Update ReactAndroid to use the AGP NDK Apis (facebook#32443)

Summary:
Pull Request resolved: facebook#32443

This diff removes all the custom Gradle machinery to build the native code and delegates to AGP
the triggering of the `ndk-build` command. This means that the native build will be now invoked
with the `:ReactAndroid:externalNativeBuild<Variant>` task.

An important thing to notice is that that task will always run, and will delegate to Make the
compilation avoidance. If you invoke the task twice, the second time it will be significantly faster.
On my machine this takes ~6/7 mins the first time, and 30 seconds the second time.

There are some gotchas that are worth noting:
* The native build will run on every build now. Given the complexity of our native build graph,
even with an up-to-date build, Make will still take ~30 seconds on my machine to analyse all the
targets and mention that there is no work to be done. I believe this could be impactful for local
development experience. The mitigation I found was to apply an `abiFilter` to build only the ABI
of the target device (e.g. arm64 for a real device and so on).
This reduces the native build to ~10 seconds.
* All the change to the `react-native-gradle-plugin` source will cause the Gradle tasks to be
considered invalid. Therefore they will re-extract the header files inside the folders that are
used by Make to compile, triggering a near-full rebuild. This can be a bit painful when building
 locally, if you plan to edit react-native-gradle-plugin and relaunch
 rn-tester (seems to be like an edge case scenario but worth pointing out). The mitigation here
 would be to invoke the tasks like

```
gw :packages:rn-tester:android:app:installHermesDebug -x prepareBoost -x prepareLibevent -x prepareGlog \
   -x prepareJSC -x extractNativeDependencies -x generateCodegenArtifactsFromSchema \
   -x generateCodegenSchemaFromJavaScript
```

Changelog:
[Internal] [Changed] - Refactor Extract Headers and JNI from AARs to an internal task

Reviewed By: ShikaSD

Differential Revision: D31683721

fbshipit-source-id: 0736891c8197b424d3db30ea593d6bc61fd69ffd

.gitignore

@@ -30,6 +30,7 @@ project.xcworkspace
 /packages/rn-tester/android/app/gradlew
 /packages/rn-tester/android/app/gradlew.bat
 /ReactAndroid/build/
+/ReactAndroid/.cxx/
 /ReactAndroid/gradle/
 /ReactAndroid/gradlew
 /ReactAndroid/gradlew.bat

ReactAndroid/build.gradle

@@ -212,39 +212,6 @@ def findNodeModulePath(baseDir, packageName) {
     return null
 }
 
-def getNdkBuildName() {
-    if (Os.isFamily(Os.FAMILY_WINDOWS)) {
-        return "ndk-build.cmd"
-    } else {
-        return "ndk-build"
-    }
-}
-
-def findNdkBuildFullPath() {
-    // android.ndkDirectory should return project.android.ndkVersion ndkDirectory
-    def ndkDir = android.ndkDirectory ? android.ndkDirectory.absolutePath : null
-    if (ndkDir) {
-        return new File(ndkDir, getNdkBuildName()).getAbsolutePath()
-    }
-
-    // we allow to provide full path to ndk-build tool
-    if (hasProperty("ndk.command")) {
-        return property("ndk.command")
-    }
-    // or just a path to the containing directory
-    if (hasProperty("ndk.path")) {
-        ndkDir = property("ndk.path")
-        return new File(ndkDir, getNdkBuildName()).getAbsolutePath()
-    }
-
-    // @TODO ANDROID_NDK && ndk.dir is deprecated and will be removed in the future.
-    if (System.getenv("ANDROID_NDK") != null) {
-        ndkDir = System.getenv("ANDROID_NDK")
-        return new File(ndkDir, getNdkBuildName()).getAbsolutePath()
-    }
-
-    return null
-}
 
 def reactNativeDevServerPort() {
     def value = project.getProperties().get("reactNativeDevServerPort")
@@ -264,82 +231,15 @@ def reactNativeArchitectures() {
     return value != null && isDebug ? value : "all"
 }
 
