Migrate metalava download to gradle's resolution process.

build.gradle

@@ -76,6 +76,9 @@ configure(subprojects) {
         google()
         jcenter()
         mavenLocal()
+        maven {
+            url 'https://storage.googleapis.com/android-ci/mvn/'
+        }
     }
 
     apply plugin: 'com.github.sherter.google-java-format'

buildSrc/src/main/java/com/google/firebase/gradle/plugins/FirebaseJavaLibraryPlugin.java

@@ -18,7 +18,6 @@
 import com.google.common.collect.ImmutableMap;
 import com.google.firebase.gradle.plugins.apiinfo.ApiInformationTask;
 import com.google.firebase.gradle.plugins.apiinfo.GenerateApiTxtFileTask;
-import com.google.firebase.gradle.plugins.apiinfo.GenerateStubsTask;
 import com.google.firebase.gradle.plugins.apiinfo.GetMetalavaJarTask;
 import com.google.firebase.gradle.plugins.ci.Coverage;
 import java.io.File;
@@ -161,8 +160,6 @@ private static void setupApiInformationAnalysis(Project project) {
                 "docStubs",
                 GenerateStubsTask.class,
                 task -> {
-                  task.setMetalavaJarPath(metalavaOutputJarFile.getAbsolutePath());
-                  task.setOutputDir(new File(project.getBuildDir(), "doc-stubs"));
                   task.dependsOn("getMetalavaJar");
 
                   task.setSourceSet(mainSourceSet);

buildSrc/src/main/java/com/google/firebase/gradle/plugins/FirebaseLibraryPlugin.java

@@ -22,7 +22,6 @@
 import com.google.common.collect.ImmutableMap;
 import com.google.firebase.gradle.plugins.apiinfo.ApiInformationTask;
 import com.google.firebase.gradle.plugins.apiinfo.GenerateApiTxtFileTask;
-import com.google.firebase.gradle.plugins.apiinfo.GenerateStubsTask;
 import com.google.firebase.gradle.plugins.apiinfo.GetMetalavaJarTask;
 import com.google.firebase.gradle.plugins.ci.Coverage;
 import com.google.firebase.gradle.plugins.ci.device.FirebaseTestServer;
@@ -102,7 +101,6 @@ public void apply(Project project) {
                     .setFreeCompilerArgs(
                         ImmutableList.of("-module-name", kotlinModuleName(project))));
 
-
     Dokka.configure(project, android, firebaseLibrary);
   }
 
@@ -174,10 +172,6 @@ private static void setupApiInformationAnalysis(Project project, LibraryExtensio
                 "docStubs",
                 GenerateStubsTask.class,
                 task -> {
-                  task.setMetalavaJarPath(metalavaOutputJarFile.getAbsolutePath());
-                  task.setOutputDir(new File(project.getBuildDir(), "doc-stubs"));
-                  task.dependsOn("getMetalavaJar");
-
                   task.setSourceSet(mainSourceSet);
                 });
     project.getTasks().getByName("check").dependsOn(docStubs);

