3. 具體編譯方法是通過 RemappingScriptSource.getResource().getText() 獲取到腳本內容，然後通過 GroovyClassLoader.parseClass 編譯的。

build.gradle 腳本內容

apply plugin: com.android.application
apply plugin: myplugin

android {
compileSdkVersion 26
defaultConfig {
applicationId "com.zy.easygradle"
minSdkVersion 19
targetSdkVersion 26
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile(proguard-android.txt), proguard-rules.pro
}
}
compileOptions {
sourceCompatibility 1.8
targetCompatibility 1.8
}

flavorDimensions "size", "color"

productFlavors {
big {
dimension "size"
}
small {
dimension "size"
}
blue {
dimension "color"
}
red {
dimension "color"
}
}
}

dependencies {
// implementation gradleApi()
implementation fileTree(dir: libs, include: [*.jar])
implementation com.android.support:appcompat-v7:26.1.0
implementation com.android.support.constraint:constraint-layout:1.1.3
implementation project(:module1)
}

gradle.addBuildListener(new BuildListener() {
@Override
void buildStarted(Gradle gradle) {
// println(構建開始)
}

@Override
void settingsEvaluated(Settings settings) {
// println(settings 文件解析完成)
}

@Override
void projectsLoaded(Gradle gradle) {
// println(項目載入完成)
}

@Override
void projectsEvaluated(Gradle gradle) {
// println(項目解析完成)
}

@Override
void buildFinished(BuildResult result) {
// println(構建完成)
}
})

gradle.addProjectEvaluationListener(new ProjectEvaluationListener() {
@Override
void beforeEvaluate(Project project) {
// println("${project.name} 項目配置之前調用")
}

@Override
void afterEvaluate(Project project, ProjectState state) {
// println("${project.name} 項目配置之後調用")
}
})

gradle.taskGraph.whenReady {
// println("task 圖構建完成")
}
gradle.taskGraph.beforeTask {
// println("task 執行完成")
}
gradle.taskGraph.afterTask {
// println("task 執行完成")
}

task task1 {
doLast {
println(task2)
}
}

task task2 {
doLast {
println(task2)
}
}
task1.finalizedBy(task2)

編譯後 class 內容

package defpackage;

import groovy.lang.MetaClass;
import java.lang.ref.SoftReference;
import org.codehaus.groovy.reflection.ClassInfo;
import org.codehaus.groovy.runtime.GStringImpl;
import org.codehaus.groovy.runtime.ScriptBytecodeAdapter;
import org.codehaus.groovy.runtime.callsite.CallSite;
import org.codehaus.groovy.runtime.callsite.CallSiteArray;
import org.codehaus.groovy.runtime.typehandling.ShortTypeHandling;
import org.gradle.api.internal.project.ProjectScript;
import org.gradle.internal.scripts.ScriptOrigin;

/* compiled from: /Users/zy/workspace/note/blog/android-training/gradle/EasyGradle/app/build.gradle */
public class build_ak168fqfikdepd6py4yef8tgs extends ProjectScript implements ScriptOrigin {
private static /* synthetic */ SoftReference $callSiteArray = null;
private static /* synthetic */ ClassInfo $staticClassInfo = null;
public static transient /* synthetic */ boolean __$stMC = false;
private static final /* synthetic */ String __originalClassName = "_BuildScript_";
private static final /* synthetic */ String __signature = "988274f32891a2a3d3b8d16074617c05";

private static /* synthetic */ CallSiteArray $createCallSiteArray() {
String[] strArr = new String[22];
build_ak168fqfikdepd6py4yef8tgs.$createCallSiteArray_1(strArr);
return new CallSiteArray(build_ak168fqfikdepd6py4yef8tgs.class, strArr);
}

