FFI plugins (#94101)

* Building shared C source code as part of the native build for platforms Android, iOS, Linux desktop, MacOS desktop, and Windows desktop.
* Sample code doing a synchronous FFI call.
* Sample code doing a long running synchronous FFI call on a helper isolate.
* Use of `package:ffigen` to generate the bindings.

dev/integration_tests/flutter_gallery/windows/flutter/generated_plugins.cmake

@@ -6,6 +6,9 @@ list(APPEND FLUTTER_PLUGIN_LIST
   url_launcher_windows
 )
 
+list(APPEND FLUTTER_FFI_PLUGIN_LIST
+)
+
 set(PLUGIN_BUNDLED_LIBRARIES)
 
 foreach(plugin ${FLUTTER_PLUGIN_LIST})
@@ -14,3 +17,8 @@ foreach(plugin ${FLUTTER_PLUGIN_LIST})
   list(APPEND PLUGIN_BUNDLED_LIBRARIES $<TARGET_FILE:${plugin}_plugin>)
   list(APPEND PLUGIN_BUNDLED_LIBRARIES ${${plugin}_bundled_libraries})
 endforeach(plugin)
+
+foreach(ffi_plugin ${FLUTTER_FFI_PLUGIN_LIST})
+  add_subdirectory(flutter/ephemeral/.plugin_symlinks/${ffi_plugin}/windows plugins/${ffi_plugin})
+  list(APPEND PLUGIN_BUNDLED_LIBRARIES ${${ffi_plugin}_bundled_libraries})
+endforeach(ffi_plugin)

packages/flutter_tools/lib/src/commands/create.dart

@@ -48,8 +48,12 @@ class CreateCommand extends CreateBase {
         flutterProjectTypeToString(FlutterProjectType.package): 'Generate a shareable Flutter project containing modular '
             'Dart code.',
         flutterProjectTypeToString(FlutterProjectType.plugin): 'Generate a shareable Flutter project containing an API '
-            'in Dart code with a platform-specific implementation for Android, for iOS code, or '
-            'for both.',
+            'in Dart code with a platform-specific implementation through method channels for Android, iOS, '
+            'Linux, macOS, Windows, web, or any combination of these.',
+        flutterProjectTypeToString(FlutterProjectType.ffiPlugin):
+            'Generate a shareable Flutter project containing an API '
+            'in Dart code with a platform-specific implementation through dart:ffi for Android, iOS, '
+            'Linux, macOS, Windows, or any combination of these.',
         flutterProjectTypeToString(FlutterProjectType.module): 'Generate a project to add a Flutter module to an '
             'existing Android or iOS application.',
       },
@@ -159,7 +163,7 @@ class CreateCommand extends CreateBase {
     final bool metadataExists = projectDir.absolute.childFile('.metadata').existsSync();
     if (argResults['template'] != null) {
       template = stringToProjectType(stringArg('template'));
-    } else {
+    }
     // If the project directory exists and isn't empty, then try to determine the template
     // type from the project directory.
     if (projectDir.existsSync() && projectDir.listSync().isNotEmpty) {
@@ -172,7 +176,6 @@ class CreateCommand extends CreateBase {
             'the new project manually.');
       }
     }
-    }
     template ??= detectedProjectType ?? FlutterProjectType.app;
     if (detectedProjectType != null && template != detectedProjectType && metadataExists) {
       // We can only be definitive that this is the wrong type if the .metadata file
@@ -206,7 +209,8 @@ class CreateCommand extends CreateBase {
 
     final FlutterProjectType template = _getProjectType(projectDir);
     final bool generateModule = template == FlutterProjectType.module;
-    final bool generatePlugin = template == FlutterProjectType.plugin;
+    final bool generateMethodChannelsPlugin = template == FlutterProjectType.plugin;
+    final bool generateFfiPlugin = template == FlutterProjectType.ffiPlugin;
     final bool generatePackage = template == FlutterProjectType.package;
 
     final List<String> platforms = stringsArg('platforms');
@@ -220,6 +224,23 @@ class CreateCommand extends CreateBase {
     } else if (platforms == null || platforms.isEmpty) {
       throwToolExit('Must specify at least one platform using --platforms',
         exitCode: 2);
+    } else if (generateFfiPlugin && argResults.wasParsed('platforms') && platforms.contains('web')) {
+      throwToolExit(
+        'The web platform is not supported in plugin_ffi template.',
+        exitCode: 2,
+      );
+    } else if (generateFfiPlugin && argResults.wasParsed('ios-language')) {
+      throwToolExit(
+        'The "ios-language" option is not supported with the plugin_ffi '
+        'template: the language will always be C or C++.',
+        exitCode: 2,
+      );
+    } else if (generateFfiPlugin && argResults.wasParsed('android-language')) {
+      throwToolExit(
+        'The "android-language" option is not supported with the plugin_ffi '
+        'template: the language will always be C or C++.',
+        exitCode: 2,
+      );
     }
 
     final String organization = await getOrganization();
@@ -257,7 +278,8 @@ class CreateCommand extends CreateBase {
       titleCaseProjectName: titleCaseProjectName,
       projectDescription: stringArg('description'),
       flutterRoot: flutterRoot,
-      withPluginHook: generatePlugin,
+      withPlatformChannelPluginHook: generateMethodChannelsPlugin,
+      withFfiPluginHook: generateFfiPlugin,
       androidLanguage: stringArg('android-language'),
       iosLanguage: stringArg('ios-language'),
       iosDevelopmentTeam: developmentTeam,
@@ -326,7 +348,15 @@ class CreateCommand extends CreateBase {
         );
         break;
       case FlutterProjectType.plugin:
-        generatedFileCount += await _generatePlugin(
+        generatedFileCount += await _generateMethodChannelPlugin(
+          relativeDir,
+          templateContext,
+          overwrite: overwrite,
+          printStatusWhenWriting: !creatingNewProject,
+        );
+        break;
+      case FlutterProjectType.ffiPlugin:
+        generatedFileCount += await _generateFfiPlugin(
           relativeDir,
           templateContext,
           overwrite: overwrite,
@@ -354,7 +384,7 @@ class CreateCommand extends CreateBase {
           'main.dart',
       ));
       globals.printStatus('Your module code is in $relativeMainPath.');
-    } else if (generatePlugin) {
+    } else if (generateMethodChannelsPlugin) {
       final String relativePluginPath = globals.fs.path.normalize(globals.fs.path.relative(projectDirPath));
       final List<String> requestedPlatforms = _getUserRequestedPlatforms();
       final String platformsString = requestedPlatforms.join(', ');
@@ -460,7 +490,7 @@ Your $application code is in $relativeAppMain.
     return generatedCount;
   }
 
-  Future<int> _generatePlugin(
+  Future<int> _generateMethodChannelPlugin(
     Directory directory,
     Map<String, dynamic> templateContext, {
     bool overwrite = false,
@@ -487,8 +517,8 @@ Your $application code is in $relativeAppMain.
         ? stringArg('description')
         : 'A new flutter plugin project.';
     templateContext['description'] = description;
-    generatedCount += await renderTemplate(
-      'plugin',
+    generatedCount += await renderMerged(
+      <String>['plugin', 'plugin_shared'],
       directory,
       templateContext,
       overwrite: overwrite,
@@ -535,6 +565,82 @@ Your $application code is in $relativeAppMain.
     return generatedCount;
   }
 
