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14.Gradle编译其他应用代码流程（三)-Load过程
继续上一篇 13. Gradle编译其他应用代码流程（二)。
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这篇从InProcessBuildActionExecuter.execute开始这一篇的内容。
在正式内容前，首先要讲个gradle构建的流程，这个也是接下来内容的流程。
Load->Configure->Build
大家可以思考下，这3步都主要做了什么事。
另外，从执行流程的事件通知来看，它还分成下面5个通知事件：
buildStarted //开始编译 settingsEvaluated //settings处理完毕 projectsLoaded //项目loaded projectsEvaluated //项目处理完毕 buildFinished //编译结束
一. InProcessBuildActionExecuter.execute
文件路径：
subprojects\launcher\src\main\java\org\gradle\launcher\exec\InProcessBuildActionExecuter.java
方法：
public Object execute(BuildAction action, BuildRequestContext buildRequestContext, BuildActionParameters actionParameters, ServiceRegistry contextServices) {
GradleLauncher gradleLauncher = gradleLauncherFactory.newInstance(action.getStartParameter(), buildRequestContext, contextServices);
try {
gradleLauncher.addStandardOutputListener(buildRequestContext.getOutputListener());
gradleLauncher.addStandardErrorListener(buildRequestContext.getErrorListener());
GradleBuildController buildController = new GradleBuildController(gradleLauncher);
buildActionRunner.run(action, buildController);
System.out.println("Sandy buildController.getResult(): " + buildController.getResult());
return buildController.getResult();
} finally {
gradleLauncher.stop();
}
}
文件路径：
subprojects\launcher\src\main\java\org\gradle\launcher\exec\InProcessBuildActionExecuter.java
方法：
public GradleInternal run() {
try {
System.out.println("Sandy GradleInternal run state: " + state);
return (GradleInternal) getLauncher().run().getGradle();
} finally {
state = State.Completed;
}
}
文件路径：
subprojects\launcher\src\main\java\org\gradle\launcher\exec\ChainingBuildActionRunner.java
方法：
@Override
public void run(BuildAction action, BuildController buildController) {
System.out.println("Sandy ChainingBuildActionRunner run runners.size: " + runners.size());
for (BuildActionRunner runner : runners) {
System.out.println("runner: " + runner);
runner.run(action, buildController);
if (buildController.hasResult()) {
return;
}
}
throw new UnsupportedOperationException(String.format("Don't know how to run a build action of type %s.", action.getClass().getSimpleName()));
}
文件路径：
subprojects\launcher\src\main\java\org\gradle\tooling\internal\provider\ExecuteBuildActionRunner.java
方法：
public void run(BuildAction action, BuildController buildController) {
System.out.println("ExecuteBuildActionRunner action: " + action
+ " buildController: " + buildController);
if (action instanceof ExecuteBuildAction) {
System.out.println("ExecuteBuildActionRunner run..");
buildController.run();
buildController.setResult(null);
System.out.println("ExecuteBuildActionRunner result: " + "null");
}
}
文件路径：
subprojects\launcher\src\main\java\org\gradle\launcher\exec\GradleBuildController.java
方法:
public GradleInternal run() {
try {
System.out.println("Sandy GradleInternal run state: " + state);
return (GradleInternal) getLauncher().run().getGradle();
} finally {
state = State.Completed;
}
}上面的步骤比较清晰明了，需要注意的是ChainingBuildActionRunner和ExecuteBuildActionRunner，其实他们都是同一个接口BuildActionRunner，所以这里又是喜闻乐见的装饰者模式。
public class ChainingBuildActionRunner implements BuildActionRunner {
private final List runners;
public ChainingBuildActionRunner(List runners) {
this.runners = runners;
}
}
public class ExecuteBuildActionRunner implements BuildActionRunner {}最后来到ExecuteBuildActionRunner.run方法，它会调用GradleBuildController.run()，顾名思义，它是GradleBuild的控制器，所以马上就要接触到Gradle build步骤了；接下来会调用DefaultGradleLauncher.run()方法。
二. DefaultGradleLauncher
@Override
public BuildResult run() {
return doBuild(Stage.Build);
}
private BuildResult doBuild(final Stage upTo) {
return buildOperationExecutor.run("Run build", new Factory() {
@Override
public BuildResult create() {
Throwable failure = null;
try {
System.out.println("buildListener: " + buildListener.getClass() + " gradle: " + gradle.getClass());
buildListener.buildStarted(gradle);
doBuildStages(upTo);
} catch (Throwable t) {
failure = exceptionAnalyser.transform(t);
}
BuildResult buildResult = new BuildResult(upTo.name(), gradle, failure);
buildListener.buildFinished(buildResult);
if (failure != null) {
throw new ReportedException(failure);
}
return buildResult;
}
});
} 首先来看buildListener.buildStarted(gradle); 这行代码的作用是通知gradle构建已经开始，那既然是通知，接收者是谁呢？
看buildListener赋值的地方：
文件路径：
subprojects\core\src\main\java\org\gradle\initialization\DefaultGradleLauncher.java
方法
public DefaultGradleLauncher(GradleInternal gradle, InitScriptHandler initScriptHandler, SettingsLoader settingsLoader,
BuildConfigurer buildConfigurer, ExceptionAnalyser exceptionAnalyser,
LoggingManagerInternal loggingManager, BuildListener buildListener,
ModelConfigurationListener modelConfigurationListener,
BuildCompletionListener buildCompletionListener, BuildOperationExecutor operationExecutor,
BuildConfigurationActionExecuter buildConfigurationActionExecuter, BuildExecuter buildExecuter, BuildScopeServices buildServices) {
...
