Export prepareLibevent to an internal task (#32425)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/32425

This diff refactors the `prepareLibevent` task to a separate Gradle task in the `.internal` package.
The reason for this change is that `prepareLibevent` was defining a `doLast` action and would result in being
invalidated whenever the `build.gradle` file would change. This means that the Libevent headers/source files
would have been extracted again, effectively invalidating the timestamps for the native build.

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

Reviewed By: ShikaSD

Differential Revision: D31661988

fbshipit-source-id: e55c2179a187fa156f701c25bae3b48a796e2660

ReactAndroid/build.gradle

@@ -122,26 +122,12 @@ task downloadLibevent(dependsOn: createNativeDepsDirectories, type: Download) {
     dest(new File(downloadsDir, "libevent-${LIBEVENT_VERSION}.tar.gz"))
 }
 
-task prepareLibevent(dependsOn: dependenciesPath ? [] : [downloadLibevent], type: Copy) {
-    from(dependenciesPath ?: tarTree(downloadLibevent.dest))
-    from("src/main/jni/third-party/libevent/Android.mk")
-    from("src/main/jni/third-party/libevent/event-config.h")
-    from("src/main/jni/third-party/libevent/evconfig-private.h")
-    include(
-        "libevent-${LIBEVENT_VERSION}-stable/*.c",
-        "libevent-${LIBEVENT_VERSION}-stable/*.h",
-        "libevent-${LIBEVENT_VERSION}-stable/include/**/*",
-        "evconfig-private.h",
-        "event-config.h",
-        "Android.mk"
-    )
-    eachFile { fname -> fname.path = (fname.path - "libevent-${LIBEVENT_VERSION}-stable/") }
-    includeEmptyDirs = false
-    into("$thirdPartyNdkDir/libevent")
 
-    doLast {
-        ant.move(file: "$thirdPartyNdkDir/libevent/event-config.h", tofile: "$thirdPartyNdkDir/libevent/include/event2/event-config.h")
-    }
+final def prepareLibevent = tasks.register("prepareLibevent", PrepareLibeventTask) {
+    it.dependsOn(dependenciesPath ? [] : [downloadLibevent])
+    it.libeventPath.setFrom(dependenciesPath ?: tarTree(downloadLibevent.dest))
+    it.libeventVersion.set(LIBEVENT_VERSION)
+    it.outputDir.set(new File(thirdPartyNdkDir, "libevent"))
 }
 
 task prepareHermes(dependsOn: createNativeDepsDirectories, type: Copy) {

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

@@ -0,0 +1,53 @@
+/*
+ * 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.ConfigurableFileCollection
+import org.gradle.api.file.DirectoryProperty
+import org.gradle.api.provider.Property
+import org.gradle.api.tasks.*
+
+/**
+ * A task that takes care of extracting Libevent from a source folder/zip and preparing it to be
+ * consumed by the NDK.
+ */
+abstract class PrepareLibeventTask : DefaultTask() {
+
+  @get:InputFiles abstract val libeventPath: ConfigurableFileCollection
+
+  @get:Input abstract val libeventVersion: Property<String>
+
+  @get:OutputDirectory abstract val outputDir: DirectoryProperty
+
+  @TaskAction
+  fun taskAction() {
+    project.copy { it ->
+      it.from(libeventPath)
+      it.from(project.file("src/main/jni/third-party/libevent/Android.mk"))
+      it.from(project.file("src/main/jni/third-party/libevent/event-config.h"))
+      it.from(project.file("src/main/jni/third-party/libevent/evconfig-private.h"))
+      it.include(
+          "libevent-${libeventVersion.get()}-stable/*.c",
+          "libevent-${libeventVersion.get()}-stable/*.h",
+          "libevent-${libeventVersion.get()}-stable/include/**/*",
+          "evconfig-private.h",
+          "event-config.h",
+          "Android.mk")
+      it.eachFile { it.path = it.path.removePrefix("libevent-${libeventVersion.get()}-stable/") }
+      it.includeEmptyDirs = false
+      it.into(outputDir)
+    }
+    File(outputDir.asFile.get(), "event-config.h").apply {
+      val destination =
+          File(this.parentFile, "include/event2/event-config.h").apply { parentFile.mkdirs() }
+      renameTo(destination)
+    }
+  }
+}

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

@@ -0,0 +1,101 @@
+/*
+ * 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 java.io.*
+import org.junit.Assert.*
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.TemporaryFolder
+
+class PrepareLibeventTaskTest {
+
+  @get:Rule val tempFolder = TemporaryFolder()
+
+  @Test(expected = IllegalStateException::class)
+  fun prepareBoostTask_withMissingConfiguration_fails() {
+    val task = createTestTask<PrepareLibeventTask>()
+
+    task.taskAction()
+  }
+
+  @Test
+  fun prepareBoostTask_copiesMakefile() {
+    val libeventPath = tempFolder.newFolder("libeventPath")
+    val output = tempFolder.newFolder("output")
+    val project = createProject()
+    val task =
+        createTestTask<PrepareLibeventTask>(project = project) {
+          it.libeventPath.setFrom(libeventPath)
+          it.libeventVersion.set("1.0.0")
+          it.outputDir.set(output)
+        }
+    File(project.projectDir, "src/main/jni/third-party/libevent/Android.mk").apply {
+      parentFile.mkdirs()
+      createNewFile()
+    }
+    task.taskAction()
+
+    assertTrue(File(output, "Android.mk").exists())
+  }
+
+  @Test
+  fun prepareBoostTask_copiesConfigFiles() {
+    val libeventPath = tempFolder.newFolder("libeventPath")
+    val output = tempFolder.newFolder("output")
+    val project = createProject()
+    val task =
+        createTestTask<PrepareLibeventTask>(project = project) {
+          it.libeventPath.setFrom(libeventPath)
+          it.libeventVersion.set("1.0.0")
+          it.outputDir.set(output)
+        }
+    File(project.projectDir, "src/main/jni/third-party/libevent/event-config.h").apply {
+      parentFile.mkdirs()
+      createNewFile()
+    }
+    File(project.projectDir, "src/main/jni/third-party/libevent/evconfig-private.h").createNewFile()
+
+    task.taskAction()
+
+    assertTrue(File(output, "evconfig-private.h").exists())
+    assertTrue(File(output, "include/event2/event-config.h").exists())
+  }
+
+  @Test
+  fun prepareBoostTask_copiesSourceFiles() {
+    val libeventPath = tempFolder.newFolder("libeventPath")
+    val output = tempFolder.newFolder("output")
+    val task =
+        createTestTask<PrepareLibeventTask> {
+          it.libeventPath.setFrom(libeventPath)
+          it.libeventVersion.set("1.0.0")
+          it.outputDir.set(output)
+        }
+    File(libeventPath, "libevent-1.0.0-stable/sample.c").apply {
+      parentFile.mkdirs()
+      createNewFile()
+    }
+    File(libeventPath, "libevent-1.0.0-stable/sample.h").apply {
+      parentFile.mkdirs()
+      createNewFile()
+    }
+    File(libeventPath, "libevent-1.0.0-stable/include/sample.h").apply {
+      parentFile.mkdirs()
+      createNewFile()
+    }
+
+    task.taskAction()
+
+    assertTrue(File(output, "sample.c").exists())
+    assertTrue(File(output, "sample.h").exists())
+    assertTrue(File(output, "include/sample.h").exists())
+  }
+}