Android Gradle源码分析_com.android.tools.build:gradle 源码

一.如何调试Android Gradle源码

最简单的方式如下：
1.配置 gradle.properties
比较方便的做法是配置全局的 gradle.properties，这样对所有 Gradle 工具都适用，配置文件位于 ~/.gradle/gradle.properties，在 gradle.properties 文件中加上 org.gradle.jvmargs 属性：

org.gradle.jvmargs=-XX:MaxPermSize=4g -XX:+HeapDumpOnOutOfMemoryError -Xmx4g -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5006
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2.启动 Gradle Daemon 进程

$ ./gradlew --stop     # 先停掉 daemon 进程
$ ./gradlew --daemon   # 启动 daemon 进程
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3.Attach daemon 进程

然后，选择 Gradle Daemon 进程，如下图所示：

4.新建一个空的module
删除所有其他文件，只留如下2个文件

gradle文件配置如下

apply plugin: 'groovy'

dependencies {
    implementation gradleApi()
    implementation localGroovy()
    implementation 'com.android.tools.build:gradle:3.5.0'
}

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这样就引入了源码，想看对应版本的源码，改变相应的引用即可
保持和classpath声明的一致

 classpath 'com.android.tools.build:gradle:3.5.0'
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5.放断点
在相应的代码行放上断点

6.运行构建，开始调试

在命令行中执行相应的 Task，例如：

$ ./gradlew assembleDebug
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二.Gralde Plugin源码分析

平时我们使用plugin都是通过apply方法，例如：

apply plugin: 'com.android.application'
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所以我们就从apply方法入手

1.AppPlugin#apply


从上面得知 ‘com.android.application’ 对应com.android.build.gradle.AppPlugin

AppPlugin继承自AbstractAppPlugin，AbstractAppPlugin继承自BasePlugin

2.BasePlugin#apply

  @Override
    public final void apply(@NonNull Project project) {
        CrashReporting.runAction(
                () -> {
                    basePluginApply(project);
                    pluginSpecificApply(project);
                });
    }
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3.BasePlugin#basePluginApply

private void basePluginApply(@NonNull Project project) {
        // We run by default in headless mode, so the JVM doesn't steal focus.
        System.setProperty("java.awt.headless", "true");

        this.project = project;
        this.projectOptions = new ProjectOptions(project);
        checkGradleVersion(project, getLogger(), projectOptions);
        DependencyResolutionChecks.registerDependencyCheck(project, projectOptions);

        project.getPluginManager().apply(AndroidBasePlugin.class);

        checkPathForErrors();
        checkModulesForErrors();

        PluginInitializer.initialize(project);
        RecordingBuildListener buildListener = ProfilerInitializer.init(project, projectOptions);
        ProfileAgent.INSTANCE.register(project.getName(), buildListener);
        threadRecorder = ThreadRecorder.get();

        Workers.INSTANCE.initFromProject(
                projectOptions,
                // possibly, in the future, consider using a pool with a dedicated size
                // using the gradle parallelism settings.
                ForkJoinPool.commonPool());

        ProcessProfileWriter.getProject(project.getPath())
                .setAndroidPluginVersion(Version.ANDROID_GRADLE_PLUGIN_VERSION)
                .setAndroidPlugin(getAnalyticsPluginType())
                .setPluginGeneration(GradleBuildProject.PluginGeneration.FIRST)
                .setOptions(AnalyticsUtil.toProto(projectOptions));

        if (!projectOptions.get(BooleanOption.ENABLE_NEW_DSL_AND_API)) {

            threadRecorder.record(
                    ExecutionType.BASE_PLUGIN_PROJECT_CONFIGURE,
                    project.getPath(),
                    null,
                    this::configureProject);

            threadRecorder.record(
                    ExecutionType.BASE_PLUGIN_PROJECT_BASE_EXTENSION_CREATION,
                    project.getPath(),
                    null,
                    this::configureExtension);

            threadRecorder.record(
                    ExecutionType.BASE_PLUGIN_PROJECT_TASKS_CREATION,
                    project.getPath(),
                    null,
                    this::createTasks);
        } else {
            // Apply the Java plugin
            project.getPlugins().apply(JavaBasePlugin.class);

            // create the delegate
            ProjectWrapper projectWrapper = new ProjectWrapper(project);
            PluginDelegate<E> delegate =
                    new PluginDelegate<>(
                            project.getPath(),
                            project.getObjects(),
                            project.getExtensions(),
                            project.getConfigurations(),
                            projectWrapper,
                            projectWrapper,
                            project.getLogger(),
                            projectOptions,
                            getTypedDelegate());

            delegate.prepareForEvaluation();