this.buildListener = buildListener;
...
}继续看调动的地方
文件路径：
subprojects\core\src\main\java\org\gradle\initialization\DefaultGradleLauncherFactory.java
方法：
return new DefaultGradleLauncher( ... gradle.getBuildListenerBroadcaster(), ... );
//文件路径：
subprojects\core\src\main\java\org\gradle\invocation\DefaultGradle.java
public BuildListener getBuildListenerBroadcaster() {
return buildListenerBroadcast.getSource();
}
public DefaultGradle(Gradle parent, StartParameter startParameter, ServiceRegistryFactory parentRegistry) {
...
buildListenerBroadcast = getListenerManager().createAnonymousBroadcaster(BuildListener.class);
projectEvaluationListenerBroadcast = getListenerManager().createAnonymousBroadcaster(ProjectEvaluationListener.class);
buildListenerBroadcast.add(new BuildAdapter() {
@Override
public void buildStarted(Gradle gradle) {
super.buildStarted(gradle);
Exception ex = new Exception("Sandy buildStarted");
ex.printStackTrace();
System.out.println("buildListenerBroadcast sandy buildStarted");
}
@Override
public void settingsEvaluated(Settings settings) {
super.settingsEvaluated(settings);
Exception ex = new Exception("Sandy settingsEvaluated");
ex.printStackTrace();
System.out.println("buildListenerBroadcast sandy settingsEvaluated");
}
@Override
public void projectsEvaluated(Gradle gradle) {
super.projectsEvaluated(gradle);
System.out.println("buildListenerBroadcast sandy projectsEvaluated");
}
@Override
public void buildFinished(BuildResult result) {
super.buildFinished(result);
System.out.println("buildListenerBroadcast sandy buildFinished");
}
@Override
public void projectsLoaded(Gradle gradle) {
System.out.println("buildListenerBroadcast sandy projectsLoaded");
rootProjectActions.execute(rootProject);
rootProjectActions = null;
}
});
}嗯，也就是接受者是在DefaultGradle里面，也就是说通知gradle build已经开始，接下来看doBuildStages(Stage.Build)方法，这个方法很重要，gradle build的主要流程都在这里面。
private void doBuildStages(Stage upTo) {
if (stage == Stage.Build) {
throw new IllegalStateException("Cannot build with GradleLauncher multiple times");
}
if (stage == null) {
// Evaluate init scripts
initScriptHandler.executeScripts(gradle);
// Build `buildSrc`, load settings.gradle, and construct composite (if appropriate)
settings = settingsLoader.findAndLoadSettings(gradle);
stage = Stage.Load;
}
if (upTo == Stage.Load) {
return;
}
if (stage == Stage.Load) {
// Configure build
buildOperationExecutor.run("Configure build", new Runnable() {
@Override
public void run() {
buildConfigurer.configure(gradle);
if (!gradle.getStartParameter().isConfigureOnDemand()) {
buildListener.projectsEvaluated(gradle);
}
modelConfigurationListener.onConfigure(gradle);
}
});
stage = Stage.Configure;
}
if (upTo == Stage.Configure) {
return;
}
// After this point, the GradleLauncher cannot be reused
stage = Stage.Build;
// Populate task graph
buildOperationExecutor.run("Calculate task graph", new Runnable() {
@Override
public void run() {
buildConfigurationActionExecuter.select(gradle);
if (gradle.getStartParameter().isConfigureOnDemand()) {
buildListener.projectsEvaluated(gradle);
}
}
});
// Execute build
buildOperationExecutor.run("Run tasks", new Runnable() {
@Override
public void run() {
buildExecuter.execute(gradle);
}
});
}还记得最开始说过的gradle构建分成3个步骤吗？Load-> Configure->Build
那这个方法doBuildStages可以很清楚的看到这个流程，大家看下上面的代码即可明白，那接下来我们一步步分析这个过程。
三. Load.executeScripts 初始化脚本
if (stage == null) {
// Evaluate init scripts
initScriptHandler.executeScripts(gradle);
// Build `buildSrc`, load settings.gradle, and construct composite (if appropriate)
settings = settingsLoader.findAndLoadSettings(gradle);
stage = Stage.Load;
}1. 首先来看第一行
initScriptHandler.executeScripts(gradle);
// Evaluate init scripts 看解释是统计初始化脚本，那具体是干什么呢？
文件路径：
subprojects\core\src\main\java\org\gradle\initialization\InitScriptHandler.java
/**
* Finds and executes all init scripts for a given build.
