TurboModule Android: properly set up RNTester ndkBuild and cleanup de…

…pendencies

Summary:
Before RNTester compilation starts, it needs to wait for :ReactAndroid NDK build to finish, so that it knows where to find the exported .so files. This tells the `preBuild` task to depends on `:ReactAndroid:prepareReactNdkLibs` task. The .so files are now copied over to the local project build dir, instead of depending on :ReactAndroid's build dir.

For cleanup, the reverse ordering is needed: before `clean` removed our temp dir to store the copied .so files, make sure the ndkBuild cleanup tasks execute beforehand.

Changelog: [Internal]

Reviewed By: hramos

Differential Revision: D23982989

fbshipit-source-id: 955d7c9bccb5855b6b066fca89764df2ede89f63

ReactAndroid/Android-prebuilt.mk

@@ -24,7 +24,7 @@ REACT_ANDROID_SRC_DIR := $(REACT_ANDROID_DIR)/src/main
 REACT_COMMON_DIR := $(REACT_ANDROID_DIR)/../ReactCommon
 REACT_GENERATED_SRC_DIR := $(REACT_ANDROID_BUILD_DIR)/generated/source
 # Note: this only have .so, not .a
-REACT_NDK_EXPORT_DIR := $(REACT_ANDROID_BUILD_DIR)/react-ndk/exported
+REACT_NDK_EXPORT_DIR := $(PROJECT_BUILD_DIR)/react-ndk/exported
 
 # fb
 include $(CLEAR_VARS)

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

@@ -186,33 +186,6 @@ android {
     }
 }
 
-if (enableCodegen) {
-    def reactAndroidProjectDir = project(':ReactAndroid').projectDir;
-    android {
-        defaultConfig {
-            externalNativeBuild {
-                ndkBuild {
-                    abiFilters "armeabi-v7a", "x86", "x86_64", "arm64-v8a"
-                    arguments "APP_PLATFORM=android-16",
-                            "APP_STL=c++_shared",
-                            "NDK_TOOLCHAIN_VERSION=clang",
-                            // The following paths assume building React Native from source.
-                            "GENERATED_SRC_DIR=$buildDir/generated/source",
-                            "REACT_ANDROID_DIR=$reactAndroidProjectDir"
-                    cFlags "-Wall", "-Werror", "-fexceptions", "-frtti", "-DWITH_INSPECTOR=1"
-                    cppFlags "-std=c++1y"
-                    targets "rntester_appmodules"
-                }
-            }
-        }
-        externalNativeBuild {
-            ndkBuild {
-                path "$projectDir/src/main/jni/Android.mk"
-            }
-        }
-    }
-}
-
 configurations {
   hermesDebugImplementation {}
   hermesReleaseImplementation {}
@@ -258,3 +231,59 @@ react {
     reactNativeRootDir = file("$rootDir")
     useJavaGenerator = System.getenv("USE_CODEGEN_JAVAPOET") ?: false
 }
+
+if (enableCodegen) {
+    // TODO: Move all this logic to CodegenPlugin.java.
+    def reactAndroidProjectDir = project(':ReactAndroid').projectDir;
+    def reactAndroidBuildDir = project(':ReactAndroid').buildDir;
+
+    android {
+        defaultConfig {
+            externalNativeBuild {
+                ndkBuild {
+                    abiFilters "armeabi-v7a", "x86", "x86_64", "arm64-v8a"
+                    arguments "APP_PLATFORM=android-16",
+                            "APP_STL=c++_shared",
+                            "NDK_TOOLCHAIN_VERSION=clang",
+                            // The following paths assume building React Native from source.
+                            "GENERATED_SRC_DIR=$buildDir/generated/source",
+                            "PROJECT_BUILD_DIR=$buildDir",
+                            "REACT_ANDROID_DIR=$reactAndroidProjectDir"
+                    cFlags "-Wall", "-Werror", "-fexceptions", "-frtti", "-DWITH_INSPECTOR=1"
+                    cppFlags "-std=c++1y"
+                    targets "rntester_appmodules"
+                }
+            }
+        }
+        externalNativeBuild {
+            ndkBuild {
+                path "$projectDir/src/main/jni/Android.mk"
+            }
+        }
+    }
+
+    def packageReactNdkLibs = tasks.register("packageReactNdkLibs", Copy) {
+        // TODO: handle extracting .so from prebuilt :ReactAndroid.
+        dependsOn(":ReactAndroid:packageReactNdkLibs")
+        from("$reactAndroidBuildDir/react-ndk/exported")
+        into("$buildDir/react-ndk/exported")
+    }
+
+    def cleanProjectNdkBuild = tasks.register("cleanProjectNdkBuild", Exec) {
+        ignoreExitValue(true)
+        tasks.forEach {
+            t ->
+                if (t.name.startsWith("externalNativeBuildClean")) {
+                    dependsOn(t);
+                }
+        }
+        // This .cxx folder may cause stale ndkBuild configuration.
+        // See https://stackoverflow.com/a/58288851.
+        commandLine("rm", "-rf", "$projectDir/.cxx")
+    }
+
+    afterEvaluate {
+        preBuild.dependsOn(packageReactNdkLibs)
+        clean.dependsOn(cleanProjectNdkBuild)
+    }
+}