            // after evaluate callbacks
            project.afterEvaluate(
                    CrashReporting.afterEvaluate(
                            p -> {
                                threadRecorder.record(
                                        ExecutionType.BASE_PLUGIN_CREATE_ANDROID_TASKS,
                                        p.getPath(),
                                        null,
                                        delegate::afterEvaluate);
                            }));
        }
    }
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threadRecoirder.recode()是记录最后一个参数的路径和执行的时间点，前面做了一些必要性的信息检测之前，其实主要做了以下几件事情：

// 配置项目，设置构建回调
this::configureProject
// 配置Extension
this::configureExtension
// 创建任务
this::createTasks
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4.configureProject

 private void configureProject() {
        final Gradle gradle = project.getGradle();
        ObjectFactory objectFactory = project.getObjects();

        extraModelInfo = new ExtraModelInfo(project.getPath(), projectOptions, project.getLogger());

        final SyncIssueHandler syncIssueHandler = extraModelInfo.getSyncIssueHandler();

        SdkComponents sdkComponents =
                SdkComponents.Companion.createSdkComponents(
                        project,
                        projectOptions,
                        // We pass a supplier here because extension will only be set later.
                        this::getExtension,
                        getLogger(),
                        syncIssueHandler);

        dataBindingBuilder = new DataBindingBuilder();
        dataBindingBuilder.setPrintMachineReadableOutput(
                SyncOptions.getErrorFormatMode(projectOptions) == ErrorFormatMode.MACHINE_PARSABLE);

        if (projectOptions.hasRemovedOptions()) {
            syncIssueHandler.reportWarning(
                    Type.GENERIC, projectOptions.getRemovedOptionsErrorMessage());
        }

        if (projectOptions.hasDeprecatedOptions()) {
            extraModelInfo
                    .getDeprecationReporter()
                    .reportDeprecatedOptions(projectOptions.getDeprecatedOptions());
        }

        if (!projectOptions.getExperimentalOptions().isEmpty()) {
            projectOptions
                    .getExperimentalOptions()
                    .forEach(extraModelInfo.getDeprecationReporter()::reportExperimentalOption);
        }

        // Enforce minimum versions of certain plugins
        GradlePluginUtils.enforceMinimumVersionsOfPlugins(project, syncIssueHandler);

        // Apply the Java plugin
        project.getPlugins().apply(JavaBasePlugin.class);

        DslScopeImpl dslScope =
                new DslScopeImpl(
                        syncIssueHandler, extraModelInfo.getDeprecationReporter(), objectFactory);

        @Nullable
        FileCache buildCache = BuildCacheUtils.createBuildCacheIfEnabled(project, projectOptions);

        globalScope =
                new GlobalScope(
                        project,
                        creator,
                        new ProjectWrapper(project),
                        projectOptions,
                        dslScope,
                        sdkComponents,
                        registry,
                        buildCache,
                        extraModelInfo.getMessageReceiver());

        project.getTasks()
                .named("assemble")
                .configure(
                        task ->
                                task.setDescription(
                                        "Assembles all variants of all applications and secondary packages."));

        // call back on execution. This is called after the whole build is done (not
        // after the current project is done).
        // This is will be called for each (android) projects though, so this should support
        // being called 2+ times.
        gradle.addBuildListener(
                new BuildListener() {
                    @Override
                    public void buildStarted(@NonNull Gradle gradle) {}

                    @Override
                    public void settingsEvaluated(@NonNull Settings settings) {}

                    @Override
                    public void projectsLoaded(@NonNull Gradle gradle) {}

                    @Override
                    public void projectsEvaluated(@NonNull Gradle gradle) {}

                    @Override
                    public void buildFinished(@NonNull BuildResult buildResult) {
                        // Do not run buildFinished for included project in composite build.
                        if (buildResult.getGradle().getParent() != null) {
                            return;
                        }
                        ModelBuilder.clearCaches();
                        Workers.INSTANCE.shutdown();
                        sdkComponents.unload();
                        SdkLocator.resetCache();
                        threadRecorder.record(
                                ExecutionType.BASE_PLUGIN_BUILD_FINISHED,
                                project.getPath(),
                                null,
                                () -> {
                                    if (!projectOptions.get(
                                            BooleanOption.KEEP_
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