*/
public class InitScriptHandler {
...
public void executeScripts(final GradleInternal gradle) {
System.out.println("executeScripts");
final List initScripts = gradle.getStartParameter().getAllInitScripts();
if (initScripts.isEmpty()) {
return;
}
BuildOperationDetails operationDetails = BuildOperationDetails.displayName("Run init scripts").progressDisplayName("init scripts").build();
buildOperationExecutor.run(operationDetails, new Runnable() {
@Override
public void run() {
for (File script : initScripts) {
System.out.println("InitScriptHandler run processor" + processor);
processor.process(new UriScriptSource("initialization script", script), gradle);
}
}
});
}
} 从类InitScriptHandler的注释就知道，这个类的作用是找到并且执行初始化脚本，那我们接下来看看：
a. 它说的初始化脚本指的是什么？
b. 怎么执行初始化脚本的？
2. 首先来看getAllInitScripts是在干什么：
subprojects\core\src\main\java\org\gradle\StartParameter.java
public ListgetAllInitScripts() { CompositeInitScriptFinder initScriptFinder = new CompositeInitScriptFinder( new UserHomeInitScriptFinder(getGradleUserHomeDir()), new DistributionInitScriptFinder(gradleHomeDir) ); List scripts = new ArrayList (getInitScripts()); initScriptFinder.findScripts(scripts); return Collections.unmodifiableList(scripts); }
subprojects\core\src\main\java\org\gradle\initialization\UserHomeInitScriptFinder.java
public void findScripts(Collectionscripts) { File userInitScript = new File(userHomeDir, "init.gradle"); if (userInitScript.isFile()) { scripts.add(userInitScript); } findScriptsInDir(new File(userHomeDir, "init.d"), scripts); }
subprojects\core\src\main\java\org\gradle\initialization\DistributionInitScriptFinder.java
public void findScripts(Collectionscripts) { if (gradleHome == null) { return; } findScriptsInDir(new File(gradleHome, "init.d"), scripts); }
3个作用:
a. 尝试找到环境变量'GRADLE_USER_HOME'目录下的init.gradle文件，并加入列表。
如果没有配置环境变量'GRADLE_USER_HOME'，那么目录就是'C:\Users\xxx(你的用户名)\.gradle'
b. 找到环境变量'GRADLE_USER_HOME'下面init.d目录下的 *.gradle配置文件，并加入列表。
c. 找到gradle home目录下init.d目录的 *.gradle配置文件，并加入列表。
我的gradle_user_home和gradle_home分别是：
gradleUserHomeDir=D:\gradle_jar_cache gradleHome=E:\work_space\gradle-source-from-csdn\gradle-3.1\build\distributions\gradle-3.1-snapshot-1
其实如果大家去看下gradle home目录的init.d目录，你会发现里面有个readme.txt文件，里面有这样的描述：
You can add .gradle init scripts to this directory. Each one is executed at the start of the build.
那我们的Gradle 源代码流程分析也验证了这句话。
3. 然后来看看processor.process在干什么
for (File script : initScripts) {
processor.process(new UriScriptSource("initialization script", script), gradle);
}首先initScripts是指上面我们统计3个目录下得到的脚本文件集合，那这里就是挨个执行它们。
那UriScriptSource是用来解析传入的script文件，把它的内容读出来。
那继续看process方法
文件路径：
subprojects\core\src\main\java\org\gradle\configuration\DefaultInitScriptProcessor.java
/**
* Processes (and runs) an init script for a specified build. Handles defining
* the classpath based on the initscript {} configuration closure.