-def getNdkBuildFullPath() {
-    def ndkBuildFullPath = findNdkBuildFullPath()
-    if (ndkBuildFullPath == null) {
-        throw new GradleScriptException(
-                "ndk-build binary cannot be found, check if you've set " +
-                        "\$ANDROID_NDK environment variable correctly or if ndk.dir is " +
-                        "setup in local.properties",
-                null)
-    }
-    if (!new File(ndkBuildFullPath).canExecute()) {
-        throw new GradleScriptException(
-                "ndk-build binary " + ndkBuildFullPath + " doesn't exist or isn't executable.\n" +
-                        "Check that the \$ANDROID_NDK environment variable, or ndk.dir in local.properties, is set correctly.\n" +
-                        "(On Windows, make sure you escape backslashes in local.properties or use forward slashes, e.g. C:\\\\ndk or C:/ndk rather than C:\\ndk)",
-                null)
-    }
-    return ndkBuildFullPath
+def ndkBuildJobs() {
+    return project.findProperty("jobs") ?: Runtime.runtime.availableProcessors()
 }
 
-def buildReactNdkLib = tasks.register("buildReactNdkLib", Exec) {
-    dependsOn(prepareJSC, prepareHermes, prepareBoost, prepareDoubleConversion, prepareFmt, prepareFolly, prepareGlog, prepareLibevent, extractNativeDependencies)
-    dependsOn("generateCodegenArtifactsFromSchema");
-
-    inputs.dir("$projectDir/../ReactCommon")
-    inputs.dir("src/main/jni")
-    inputs.dir("src/main/java/com/facebook/react/turbomodule/core/jni")
-    inputs.dir("src/main/java/com/facebook/react/modules/blob")
-    outputs.dir("$buildDir/react-ndk/all")
-    def commandLineArgs = [
-            getNdkBuildFullPath(),
-            "APP_ABI=${reactNativeArchitectures()}",
-            "NDK_DEBUG=" + (nativeBuildType.equalsIgnoreCase("debug") ? "1" : "0"),
-            "NDK_PROJECT_PATH=null",
-            "NDK_APPLICATION_MK=$projectDir/src/main/jni/Application.mk",
-            "NDK_OUT=" + temporaryDir,
-            "NDK_LIBS_OUT=$buildDir/react-ndk/all",
-            "THIRD_PARTY_NDK_DIR=$thirdPartyNdkDir",
-            "REACT_COMMON_DIR=$projectDir/../ReactCommon",
-            "REACT_GENERATED_SRC_DIR=$buildDir/generated/source",
-            "REACT_SRC_DIR=$projectDir/src/main/java/com/facebook/react",
-            "-C", file("src/main/jni/react/jni").absolutePath,
-            "--jobs", project.findProperty("jobs") ?: Runtime.runtime.availableProcessors()
-    ]
-    if (Os.isFamily(Os.FAMILY_MAC)) {
-        // This flag will suppress "fcntl(): Bad file descriptor" warnings on local builds.
-        commandLineArgs.add("--output-sync=none")
-    }
-    commandLine(commandLineArgs)
-}
-
-def cleanReactNdkLib = tasks.register("cleanReactNdkLib", Exec) {
-    ignoreExitValue(true)
-    errorOutput(new ByteArrayOutputStream())
-    commandLine(getNdkBuildFullPath(),
-            "NDK_APPLICATION_MK=$projectDir/src/main/jni/Application.mk",
-            "THIRD_PARTY_NDK_DIR=$thirdPartyNdkDir",
-            "REACT_COMMON_DIR=$projectDir/../ReactCommon",
-            "-C", file("src/main/jni/react/jni").absolutePath,
-            "clean")
-    doLast {
-        file(AAR_OUTPUT_URL).delete()
-        println("Deleted aar output dir at ${file(AAR_OUTPUT_URL)}")
-    }
-}
-
-def packageReactNdkLibs = tasks.register("packageReactNdkLibs", Copy) {
-    dependsOn(buildReactNdkLib)
-    from("$buildDir/react-ndk/all")
-    into("$buildDir/react-ndk/exported")
+tasks.register("packageReactNdkLibsForBuck", Copy) {
+    dependsOn("mergeDebugNativeLibs")
+    from("$buildDir/intermediates/merged_native_libs/debug/out/lib/")
     exclude("**/libjsc.so")
     exclude("**/libhermes.so")
-}
-
-def packageReactNdkLibsForBuck = tasks.register("packageReactNdkLibsForBuck", Copy) {
-    dependsOn(packageReactNdkLibs)
-    from("$buildDir/react-ndk/exported")
     into("src/main/jni/prebuilt/lib")
 }
 