+  Future<int> _generateFfiPlugin(
+    Directory directory,
+    Map<String, dynamic> templateContext, {
+    bool overwrite = false,
+    bool printStatusWhenWriting = true,
+  }) async {
+    // Plugins only add a platform if it was requested explicitly by the user.
+    if (!argResults.wasParsed('platforms')) {
+      for (final String platform in kAllCreatePlatforms) {
+        templateContext[platform] = false;
+      }
+    }
+    final List<String> platformsToAdd =
+        _getSupportedPlatformsFromTemplateContext(templateContext);
+
+    final List<String> existingPlatforms =
+        _getSupportedPlatformsInPlugin(directory);
+    for (final String existingPlatform in existingPlatforms) {
+      // re-generate files for existing platforms
+      templateContext[existingPlatform] = true;
+    }
+
+    final bool willAddPlatforms = platformsToAdd.isNotEmpty;
+    templateContext['no_platforms'] = !willAddPlatforms;
+    int generatedCount = 0;
+    final String description = argResults.wasParsed('description')
+        ? stringArg('description')
+        : 'A new Flutter FFI plugin project.';
+    templateContext['description'] = description;
+    generatedCount += await renderMerged(
+      <String>['plugin_ffi', 'plugin_shared'],
+      directory,
+      templateContext,
+      overwrite: overwrite,
+      printStatusWhenWriting: printStatusWhenWriting,
+    );
+
+    if (boolArg('pub')) {
+      await pub.get(
+        context: PubContext.createPlugin,
+        directory: directory.path,
+        offline: boolArg('offline'),
+        generateSyntheticPackage: false,
+      );
+    }
+
+    final FlutterProject project = FlutterProject.fromDirectory(directory);
+    final bool generateAndroid = templateContext['android'] == true;
+    if (generateAndroid) {
+      gradle.updateLocalProperties(project: project, requireAndroidSdk: false);
+    }
+
+    final String projectName = templateContext['projectName'] as String;
+    final String organization = templateContext['organization'] as String;
+    final String androidPluginIdentifier = templateContext['androidIdentifier'] as String;
+    final String exampleProjectName = '${projectName}_example';
+    templateContext['projectName'] = exampleProjectName;
+    templateContext['androidIdentifier'] = CreateBase.createAndroidIdentifier(organization, exampleProjectName);
+    templateContext['iosIdentifier'] = CreateBase.createUTIIdentifier(organization, exampleProjectName);
+    templateContext['macosIdentifier'] = CreateBase.createUTIIdentifier(organization, exampleProjectName);
+    templateContext['windowsIdentifier'] = CreateBase.createWindowsIdentifier(organization, exampleProjectName);
+    templateContext['description'] = 'Demonstrates how to use the $projectName plugin.';
+    templateContext['pluginProjectName'] = projectName;
+    templateContext['androidPluginIdentifier'] = androidPluginIdentifier;
+
+    generatedCount += await generateApp(
+      'app',
+      project.example.directory,
+      templateContext,
+      overwrite: overwrite,
+      pluginExampleApp: true,
+      printStatusWhenWriting: printStatusWhenWriting,
+    );
+    return generatedCount;
+  }
+
   // Takes an application template and replaces the main.dart with one from the
   // documentation website in sampleCode.  Returns the difference in the number
   // of files after applying the sample, since it also deletes the application's

packages/flutter_tools/lib/src/commands/create_base.dart

@@ -339,7 +339,8 @@ abstract class CreateBase extends FlutterCommand {
     String agpVersion,
     String kotlinVersion,
     String gradleVersion,
-    bool withPluginHook = false,
+    bool withPlatformChannelPluginHook = false,
+    bool withFfiPluginHook = false,
     bool ios = false,
     bool android = false,
     bool web = false,
@@ -384,7 +385,9 @@ abstract class CreateBase extends FlutterCommand {
       'pluginClassCapitalSnakeCase': pluginClassCapitalSnakeCase,
       'pluginDartClass': pluginDartClass,
       'pluginProjectUUID': const Uuid().v4().toUpperCase(),
-      'withPluginHook': withPluginHook,
+      'withFfiPluginHook': withFfiPluginHook,
+      'withPlatformChannelPluginHook': withPlatformChannelPluginHook,
+      'withPluginHook': withFfiPluginHook || withPlatformChannelPluginHook,
       'androidLanguage': androidLanguage,
       'iosLanguage': iosLanguage,
       'hasIosDevelopmentTeam': iosDevelopmentTeam != null && iosDevelopmentTeam.isNotEmpty,

packages/flutter_tools/lib/src/flutter_project_metadata.dart

@@ -23,9 +23,14 @@ enum FlutterProjectType {
   package,
   /// This is a native plugin project.
   plugin,
+  /// This is an FFI native plugin project.
+  ffiPlugin,
 }
 
 String flutterProjectTypeToString(FlutterProjectType type) {
+  if (type == FlutterProjectType.ffiPlugin) {
+    return 'plugin_ffi';
+  }
   return getEnumName(type);
 }
 

packages/flutter_tools/lib/src/plugins.dart

@@ -47,12 +47,17 @@ class Plugin {
   ///            package: io.flutter.plugins.sample
   ///            pluginClass: SamplePlugin
   ///          ios:
+  ///            # A plugin implemented through method channels.
   ///            pluginClass: SamplePlugin
   ///          linux:
-  ///            pluginClass: SamplePlugin
+  ///            # A plugin implemented purely in Dart code.
+  ///            dartPluginClass: SamplePlugin
   ///          macos:
-  ///            pluginClass: SamplePlugin
+  ///            # A plugin implemented `dart:ffi`.
+  ///            ffiPlugin: true
   ///          windows:
+  ///            # A plugin using platform-specific Dart and method channels.
+  ///            dartPluginClass: SamplePlugin
   ///            pluginClass: SamplePlugin
   factory Plugin.fromYaml(
     String name,

packages/flutter_tools/templates/README.md

 This directory contains templates for `flutter create`.
 
