Add support for Build Variants to react.gradle

Summary:
This PR adds support for Android Gradle [Build Variants](https://sites.google.com/a/android.com/tools/tech-docs/new-build-system/user-guide#TOC-Build-Variants) when generating the JS bundle.

**Before**: only supported "bundleDebugJsAndAssets" and "bundleReleaseJsAndAssets"

**Now**: all variants are supported
Examples: "bundleDevDebugJsAndAssets", "bundleStageAlphaJsAndAssets", or "bundleBetaJsAndAssets"

The Gradle script will automatically create bundle tasks for each build variant found in a project.
Closes https://github.com/facebook/react-native/pull/4686

Reviewed By: svcscm

Differential Revision: D2815856

Pulled By: foghina

fb-gh-sync-id: 4518de70d178205bc3e5044d2446b56c40298da2

local-cli/generator-android/templates/src/app/build.gradle

@@ -3,7 +3,8 @@ apply plugin: "com.android.application"
 import com.android.build.OutputFile
 
 /**
- * The react.gradle file registers two tasks: bundleDebugJsAndAssets and bundleReleaseJsAndAssets.
+ * The react.gradle file registers a task for each build variant (e.g. bundleDebugJsAndAssets
+ * and bundleReleaseJsAndAssets).
  * These basically call `react-native bundle` with the correct arguments during the Android build
  * cycle. By default, bundleDebugJsAndAssets is skipped, as in debug/dev mode we prefer to load the
  * bundle directly from the development server. Below you can see all the possible configurations
@@ -23,6 +24,13 @@ import com.android.build.OutputFile
  *   // whether to bundle JS and assets in release mode
  *   bundleInRelease: true,
  *
+ *   // whether to bundle JS and assets in another build variant (if configured).
+ *   // See http://tools.android.com/tech-docs/new-build-system/user-guide#TOC-Build-Variants
+ *   // The configuration property is in the format 'bundleIn${productFlavor}${buildType}'
+ *   // bundleInFreeDebug: true,
+ *   // bundleInPaidRelease: true,
+ *   // bundleInBeta: true,
+ *
  *   // the root of your project, i.e. where "package.json" lives
  *   root: "../../",
  *

local-cli/generator-android/templates/src/app/react.gradle

@@ -11,69 +11,8 @@ def elvisFile(thing) {
 }
 
 def reactRoot = elvisFile(config.root) ?: file("../../")
-def jsBundleDirDebug = elvisFile(config.jsBundleDirDebug) ?:
-        file("$buildDir/intermediates/assets/debug")
-def jsBundleDirRelease = elvisFile(config.jsBundleDirRelease) ?:
-        file("$buildDir/intermediates/assets/release")
-def resourcesDirDebug = elvisFile(config.resourcesDirDebug) ?:
-        file("$buildDir/intermediates/res/merged/debug")
-def resourcesDirRelease = elvisFile(config.resourcesDirRelease) ?:
-        file("$buildDir/intermediates/res/merged/release")
 def inputExcludes = config.inputExcludes ?: ["android/**", "ios/**"]
 
-def jsBundleFileDebug = file("$jsBundleDirDebug/$bundleAssetName")
-def jsBundleFileRelease = file("$jsBundleDirRelease/$bundleAssetName")
-
-task bundleDebugJsAndAssets(type: Exec) {
-    // create dirs if they are not there (e.g. the "clean" task just ran)
-    doFirst {
-        jsBundleDirDebug.mkdirs()
-        resourcesDirDebug.mkdirs()
-    }
-
-    // set up inputs and outputs so gradle can cache the result
-    inputs.files fileTree(dir: reactRoot, excludes: inputExcludes)
-    outputs.dir jsBundleDirDebug
-    outputs.dir resourcesDirDebug
-
-    // set up the call to the react-native cli
-    workingDir reactRoot
-    if (Os.isFamily(Os.FAMILY_WINDOWS)) {
-        commandLine "cmd", "/c", "react-native", "bundle", "--platform", "android", "--dev", "true", "--entry-file",
-            entryFile, "--bundle-output", jsBundleFileDebug, "--assets-dest", resourcesDirDebug
-    } else {
-        commandLine "react-native", "bundle", "--platform", "android", "--dev", "true", "--entry-file",
-            entryFile, "--bundle-output", jsBundleFileDebug, "--assets-dest", resourcesDirDebug
-    }
-
-    enabled config.bundleInDebug ?: false
-}
-
-task bundleReleaseJsAndAssets(type: Exec) {
-    // create dirs if they are not there (e.g. the "clean" task just ran)
-    doFirst {
-        jsBundleDirRelease.mkdirs()
-        resourcesDirRelease.mkdirs()
-    }
-
-    // set up inputs and outputs so gradle can cache the result
-    inputs.files fileTree(dir: reactRoot, excludes: inputExcludes)
-    outputs.dir jsBundleDirRelease
-    outputs.dir resourcesDirRelease
-
-    // set up the call to the react-native cli
-    workingDir reactRoot
-    if (Os.isFamily(Os.FAMILY_WINDOWS)) {
-        commandLine "cmd","/c", "react-native", "bundle", "--platform", "android", "--dev", "false", "--entry-file",
-            entryFile, "--bundle-output", jsBundleFileRelease, "--assets-dest", resourcesDirRelease
-    } else {
-        commandLine "react-native", "bundle", "--platform", "android", "--dev", "false", "--entry-file",
-            entryFile, "--bundle-output", jsBundleFileRelease, "--assets-dest", resourcesDirRelease
-    }
-
-    enabled config.bundleInRelease ?: true
-}
-
 void runBefore(String dependentTaskName, Task task) {
     Task dependentTask = tasks.findByPath(dependentTaskName);
     if (dependentTask != null) {
@@ -82,25 +21,76 @@ void runBefore(String dependentTaskName, Task task) {
 }
 