*/
public class DefaultInitScriptProcessor implements InitScriptProcessor {
...
public void process(final ScriptSource initScript, GradleInternal gradle) {
....
configurer.apply(gradle);
}
}文件路径：
subprojects\core\src\main\java\org\gradle\configuration\DefaultScriptPluginFactory.java
public void apply(final Object target) {
System.out.println("ScriptPluginImpl apply 1");
...
// Pass 1, extract plugin requests and plugin repositories and execute buildscript {}, ignoring (i.e. not even compiling) anything else
Class scriptType = initialPassScriptTarget.getScriptClass();
InitialPassStatementTransformer initialPassStatementTransformer = new InitialPassStatementTransformer(scriptSource, initialPassScriptTarget, documentationRegistry);
SubsetScriptTransformer initialTransformer = new SubsetScriptTransformer(initialPassStatementTransformer);
String id = INTERNER.intern("cp_" + initialPassScriptTarget.getId());
CompileOperation initialOperation = new FactoryBackedCompileOperation(id, initialTransformer, initialPassStatementTransformer, pluginRequestsSerializer);
ScriptRunner initialRunner = compiler.compile(scriptType, initialOperation, baseScope.getExportClassLoader(), Actions.doNothing());
initialRunner.run(target, services);
PluginRequests pluginRequests = initialRunner.getData();
PluginManagerInternal pluginManager = initialPassScriptTarget.getPluginManager();
System.out.println("ScriptPluginImpl apply is empty: " + pluginRequests.isEmpty());
pluginRequestApplicator.applyPlugins(pluginRequests, scriptHandler, pluginManager, targetScope);
System.out.println("ScriptPluginImpl apply 4");
// Pass 2, compile everything except buildscript {}, pluginRepositories{}, and plugin requests, then run
final ScriptTarget scriptTarget = secondPassTarget(target);
scriptType = scriptTarget.getScriptClass();
BuildScriptTransformer buildScriptTransformer = new BuildScriptTransformer(scriptSource, scriptTarget);
String operationId = scriptTarget.getId();
CompileOperation operation = new FactoryBackedCompileOperation(operationId, buildScriptTransformer, buildScriptTransformer, buildScriptDataSerializer);
final ScriptRunner runner = compiler.compile(scriptType, operation, targetScope.getLocalClassLoader(), ClosureCreationInterceptingVerifier.INSTANCE);
if (scriptTarget.getSupportsMethodInheritance() && runner.getHasMethods()) {
System.out.println("ScriptPluginImpl apply 5");
scriptTarget.attachScript(runner.getScript());
}
System.out.println("ScriptPluginImpl apply 6");
if (!runner.getRunDoesSomething()) {
System.out.println("ScriptPluginImpl apply 7");
return;
}
Runnable buildScriptRunner = new Runnable() {
public void run() {
System.out.println("ScriptPluginImpl apply 8");
runner.run(target, services);
}
};
System.out.println("ScriptPluginImpl apply 9");
boolean hasImperativeStatements = runner.getData().getHasImperativeStatements();
scriptTarget.addConfiguration(buildScriptRunner, !hasImperativeStatements);
} 执行流程:
a. 在DefaultScriptPluginFactory的apply里面主要有两步 pass1/ pass2
在pass1的时候，处理的文件是
'D:\gradle_jar_cache\caches\3.1-snapshot-1\scripts-remapped\settings_brbxf8awmquo5r6nxrgcmg7fq\iaw3k0vmpedkxsp2gv9xvnom\cp_settingsd7eae713beda1bd9e69f8461da734880\metadata\metadata.bin'
b. 在pass2的时候，处理初始化脚本，如果脚本文件里面有配置，则会到走到'ScriptPluginImpl apply 8' 加载这个脚本的属性；
如果脚本里面有配置，只是一个空文件，则从'ScriptPluginImpl apply 7'返回。
总结下这个步骤的内容：
a. 加载gradle_user_home下面init.gradle和init.d/目录下 *.gradle以及gradle home 目录下的init.d/目录下的 *.gradle文件
b. 如果有这些文件，而且内容不为空，那么将会加载它们配置的属性。
比较重要也很令人费解是这行代码：
scriptCompilerFactory.createCompiler(scriptSource);
这行代码粗看没有什么，但是仔细分析后其实大有乾坤！它是在为下一行
initialRunner.run(target, services);
生成可以加载的Java类，最终调用DefaultScriptCompilationHandler.compileToDir来生成类。 生成的类路径如下：
D:\gradle_jar_cache\caches\3.1-snapshot-1\scripts\df5frxe005h8vnbjcuzkr2g0s\cp_settings\cp_settingsd7eae713beda1bd9e69f8461da734880
执行堆栈如下：