-The `app_shared` subdirectory is special. It provides files for all app
-templates (as opposed to plugin or module templates).
-As of May 2021, there are two app templates: `app` (the counter app)
+The `*_shared` subdirectories provide files for multiple templates.
+
+* `app_shared` for `app` and `skeleton`.
+* `plugin_shared` for (method channel) `plugin` and `plugin_ffi`.
+
+For example, there are two app templates: `app` (the counter app)
 and `skeleton` (the more advanced list view/detail view app).
 
 ```plain

packages/flutter_tools/templates/app/lib/main.dart.tmpl

 import 'package:flutter/material.dart';
-{{#withPluginHook}}
+{{#withPlatformChannelPluginHook}}
 import 'dart:async';
 
 import 'package:flutter/services.dart';
 import 'package:{{pluginProjectName}}/{{pluginProjectName}}.dart';
-{{/withPluginHook}}
+{{/withPlatformChannelPluginHook}}
+{{#withFfiPluginHook}}
+import 'dart:async';
+
+import 'package:{{pluginProjectName}}/{{pluginProjectName}}.dart' as {{pluginProjectName}};
+{{/withFfiPluginHook}}
 
 void main() {
   runApp(const MyApp());
@@ -121,7 +126,7 @@ class _MyHomePageState extends State<MyHomePage> {
   }
 }
 {{/withPluginHook}}
-{{#withPluginHook}}
+{{#withPlatformChannelPluginHook}}
 class MyApp extends StatefulWidget {
   const MyApp({Key? key}) : super(key: key);
 
@@ -174,4 +179,71 @@ class _MyAppState extends State<MyApp> {
     );
   }
 }
-{{/withPluginHook}}
+{{/withPlatformChannelPluginHook}}
+{{#withFfiPluginHook}}
+class MyApp extends StatefulWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  @override
+  _MyAppState createState() => _MyAppState();
+}
+
+class _MyAppState extends State<MyApp> {
+  late int sumResult;
+  late Future<int> sumAsyncResult;
+
+  @override
+  void initState() {
+    super.initState();
+    sumResult = {{pluginProjectName}}.sum(1, 2);
+    sumAsyncResult = {{pluginProjectName}}.sumAsync(3, 4);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    const textStyle = TextStyle(fontSize: 25);
+    const spacerSmall = SizedBox(height: 10);
+    return MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(
+          title: const Text('Native Packages'),
+        ),
+        body: SingleChildScrollView(
+          child: Container(
+            padding: const EdgeInsets.all(10),
+            child: Column(
+              children: [
+                const Text(
+                  'This calls a native function through FFI that is shipped as source in the package. '
+                  'The native code is built as part of the Flutter Runner build.',
+                  style: textStyle,
+                  textAlign: TextAlign.center,
+                ),
+                spacerSmall,
+                Text(
+                  'sum(1, 2) = $sumResult',
+                  style: textStyle,
+                  textAlign: TextAlign.center,
+                ),
+                spacerSmall,
+                FutureBuilder<int>(
+                  future: sumAsyncResult,
+                  builder: (BuildContext context, AsyncSnapshot<int> value) {
+                    final displayValue =
+                        (value.hasData) ? value.data : 'loading';
+                    return Text(
+                      'await sumAsync(3, 4) = $displayValue',
+                      style: textStyle,
+                      textAlign: TextAlign.center,
+                    );
+                  },
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}
+{{/withFfiPluginHook}}

packages/flutter_tools/templates/app/pubspec.yaml.tmpl

@@ -4,7 +4,7 @@ description: {{description}}
 # The following line prevents the package from being accidentally published to
 # pub.dev using `flutter pub publish`. This is preferred for private packages.
 publish_to: 'none' # Remove this line if you wish to publish to pub.dev
-{{^withPluginHook}}
+{{^withPlatformChannelPluginHook}}
 
 # The following defines the version and build number for your application.
 # A version number is three numbers separated by dots, like 1.2.43
@@ -17,7 +17,7 @@ publish_to: 'none' # Remove this line if you wish to publish to pub.dev
 # Read more about iOS versioning at
 # https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
 version: 1.0.0+1
-{{/withPluginHook}}
+{{/withPlatformChannelPluginHook}}
 
 environment:
   sdk: {{dartSdkVersionBounds}}

packages/flutter_tools/templates/app/test/widget_test.dart.tmpl

@@ -8,7 +8,9 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+{{^withFfiPluginHook}}
 import 'package:{{projectName}}/main.dart';
+{{/withFfiPluginHook}}
 
 {{^withPluginHook}}
 void main() {
@@ -30,7 +32,7 @@ void main() {
   });
 }
 {{/withPluginHook}}
-{{#withPluginHook}}
+{{#withPlatformChannelPluginHook}}
 void main() {
   testWidgets('Verify Platform version', (WidgetTester tester) async {
     // Build our app and trigger a frame.
@@ -46,4 +48,4 @@ void main() {
     );
   });
 }
-{{/withPluginHook}}
+{{/withPlatformChannelPluginHook}}

packages/flutter_tools/templates/app_shared/linux.tmpl/CMakeLists.txt.tmpl

@@ -94,11 +94,11 @@ install(FILES "${FLUTTER_ICU_DATA_FILE}" DESTINATION "${INSTALL_BUNDLE_DATA_DIR}
 install(FILES "${FLUTTER_LIBRARY}" DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
   COMPONENT Runtime)
 
-if(PLUGIN_BUNDLED_LIBRARIES)
-  install(FILES "${PLUGIN_BUNDLED_LIBRARIES}"
+foreach(bundled_library ${PLUGIN_BUNDLED_LIBRARIES})
+  install(FILES "${bundled_library}"
     DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
     COMPONENT Runtime)
-endif()
+endforeach(bundled_library)
 
 # Fully re-copy the assets directory on each build to avoid having stale files
 # from a previous install.

packages/flutter_tools/templates/module/common/lib/main.dart.tmpl

 import 'package:flutter/material.dart';
-{{#withPluginHook}}
+{{#withPlatformChannelPluginHook}}
 import 'dart:async';
 
 import 'package:flutter/services.dart';
 import 'package:{{pluginProjectName}}/{{pluginProjectName}}.dart';
-{{/withPluginHook}}
+{{/withPlatformChannelPluginHook}}
 
 void main() => runApp(const MyApp());
 
-{{^withPluginHook}}
+{{^withPlatformChannelPluginHook}}
 class MyApp extends StatelessWidget {
   const MyApp({Key? key}) : super(key: key);
 
@@ -117,8 +117,8 @@ class _MyHomePageState extends State<MyHomePage> {
     );
   }
 }
-{{/withPluginHook}}
-{{#withPluginHook}}
+{{/withPlatformChannelPluginHook}}
+{{#withPlatformChannelPluginHook}}
 class MyApp extends StatefulWidget {
   const MyApp({Key? key}) : super(key: key);
 
@@ -171,4 +171,4 @@ class _MyAppState extends State<MyApp> {
     );
   }
 }
-{{/withPluginHook}}
+{{/withPlatformChannelPluginHook}}

packages/flutter_tools/templates/module/common/test/widget_test.dart.tmpl

@@ -8,7 +8,9 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+{{^withFfiPluginHook}}
 import 'package:{{projectName}}/main.dart';
+{{/withFfiPluginHook}}
 
 {{^withPluginHook}}
 void main() {
@@ -30,7 +32,7 @@ void main() {
   });
 }
 {{/withPluginHook}}
-{{#withPluginHook}}
+{{#withPlatformChannelPluginHook}}
 void main() {
   testWidgets('Verify Platform version', (WidgetTester tester) async {
     // Build our app and trigger a frame.
@@ -46,4 +48,4 @@ void main() {
     );
   });
 }
-{{/withPluginHook}}
+{{/withPlatformChannelPluginHook}}

packages/flutter_tools/templates/plugin/.idea/libraries/Dart_SDK.xml.tmpl

-<component name="libraryTable">
-  <library name="Dart SDK">
-    <CLASSES>
-      <root url="file://{{{dartSdk}}}/lib/async" />
-      <root url="file://{{{dartSdk}}}/lib/collection" />
-      <root url="file://{{{dartSdk}}}/lib/convert" />
-      <root url="file://{{{dartSdk}}}/lib/core" />
-      <root url="file://{{{dartSdk}}}/lib/developer" />
-      <root url="file://{{{dartSdk}}}/lib/html" />
-      <root url="file://{{{dartSdk}}}/lib/io" />
-      <root url="file://{{{dartSdk}}}/lib/isolate" />
-      <root url="file://{{{dartSdk}}}/lib/math" />
-      <root url="file://{{{dartSdk}}}/lib/mirrors" />
-      <root url="file://{{{dartSdk}}}/lib/typed_data" />
-    </CLASSES>
-    <JAVADOC />
-    <SOURCES />
-  </library>
-</component>
\ No newline at end of file

packages/flutter_tools/templates/plugin/.idea/modules.xml.tmpl

-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="ProjectModuleManager">
-    <modules>