buildSrc/src/main/java/com/google/firebase/gradle/plugins/Metalava.kt

@@ -0,0 +1,94 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.firebase.gradle.plugins
+
+import com.android.build.gradle.api.AndroidSourceSet
+import java.io.File
+import org.gradle.api.DefaultTask
+import org.gradle.api.Project
+import org.gradle.api.artifacts.Configuration
+import org.gradle.api.file.FileCollection
+import org.gradle.api.tasks.InputFiles
+import org.gradle.api.tasks.OutputDirectory
+import org.gradle.api.tasks.SourceSet
+import org.gradle.api.tasks.TaskAction
+
+val Project.metalavaConfig: Configuration
+    get() =
+        configurations.findByName("metalavaArtifacts")
+                ?: configurations.create("metalavaArtifacts") {
+                    this.dependencies.add([email protected]("com.android:metalava:1.3.0"))
+                }
+
+fun Project.runMetalavaWithArgs(
+    arguments: List<String>
+) {
+    val allArgs = listOf(
+            "--no-banner",
+            "--hide",
+            "HiddenSuperclass" // We allow having a hidden parent class
+    ) + arguments
+
+    project.javaexec {
+        main = "com.android.tools.metalava.Driver"
+        classpath = project.metalavaConfig
+        args = allArgs
+    }
+}
+
+abstract class GenerateStubsTask : DefaultTask() {
+    /** Source files against which API signatures will be validated. */
+    lateinit var sourceSet: Object
+
+    @get:InputFiles
+    lateinit var classPath: FileCollection
+
+    @get:OutputDirectory
+    val outputDir: File = File(project.buildDir, "doc-stubs")
+
+    private val sourceDirs: Set<File>
+        get() = with(sourceSet) {
+            when (this) {
+                is SourceSet -> java.srcDirs
+                is AndroidSourceSet -> java.srcDirs
+                else -> throw IllegalStateException("Unsupported sourceSet provided: $javaClass")
+            }
+        }
+
+    @TaskAction
+    fun run() {
+        val sourcePath = sourceDirs.asSequence()
+                .filter { it.exists() }
+                .map { it.absolutePath }
+                .joinToString(":")
+
+        val classPath = classPath.files.asSequence()
+                .map { it.absolutePath }.toMutableList()
+        project.androidJar?.let {
+            classPath += listOf(it.absolutePath)
+        }
+
+        project.runMetalavaWithArgs(
+                listOf(
+                        "--source-path",
+                        sourcePath,
+                        "--classpath",
+                        classPath.joinToString(":"),
+                        "--include-annotations",
+                        "--doc-stubs",
+                        outputDir.absolutePath
+                ))
+    }
+}

buildSrc/src/main/java/com/google/firebase/gradle/plugins/SdkUtil.kt

@@ -0,0 +1,50 @@
+// Copyright 2019 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.firebase.gradle.plugins
+
+import com.android.build.gradle.LibraryExtension
+import java.io.File
+import java.io.FileInputStream
+import java.io.IOException
+import java.util.Properties
+import org.gradle.api.GradleException
+import org.gradle.api.Project
+
+val Project.sdkDir: File
+    get() {
+        val properties = Properties()
+        val localProperties = rootProject.file("local.properties")
+        if (localProperties.exists()) {
+            try {
+                FileInputStream(localProperties).use { fis -> properties.load(fis) }
+            } catch (ex: IOException) {
+                throw GradleException("Could not load local.properties", ex)
+            }
+        }
+        val sdkDir = properties.getProperty("sdk.dir")
+        if (sdkDir != null) {
+            return file(sdkDir)
+        }
+        val androidHome = System.getenv("ANDROID_HOME")
+                ?: throw GradleException("No sdk.dir or ANDROID_HOME set.")
+        return file(androidHome)
+    }
+
+val Project.androidJar: File?
+    get() {
+        val android = project.extensions.findByType(LibraryExtension::class.java)
+                ?: return null
+        return File(
+                sdkDir, String.format("/platforms/%s/android.jar", android.compileSdkVersion))
+    }

buildSrc/src/main/java/com/google/firebase/gradle/plugins/apiinfo/ApiInformationTask.java

@@ -15,7 +15,7 @@
 package com.google.firebase.gradle.plugins.apiinfo;
 
 import com.android.build.gradle.api.AndroidSourceSet;
-import com.google.firebase.gradle.plugins.SdkUtil;
+import com.google.firebase.gradle.plugins.SdkUtilKt;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
@@ -107,7 +107,7 @@ void execute() {
             .map(File::getAbsolutePath)
             .collect(Collectors.joining(":"));
 
-    File androidJar = SdkUtil.getAndroidJar(getProject());
+    File androidJar = SdkUtilKt.getAndroidJar(getProject());
     if (androidJar != null) {
       classPath += ":" + androidJar.getAbsolutePath();
     }

buildSrc/src/main/java/com/google/firebase/gradle/plugins/apiinfo/GenerateApiTxtFileTask.java

@@ -15,7 +15,7 @@
 package com.google.firebase.gradle.plugins.apiinfo;
 
 import com.android.build.gradle.api.AndroidSourceSet;
-import com.google.firebase.gradle.plugins.SdkUtil;
+import com.google.firebase.gradle.plugins.SdkUtilKt;
 import java.io.File;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -88,7 +88,7 @@ void execute() {
             .map(File::getAbsolutePath)
             .collect(Collectors.joining(":"));
 
-    File androidJar = SdkUtil.getAndroidJar(getProject());
+    File androidJar = SdkUtilKt.getAndroidJar(getProject());
     if (androidJar != null) {
       classPath += ":" + androidJar.getAbsolutePath();
     }