 gradle.projectsEvaluated {
+    // Grab all build types and product flavors
+    def buildTypes = android.buildTypes.collect { type -> type.name }
+    def productFlavors = android.productFlavors.collect { flavor -> flavor.name }
 
-    // hook bundleDebugJsAndAssets into the android build process
+    // When no product flavors defined, use empty
+    if (!productFlavors) productFlavors.add('')
 
-    bundleDebugJsAndAssets.dependsOn mergeDebugResources
+    productFlavors.each { productFlavorName ->
-    bundleDebugJsAndAssets.dependsOn mergeDebugAssets
+        buildTypes.each { buildTypeName ->
+            // Create variant and source names
+            def sourceName = "${buildTypeName}"
+            def targetName = "${sourceName.capitalize()}"
+            if (productFlavorName) {
+                sourceName = "${productFlavorName}${targetName}"
+            }
 
-    runBefore('processArmeabi-v7aDebugResources', bundleDebugJsAndAssets)
+            // React js bundle directories
-    runBefore('processX86DebugResources', bundleDebugJsAndAssets)
+            def jsBundleDirConfigName = "jsBundleDir${targetName}"
-    runBefore('processUniversalDebugResources', bundleDebugJsAndAssets)
+            def jsBundleDir = elvisFile(config."$jsBundleDirConfigName") ?:
-    runBefore('processDebugResources', bundleDebugJsAndAssets)
+                    file("$buildDir/intermediates/assets/${sourceName}")
 
-    // hook bundleReleaseJsAndAssets into the android build process
+            def resourcesDirConfigName = "jsBundleDir${targetName}"
+            def resourcesDir = elvisFile(config."${resourcesDirConfigName}") ?:
+                    file("$buildDir/intermediates/res/merged/${sourceName}")
+            def jsBundleFile = file("$jsBundleDir/$bundleAssetName")
 
-    bundleReleaseJsAndAssets.dependsOn mergeReleaseResources
+            // Bundle task name for variant
-    bundleReleaseJsAndAssets.dependsOn mergeReleaseAssets
+            def bundleJsAndAssetsTaskName = "bundle${targetName}JsAndAssets"
 
-    runBefore('processArmeabi-v7aReleaseResources', bundleReleaseJsAndAssets)
+            def currentBundleTask = tasks.create(
-    runBefore('processX86ReleaseResources', bundleReleaseJsAndAssets)
+                    name: bundleJsAndAssetsTaskName,
-    runBefore('processUniversalReleaseResources', bundleReleaseJsAndAssets)
+                    type: Exec) {
-    runBefore('processReleaseResources', bundleReleaseJsAndAssets)
+                group = "react"
+                description = "bundle JS and assets for ${targetName}."
 
+                // Create dirs if they are not there (e.g. the "clean" task just ran)
+                doFirst {
+                    jsBundleDir.mkdirs()
+                    resourcesDir.mkdirs()
+                }
+
+                // Set up inputs and outputs so gradle can cache the result
+                inputs.files fileTree(dir: reactRoot, excludes: inputExcludes)
+                outputs.dir jsBundleDir
+                outputs.dir resourcesDir
+
+                // Set up the call to the react-native cli
+                workingDir reactRoot
+
+                // Set up dev mode
+                def devEnabled = !targetName.toLowerCase().contains("release")
+                if (Os.isFamily(Os.FAMILY_WINDOWS)) {
+                    commandLine "cmd", "/c", "react-native", "bundle", "--platform", "android", "--dev", "${devEnabled}",
+                            "--entry-file", entryFile, "--bundle-output", jsBundleFile, "--assets-dest", resourcesDir
+                } else {
+                    commandLine "react-native", "bundle", "--platform", "android", "--dev", "${devEnabled}",
+                            "--entry-file", entryFile, "--bundle-output", jsBundleFile, "--assets-dest", resourcesDir
+                }
+
+                enabled config."bundleIn${targetName}" ?: targetName.toLowerCase().contains("release")
+            }
+
+            // Hook bundle${productFlavor}${buildType}JsAndAssets into the android build process
+            currentBundleTask.dependsOn("merge${targetName}Resources")
+            currentBundleTask.dependsOn("merge${targetName}Assets")
+
+            runBefore("processArmeabi-v7a${targetName}Resources", currentBundleTask)
+            runBefore("processX86${targetName}Resources", currentBundleTask)
+            runBefore("processUniversal${targetName}Resources", currentBundleTask)
+            runBefore("process${targetName}Resources", currentBundleTask)
+        }
+    }
 }