-      <module fileurl="file://$PROJECT_DIR$/{{projectName}}.iml" filepath="$PROJECT_DIR$/{{projectName}}.iml" />
-      <module fileurl="file://$PROJECT_DIR$/android/{{projectName}}_android.iml" filepath="$PROJECT_DIR$/android/{{projectName}}_android.iml" />
-      <module fileurl="file://$PROJECT_DIR$/example/android/{{projectName}}_example_android.iml" filepath="$PROJECT_DIR$/example/android/{{projectName}}_example_android.iml" />
-    </modules>
-  </component>
-</project>

packages/flutter_tools/templates/plugin/.idea/runConfigurations/example_lib_main_dart.xml.tmpl

-<component name="ProjectRunConfigurationManager">
-  <configuration default="false" name="example/lib/main.dart" type="FlutterRunConfigurationType" factoryName="Flutter">
-    <option name="filePath" value="$PROJECT_DIR$/example/lib/main.dart" />
-    <method />
-  </configuration>
-</component>
\ No newline at end of file

packages/flutter_tools/templates/plugin/.idea/workspace.xml.tmpl

-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="FileEditorManager">
-    <leaf>
-      <file leaf-file-name="{{projectName}}.dart" pinned="false" current-in-tab="true">
-        <entry file="file://$PROJECT_DIR$/lib/{{projectName}}.dart">
-          <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="0">
-              <caret line="0" column="0" lean-forward="false" selection-start-line="0" selection-start-column="0" selection-end-line="0" selection-end-column="0" />
-            </state>
-          </provider>
-        </entry>
-      </file>
-      <file leaf-file-name="main.dart" pinned="false" current-in-tab="false">
-        <entry file="file://$PROJECT_DIR$/example/lib/main.dart">
-          <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="0">
-              <caret line="0" column="0" lean-forward="false" selection-start-line="0" selection-start-column="0" selection-end-line="0" selection-end-column="0" />
-            </state>
-          </provider>
-        </entry>
-      </file>
-    </leaf>
-  </component>
-  <component name="ToolWindowManager">
-    <editor active="true" />
-    <layout>
-      <window_info id="Project" active="true" anchor="left" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="true" show_stripe_button="true" weight="0.25" sideWeight="0.5" order="0" side_tool="false" content_ui="combo" />
-    </layout>
-  </component>
-  <component name="ProjectView">
-    <navigator currentView="ProjectPane" proportions="" version="1">
-    </navigator>
-    <panes>
-      <pane id="ProjectPane">
-        <option name="show-excluded-files" value="false" />
-      </pane>
-    </panes>
-  </component>
-  <component name="PropertiesComponent">
-    <property name="last_opened_file_path" value="$PROJECT_DIR$" />
-    <property name="dart.analysis.tool.window.force.activate" value="true" />
-    <property name="show.migrate.to.gradle.popup" value="false" />
-  </component>
-</project>

packages/flutter_tools/templates/plugin/README.md.tmpl

@@ -15,6 +15,6 @@ samples, guidance on mobile development, and a full API reference.
 
 {{#no_platforms}}
 The plugin project was generated without specifying the `--platforms` flag, no platforms are currently supported.
-To add platforms, run `flutter create -t plugin --platforms <platforms> .` under the same
-directory. You can also find a detailed instruction on how to add platforms in the `pubspec.yaml` at https://flutter.dev/docs/development/packages-and-plugins/developing-packages#plugin-platforms.
+To add platforms, run `flutter create -t plugin --platforms <platforms> .` in this directory.
+You can also find a detailed instruction on how to add platforms in the `pubspec.yaml` at https://flutter.dev/docs/development/packages-and-plugins/developing-packages#plugin-platforms.
 {{/no_platforms}}

packages/flutter_tools/templates/plugin/linux.tmpl/CMakeLists.txt.tmpl

@@ -18,7 +18,7 @@ target_include_directories(${PLUGIN_NAME} INTERFACE
 target_link_libraries(${PLUGIN_NAME} PRIVATE flutter)
 target_link_libraries(${PLUGIN_NAME} PRIVATE PkgConfig::GTK)
 
-# List of absolute paths to libraries that should be bundled with the plugin
+# List of absolute paths to libraries that should be bundled with the plugin.
 set({{projectName}}_bundled_libraries
   ""
   PARENT_SCOPE

packages/flutter_tools/templates/plugin/windows.tmpl/CMakeLists.txt.tmpl

@@ -17,7 +17,7 @@ target_include_directories(${PLUGIN_NAME} INTERFACE
   "${CMAKE_CURRENT_SOURCE_DIR}/include")
 target_link_libraries(${PLUGIN_NAME} PRIVATE flutter flutter_wrapper_plugin)
 
-# List of absolute paths to libraries that should be bundled with the plugin
+# List of absolute paths to libraries that should be bundled with the plugin.
 set({{projectName}}_bundled_libraries
   ""
   PARENT_SCOPE

packages/flutter_tools/templates/plugin_ffi/README.md.tmpl

+# {{projectName}}
+
+{{description}}
+
+## Getting Started
+
+This project is a starting point for a Flutter 
+[FFI plugin](https://docs.flutter.dev/development/platform-integration/c-interop),
+a specialized package that includes native code directly invoked with Dart FFI.
+
+## Project stucture
+
+This template uses the following structure:
+
+* `src`: Contains the native source code, and a CmakeFile.txt file for building
+  that source code into a dynamic library
+
+* `lib`: Contains the Dart code that defines the API of the plugin, and which
+  calls into the native code using `dart:ffi`
+
+* platform folders (`android`, `ios`, `windows`, etc.): Contains the build files
+  for building and bundling the native code library with the platform application.
+
+## Buidling and bundling native code
+
+The `pubspec.yaml` specifies FFI plugins as follows.
+
+```yaml
+  plugin:
+    platforms:
+      some_platform:
+        ffiPlugin: true
+```
+
+This configuration invokes the native build for the various target platforms
+and bundles the binaries in Flutter applications using these FFI plugins.
+
+A plugin can have both FFI and method channels:
+
+```yaml
+  plugin:
+    platforms:
+      some_platform:
+        pluginClass: SomeName
+        ffiPlugin: true
+```
+
+The native build systems that are invoked by FFI (and method channel) plugins are:
+
+* For Android: Gradle, which invokes the Android NDK for native builds.
+  * See the documentation in android/build.gradle.
+* For iOS and MacOS: Xcode, via CocoaPods.
+  * See the documentation in ios/{{projectName}}.podspec.
+  * See the documentation in macos/{{projectName}}.podspec.
+* For Linux and Windows: CMake.
+  * See the documentation in linux/CMakeLists.txt.
+  * See the documentation in windows/CMakeLists.txt.
+
+## Binding to native code
+
+To use the native code, bindings in Dart are needed.
+To avoid writing these by hand, they are generated from the header file
+(`src/{{projectName}}.h`) by `package:ffigen`.
+Regenerate the bindings by running `flutter pub run ffigen --config ffigen.yaml`.
+
+## Invoking native code
+
+Very short-running native functions can be directly invoked from any isolate.
+For example, see `sum` in `lib/{{projectName}}.dart`.
+
+Longer-running functions should be invoked on a helper isolate to avoid
+dropping frames in Flutter applications.
+For example, see `sumAsync` in `lib/{{projectName}}.dart`.
+
+## Flutter help
+
+For help getting started with Flutter, view our
+[online documentation](https://flutter.dev/docs), which offers tutorials,
+samples, guidance on mobile development, and a full API reference.
+
+{{#no_platforms}}
+The plugin project was generated without specifying the `--platforms` flag, so no platforms are currently supported.
+To add platforms, run `flutter create -t plugin_ffi --platforms <platforms> .` in this directory.
+You can also find a detailed instruction on how to add platforms in the `pubspec.yaml` at https://flutter.dev/docs/development/packages-and-plugins/developing-packages#plugin-platforms.
+{{/no_platforms}}

packages/flutter_tools/templates/plugin_ffi/android.tmpl/build.gradle.tmpl

+// The Android Gradle Plugin builds the native code with the Android NDK.
+
+group '{{androidIdentifier}}'
+version '1.0'
+
+buildscript {
+    repositories {
+        google()
+        mavenCentral()
+    }
+
+    dependencies {
+        // The Android Gradle Plugin knows how to build native code with the NDK.