java.lang.Exception: Sandy compile to dir at org.gradle.groovy.scripts.internal.DefaultScriptCompilationHandler.compileToDir(DefaultScriptCompilationHandler.java:97) at org.gradle.groovy.scripts.internal.FileCacheBackedScriptClassCompiler$CompileToCrossBuildCacheAction.execute(FileCacheBackedScriptClassCompiler.java:160) at org.gradle.groovy.scripts.internal.FileCacheBackedScriptClassCompiler$CompileToCrossBuildCacheAction.execute(FileCacheBackedScriptClassCompiler.java:141) at org.gradle.groovy.scripts.internal.FileCacheBackedScriptClassCompiler$Progre***eportingInitializer.execute(FileCacheBackedScriptClassCompiler.java:185) at org.gradle.groovy.scripts.internal.FileCacheBackedScriptClassCompiler$Progre***eportingInitializer.execute(FileCacheBackedScriptClassCompiler.java:164) at org.gradle.cache.internal.DefaultPersistentDirectoryCache$Initializer.initialize(DefaultPersistentDirectoryCache.java:100) at org.gradle.cache.internal.DefaultCacheAccess$2.run(DefaultCacheAccess.java:116) at org.gradle.cache.internal.DefaultFileLockManager$DefaultFileLock.doWriteAction(DefaultFileLockManager.java:179) at org.gradle.cache.internal.DefaultFileLockManager$DefaultFileLock.writeFile(DefaultFileLockManager.java:169) at org.gradle.cache.internal.DefaultCacheAccess.open(DefaultCacheAccess.java:113) at org.gradle.cache.internal.DefaultPersistentDirectoryStore.open(DefaultPersistentDirectoryStore.java:47) at org.gradle.cache.internal.DefaultPersistentDirectoryStore.open(DefaultPersistentDirectoryStore.java:28) at org.gradle.cache.internal.DefaultCacheFactory.doOpen(DefaultCacheFactory.java:83) at org.gradle.cache.internal.DefaultCacheFactory.open(DefaultCacheFactory.java:51) at org.gradle.cache.internal.DefaultCacheRepository$PersistentCacheBuilder.doOpen(DefaultCacheRepository.java:147) at org.gradle.cache.internal.DefaultCacheRepository$AbstractCacheBuilder.open(DefaultCacheRepository.java:121) at org.gradle.groovy.scripts.internal.FileCacheBackedScriptClassCompiler$RemapBuildScriptsAction.execute(FileCacheBackedScriptClassCompiler.java:365) at org.gradle.groovy.scripts.internal.FileCacheBackedScriptClassCompiler$RemapBuildScriptsAction.execute(FileCacheBackedScriptClassCompiler.java:333) at org.gradle.groovy.scripts.internal.FileCacheBackedScriptClassCompiler$Progre***eportingInitializer.execute(FileCacheBackedScriptClassCompiler.java:185) at org.gradle.groovy.scripts.internal.FileCacheBackedScriptClassCompiler$Progre***eportingInitializer.execute(FileCacheBackedScriptClassCompiler.java:164) at org.gradle.cache.internal.DefaultPersistentDirectoryCache$Initializer.initialize(DefaultPersistentDirectoryCache.java:100) at org.gradle.cache.internal.DefaultCacheAccess$2.run(DefaultCacheAccess.java:116) at org.gradle.cache.internal.DefaultFileLockManager$DefaultFileLock.doWriteAction(DefaultFileLockManager.java:179) at org.gradle.cache.internal.DefaultFileLockManager$DefaultFileLock.writeFile(DefaultFileLockManager.java:169) at org.gradle.cache.internal.DefaultCacheAccess.open(DefaultCacheAccess.java:113) at org.gradle.cache.internal.DefaultPersistentDirectoryStore.open(DefaultPersistentDirectoryStore.java:47) at org.gradle.cache.internal.DefaultPersistentDirectoryStore.open(DefaultPersistentDirectoryStore.java:28) at org.gradle.cache.internal.DefaultCacheFactory.doOpen(DefaultCacheFactory.java:83) at org.gradle.cache.internal.DefaultCacheFactory.open(DefaultCacheFactory.java:51) at org.gradle.cache.internal.DefaultCacheRepository$PersistentCacheBuilder.doOpen(DefaultCacheRepository.java:147) at org.gradle.cache.internal.DefaultCacheRepository$AbstractCacheBuilder.open(DefaultCacheRepository.java:121) at org.gradle.groovy.scripts.internal.FileCacheBackedScriptClassCompiler.compile(FileCacheBackedScriptClassCompiler.java:111) at org.gradle.groovy.scripts.internal.CrossBuildInMemoryCachingScriptClassCache.getOrCompile(CrossBuildInMemoryCachingScriptClassCache.java:46) at org.gradle.groovy.scripts.internal.BuildScopeInMemoryCachingScriptClassCompiler.compile(BuildScopeInMemoryCachingScriptClassCompiler.java:48) at