FFI plugins (#96225)

dev/devicelab/bin/tasks/plugin_test.dart

@@ -18,5 +18,7 @@ Future<void> main() async {
         <String, String>{'ENABLE_ANDROID_EMBEDDING_V2': 'true'}),
     // Test that Dart-only plugins are supported.
     PluginTest('apk', <String>['--platforms=android'], dartOnlyPlugin: true),
+    // Test that FFI plugins are supported.
+    PluginTest('apk', <String>['--platforms=android'], template: 'plugin_ffi'),
   ]));
 }

dev/devicelab/bin/tasks/plugin_test_ios.dart

@@ -13,5 +13,8 @@ Future<void> main() async {
     // Test that Dart-only plugins are supported.
     PluginTest('ios', <String>['--platforms=ios'], dartOnlyPlugin: true),
     PluginTest('macos', <String>['--platforms=macos'], dartOnlyPlugin: true),
+    // Test that FFI plugins are supported.
+    PluginTest('ios', <String>['--platforms=ios'], template: 'plugin_ffi'),
+    PluginTest('macos', <String>['--platforms=macos'], template: 'plugin_ffi'),
   ]));
 }

dev/devicelab/lib/tasks/plugin_tests.dart

@@ -32,27 +32,35 @@ class PluginTest {
     this.pluginCreateEnvironment,
     this.appCreateEnvironment,
     this.dartOnlyPlugin = false,
+    this.template = 'plugin',
   });
 
   final String buildTarget;
   final List<String> options;
   final Map<String, String>? pluginCreateEnvironment;
   final Map<String, String>? appCreateEnvironment;
   final bool dartOnlyPlugin;
+  final String template;
 
   Future<TaskResult> call() async {
     final Directory tempDir =
         Directory.systemTemp.createTempSync('flutter_devicelab_plugin_test.');
+    // FFI plugins do not have support for `flutter test`.
+    // `flutter test` does not do a native build.
+    // Supporting `flutter test` would require invoking a native build.
+    final bool runFlutterTest = template != 'plugin_ffi';
     try {
       section('Create plugin');
       final _FlutterProject plugin = await _FlutterProject.create(
           tempDir, options, buildTarget,
-          name: 'plugintest', template: 'plugin', environment: pluginCreateEnvironment);
+          name: 'plugintest', template: template, environment: pluginCreateEnvironment);
       if (dartOnlyPlugin) {
         await plugin.convertDefaultPluginToDartPlugin();
       }
       section('Test plugin');
-      await plugin.test();
+      if (runFlutterTest) {
+        await plugin.test();
+      }
       section('Create Flutter app');
       final _FlutterProject app = await _FlutterProject.create(tempDir, options, buildTarget,
           name: 'plugintestapp', template: 'app', environment: appCreateEnvironment);
@@ -63,8 +71,10 @@ class PluginTest {
         await app.addPlugin('path_provider');
         section('Build app');
         await app.build(buildTarget, validateNativeBuildProject: !dartOnlyPlugin);
-        section('Test app');
-        await app.test();
+        if (runFlutterTest) {
+          section('Test app');
+          await app.test();
+        }
       } finally {
         await plugin.delete();
         await app.delete();

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/gradle/flutter.gradle

@@ -38,6 +38,12 @@ class FlutterExtension {
     /** Sets the targetSdkVersion used by default in Flutter app projects. */
     static int targetSdkVersion = 31
 
+    /**
+     * Sets the ndkVersion used by default in Flutter app projects.
+     * Chosen as default version of the AGP version below.
+     */
+    static String ndkVersion = "21.1.6352462"
+
     /**
      * Specifies the relative directory to the Flutter project directory.
      * In an app project, this is ../.. since the app's build.gradle is under android/app.
@@ -54,6 +60,7 @@ buildscript {
         mavenCentral()
     }
     dependencies {
+        /* When bumping, also update ndkVersion above. */
         classpath 'com.android.tools.build:gradle:4.1.0'
     }
 }
@@ -409,24 +416,63 @@ class FlutterPlugin implements Plugin<Project> {
         }
     }
 