+        classpath 'com.android.tools.build:gradle:4.1.0'
+    }
+}
+
+rootProject.allprojects {
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+apply plugin: 'com.android.library'
+
+android {
+    compileSdkVersion 31
+
+    // Invoke the shared CMake build with the Android Gradle Plugin.
+    //
+    // We do _not_ specify the NDK and CMake version here. This way we will
+    // automatically get the default versions from the Android Gradle Plugin.
+    //
+    // Android Gradle Plugin 4.1.0: Android NDK 21.1.6352462.
+    // https://developer.android.com/studio/projects/install-ndk#default-ndk-per-agp
+    // CMake 3.10.2.
+    // https://developer.android.com/studio/projects/install-ndk#vanilla_cmake
+    //
+    // You are strongly encouraged to not ship FFI plugins requiring newer
+    // versions of the NDK or CMake, because your clients will not be able to
+    // use them.
+    externalNativeBuild {
+        cmake {
+            path "../src/CMakeLists.txt"
+        }
+    }
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+
+    defaultConfig {
+        minSdkVersion 16
+    }
+}

packages/flutter_tools/templates/plugin_ffi/android.tmpl/projectName_android.iml.tmpl

+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="FacetManager">
+    <facet type="android" name="Android">
+      <configuration>
+        <option name="ALLOW_USER_CONFIGURATION" value="false" />
+        <option name="GEN_FOLDER_RELATIVE_PATH_APT" value="/gen" />
+        <option name="GEN_FOLDER_RELATIVE_PATH_AIDL" value="/gen" />
+        <option name="MANIFEST_FILE_RELATIVE_PATH" value="/src/main/AndroidManifest.xml" />
+        <option name="RES_FOLDER_RELATIVE_PATH" value="/src/main/res" />
+        <option name="ASSETS_FOLDER_RELATIVE_PATH" value="/src/main/assets" />
+        <option name="LIBS_FOLDER_RELATIVE_PATH" value="/src/main/libs" />
+        <option name="PROGUARD_LOGS_FOLDER_RELATIVE_PATH" value="/src/main/proguard_logs" />
+      </configuration>
+    </facet>
+  </component>
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src/main/java" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/gen" isTestSource="false" generated="true" />
+    </content>
+    <orderEntry type="jdk" jdkName="Android API {{androidSdkVersion}} Platform" jdkType="Android SDK" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="Flutter for Android" level="project" />
+  </component>
+</module>

packages/flutter_tools/templates/plugin_ffi/ffigen.yaml.tmpl

+# Run with `dart run ffigen --config ffigen.yaml`.
+name: {{pluginDartClass}}Bindings
+description: |
+  Bindings for `src/{{projectName}}.h`.
+
+  Regenerate bindings with `dart run ffigen --config ffigen.yaml`.
+output: 'lib/{{projectName}}_bindings_generated.dart'
+headers:
+  entry-points:
+    - 'src/{{projectName}}.h'
+  include-directives:
+    - 'src/{{projectName}}.h'
+preamble: |
+  // ignore_for_file: always_specify_types
+  // ignore_for_file: camel_case_types
+  // ignore_for_file: non_constant_identifier_names
+comments:
+  style: any
+  length: full

packages/flutter_tools/templates/plugin_ffi/ios.tmpl/Classes/projectName.c.tmpl

+// Relative import to be able to reuse the C sources.
+#include "../../src/{{projectName}}.c"

packages/flutter_tools/templates/plugin_ffi/ios.tmpl/projectName.podspec.tmpl

+#
+# To learn more about a Podspec see http://guides.cocoapods.org/syntax/podspec.html.
+# Run `pod lib lint {{projectName}}.podspec` to validate before publishing.
+#
+Pod::Spec.new do |s|
+  s.name             = '{{projectName}}'
+  s.version          = '0.0.1'
+  s.summary          = '{{description}}'
+  s.description      = <<-DESC
+{{description}}
+                       DESC
+  s.homepage         = 'http://example.com'
+  s.license          = { :file => '../LICENSE' }
+  s.author           = { 'Your Company' => 'email@example.com' }
+
+  # This will ensure the source files in Classes/ are included in the native
+  # builds of apps using this FFI plugin. Podspec does not support relative
+  # paths, so Classes contains a forwarder C file that relatively imports
+  # `../src/*` so that the C sources can be shared among all target platforms.
+  s.source           = { :path => '.' }
+  s.source_files = 'Classes/**/*'
+  s.dependency 'Flutter'
+  s.platform = :ios, '9.0'
+
+  # Flutter.framework does not contain a i386 slice.
+  s.pod_target_xcconfig = { 'DEFINES_MODULE' => 'YES', 'EXCLUDED_ARCHS[sdk=iphonesimulator*]' => 'i386' }
+  s.swift_version = '5.0'
+end

packages/flutter_tools/templates/plugin_ffi/lib/projectName.dart.tmpl

+{{#no_platforms}}
+// You have generated a new plugin project without specifying the `--platforms`
+// flag. An FFI plugin project that supports no platforms is generated.
+// To add platforms, run `flutter create -t plugin_ffi --platforms <platforms> .`
+// in this directory. You can also find a detailed instruction on how to
+// add platforms in the `pubspec.yaml` at
+// https://flutter.dev/docs/development/packages-and-plugins/developing-packages#plugin-platforms.
+{{/no_platforms}}
+
+import 'dart:async';
+import 'dart:ffi';
+import 'dart:io';
+import 'dart:isolate';
+
+import '{{projectName}}_bindings_generated.dart';
+
+/// A very short-lived native function.
+///
+/// For very short-lived functions, it is fine to call them on the main isolate.
+/// They will block the Dart execution while running the native function, so
+/// only do this for native functions which are guaranteed to be short-lived.
+int sum(int a, int b) => _bindings.sum(a, b);
+
+/// A longer lived native function, which occupies the thread calling it.
+///
+/// Do not call these kind of native functions in the main isolate. They will
+/// block Dart execution. This will cause dropped frames in Flutter applications.
+/// Instead, call these native functions on a separate isolate.
+///
+/// Modify this to suit your own use case. Example use cases:
+///
+/// 1. Reuse a single isolate for various different kinds of requests.
+/// 2. Use multiple helper isolates for parallel execution.
+Future<int> sumAsync(int a, int b) async {
+  final SendPort helperIsolateSendPort = await _helperIsolateSendPort;
+  final int requestId = _nextSumRequestId++;
+  final _SumRequest request = _SumRequest(requestId, a, b);
+  final Completer<int> completer = Completer<int>();
+  _sumRequests[requestId] = completer;
+  helperIsolateSendPort.send(request);
+  return completer.future;
+}
+
+const String _libName = '{{projectName}}';
+
+/// The dynamic library in which the symbols for [{{pluginDartClass}}Bindings] can be found.
+final DynamicLibrary _dylib = () {
+  if (Platform.isMacOS || Platform.isIOS) {
+    return DynamicLibrary.open('$_libName.framework/$_libName');
+  }
+  if (Platform.isAndroid || Platform.isLinux) {
+    return DynamicLibrary.open('lib$_libName.so');
+  }
+  if (Platform.isWindows) {
+    return DynamicLibrary.open('$_libName.dll');
+  }
+  throw UnsupportedError('Unknown platform: ${Platform.operatingSystem}');
+}();
+
+/// The bindings to the native functions in [_dylib].
+final {{pluginDartClass}}Bindings _bindings = {{pluginDartClass}}Bindings(_dylib);
+
+
+/// A request to compute `sum`.
+///
+/// Typically sent from one isolate to another.
+class _SumRequest {
+  final int id;
+  final int a;
+  final int b;
+
+  const _SumRequest(this.id, this.a, this.b);
+}
+
+/// A response with the result of `sum`.
+///
+/// Typically sent from one isolate to another.
+class _SumResponse {
+  final int id;
+  final int result;
+
+  const _SumResponse(this.id, this.result);
+}
+
+/// Counter to identify [_SumRequest]s and [_SumResponse]s.
+int _nextSumRequestId = 0;
+
+/// Mapping from [_SumRequest] `id`s to the completers corresponding to the correct future of the pending request.
+final Map<int, Completer<int>> _sumRequests = <int, Completer<int>>{};
+
+/// The SendPort belonging to the helper isolate.
+Future<SendPort> _helperIsolateSendPort = () async {
+  // The helper isolate is going to send us back a SendPort, which we want to
+  // wait for.
+  final Completer<SendPort> completer = Completer<SendPort>();
+
+  // Receive port on the main isolate to receive messages from the helper.
+  // We receive two types of messages:
+  // 1. A port to send messages on.
+  // 2. Responses to requests we sent.
+  final ReceivePort receivePort = ReceivePort()
+    ..listen((dynamic data) {
+      if (data is SendPort) {
+        // The helper isolate sent us the port on which we can sent it requests.
+        completer.complete(data);
+        return;
+      }
+      if (data is _SumResponse) {
+        // The helper isolate sent us a response to a request we sent.
+        final Completer<int> completer = _sumRequests[data.id]!;
+        _sumRequests.remove(data.id);
+        completer.complete(data.result);
+        return;
+      }
+      throw UnsupportedError('Unsupported message type: ${data.runtimeType}');
+    });
+
+  // Start the helper isolate.
+  await Isolate.spawn((SendPort sendPort) async {
+    final ReceivePort helperReceivePort = ReceivePort()
+      ..listen((dynamic data) {
+        // On the helper isolate listen to requests and respond to them.
+        if (data is _SumRequest) {
+          final int result = _bindings.sum_long_running(data.a, data.b);
+          final _SumResponse response = _SumResponse(data.id, result);
+          sendPort.send(response);
+          return;
+        }
+        throw UnsupportedError('Unsupported message type: ${data.runtimeType}');
+      });
+
+    // Send the the port to the main isolate on which we can receive requests.
+    sendPort.send(helperReceivePort.sendPort);
+  }, receivePort.sendPort);
+
+  // Wait until the helper isolate has sent us back the SendPort on which we
+  // can start sending requests.
+  return completer.future;
+}();

packages/flutter_tools/templates/plugin_ffi/lib/projectName_bindings_generated.dart.tmpl

+// ignore_for_file: always_specify_types
+// ignore_for_file: camel_case_types
+// ignore_for_file: non_constant_identifier_names
+
+// AUTO GENERATED FILE, DO NOT EDIT.
+//
+// Generated by `package:ffigen`.
+import 'dart:ffi' as ffi;
+
+/// Bindings for `src/{{projectName}}.h`.
+///
+/// Regenerate bindings with `dart run ffigen --config ffigen.yaml`.
+///
+class {{pluginDartClass}}Bindings {
+  /// Holds the symbol lookup function.
+  final ffi.Pointer<T> Function<T extends ffi.NativeType>(String symbolName)
+      _lookup;
+
+  /// The symbols are looked up in [dynamicLibrary].
+  {{pluginDartClass}}Bindings(ffi.DynamicLibrary dynamicLibrary)
+      : _lookup = dynamicLibrary.lookup;
+
+  /// The symbols are looked up with [lookup].
+  {{pluginDartClass}}Bindings.fromLookup(
+      ffi.Pointer<T> Function<T extends ffi.NativeType>(String symbolName)
+          lookup)
+      : _lookup = lookup;
+
+  /// A very short-lived native function.
+  ///
+  /// For very short-lived functions, it is fine to call them on the main isolate.
+  /// They will block the Dart execution while running the native function, so
+  /// only do this for native functions which are guaranteed to be short-lived.
+  int sum(
+    int a,
+    int b,
+  ) {
+    return _sum(
+      a,
+      b,
+    );
+  }
+
+  late final _sumPtr =
+      _lookup<ffi.NativeFunction<ffi.IntPtr Function(ffi.IntPtr, ffi.IntPtr)>>(
+          'sum');
+  late final _sum = _sumPtr.asFunction<int Function(int, int)>();
+
+  /// A longer lived native function, which occupies the thread calling it.
+  ///
+  /// Calling these kind of native functions in the main isolate will
+  /// block Dart execution and cause dropped frames in Flutter applications.
+  /// Consider calling such native functions from a separate isolate.
+  int sum_long_running(
+    int a,
+    int b,
+  ) {
+    return _sum_long_running(
+      a,
+      b,
+    );
+  }
+
+  late final _sum_long_runningPtr =
+      _lookup<ffi.NativeFunction<ffi.IntPtr Function(ffi.IntPtr, ffi.IntPtr)>>(
+          'sum_long_running');
+  late final _sum_long_running =
+      _sum_long_runningPtr.asFunction<int Function(int, int)>();
+}

packages/flutter_tools/templates/plugin_ffi/linux.tmpl/CMakeLists.txt.tmpl

+cmake_minimum_required(VERSION 3.10)
+set(PROJECT_NAME "{{projectName}}")
+project(${PROJECT_NAME} LANGUAGES CXX)
+
+# Invoke the build for native code shared with the other target platforms.
+add_subdirectory("${CMAKE_CURRENT_SOURCE_DIR}/../src" "${CMAKE_CURRENT_BINARY_DIR}/shared")
+
+# List of absolute paths to libraries that should be bundled with the plugin.
+set({{projectName}}_bundled_libraries
+  # Defined in ../src/CMakeLists.txt.
+  $<TARGET_FILE:{{projectName}}>
+  PARENT_SCOPE
+)

packages/flutter_tools/templates/plugin_ffi/macos.tmpl/Classes/projectName.c.tmpl

+// Relative import to be able to reuse the C sources.
+#include "../../src/{{projectName}}.c"

packages/flutter_tools/templates/plugin_ffi/src.tmpl/CMakeLists.txt.tmpl

+# We use the CMake version connected to the version of the Android Gradle Plugin.
+#
+# Android Gradle Plugin 4.1.0: Android NDK 21.1.6352462.
+# https://developer.android.com/studio/projects/install-ndk#default-ndk-per-agp
+# CMake 3.10.2.
+# https://developer.android.com/studio/projects/install-ndk#vanilla_cmake
+#
+# You are strongly encouraged to not ship FFI plugins requiring newer versions
+# of the NDK or CMake, because your clients will not be able to use them.
+cmake_minimum_required(VERSION 3.10 FATAL_ERROR)
+
+project({{projectName}}_library VERSION 0.0.1 LANGUAGES C)
+
+add_library(
+    {{projectName}}
+    SHARED
+    "{{projectName}}.c"
+)
+
+set_target_properties({{projectName}} PROPERTIES
+    PUBLIC_HEADER {{projectName}}.h
+    OUTPUT_NAME "{{projectName}}"
+)
+
+target_compile_definitions({{projectName}} PUBLIC DART_SHARED_LIB)

packages/flutter_tools/templates/plugin_ffi/src.tmpl/projectName.c.tmpl

+#include "{{projectName}}.h"
+
+// A very short-lived native function.
+//
+// For very short-lived functions, it is fine to call them on the main isolate.
+// They will block the Dart execution while running the native function, so
+// only do this for native functions which are guaranteed to be short-lived.
+MYLIB_EXPORT intptr_t sum(intptr_t a, intptr_t b) { return a + b; }
+
+// A longer-lived native function, which occupies the thread calling it.
+//
+// Do not call these kind of native functions in the main isolate. They will
+// block Dart execution. This will cause dropped frames in Flutter applications.
+// Instead, call these native functions on a separate isolate.
+MYLIB_EXPORT intptr_t sum_long_running(intptr_t a, intptr_t b) {
+  // Simulate work.
+#if _WIN32
+  Sleep(5000);
+#else
+  usleep(5000 * 1000);
+#endif
+  return a + b;
+}

packages/flutter_tools/templates/plugin_ffi/src.tmpl/projectName.h.tmpl

+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#if _WIN32
+#include <windows.h>
+#else
+#include <pthread.h>
+#include <unistd.h>
+#endif
+
+#if _WIN32
+#define MYLIB_EXPORT __declspec(dllexport)
+#else
+#define MYLIB_EXPORT
+#endif
+
+// A very short-lived native function.
+//
+// For very short-lived functions, it is fine to call them on the main isolate.
+// They will block the Dart execution while running the native function, so
+// only do this for native functions which are guaranteed to be short-lived.
+MYLIB_EXPORT intptr_t sum(intptr_t a, intptr_t b);
+
+// A longer lived native function, which occupies the thread calling it.
+//
+// Do not call these kind of native functions in the main isolate. They will
+// block Dart execution. This will cause dropped frames in Flutter applications.
+// Instead, call these native functions on a separate isolate.
+MYLIB_EXPORT intptr_t sum_long_running(intptr_t a, intptr_t b);

packages/flutter_tools/templates/plugin_ffi/windows.tmpl/CMakeLists.txt.tmpl

+cmake_minimum_required(VERSION 3.14)
+set(PROJECT_NAME "{{projectName}}")
+project(${PROJECT_NAME} LANGUAGES CXX)
+
+# Invoke the build for native code shared with the other target platforms.
+add_subdirectory("${CMAKE_CURRENT_SOURCE_DIR}/../src" "${CMAKE_CURRENT_BINARY_DIR}/shared")
+
+# List of absolute paths to libraries that should be bundled with the plugin.
+set({{projectName}}_bundled_libraries
+  # Defined in ../src/CMakeLists.txt.
+  $<TARGET_FILE:{{projectName}}>
+  PARENT_SCOPE
+)

packages/flutter_tools/templates/plugin/.metadata.tmpl → packages/flutter_tools/templates/plugin_shared/.metadata.tmpl

@@ -7,4 +7,9 @@ version:
   revision: {{flutterRevision}}