org.gradle.groovy.scripts.DefaultScriptCompilerFactory$ScriptCompilerImpl.compile(DefaultScriptCompilerFactory.java:50) at org.gradle.configuration.DefaultScriptPluginFactory$ScriptPluginImpl.apply(DefaultScriptPluginFactory.java:154) at org.gradle.configuration.project.BuildScriptProcessor.execute(BuildScriptProcessor.java:40) at org.gradle.configuration.project.BuildScriptProcessor.execute(BuildScriptProcessor.java:25) at org.gradle.configuration.project.ConfigureActionsProjectEvaluator.evaluate(ConfigureActionsProjectEvaluator.java:34) at org.gradle.configuration.project.LifecycleProjectEvaluator.evaluate(LifecycleProjectEvaluator.java:55) at org.gradle.api.internal.project.DefaultProject.evaluate(DefaultProject.java:573) at org.gradle.api.internal.project.DefaultProject.evaluate(DefaultProject.java:125) at org.gradle.execution.TaskPathProjectEvaluator.configureHierarchy(TaskPathProjectEvaluator.java:42) at org.gradle.configuration.DefaultBuildConfigurer.configure(DefaultBuildConfigurer.java:38) at org.gradle.initialization.DefaultGradleLauncher$2.run(DefaultGradleLauncher.java:154) at org.gradle.internal.Factories$1.create(Factories.java:22) at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:91) at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:53) at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(DefaultGradleLauncher.java:151) at org.gradle.initialization.DefaultGradleLauncher.access$200(DefaultGradleLauncher.java:33) at org.gradle.initialization.DefaultGradleLauncher$1.create(DefaultGradleLauncher.java:114) at org.gradle.initialization.DefaultGradleLauncher$1.create(DefaultGradleLauncher.java:106) at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:91) at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:63) at org.gradle.initialization.DefaultGradleLauncher.doBuild(DefaultGradleLauncher.java:106) at org.gradle.initialization.DefaultGradleLauncher.run(DefaultGradleLauncher.java:92) at org.gradle.launcher.exec.GradleBuildController.run(GradleBuildController.java:67) at org.gradle.tooling.internal.provider.ExecuteBuildActionRunner.run(ExecuteBuildActionRunner.java:31) at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:43) at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:42) at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:26) at org.gradle.tooling.internal.provider.ContinuousBuildActionExecuter.execute(ContinuousBuildActionExecuter.java:79) at org.gradle.tooling.internal.provider.ContinuousBuildActionExecuter.execute(ContinuousBuildActionExecuter.java:51) at org.gradle.launcher.cli.RunBuildAction.run(RunBuildAction.java:54) at org.gradle.internal.Actions$RunnableActionAdapter.execute(Actions.java:173) at org.gradle.launcher.cli.CommandLineActionFactory$ParseAndBuildAction.execute(CommandLineActionFactory.java:250) at org.gradle.launcher.cli.CommandLineActionFactory$ParseAndBuildAction.execute(CommandLineActionFactory.java:217) at org.gradle.launcher.cli.JavaRuntimeValidationAction.execute(JavaRuntimeValidationAction.java:33) at org.gradle.launcher.cli.JavaRuntimeValidationAction.execute(JavaRuntimeValidationAction.java:24) at org.gradle.launcher.cli.ExceptionReportingAction.execute(ExceptionReportingAction.java:33) at org.gradle.launcher.cli.ExceptionReportingAction.execute(ExceptionReportingAction.java:22) at org.gradle.launcher.cli.CommandLineActionFactory$WithLogging.execute(CommandLineActionFactory.java:210) at org.gradle.launcher.cli.CommandLineActionFactory$WithLogging.execute(CommandLineActionFactory.java:174) at org.gradle.launcher.Main.doAction(Main.java:33) at org.gradle.launcher.bootstrap.EntryPoint.run(EntryPoint.java:45) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:483) at org.gradle.launcher.bootstrap.ProcessBootstrap.runNoExit(ProcessBootstrap.java:60) at org.gradle.launcher.bootstrap.ProcessBootstrap.run(ProcessBootstrap.java:37) at org.gradle.launcher.GradleMain.main(GradleMain.java:24)
接下来，继续往下面看Load步骤的第二个步骤findAndLoadSettings.