-     /** Prints error message and fix for any plugin compileSdkVersion that are higher than the project. */
-    private void detectLowCompileSdkVersion() {
+    /**
+     * Compares semantic versions ignoring labels.
+     * 
+     * If the versions are equal (ignoring labels), returns one of the two strings arbitrarily.
+     *
+     * If minor or patch are omitted (non-conformant to semantic versioning), they are considered zero.
+     * If the provided versions in both are equal, the longest version string is returned.
+     * For example, "2.8.0" vs "2.8" will always consider "2.8.0" to be the most recent version.
+     */
+    static String mostRecentSemanticVersion(String version1, String version2) {
+        List version1Tokenized = version1.tokenize('.')
+        List version2Tokenized = version2.tokenize('.')
+        def version1numTokens = version1Tokenized.size()
+        def version2numTokens = version2Tokenized.size()
+        def minNumTokens = Math.min(version1numTokens, version2numTokens)
+        for (int i = 0; i < minNumTokens; i++) {
+            def num1 = version1Tokenized[i].toInteger()
+            def num2 = version2Tokenized[i].toInteger()
+            if (num1 > num2) {
+                return version1
+            }
+            if (num2 > num1) {
+                return version2
+            }
+        }
+        if (version1numTokens > version2numTokens) {
+            return version1
+        }
+        return version2
+    }
+
+    /** Prints error message and fix for any plugin compileSdkVersion or ndkVersion that are higher than the project. */
+    private void detectLowCompileSdkVersionOrNdkVersion() {
         project.afterEvaluate {
             int projectCompileSdkVersion = project.android.compileSdkVersion.substring(8) as int
             int maxPluginCompileSdkVersion = projectCompileSdkVersion
+            String ndkVersionIfUnspecified = "21.1.6352462" /* The default for AGP 4.1.0 used in old templates. */
+            String projectNdkVersion = project.android.ndkVersion ?: ndkVersionIfUnspecified
+            String maxPluginNdkVersion = projectNdkVersion
             int numProcessedPlugins = getPluginList().size()
 
             getPluginList().each { plugin ->
                 Project pluginProject = project.rootProject.findProject(plugin.key)
                 pluginProject.afterEvaluate {
                     int pluginCompileSdkVersion = pluginProject.android.compileSdkVersion.substring(8) as int
                     maxPluginCompileSdkVersion = Math.max(pluginCompileSdkVersion, maxPluginCompileSdkVersion)
+                    String pluginNdkVersion = pluginProject.android.ndkVersion ?: ndkVersionIfUnspecified
+                    maxPluginNdkVersion = mostRecentSemanticVersion(pluginNdkVersion, maxPluginNdkVersion)
 
                     numProcessedPlugins--
                     if (numProcessedPlugins == 0) {
                         if (maxPluginCompileSdkVersion > projectCompileSdkVersion) {
                             project.logger.error("One or more plugins require a higher Android SDK version.\nFix this issue by adding the following to ${project.projectDir}${File.separator}build.gradle:\nandroid {\n  compileSdkVersion ${maxPluginCompileSdkVersion}\n  ...\n}\n")
                         }
+                        if (maxPluginNdkVersion != projectNdkVersion) {
+                            project.logger.error("One or more plugins require a higher Android NDK version.\nFix this issue by adding the following to ${project.projectDir}${File.separator}build.gradle:\nandroid {\n  ndkVersion ${maxPluginNdkVersion}\n  ...\n}\n")
+                        }
                     }
                 }
             }
@@ -963,7 +1009,7 @@ class FlutterPlugin implements Plugin<Project> {
                 }
             }
             configurePlugins()
-            detectLowCompileSdkVersion()
+            detectLowCompileSdkVersionOrNdkVersion()
             return
         }
         // Flutter host module project (Add-to-app).
@@ -1015,7 +1061,7 @@ class FlutterPlugin implements Plugin<Project> {
             }
         }
         configurePlugins()
-        detectLowCompileSdkVersion()
+        detectLowCompileSdkVersionOrNdkVersion()
     }
 }