   channel: {{flutterChannel}}
 
+{{#withFfiPluginHook}}
+project_type: plugin_ffi
+{{/withFfiPluginHook}}
+{{#withPlatformChannelPluginHook}}
 project_type: plugin
+{{/withPlatformChannelPluginHook}}

packages/flutter_tools/templates/plugin_shared/android.tmpl/.gitignore

+*.iml
+.gradle
+/local.properties
+/.idea/workspace.xml
+/.idea/libraries
+.DS_Store
+/build
+/captures
+.cxx

packages/flutter_tools/templates/plugin_shared/android.tmpl/settings.gradle.tmpl

+rootProject.name = '{{projectName}}'

packages/flutter_tools/templates/plugin_shared/android.tmpl/src/main/AndroidManifest.xml.tmpl

+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+  package="{{androidIdentifier}}">
+</manifest>

packages/flutter_tools/templates/plugin/macos.tmpl/projectName.podspec.tmpl → packages/flutter_tools/templates/plugin_shared/macos.tmpl/projectName.podspec.tmpl

@@ -12,6 +12,13 @@ Pod::Spec.new do |s|
   s.homepage         = 'http://example.com'
   s.license          = { :file => '../LICENSE' }
   s.author           = { 'Your Company' => 'email@example.com' }
+
+{{#withFfiPluginHook}}
+  # This will ensure the source files in Classes/ are included in the native
+  # builds of apps using this FFI plugin. Podspec does not support relative
+  # paths, so Classes contains a forwarder C file that relatively imports
+  # `../src/*` so that the C sources can be shared among all target platforms.
+{{/withFfiPluginHook}}
   s.source           = { :path => '.' }
   s.source_files     = 'Classes/**/*'
   s.dependency 'FlutterMacOS'

packages/flutter_tools/templates/plugin/pubspec.yaml.tmpl → packages/flutter_tools/templates/plugin_shared/pubspec.yaml.tmpl

@@ -16,6 +16,9 @@ dependencies:
 {{/web}}
 
 dev_dependencies:
+{{#withFfiPluginHook}}
+  ffigen: ^4.1.2
+{{/withFfiPluginHook}}
   flutter_test:
     sdk: flutter
   flutter_lints: ^1.0.0
@@ -26,9 +29,52 @@ dev_dependencies:
 # The following section is specific to Flutter.
 flutter:
   # This section identifies this Flutter project as a plugin project.
-  # The 'pluginClass' and Android 'package' identifiers should not ordinarily
-  # be modified. They are used by the tooling to maintain consistency when
+  # The 'pluginClass' specifies the class (in Java, Kotlin, Swift, ObjectiveC)
+  # which should be registered in the plugin registry. This is required for
+  # using method channels.
+  # The Android 'package' specifies package in which the registered class is.
+  # This is required for using method channels on Android.
+  # The 'ffiPlugin' specifies that native code should be built and bundled.
+  # This is required for using `dart:ffi`.
+  # All these are used by the tooling to maintain consistency when
   # adding or updating assets for this project.
+{{#withFfiPluginHook}}
+  #
+  # Please refer to README.md for a detailed explanation.
+  plugin:
+    platforms:
+{{#no_platforms}}
+    # This FFI plugin project was generated without specifying any
+    # platforms with the `--platform` argument. If you see the `some_platform` map below, remove it and
+    # then add platforms following the instruction here:
+    # https://flutter.dev/docs/development/packages-and-plugins/developing-packages#plugin-platforms
+    # -------------------
+      some_platform:
+        ffiPlugin: true
+    # -------------------
+{{/no_platforms}}
+{{#android}}
+      android:
+        ffiPlugin: true
+{{/android}}
+{{#ios}}
+      ios:
+        ffiPlugin: true
+{{/ios}}
+{{#linux}}
+      linux:
+        ffiPlugin: true
+{{/linux}}
+{{#macos}}
+      macos:
+        ffiPlugin: true
+{{/macos}}
+{{#windows}}
+      windows:
+        ffiPlugin: true
+{{/windows}}
+{{/withFfiPluginHook}}
+{{#withPlatformChannelPluginHook}}
   plugin:
     platforms:
 {{#no_platforms}}
@@ -67,6 +113,7 @@ flutter:
         pluginClass: {{pluginDartClass}}Web
         fileName: {{projectName}}_web.dart
 {{/web}}
+{{/withPlatformChannelPluginHook}}
 
   # To add assets to your plugin package, add an assets section, like this:
   # assets:

packages/flutter_tools/templates/template_manifest.json

@@ -304,13 +304,6 @@
         "templates/package/README.md.tmpl",
         "templates/package/test/projectName_test.dart.tmpl",
 
-        "templates/plugin/.gitignore.tmpl",
-        "templates/plugin/.idea/libraries/Dart_SDK.xml.tmpl",
-        "templates/plugin/.idea/modules.xml.tmpl",
-        "templates/plugin/.idea/runConfigurations/example_lib_main_dart.xml.tmpl",
-        "templates/plugin/.idea/workspace.xml.tmpl",
-        "templates/plugin/.metadata.tmpl",
-        "templates/plugin/analysis_options.yaml.tmpl",
         "templates/plugin/android-java.tmpl/build.gradle.tmpl",
         "templates/plugin/android-java.tmpl/projectName_android.iml.tmpl",
         "templates/plugin/android-java.tmpl/src/main/java/androidIdentifier/pluginClass.java.tmpl",
@@ -322,7 +315,6 @@
         "templates/plugin/android.tmpl/gradle.properties.tmpl",
         "templates/plugin/android.tmpl/settings.gradle.tmpl",
         "templates/plugin/android.tmpl/src/main/AndroidManifest.xml.tmpl",
-        "templates/plugin/CHANGELOG.md.tmpl",
         "templates/plugin/ios-objc.tmpl/Classes/pluginClass.h.tmpl",
         "templates/plugin/ios-objc.tmpl/Classes/pluginClass.m.tmpl",
         "templates/plugin/ios-objc.tmpl/projectName.podspec.tmpl",
@@ -333,22 +325,51 @@
         "templates/plugin/ios.tmpl/.gitignore",
         "templates/plugin/ios.tmpl/Assets/.gitkeep",
         "templates/plugin/lib/projectName.dart.tmpl",
-        "templates/plugin/LICENSE.tmpl",
         "templates/plugin/linux.tmpl/CMakeLists.txt.tmpl",
         "templates/plugin/linux.tmpl/include/projectName.tmpl/pluginClassSnakeCase.h.tmpl",
         "templates/plugin/linux.tmpl/pluginClassSnakeCase.cc.tmpl",
         "templates/plugin/macos.tmpl/Classes/pluginClass.swift.tmpl",
-        "templates/plugin/macos.tmpl/projectName.podspec.tmpl",
-        "templates/plugin/projectName.iml.tmpl",
-        "templates/plugin/pubspec.yaml.tmpl",
         "templates/plugin/README.md.tmpl",
         "templates/plugin/test/projectName_test.dart.tmpl",
-        "templates/plugin/windows.tmpl/.gitignore",
         "templates/plugin/windows.tmpl/CMakeLists.txt.tmpl",
         "templates/plugin/windows.tmpl/include/projectName.tmpl/pluginClassSnakeCase.h.tmpl",
         "templates/plugin/windows.tmpl/pluginClassSnakeCase.cpp.tmpl",
         "templates/plugin/lib/projectName_web.dart.tmpl",
 
+        "templates/plugin_ffi/android.tmpl/build.gradle.tmpl",
+        "templates/plugin_ffi/android.tmpl/projectName_android.iml.tmpl",
+        "templates/plugin_ffi/ffigen.yaml.tmpl",
+        "templates/plugin_ffi/ios.tmpl/.gitignore",
+        "templates/plugin_ffi/ios.tmpl/Classes/projectName.c.tmpl",
+        "templates/plugin_ffi/ios.tmpl/projectName.podspec.tmpl",
+        "templates/plugin_ffi/lib/projectName_bindings_generated.dart.tmpl",
+        "templates/plugin_ffi/lib/projectName.dart.tmpl",
+        "templates/plugin_ffi/linux.tmpl/CMakeLists.txt.tmpl",
+        "templates/plugin_ffi/linux.tmpl/include/projectName.tmpl/plugin_ffiClassSnakeCase.h.tmpl",
+        "templates/plugin_ffi/macos.tmpl/Classes/projectName.c.tmpl",
+        "templates/plugin_ffi/README.md.tmpl",
+        "templates/plugin_ffi/src.tmpl/CMakeLists.txt.tmpl",
+        "templates/plugin_ffi/src.tmpl/projectName.c.tmpl",
+        "templates/plugin_ffi/src.tmpl/projectName.h.tmpl",
+        "templates/plugin_ffi/windows.tmpl/CMakeLists.txt.tmpl",
+
+        "templates/plugin_shared/.gitignore.tmpl",
+        "templates/plugin_shared/.idea/libraries/Dart_SDK.xml.tmpl",
+        "templates/plugin_shared/.idea/modules.xml.tmpl",
+        "templates/plugin_shared/.idea/runConfigurations/example_lib_main_dart.xml.tmpl",
+        "templates/plugin_shared/.idea/workspace.xml.tmpl",
+        "templates/plugin_shared/.metadata.tmpl",
+        "templates/plugin_shared/analysis_options.yaml.tmpl",
+        "templates/plugin_shared/android.tmpl/.gitignore",
+        "templates/plugin_shared/android.tmpl/settings.gradle.tmpl",
+        "templates/plugin_shared/android.tmpl/src/main/AndroidManifest.xml.tmpl",
+        "templates/plugin_shared/CHANGELOG.md.tmpl",
+        "templates/plugin_shared/LICENSE.tmpl",
