Export prepareBoost to an internal task

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

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

Reviewed By: ShikaSD

Differential Revision: D31662120

fbshipit-source-id: 1af56d1e4405cb7da66b246498d30f1b364a9ca3

ReactAndroid/build.gradle

@@ -56,15 +56,11 @@ task downloadBoost(dependsOn: createNativeDepsDirectories, type: Download) {
     dest(new File(downloadsDir, "boost_${BOOST_VERSION}.tar.gz"))
 }
 
-task prepareBoost(dependsOn: boostPath ? [] : [downloadBoost], type: Copy) {
-    from(boostPath ?: tarTree(resources.gzip(downloadBoost.dest)))
-    from("src/main/jni/third-party/boost")
-    include("Android.mk", "boost_${BOOST_VERSION}/boost/**/*.hpp", "boost/boost/**/*.hpp", "asm/**/*.S")
-    includeEmptyDirs = false
-    into("$thirdPartyNdkDir/boost")
-    doLast {
-        file("$thirdPartyNdkDir/boost/boost").renameTo("$thirdPartyNdkDir/boost/boost_${BOOST_VERSION}")
-    }
+final def prepareBoost = tasks.register("prepareBoost", PrepareBoostTask) {
+    it.dependsOn(boostPath ? [] : [downloadBoost])
+    it.boostPath.setFrom(boostPath ?: tarTree(resources.gzip(downloadBoost.dest)))
+    it.boostVersion.set(BOOST_VERSION)
+    it.outputDir.set(new File(thirdPartyNdkDir, "boost"))
 }
 
 task downloadDoubleConversion(dependsOn: createNativeDepsDirectories, type: Download) {

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

@@ -0,0 +1,46 @@
+/*
+ * 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 Boost from a source folder/zip and preparing it to be
+ * consumed by the NDK
+ */
+abstract class PrepareBoostTask : DefaultTask() {
+
+  @get:InputFiles abstract val boostPath: ConfigurableFileCollection
+
+  @get:Input abstract val boostVersion: Property<String>
+
+  @get:OutputDirectory abstract val outputDir: DirectoryProperty
+
+  @TaskAction
+  fun taskAction() {
+    project.copy { it ->
+      it.from(boostPath)
+      it.from(project.file("src/main/jni/third-party/boost"))
+      it.include(
+          "Android.mk",
+          "boost_${boostVersion.get()}/boost/**/*.hpp",
+          "boost/boost/**/*.hpp",
+          "asm/**/*.S")
+      it.includeEmptyDirs = false
+      it.into(outputDir)
+    }
+    File(outputDir.asFile.get(), "boost").apply {
+      renameTo(File(this.parentFile, "boost_${boostVersion.get()}"))
+    }
+  }
+}

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

@@ -0,0 +1,105 @@
+/*
+ * 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 PrepareBoostTaskTest {
+
+  @get:Rule val tempFolder = TemporaryFolder()
+
+  @Test(expected = IllegalStateException::class)
+  fun prepareBoostTask_withMissingConfiguration_fails() {
+    val task = createTestTask<PrepareBoostTask>()
+
+    task.taskAction()
+  }
+
+  @Test
+  fun prepareBoostTask_copiesMakefile() {
+    val boostpath = tempFolder.newFolder("boostpath")
+    val output = tempFolder.newFolder("output")
+    val project = createProject()
+    val task =
+        createTestTask<PrepareBoostTask>(project = project) {
+          it.boostPath.setFrom(boostpath)
+          it.boostVersion.set("1.0.0")
+          it.outputDir.set(output)
+        }
+    File(project.projectDir, "src/main/jni/third-party/boost/Android.mk").apply {
+      parentFile.mkdirs()
+      createNewFile()
+    }
+    task.taskAction()
+
+    assertTrue(output.listFiles()!!.any { it.name == "Android.mk" })
+  }
+
+  @Test
+  fun prepareBoostTask_copiesAsmFiles() {
+    val boostpath = tempFolder.newFolder("boostpath")
+    val output = tempFolder.newFolder("output")
+    val task =
+        createTestTask<PrepareBoostTask>() {
+          it.boostPath.setFrom(boostpath)
+          it.boostVersion.set("1.0.0")
+          it.outputDir.set(output)
+        }
+    File(boostpath, "asm/asm.S").apply {
+      parentFile.mkdirs()
+      createNewFile()
+    }
+    task.taskAction()
+
+    assertTrue(File(output, "asm/asm.S").exists())
+  }
+
+  @Test
+  fun prepareBoostTask_copiesBoostSourceFiles() {
+    val boostpath = tempFolder.newFolder("boostpath")
+    val output = tempFolder.newFolder("output")
+    val task =
+        createTestTask<PrepareBoostTask> {
+          it.boostPath.setFrom(boostpath)
+          it.boostVersion.set("1.0.0")
+          it.outputDir.set(output)
+        }
+    File(boostpath, "boost_1.0.0/boost/config.hpp").apply {
+      parentFile.mkdirs()
+      createNewFile()
+    }
+    task.taskAction()
+
+    assertTrue(File(output, "boost_1.0.0/boost/config.hpp").exists())
+  }
+
+  @Test
+  fun prepareBoostTask_copiesVersionlessBoostSourceFiles() {
+    val boostpath = tempFolder.newFolder("boostpath")
+    val output = tempFolder.newFolder("output")
+    val task =
+        createTestTask<PrepareBoostTask> {
+          it.boostPath.setFrom(boostpath)
+          it.boostVersion.set("1.0.0")
+          it.outputDir.set(output)
+        }
+    File(boostpath, "boost/boost/config.hpp").apply {
+      parentFile.mkdirs()
+      createNewFile()
+    }
+    task.taskAction()
+
+    assertTrue(File(output, "boost_1.0.0/boost/config.hpp").exists())
+  }
+}