@@ -387,11 +287,36 @@ android {
 
         testApplicationId("com.facebook.react.tests.gradle")
         testInstrumentationRunner("androidx.test.runner.AndroidJUnitRunner")
+
+        externalNativeBuild {
+            ndkBuild {
+                arguments "APP_ABI=${reactNativeArchitectures()}",
+                        "NDK_APPLICATION_MK=$projectDir/src/main/jni/Application.mk",
+                        "THIRD_PARTY_NDK_DIR=$thirdPartyNdkDir",
+                        "REACT_COMMON_DIR=$projectDir/../ReactCommon",
+                        "REACT_GENERATED_SRC_DIR=$buildDir/generated/source",
+                        "REACT_SRC_DIR=$projectDir/src/main/java/com/facebook/react",
+                        "-j${ndkBuildJobs()}"
+
+                if (Os.isFamily(Os.FAMILY_MAC)) {
+                    // This flag will suppress "fcntl(): Bad file descriptor" warnings on local builds.
+                    arguments "--output-sync=none"
+                }
+            }
+        }
     }
 
+    externalNativeBuild {
+        ndkBuild {
+            path "src/main/jni/react/jni/Android.mk"
+        }
+    }
+
+    preBuild.dependsOn(prepareJSC, prepareHermes, prepareBoost, prepareDoubleConversion, prepareFmt, prepareFolly, prepareGlog, prepareLibevent, extractNativeDependencies)
+    preBuild.dependsOn("generateCodegenArtifactsFromSchema")
+
     sourceSets.main {
         jni.srcDirs = []
-        jniLibs.srcDir("$buildDir/react-ndk/exported")
         res.srcDirs = ["src/main/res/devsupport", "src/main/res/shell", "src/main/res/views/modal", "src/main/res/views/uimanager"]
         java {
             srcDirs = ["src/main/java", "src/main/libraries/soloader/java", "src/main/jni/first-party/fb/jni/java"]
@@ -400,9 +325,6 @@ android {
         }
     }
 
-    preBuild.dependsOn(packageReactNdkLibs)
-    clean.dependsOn(cleanReactNdkLib)
-
     lintOptions {
         abortOnError(false)
     }

ReactAndroid/src/main/jni/react/jni/Android.mk

@@ -89,7 +89,7 @@ LOCAL_STATIC_LIBRARIES := libreactnative libruntimeexecutor libcallinvokerholder
 LOCAL_MODULE := reactnativejni
 
 # Compile all local c++ files.
-LOCAL_SRC_FILES := $(wildcard *.cpp)
+LOCAL_SRC_FILES := $(wildcard $(LOCAL_PATH)/*.cpp)
 
 ifeq ($(APP_OPTIM),debug)
   # Keep symbols by overriding the strip command invoked by ndk-build.

packages/rn-tester/android/app/build.gradle

@@ -213,6 +213,10 @@ android {
             ]
         }
     }
+    packagingOptions {
+        pickFirst '**/libhermes.so'
+        pickFirst '**/libjsc.so'
+    }
 }
 
 configurations {
@@ -287,9 +291,9 @@ if (enableCodegen) {
 
     def packageReactNdkLibs = tasks.register("packageReactNdkLibs", Copy) {
         // TODO: handle extracting .so from prebuilt :ReactAndroid.
-        dependsOn(":ReactAndroid:packageReactNdkLibs")
+        dependsOn(":ReactAndroid:packageReactNdkLibsForBuck")
         dependsOn("generateCodegenSchemaFromJavaScript")
-        from("$reactAndroidBuildDir/react-ndk/exported")
+        from("$reactAndroidProjectDir/src/main/jni/prebuilt/lib")
         into("$buildDir/react-ndk/exported")
     }
 

template/android/app/build.gradle

@@ -186,6 +186,11 @@ android {
 
         }
     }
+
+    packagingOptions {
+        pickFirst '**/libhermes.so'
+        pickFirst '**/libjsc.so'
+    }
 }
 
 dependencies {