Export GenerateCodegenSchemaTask to its own task.

Summary:
Similarly to the previous diff, this is moving another small part of the codegen
to its own Kotlin separate task. I've used the Gradle idiomatic APIs and added a couple of tests.

Changelog:
[Internal] [Changed] - Export `GenerateCodegenSchemaTask` to its own task.

Reviewed By: ShikaSD

Differential Revision: D31017274

fbshipit-source-id: f0d288a63883e92a9d725eb3bf695a3aa77f9030

packages/react-native-gradle-plugin/src/main/java/com/facebook/react/codegen/plugin/CodegenPlugin.java

@@ -11,6 +11,7 @@
 import com.facebook.react.ReactExtension;
 import com.facebook.react.codegen.generator.JavaGenerator;
 import com.facebook.react.tasks.BuildCodegenCLITask;
+import com.facebook.react.tasks.GenerateCodegenSchemaTask;
 import com.facebook.react.utils.GradleUtils;
 import com.facebook.react.utils.PathUtils;
 import com.google.common.collect.ImmutableList;
@@ -51,45 +52,19 @@ public void apply(final Project project) {
                   task.getBashWindowsHome().set(bashWindowsHome);
                 });
 
-    project
-        .getTasks()
-        .register(
-            "generateCodegenSchemaFromJavaScript",
-            Exec.class,
-            task -> {
-              // This is needed when using codegen from source, not from npm.
-              task.dependsOn(buildCodegenTask);
-
-              task.doFirst(
-                  s -> {
-                    generatedSrcDir.delete();
-                    generatedSrcDir.mkdirs();
-                  });
-
-              task.getInputs()
-                  .files(
-                      project.fileTree(
-                          ImmutableMap.of("dir", extension.getCodegenDir().getAsFile().get())));
-              task.getInputs()
-                  .files(
-                      project.fileTree(
-                          ImmutableMap.of(
-                              "dir",
-                              extension.getJsRootDir().getAsFile().get(),
-                              "includes",
-                              ImmutableList.of("**/*.js"))));
-              task.getOutputs().file(generatedSchemaFile);
-
-              ImmutableList<String> execCommands =
-                  new ImmutableList.Builder<String>()
-                      .add(os.contains("windows") ? "yarn.cmd" : "yarn")
-                      .addAll(ImmutableList.copyOf(extension.getNodeExecutableAndArgs().get()))
-                      .add(PathUtils.codegenGenerateSchemaCLI(extension).getAbsolutePath())
-                      .add(generatedSchemaFile.getAbsolutePath())
-                      .add(extension.getJsRootDir().getAsFile().get().getAbsolutePath())
-                      .build();
-              task.commandLine(execCommands);
-            });
+    TaskProvider<GenerateCodegenSchemaTask> generateCodegenSchemaTask =
+        project
+            .getTasks()
+            .register(
+                "generateCodegenSchemaFromJavaScript",
+                GenerateCodegenSchemaTask.class,
+                task -> {
+                  task.getJsRootDir().set(extension.getJsRootDir());
+                  task.getNodeExecutableAndArgs().set(extension.getNodeExecutableAndArgs());
+                  task.getCodegenDir().set(extension.getCodegenDir());
+                  task.getGeneratedSrcDir().set(generatedSrcDir);
+                  task.dependsOn(buildCodegenTask);
+                });
 
     // 3. Task: generate Java code from schema.
     project
@@ -98,7 +73,7 @@ public void apply(final Project project) {
             "generateCodegenArtifactsFromSchema",
             Exec.class,
             task -> {
-              task.dependsOn("generateCodegenSchemaFromJavaScript");
+              task.dependsOn(generateCodegenSchemaTask);
 
               task.getInputs()
                   .files(

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

@@ -0,0 +1,56 @@
+/*
+ * 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
+
+import com.facebook.react.utils.windowsAwareYarn
+import org.gradle.api.file.DirectoryProperty
+import org.gradle.api.file.RegularFile
+import org.gradle.api.provider.ListProperty
+import org.gradle.api.provider.Provider
+import org.gradle.api.tasks.*
+
+/**
+ * A task that will collect all the *.js files inside the provided [jsRootDir] and will run the
+ * `combine-js-to-schema-cli.js` on top of it (from `react-native-codegen`). The output is a
+ * `schema.json` file that contains an intermediate representation of the code to be generated.
+ */
+abstract class GenerateCodegenSchemaTask : Exec() {
+
+  @get:Internal abstract val jsRootDir: DirectoryProperty
+
+  @get:Internal abstract val codegenDir: DirectoryProperty
+
+  @get:Internal abstract val generatedSrcDir: DirectoryProperty
+
+  @get:Input abstract val nodeExecutableAndArgs: ListProperty<String>
+
+  @get:InputFiles val jsInputFiles = project.fileTree(jsRootDir) { it.include("**/*.js") }
+
+  @get:OutputFile
+  val generatedSchemaFile: Provider<RegularFile> = generatedSrcDir.file("schema.json")
+
+  override fun exec() {
+    generatedSrcDir.asFile.get().apply {
+      delete()
+      mkdirs()
+    }
+
+    commandLine(
+        windowsAwareYarn(
+            *nodeExecutableAndArgs.get().toTypedArray(),
+            codegenDir
+                .file("lib/cli/combine/combine-js-to-schema-cli.js")
+                .get()
+                .asFile
+                .absolutePath,
+            generatedSchemaFile.get().asFile.absolutePath,
+            jsRootDir.asFile.get().absolutePath,
+        ))
+    super.exec()
+  }
+}

packages/react-native-gradle-plugin/src/main/kotlin/com/facebook/react/utils/TaskUtils.kt

@@ -14,6 +14,13 @@ internal fun windowsAwareCommandLine(vararg args: Any): List<Any> =
       args.toList()
     }
 
+internal fun windowsAwareYarn(vararg args: Any): List<Any> =
+    if (Os.isWindows()) {
+      listOf("yarn.cmd") + args
+    } else {
+      listOf("yarn") + args
+    }
+
 internal fun windowsAwareBashCommandLine(
     vararg args: String,
     bashWindowsHome: String? = null

packages/react-native-gradle-plugin/src/test/kotlin/com/facebook/react/utils/TaskUtilsTest.kt

@@ -42,6 +42,24 @@ class TaskUtilsTest {
     assertEquals(listOf("cmd", "/c", "a", "b", "c"), windowsAwareCommandLine("a", "b", "c"))
   }
 
+  @Test
+  @WithOs(OS.MAC)
+  fun windowsAwareYarn_onMac_returnsTheList() {
+    assertEquals(listOf("yarn", "a", "b", "c"), windowsAwareYarn("a", "b", "c"))
+  }
+
+  @Test
+  @WithOs(OS.UNIX)
+  fun windowsAwareYarn_onLinux_returnsTheList() {
+    assertEquals(listOf("yarn", "a", "b", "c"), windowsAwareYarn("a", "b", "c"))
+  }
+
+  @Test
+  @WithOs(OS.WIN)
+  fun windowsAwareYarn_onWindows_prependsCmd() {
+    assertEquals(listOf("yarn.cmd", "a", "b", "c"), windowsAwareYarn("a", "b", "c"))
+  }
+
   @Test
   @WithOs(OS.MAC)
   fun windowsAwareBashCommandLine_onMac_returnsTheList() {