private static /* synthetic */ void $createCallSiteArray_1(String[] strArr) {
strArr[0] = "apply";
strArr[1] = "apply";
strArr[2] = "android";
strArr[3] = "dependencies";
strArr[4] = "addBuildListener";
strArr[5] = "gradle";
strArr[6] = "addProjectEvaluationListener";
strArr[7] = "gradle";
strArr[8] = "whenReady";
strArr[9] = "taskGraph";
strArr[10] = "gradle";
strArr[11] = "beforeTask";
strArr[12] = "taskGraph";
strArr[13] = "gradle";
strArr[14] = "afterTask";
strArr[15] = "taskGraph";
strArr[16] = "gradle";
strArr[17] = "task";
strArr[18] = "task";
strArr[19] = "finalizedBy";
strArr[20] = "task1";
strArr[21] = "task2";
}

/* JADX WARNING: inconsistent code. */
/* Code decompiled incorrectly, please refer to instructions dump. */
private static /* synthetic */ org.codehaus.groovy.runtime.callsite.CallSite[] $getCallSiteArray() {
/*
r0 = $callSiteArray;
if (r0 == 0) goto L_0x000e;
L_0x0004:
r0 = $callSiteArray;
r0 = r0.get();
r0 = (org.codehaus.groovy.runtime.callsite.CallSiteArray) r0;
if (r0 != 0) goto L_0x0019;
L_0x000e:
r0 = defpackage.build_ak168fqfikdepd6py4yef8tgs.$createCallSiteArray();
r1 = new java.lang.ref.SoftReference;
r1.<init>(r0);
$callSiteArray = r1;
L_0x0019:
r0 = r0.array;
return r0;
*/
throw new UnsupportedOperationException("Method not decompiled: build_ak168fqfikdepd6py4yef8tgs.$getCallSiteArray():org.codehaus.groovy.runtime.callsite.CallSite[]");
}

public build_ak168fqfikdepd6py4yef8tgs() {
build_ak168fqfikdepd6py4yef8tgs.$getCallSiteArray();
}

protected /* synthetic */ MetaClass $getStaticMetaClass() {
if (getClass() != build_ak168fqfikdepd6py4yef8tgs.class) {
return ScriptBytecodeAdapter.initMetaClass(this);
}
ClassInfo classInfo = $staticClassInfo;
if (classInfo == null) {
classInfo = ClassInfo.getClassInfo(getClass());
$staticClassInfo = classInfo;
}
return classInfo.getMetaClass();
}

public String getContentHash() {
return __signature;
}

public String getOriginalClassName() {
return __originalClassName;
}

public Object run() {
CallSite[] $getCallSiteArray = build_ak168fqfikdepd6py4yef8tgs.$getCallSiteArray();
$getCallSiteArray[0].callCurrent(this, ScriptBytecodeAdapter.createMap(new Object[]{"plugin", "com.android.application"}));
$getCallSiteArray[1].callCurrent(this, ScriptBytecodeAdapter.createMap(new Object[]{"plugin", "myplugin"}));
$getCallSiteArray[2].callCurrent(this, new _run_closure1(this, this));
$getCallSiteArray[3].callCurrent(this, new _run_closure2(this, this));
$getCallSiteArray[4].call($getCallSiteArray[5].callGroovyObjectGetProperty(this), new 1(this));
$getCallSiteArray[6].call($getCallSiteArray[7].callGroovyObjectGetProperty(this), new 2(this));
$getCallSiteArray[8].call($getCallSiteArray[9].callGetProperty($getCallSiteArray[10].callGroovyObjectGetProperty(this)), new _run_closure3(this, this));
$getCallSiteArray[11].call($getCallSiteArray[12].callGetProperty($getCallSiteArray[13].callGroovyObjectGetProperty(this)), new _run_closure4(this, this));
$getCallSiteArray[14].call($getCallSiteArray[15].callGetProperty($getCallSiteArray[16].callGroovyObjectGetProperty(this)), new _run_closure5(this, this));
$getCallSiteArray[17].callCurrent(this, "task1", new _run_closure6(this, this));
$getCallSiteArray[18].callCurrent(this, "task2", new _run_closure7(this, this));
return $getCallSiteArray[19].call($getCallSiteArray[20].callGroovyObjectGetProperty(this), $getCallSiteArray[21].callGroovyObjectGetProperty(this));
}