+        "templates/plugin_shared/macos.tmpl/projectName.podspec.tmpl",
+        "templates/plugin_shared/projectName.iml.tmpl",
+        "templates/plugin_shared/pubspec.yaml.tmpl",
+        "templates/plugin_shared/windows.tmpl/.gitignore",
+
         "templates/skeleton/assets/images/2.0x/flutter_logo.png.img.tmpl",
         "templates/skeleton/assets/images/3.0x/flutter_logo.png.img.tmpl",
         "templates/skeleton/assets/images/flutter_logo.png.img.tmpl",

packages/flutter_tools/test/commands.shard/hermetic/create_usage_test.dart

@@ -48,6 +48,8 @@ void main() {
           globals.fs.path.join('flutter', 'packages', 'flutter_tools', 'templates', 'module', 'common'),
           globals.fs.path.join('flutter', 'packages', 'flutter_tools', 'templates', 'package'),
           globals.fs.path.join('flutter', 'packages', 'flutter_tools', 'templates', 'plugin'),
+          globals.fs.path.join('flutter', 'packages', 'flutter_tools', 'templates', 'plugin_ffi'),
+          globals.fs.path.join('flutter', 'packages', 'flutter_tools', 'templates', 'plugin_shared'),
         ];
         for (final String templatePath in templatePaths) {
           globals.fs.directory(templatePath).createSync(recursive: true);
@@ -96,6 +98,9 @@ void main() {
 
       await runner.run(<String>['create', '--no-pub', '--template=plugin', 'testy']);
       expect((await command.usageValues).commandCreateProjectType, 'plugin');
+
+      await runner.run(<String>['create', '--no-pub', '--template=plugin_ffi', 'testy']);
+      expect((await command.usageValues).commandCreateProjectType, 'plugin_ffi');
     }));
 
     testUsingContext('set iOS host language type as usage value', () => testbed.run(() async {

packages/flutter_tools/test/commands.shard/permeable/create_test.dart

@@ -2761,6 +2761,71 @@ void main() {
       platform: globals.platform,
     ),
   });
+
+  testUsingContext('create an FFI plugin with ios, then add macos', () async {
+    Cache.flutterRoot = '../..';
+
+    final CreateCommand command = CreateCommand();
+    final CommandRunner<void> runner = createTestCommandRunner(command);
+    await runner.run(<String>['create', '--no-pub', '--template=plugin_ffi', '--platform=ios', projectDir.path]);
+    expect(projectDir.childDirectory('src'), exists);
+    expect(projectDir.childDirectory('ios'), exists);
+    expect(projectDir.childDirectory('example').childDirectory('ios'), exists);
+    validatePubspecForPlugin(
+      projectDir: projectDir.absolute.path,
+      expectedPlatforms: const <String>[
+        'ios',
+      ],
+      ffiPlugin: true,
+      unexpectedPlatforms: <String>['some_platform'],
+    );
+
+    await runner.run(<String>['create', '--no-pub', '--template=plugin_ffi', '--platform=macos', projectDir.path]);
+    expect(projectDir.childDirectory('macos'), exists);
+    expect(
+        projectDir.childDirectory('example').childDirectory('macos'), exists);
+    expect(projectDir.childDirectory('ios'), exists);
+    expect(projectDir.childDirectory('example').childDirectory('ios'), exists);
+  }, overrides: <Type, Generator>{
+    FeatureFlags: () => TestFeatureFlags(isMacOSEnabled: true),
+  });
+
+  testUsingContext('FFI plugins error android and ios language', () async {
+    final CreateCommand command = CreateCommand();
+    final CommandRunner<void> runner = createTestCommandRunner(command);
+    final List<String> args = <String>[
+      'create',
+      '--no-pub',
+      '--template=plugin_ffi',
+      '-a',
+      'kotlin',
+      '--ios-language',
+      'swift',
+      '--platforms=ios,android',
+      projectDir.path,
+    ];
+
+    await expectLater(
+        runner.run(args),
+        throwsToolExit(
+            message:
+                'The "ios-language" option is not supported with the plugin_ffi template: the language will always be C or C++.'));
+  });
+
+  testUsingContext('should show warning when disabled platforms are selected while creating an FFI plugin', () async {
+    Cache.flutterRoot = '../..';
+
+    final CreateCommand command = CreateCommand();
+    final CommandRunner<void> runner = createTestCommandRunner(command);
+
+    await runner.run(<String>['create', '--no-pub', '--template=plugin_ffi', '--platforms=android,ios,windows,macos,linux', projectDir.path]);
+    await runner.run(<String>['create', '--no-pub', '--template=plugin_ffi', projectDir.path]);
+    expect(logger.statusText, contains(_kDisabledPlatformRequestedMessage));
+
+  }, overrides: <Type, Generator>{
+    FeatureFlags: () => TestFeatureFlags(),
+    Logger: () => logger,
+  });
 }
 
 Future<void> _createProject(

packages/flutter_tools/test/integration.shard/android_plugin_example_app_build_test.dart

@@ -9,33 +9,43 @@ import '../src/common.dart';
 import 'test_utils.dart';
 
 void main() {
-  late Directory tempDir;
+  late Directory tempDirPluginMethodChannels;
+  late Directory tempDirPluginFfi;
 
   setUp(() async {
-    tempDir = createResolvedTempDirectorySync('flutter_plugin_test.');
+    tempDirPluginMethodChannels = createResolvedTempDirectorySync('flutter_plugin_test.');
+    tempDirPluginFfi =
+        createResolvedTempDirectorySync('flutter_ffi_plugin_test.');
   });
 
   tearDown(() async {
-    tryToDelete(tempDir);
+    tryToDelete(tempDirPluginMethodChannels);
+    tryToDelete(tempDirPluginFfi);
   });
 
-  test('plugin example can be built using current Flutter Gradle plugin', () async {
+  Future<void> testPlugin({
+    required String template,
+    required Directory tempDir,
+  }) async {
     final String flutterBin = fileSystem.path.join(
       getFlutterRoot(),
       'bin',
       'flutter',
     );
 
+    final String testName = '${template}_test';
+
     processManager.runSync(<String>[
       flutterBin,
       ...getLocalEngineArguments(),
       'create',
-      '--template=plugin',
+      '--template=$template',
       '--platforms=android',
-      'plugin_test',
+      testName,
     ], workingDirectory: tempDir.path);
 
-    final Directory exampleAppDir = tempDir.childDirectory('plugin_test').childDirectory('example');
+    final Directory exampleAppDir =
+        tempDir.childDirectory(testName).childDirectory('example');
 
     final File buildGradleFile = exampleAppDir.childDirectory('android').childFile('build.gradle');
     expect(buildGradleFile, exists);
@@ -68,6 +78,11 @@ void main() {
     ));
     expect(exampleApk, exists);
 
+    if (template == 'plugin_ffi') {
+      // Does not support AGP 3.3.0.
+      return;
+    }
+
     // Clean
     processManager.runSync(<String>[
       flutterBin,
@@ -101,5 +116,21 @@ android.enableR8=true''');
       '--target-platform=android-arm',
     ], workingDirectory: exampleAppDir.path);
     expect(exampleApk, exists);
+  }
+
+  test('plugin example can be built using current Flutter Gradle plugin',
+      () async {
+    await testPlugin(
+      template: 'plugin',
+      tempDir: tempDirPluginMethodChannels,
+    );
+  });
+
+  test('FFI plugin example can be built using current Flutter Gradle plugin',
+      () async {
+    await testPlugin(
+      template: 'plugin_ffi',
+      tempDir: tempDirPluginFfi,
+    );
   });
 }

packages/flutter_tools/test/src/pubspec_schema.dart

@@ -11,19 +11,23 @@ import 'common.dart';
 /// Check if the pubspec.yaml file under the `projectDir` is valid for a plugin project.
 void validatePubspecForPlugin({
   required String projectDir,
-  required String pluginClass,
+  String? pluginClass,
+  bool ffiPlugin = false,
   required List<String> expectedPlatforms,
   List<String> unexpectedPlatforms = const <String>[],
   String? androidIdentifier,
   String? webFileName,
 }) {
+  assert(pluginClass != null || ffiPlugin);
   final FlutterManifest manifest =
       FlutterManifest.createFromPath('$projectDir/pubspec.yaml', fileSystem: globals.fs, logger: globals.logger)!;
   final YamlMap platformMaps = YamlMap.wrap(manifest.supportedPlatforms!);
   for (final String platform in expectedPlatforms) {
     expect(platformMaps[platform], isNotNull);
     final YamlMap platformMap = platformMaps[platform]! as YamlMap;
+    if (pluginClass != null) {
       expect(platformMap['pluginClass'], pluginClass);
+    }
     if (platform == 'android') {
       expect(platformMap['package'], androidIdentifier);
     }