// Build `buildSrc`, load settings.gradle, and construct composite (if appropriate) settings = settingsLoader.findAndLoadSettings(gradle);
四. Load.findAndLoadSettings
settings = settingsLoader.findAndLoadSettings(gradle);
首先settingsLoader使用了装饰者模式，从外到内包装顺序是：
public class NotifyingSettingsLoader implements SettingsLoader {
private final SettingsLoader settingsLoader;
...
@Override
public SettingsInternal findAndLoadSettings(GradleInternal gradle) {
SettingsInternal settings = settingsLoader.findAndLoadSettings(gradle);
gradle.getBuildListenerBroadcaster().settingsEvaluated(settings);
buildLoader.load(settings.getRootProject(), settings.getDefaultProject(), gradle, settings.getRootClassLoaderScope());
gradle.getBuildListenerBroadcaster().projectsLoaded(gradle);
return settings;
}
}
public class CompositeBuildSettingsLoader implements SettingsLoader {
private final SettingsLoader delegate;
...
@Override
public SettingsInternal findAndLoadSettings(GradleInternal gradle) {
SettingsInternal settings = delegate.findAndLoadSettings(gradle);
...
}
}
/**
* Handles locating and processing setting.gradle files. Also deals with the buildSrc module, since that modules is
* found after settings is located, but needs to be built before settings is processed.
*/
public class DefaultSettingsLoader implements SettingsLoader {
...
@Override
public SettingsInternal findAndLoadSettings(GradleInternal gradle) {
...
SettingsInternal settings = findSettingsAndLoadIfAppropriate(gradle, startParameter);
...
ProjectSpec spec = ProjectSpecs.forStartParameter(startParameter, settings);
System.out.println(" spec: " + spec);
if (spec.containsProject(settings.getProjectRegistry())) {
System.out.println("spec.containsProject");
setDefaultProject(spec, settings);
return settings;
}
// Try again with empty settings
StartParameter noSearchParameter = startParameter.newInstance();
noSearchParameter.useEmptySettings();
settings = findSettingsAndLoadIfAppropriate(gradle, noSearchParameter);
// Set explicit build file, if required
if (noSearchParameter.getBuildFile() != null) {
ProjectDescriptor rootProject = settings.getRootProject();
rootProject.setBuildFileName(noSearchParameter.getBuildFile().getName());
}
setDefaultProject(spec, settings);
return settings;
}NotifyingSettingsLoader首先会根据装饰者模式逐个的调用进去，所以DefaultSettingsLoader.findAndLoadSettings方法，然后在回头看NotifyingSettingsLoader.findAndLoadSettings的其他代码。
DefaultSettingsLoader根据注释，它是要处理项目目录下的setting.gradle文件，同时处理buildSrc模块，这个好像一般项目没有。
所以，可以先看DefaultSettingsLoader.findAndLoadSettings方法。
1. DefaultSettingsLoader
文件路径：
subprojects\core\src\main\java\org\gradle\initialization\DefaultSettingsLoader.java
@Override
public SettingsInternal findAndLoadSettings(GradleInternal gradle) {
StartParameter startParameter = gradle.getStartParameter();
System.out.println("DefaultSettingsLoader.findAndLoadSettings startParameter: " + startParameter
+ " gradle: " + gradle);
SettingsInternal settings = findSettingsAndLoadIfAppropriate(gradle, startParameter);
System.out.println(" settings: " + settings);
ProjectSpec spec = ProjectSpecs.forStartParameter(startParameter, settings);
System.out.println(" spec: " + spec);
if (spec.containsProject(settings.getProjectRegistry())) {
System.out.println("spec.containsProject");
setDefaultProject(spec, settings);
return settings;
}
// Try again with empty settings
StartParameter noSearchParameter = startParameter.newInstance();
noSearchParameter.useEmptySettings();
settings = findSettingsAndLoadIfAppropriate(gradle, noSearchParameter);
// Set explicit build file, if required
if (noSearchParameter.getBuildFile() != null) {
ProjectDescriptor rootProject = settings.getRootProject();
rootProject.setBuildFileName(noSearchParameter.getBuildFile().getName());
}
setDefaultProject(spec, settings);
return settings;
}
private SettingsInternal findSettingsAndLoadIfAppropriate(GradleInternal gradle,
...