public /* synthetic */ Object this$dist$get$7(String name) {
build_ak168fqfikdepd6py4yef8tgs.$getCallSiteArray();
return ScriptBytecodeAdapter.getGroovyObjectProperty(build_ak168fqfikdepd6py4yef8tgs.class, this, ShortTypeHandling.castToString(new GStringImpl(new Object[]{name}, new String[]{"", ""})));
}

public /* synthetic */ Object this$dist$invoke$7(String name, Object args) {
build_ak168fqfikdepd6py4yef8tgs.$getCallSiteArray();
return ScriptBytecodeAdapter.invokeMethodOnCurrentN(build_ak168fqfikdepd6py4yef8tgs.class, this, ShortTypeHandling.castToString(new GStringImpl(new Object[]{name}, new String[]{"", ""})), ScriptBytecodeAdapter.despreadList(new Object[0], new Object[]{args}, new int[]{0}));
}

public /* synthetic */ void this$dist$set$7(String name, Object value) {
build_ak168fqfikdepd6py4yef8tgs.$getCallSiteArray();
ScriptBytecodeAdapter.setGroovyObjectProperty(value, build_ak168fqfikdepd6py4yef8tgs.class, this, ShortTypeHandling.castToString(new GStringImpl(new Object[]{name}, new String[]{"", ""})));
}
}

可以看到，腳本類繼承自 ProjectScript，實現了 run 方法。

CallSite[] $getCallSiteArray = build_ak168fqfikdepd6py4yef8tgs.$getCallSiteArray();

獲取到 callsiteArray，這個就是 createCallSiteArray_1() 方法中賦值的，可以看到，此處的 callsiteArray，都是腳本中的 dsl，其實也就是調用的方法名。 獲取到 callsiteArray 以後，執行 $getCallSiteArray[0].callCurrent() 類似的方法，這個就是在調用方法。調用的方法對應的腳本代碼在下面加了注釋。

public Object run() {
CallSite[] $getCallSiteArray = build_ak168fqfikdepd6py4yef8tgs.$getCallSiteArray();
// apply plugin "com.android.application" 依賴插件
$getCallSiteArray[0].callCurrent(this, ScriptBytecodeAdapter.createMap(new Object[]{"plugin", "com.android.application"}));
// apply plugin myplugin
$getCallSiteArray[1].callCurrent(this, ScriptBytecodeAdapter.createMap(new Object[]{"plugin", "myplugin"}));
// android {}
$getCallSiteArray[2].callCurrent(this, new _run_closure1(this, this));
// dependencies {}
$getCallSiteArray[3].callCurrent(this, new _run_closure2(this, this));
// task {}
$getCallSiteArray[17].callCurrent(this, "task1", new _run_closure6(this, this));
// ...
return $getCallSiteArray[19].call($getCallSiteArray[20].callGroovyObjectGetProperty(this), $getCallSiteArray[21].callGroovyObjectGetProperty(this));
}

上面看到，task1 對應的是 _run_closure6 這個類，我們看看這個類的內容。

/* compiled from: /Users/zy/workspace/note/blog/android-training/gradle/EasyGradle/app/build.gradle */
public class build_ak168fqfikdepd6py4yef8tgs$_run_closure6 extends Closure implements GeneratedClosure, ScriptOrigin {
private static final /* synthetic */ String __originalClassName = "_BuildScript_$_run_closure6";

private static /* synthetic */ CallSiteArray $createCallSiteArray() {
String[] strArr = new String[1];
strArr[0] = "doLast";
return new CallSiteArray(build_ak168fqfikdepd6py4yef8tgs$_run_closure6.class, strArr);
}

