Export prepareJSC to an internal task (#32427)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/32427

This diff refactors the `prepareJSC` task to a separate Gradle task in the `.internal` package.

The reason for this change is that `prepareJSC` was just a plain `Task` and not a `Copy` task.
It was defining a top level `doLast` action and would result in being
invalidated whenever the `build.gradle` file would change. This means that the JSC headers/source files
would have been extracted again, effectively invalidating the timestamps for the native build.

Changelog:
[Internal] [Changed] - Export prepareJSC to an internal task

Reviewed By: ShikaSD

Differential Revision: D31682293

fbshipit-source-id: 3d4cd9d9ce2fcd45e61f3c8c6685b69a622a1912

ReactAndroid/build.gradle

@@ -161,35 +161,11 @@ final def prepareGlog = tasks.register("prepareGlog", PrepareGlogTask) {
 }
 
 // Create Android.mk library module based on jsc from npm
-task prepareJSC {
-    doLast {
-        def jscPackagePath = findNodeModulePath(projectDir, "jsc-android")
-        if (!jscPackagePath) {
-            throw new GradleScriptException("Could not find the jsc-android npm package", null)
-        }
-
-        def jscDist = file("$jscPackagePath/dist")
-        if (!jscDist.exists()) {
-            throw new GradleScriptException("The jsc-android npm package is missing its \"dist\" directory", null)
-        }
-
-        def jscAAR = fileTree(jscDist).matching({ it.include "**/android-jsc/**/*.aar" }).singleFile
-        def soFiles = zipTree(jscAAR).matching({ it.include "**/*.so" })
-
-        def headerFiles = fileTree(jscDist).matching({ it.include "**/include/*.h" })
-
-        copy {
-            from(soFiles)
-            from(headerFiles)
-            from("src/main/jni/third-party/jsc/Android.mk")
-
-            filesMatching("**/*.h", { it.path = "JavaScriptCore/${it.name}" })
-
-            includeEmptyDirs(false)
-            into("$thirdPartyNdkDir/jsc")
-        }
-    }
+tasks.register('prepareJSC', PrepareJSCTask) {
+    it.jscPackagePath.set(findNodeModulePath(projectDir, "jsc-android"))
+    it.outputDir = project.layout.buildDirectory.dir("third-party-ndk/jsc")
 }
+
 task downloadNdkBuildDependencies {
     if (!boostPath) {
         dependsOn(downloadBoost)

packages/react-native-gradle-plugin/src/main/kotlin/com/facebook/react/tasks/internal/PrepareJSCTask.kt

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.react.tasks.internal
+
+import java.io.File
+import org.gradle.api.DefaultTask
+import org.gradle.api.file.DirectoryProperty
+import org.gradle.api.provider.Property
+import org.gradle.api.tasks.*
+
+/**
+ * A task that takes care of unbundling JSC and preparing it for be consumed by the Android NDK.
+ * Specifically it will unbundle shared libs, headers and will copy over the Makefile from
+ * `src/main/jni/third-party/jsc/`
+ */
+abstract class PrepareJSCTask : DefaultTask() {
+
+  @get:Input abstract val jscPackagePath: Property<String>
+
+  @get:OutputDirectory abstract val outputDir: DirectoryProperty
+
+  @TaskAction
+  fun taskAction() {
+    if (!jscPackagePath.isPresent || jscPackagePath.orNull == null) {
+      error("Could not find the jsc-android npm package")
+    }
+    val jscDist = File(jscPackagePath.get(), "dist")
+    if (!jscDist.exists()) {
+      error("The jsc-android npm package is missing its \"dist\" directory")
+    }
+    val jscAAR =
+        project.fileTree(jscDist).matching { it.include("**/android-jsc/**/*.aar") }.singleFile
+    val soFiles = project.zipTree(jscAAR).matching { it.include("**/*.so") }
+    val headerFiles = project.fileTree(jscDist).matching { it.include("**/include/*.h") }
+
+    project.copy { it ->
+      it.from(soFiles)
+      it.from(headerFiles)
+      it.from(project.file("src/main/jni/third-party/jsc/Android.mk"))
+      it.filesMatching("**/*.h") { it.path = "JavaScriptCore/${it.name}" }
+      it.includeEmptyDirs = false
+      it.into(outputDir)
+    }
+  }
+}

packages/react-native-gradle-plugin/src/test/kotlin/com/facebook/react/tasks/internal/PrepareJSCTaskTest.kt