return settingsProcessor.process(gradle, settingsLocation, buildSourceClassLoader, startParameter);
}
2. 首先看findSettingsAndLoadIfAppropriate 这个方法。看名字应该是寻找Settings并尝试加载它。
它调用的是settingsProcessor.process 这个settingsProcessor又使用了装饰者模式，共有3个类。
public class NotifyingSettingsProcessor implements SettingsProcessor {}
public class PropertiesLoadingSettingsProcessor implements SettingsProcessor {
public SettingsInternal process(GradleInternal gradle,
SettingsLocation settingsLocation,
ClassLoaderScope baseClassLoaderScope,
StartParameter startParameter) {
System.out.println("PropertiesLoadingSettingsProcessor run");
propertiesLoader.loadProperties(settingsLocation.getSettingsDir());
return processor.process(gradle, settingsLocation, baseClassLoaderScope, startParameter);
}
}
public class ScriptEvaluatingSettingsProcessor implements SettingsProcessor {
public SettingsInternal process(GradleInternal gradle,
SettingsLocation settingsLocation,
ClassLoaderScope baseClassLoaderScope,
StartParameter startParameter) {
System.out.println("Script Process process");
Clock settingsProcessingClock = new Clock();
Map properties = propertiesLoader.mergeProperties(Collections.emptyMap());
SettingsInternal settings = settingsFactory.createSettings(gradle, settingsLocation.getSettingsDir(),
settingsLocation.getSettingsScriptSource(), properties, startParameter, baseClassLoaderScope);
applySettingsScript(settingsLocation, settings);
LOGGER.debug("Timing: Processing settings took: {}", settingsProcessingClock.getTime());
return settings;
}
} 真的，gradle源代码使用了很多装饰者模式。
3. 首先看看PropertiesLoadingSettingsProcessor.process方法
文件路径：subprojects\core\src\main\java\org\gradle\initialization\PropertiesLoadingSettingsProcessor.java
public class PropertiesLoadingSettingsProcessor implements SettingsProcessor {
...
public SettingsInternal process(GradleInternal gradle,
SettingsLocation settingsLocation,
ClassLoaderScope baseClassLoaderScope,
StartParameter startParameter) {
System.out.println("PropertiesLoadingSettingsProcessor run");
propertiesLoader.loadProperties(settingsLocation.getSettingsDir());
return processor.process(gradle, settingsLocation, baseClassLoaderScope, startParameter);
}
}文件路径：
subprojects\core\src\main\java\org\gradle\initialization\DefaultGradlePropertiesLoader.java
public static final String SYSTEM_PROP_PREFIX = "systemProp";
String ENV_PROJECT_PROPERTIES_PREFIX = "ORG_GRADLE_PROJECT_";
String SYSTEM_PROJECT_PROPERTIES_PREFIX = "org.gradle.project.";
public void loadProperties(File settingsDir) {
loadProperties(settingsDir, startParameter, getAllSystemProperties(), getAllEnvProperties());
}
void loadProperties(File settingsDir, StartParameter startParameter, Map systemProperties, Map envProperties) {
defaultProperties.clear();
overrideProperties.clear();
addGradleProperties(defaultProperties, new File(settingsDir, Project.GRADLE_PROPERTIES));
addGradleProperties(overrideProperties, new File(startParameter.getGradleUserHomeDir(), Project.GRADLE_PROPERTIES));
setSystemProperties(startParameter.getSystemPropertiesArgs());
overrideProperties.putAll(getEnvProjectProperties(envProperties));
overrideProperties.putAll(getSystemProjectProperties(systemProperties));
for (String key : systemProperties.keySet()) {
System.out.println("system properties, key: " + key + " value: " + systemProperties.get(key));
}
for (String key : envProperties.keySet()) {
System.out.println("env properties, key: " + key + " value: " + envProperties.get(key));
}
overrideProperties.putAll(startParameter.getProjectProperties());
}
private void setSystemProperties(Map properties) {
addSystemPropertiesFromGradleProperties(defaultProperties);
addSystemPropertiesFromGradleProperties(overrideProperties);
System.getProperties().putAll(properties);
}
private void addSystemPropertiesFromGradleProperties(Map properties) {
for (String key : properties.keySet()) {
if (key.startsWith(Project.SYSTEM_PROP_PREFIX + '.')) {
System.setProperty(key.substring((Project.SYSTEM_PROP_PREFIX + '.').length()), properties.get(key));
}
}
} 在loadProperties方法里面，它首先调用addGradleProperties方法分别把
a. 项目路径下面的gradle.properties
b. gradle_user_home路径下面的gradle.properties
两个文件分别读取到defaultProperties和overrideProperties两个map中。
比如，像这种属性：
org.gradle.jvmargs=-Xmx1536m # When configured, Gradle will run in incubating parallel mode. # This option should only be used with decoupled projects. More details, visit # http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects # org.gradle.parallel=true
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