public build_ak168fqfikdepd6py4yef8tgs$_run_closure6(Object _outerInstance, Object _thisObject) {
build_ak168fqfikdepd6py4yef8tgs$_run_closure6.$getCallSiteArray();
super(_outerInstance, _thisObject);
}

public Object doCall() {
build_ak168fqfikdepd6py4yef8tgs$_run_closure6.$getCallSiteArray();
return doCall(null);
}

public Object doCall(Object it) {
return build_ak168fqfikdepd6py4yef8tgs$_run_closure6.$getCallSiteArray()[0].callCurrent(this, new _closure17(this, getThisObject()));
}
}

省略了一些內容，可以看到，這個閉包的類繼承了 Closure，然後實現了 doCall 方法，在 doCall 方法里，調用了 doLast 方法，傳入了 _closure17 實例。這個就是腳本中的 task { doLast {} } 對應的實現。

/* compiled from: /Users/zy/workspace/note/blog/android-training/gradle/EasyGradle/app/build.gradle */
public class build_ak168fqfikdepd6py4yef8tgs$_run_closure6$_closure17 extends Closure implements GeneratedClosure, ScriptOrigin {
private static /* synthetic */ SoftReference $callSiteArray = null;
private static /* synthetic */ ClassInfo $staticClassInfo = null;
public static transient /* synthetic */ boolean __$stMC = false;
private static final /* synthetic */ String __originalClassName = "_BuildScript_$_run_closure6$_closure17";
private static final /* synthetic */ String __signature = "ab46bccc923a8e0a93329f7333d732c8";

private static /* synthetic */ CallSiteArray $createCallSiteArray() {
String[] strArr = new String[1];
strArr[0] = "println";
return new CallSiteArray(build_ak168fqfikdepd6py4yef8tgs$_run_closure6$_closure17.class, strArr);
}
public Object doCall() {
build_ak168fqfikdepd6py4yef8tgs$_run_closure6$_closure17.$getCallSiteArray();
return doCall(null);
}
public Object doCall(Object it) {
return build_ak168fqfikdepd6py4yef8tgs$_run_closure6$_closure17.$getCallSiteArray()[0].callCurrent(this, "task2");
}
}

同樣也是繼承了 Closure，在 doCall 方法里調用了 println，這正是我們在 task 的里執行的任務，也就是前面提到的 task 的 actions。

這裡我們再理順一下，每一個 build.gradle 腳本，對應一個繼承了 ProjectScript 的類，每一個閉包，對應了一個繼承自 Closure 的類

7.2 調用腳本 run 方法

接著就是執行腳本類的 run 方法，也就是我們在上面分析的 run 方法。

task task1 {
// 配置階段會執行
println(configure)
doLast {
// 運行階段執行
println(run)
}
}

八、插件調用流程

之前在 Gradle的基本使用 里講到過自定義插件，使用的時候是通過 apply plugin xxx 來使用的，具體的調用鏈路如下：

apply: "xxx" -> Script.run -> ProjectScript.apply -> DefaultObjectConfigurationAction.run -> DefaultObjectConfigurationAction.applyType(pluginId) -> DefaultPluginManager.apply -> DefaultPluginManager.AddPluginBuildOperation.run -> AddPluginBuildOperation.addPlugin -> RuleBasedPluginTarget.applyImpreative -> ImperativeOnlyPluginTarget.applyImperative -> Plugin.apply

最後的 Plugin.apply 就調用到插件里實現的 apply() 函數了

九、總結

整體結構圖

1. gradle 運行流程

loadSettings
configureBuild
constructTaskGraph
runTasks
finishBuild

1. Task 的本質，就是一系列的 Actions
2. 腳本編譯流程 獲取腳本內容 -> 編譯成 class 文件，繼承自 ProjectScript -> 執行 ProjectScript.run 方法
3. 腳本的 buildscript 在腳本其他內容前執行

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