrayList<String> names;

    public AmsClassVisitor(ClassVisitor cv) {
        super(Opcodes.ASM5, cv);
        List<String> list = Arrays.asList(methodNames);
        names = new ArrayList<>(list);
    }

    @Override
    public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
        this.mClassName = name;
        super.visit(version, access, name, signature, superName, interfaces);
    }

    @Override
    public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
        MethodVisitor mv = cv.visitMethod(access, name, desc, signature, exceptions);
        if (this.mClassName.contains("Activity") && !this.mClassName.contains("android/")) {
            if (match(name)) {
                System.out.println("AmsClassVisitor : change method ----> " + name);
                return new AmsMethodVisitor(mv, name);
            }
        }
        return mv;
    }

    private boolean match(String name) {
        return names.contains(name);
    }

    @Override
    public void visitEnd() {
        super.visitEnd();
    }
}

public class AmsMethodVisitor extends MethodVisitor {

    private String mMethodName;

    public AmsMethodVisitor(MethodVisitor mv, String name) {
        super(Opcodes.ASM4, mv);
        mMethodName = name;
    }

    @Override
    public void visitCode() {
        super.visitCode();
        mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/System", "currentTimeMillis", "()J", false);
        mv.visitVarInsn(Opcodes.LSTORE, 2);
    }

    @Override
    public void visitInsn(int opcode) {
        if (((opcode >= Opcodes.IRETURN && opcode <= Opcodes.RETURN) || opcode == Opcodes.ATHROW) && mv != null) {
            mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/System", "currentTimeMillis", "()J", false);
            mv.visitVarInsn(Opcodes.LSTORE, 5);
            Label l9 = new Label();
            mv.visitLabel(l9);
            mv.visitLineNumber(21, l9);
            mv.visitLdcInsn("benz");
            mv.visitTypeInsn(Opcodes.NEW, "java/lang/StringBuilder");
            mv.visitInsn(Opcodes.DUP);
            mv.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/lang/StringBuilder", "<init>", "()V", false);
            mv.visitVarInsn(Opcodes.ALOAD, 0);
            mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Object", "getClass", "()Ljava/lang/Class;", false);
            mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Class", "getSimpleName", "()Ljava/lang/String;", false);
            mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/String;)Ljava/lang/StringBuilder;", false);
            mv.visitLdcInsn(" ----> " + mMethodName + " execute cost ");
            mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/String;)Ljava/lang/StringBuilder;", false);
            mv.visitVarInsn(Opcodes.LLOAD, 5);
            mv.visitVarInsn(Opcodes.LLOAD, 2);
            mv.visitInsn(Opcodes.LSUB);
            mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(J)Ljava/lang/StringBuilder;", false);
            mv.visitLdcInsn("ms");
            mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(Ljava/lang/String;)Ljava/lang/StringBuilder;", false);
            mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/StringBuilder", "toString", "()Ljava/lang/String;", false);
            mv.visitMethodInsn(Opcodes.INVOKESTATIC, "android/util/Log", "i", "(Ljava/lang/String;Ljava/lang/String;)I", false);
            mv.visitInsn(Opcodes.POP);
        }
        super.visitInsn(opcode);
    }
}

这里的代码不会写没关系，可以使用as中的一个插件（Ams Bytecode Outline）生成
具体使用方式如下：

long start = System.currentTimeMillis();
long end = System.currentTimeMillis();
Log.i("benz", this.getClass().getSimpleName() + " ----> OnCreate execute cost " + (end - start) + "ms");

先写成如上所示的代码然后选中代码右键选择show bytecode outline就能看到入下图所示的代码段

image.png

怎么让插件生效？
如下图，当修改了代码时使用uploadArchives生成插件

image.png

主module中使用

配置项目gradle文件

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
    repositories {
        google()
        jcenter()
        maven {
            url uri('./lib-ams/plugin')//使用上面创建的插件
        }
    }
    dependencies {
        classpath "com.android.tools.build:gradle:3.1.3"
        classpath 'com.benz.ams:lib-ams:1.0.0'//使用上面创建的插件
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

配置主module gradle文件

apply plugin: 'com.android.application'
apply plugin: 'com.benz.ams' //使用上面创建的插件

android {
    compileSdkVersion 27

    defaultConfig {
        applicationId "com.benz.ams.demo"
        minSdkVersion 21
        targetSdkVersion 27
        versionCode 1
        versionName "1.0"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: "libs", include: ["*.jar"])
    implementation 'com.android.support:appcompat-v7:27.1.1'
}

运行代码
我们可以在build目录下找到MainActivity的源码对比自己写的MainActivity的代码会发现插桩成功，如下所示

image.png
运行结果

image.png

demo