@@ -0,0 +1,128 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.react.tasks.internal
+
+import com.facebook.react.tests.createProject
+import com.facebook.react.tests.createTestTask
+import com.facebook.react.tests.zipFiles
+import java.io.*
+import org.junit.Assert.*
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.TemporaryFolder
+
+class PrepareJSCTaskTest {
+
+  @get:Rule val tempFolder = TemporaryFolder()
+
+  @Test(expected = IllegalStateException::class)
+  fun prepareJSCTask_withMissingPackage_fails() {
+    val task = createTestTask<PrepareJSCTask>()
+
+    task.taskAction()
+  }
+
+  @Test(expected = IllegalStateException::class)
+  fun prepareJSCTask_withNullPackage_fails() {
+    val task = createTestTask<PrepareJSCTask> { it.jscPackagePath.set(null as String?) }
+
+    task.taskAction()
+  }
+
+  @Test(expected = IllegalStateException::class)
+  fun prepareJSCTask_withMissingDistFolder_fails() {
+    val task =
+        createTestTask<PrepareJSCTask> { it.jscPackagePath.set(tempFolder.root.absolutePath) }
+
+    task.taskAction()
+  }
+
+  @Test
+  fun prepareJSCTask_ignoresEmptyDirs() {
+    prepareInputFolder()
+    val output = tempFolder.newFolder("output")
+    File(tempFolder.root, "dist/just/an/empty/folders/").apply { mkdirs() }
+
+    val task =
+        createTestTask<PrepareJSCTask> {
+          it.jscPackagePath.set(tempFolder.root.absolutePath)
+          it.outputDir.set(output)
+        }
+
+    task.taskAction()
+
+    assertFalse(File(output, "just/an/empty/folders/").exists())
+  }
+
+  @Test
+  fun prepareJSCTask_copiesSoFiles() {
+    val soFile = tempFolder.newFile("libsomething.so")
+    prepareInputFolder(aarContent = listOf(soFile))
+    val output = tempFolder.newFolder("output")
+
+    val task =
+        createTestTask<PrepareJSCTask> {
+          it.jscPackagePath.set(tempFolder.root.absolutePath)
+          it.outputDir.set(output)
+        }
+
+    task.taskAction()
+
+    assertEquals("libsomething.so", output.listFiles()?.first()?.name)
+  }
+
+  @Test
+  fun prepareJSCTask_copiesHeaderFilesToCorrectFolder() {
+    prepareInputFolder()
+    File(tempFolder.root, "dist/include/justaheader.h").apply {
+      parentFile.mkdirs()
+      createNewFile()
+    }
+    val output = tempFolder.newFolder("output")
+
+    val task =
+        createTestTask<PrepareJSCTask> {
+          it.jscPackagePath.set(tempFolder.root.absolutePath)
+          it.outputDir.set(output)
+        }
+
+    task.taskAction()
+
+    assertTrue(File(output, "JavaScriptCore/justaheader.h").exists())
+  }
+
+  @Test
+  fun prepareJSCTask_copiesMakefile() {
+    val project = createProject()
+    prepareInputFolder()
+    File(project.projectDir, "src/main/jni/third-party/jsc/Android.mk").apply {
+      parentFile.mkdirs()
+      createNewFile()
+    }
+    val output = tempFolder.newFolder("output")
+
+    val task =
+        createTestTask<PrepareJSCTask>(project = project) {
+          it.jscPackagePath.set(tempFolder.root.absolutePath)
+          it.outputDir.set(output)
+        }
+
+    task.taskAction()
+
+    assertTrue(File(output, "Android.mk").exists())
+  }
+
+  private fun prepareInputFolder(aarContent: List<File> = listOf(tempFolder.newFile())) {
+    val dist = tempFolder.newFolder("dist")
+    File(dist, "android-jsc/android-library.aar").apply {
+      parentFile.mkdirs()
+      createNewFile()
+    }
+    zipFiles(File(dist, "android-jsc/android-library.aar"), aarContent)
+  }
+}

packages/react-native-gradle-plugin/src/test/kotlin/com/facebook/react/tests/TaskTestUtils.kt

@@ -7,6 +7,9 @@
 
 package com.facebook.react.tests
 
+import java.io.*
+import java.util.zip.ZipEntry
+import java.util.zip.ZipOutputStream
 import org.gradle.api.Project
 import org.gradle.api.Task
 import org.gradle.testfixtures.ProjectBuilder
@@ -23,3 +26,18 @@ internal inline fun <reified T : Task> createTestTask(
     taskName: String = T::class.java.simpleName,
     crossinline block: (T) -> Unit = {}
 ): T = project.tasks.register(taskName, T::class.java) { block(it) }.get()
+
+/** A util function to zip a list of files from [contents] inside the zipfile at [destination]. */
+internal fun zipFiles(destination: File, contents: List<File>) {
+  ZipOutputStream(BufferedOutputStream(FileOutputStream(destination.absolutePath))).use { out ->
+    for (file in contents) {
+      FileInputStream(file).use { fi ->
+        BufferedInputStream(fi).use { origin ->
+          val entry = ZipEntry(file.name)
+          out.putNextEntry(entry)
+          origin.copyTo(out, 1024)
+        }
+      }
+    }
+  }
+}