[flutter_tools] write SkSL file to local file (#53859)

packages/flutter_tools/lib/src/base/command_help.dart

@@ -165,6 +165,12 @@ class CommandHelp {
     'Toggle CanvasKit rendering.',
   );
 
+  CommandHelpOption _M;
+  CommandHelpOption get M => _M ??= _makeOption(
+    'M',
+    'Write SkSL shaders to a unique file in the project directory.',
+  );
+
   CommandHelpOption _makeOption(String key, String description, [
     String inParenthesis = '',
   ]) {

packages/flutter_tools/lib/src/build_runner/resident_web_runner.dart

@@ -103,6 +103,9 @@ abstract class ResidentWebRunner extends ResidentRunner {
   /// WebServer device is debuggable when running with --start-paused.
   bool get deviceIsDebuggable => device.device is! WebServerDevice || debuggingOptions.startPaused;
 
+  @override
+  bool get supportsWriteSkSL => false;
+
   bool get _enableDwds => debuggingEnabled;
 
   ConnectionResult _connectionResult;

packages/flutter_tools/lib/src/resident_runner.dart

@@ -20,6 +20,7 @@ import 'base/utils.dart';
 import 'build_info.dart';
 import 'codegen.dart';
 import 'compile.dart';
+import 'convert.dart';
 import 'dart/package_map.dart';
 import 'devfs.dart';
 import 'device.dart';
@@ -673,6 +674,7 @@ abstract class ResidentRunner {
   bool get isRunningRelease => debuggingOptions.buildInfo.isRelease;
   bool get supportsServiceProtocol => isRunningDebug || isRunningProfile;
   bool get supportsCanvasKit => false;
+  bool get supportsWriteSkSL => supportsServiceProtocol;
 
   // Returns the Uri of the first connected device for mobile,
   // and only connected device for web.
@@ -740,6 +742,37 @@ abstract class ResidentRunner {
     throw Exception('Canvaskit not supported by this runner.');
   }
 
+  /// Write the SkSL shaders to a zip file in build directory.
+  Future<void> writeSkSL() async {
+    if (!supportsWriteSkSL) {
+      throw Exception('writeSkSL is not supported by this runner.');
+    }
+    final Map<String, Object> data = await flutterDevices.first.views.first.getSkSLs();
+    if (data.isEmpty) {
+      globals.logger.printStatus(
+        'No data was receieved. To ensure SkSL data can be generated use a '
+        'physical device then:\n'
+        '  1. Pass "--cache-sksl" as an argument to flutter run.\n'
+        '  2. Interact with the application to force shaders to be compiled.\n'
+      );
+      return;
+    }
+    final File outputFile = globals.fsUtils.getUniqueFile(
+      globals.fs.currentDirectory,
+      'flutter',
+      'sksl',
+    );
+    final Device device = flutterDevices.first.device;
+    final Map<String, Object> manifest = <String, Object>{
+      'platform': getNameForTargetPlatform(await flutterDevices.first.device.targetPlatform),
+      'name': device.name,
+      'engineRevision': globals.flutterVersion.engineRevision,
+      'data': data,
+    };
+    outputFile.writeAsStringSync(json.encode(manifest));
+    globals.logger.printStatus('Wrote SkSL data to ${outputFile.path}.');
+  }
+
   /// The resident runner API for interaction with the reloadMethod vmservice
   /// request.
   ///
@@ -1094,6 +1127,9 @@ abstract class ResidentRunner {
       if (supportsCanvasKit){
         commandHelp.k.print();
       }
+      if (supportsWriteSkSL) {
+        commandHelp.M.print();
+      }
       commandHelp.v.print();
       // `P` should precede `a`
       commandHelp.P.print();
@@ -1262,6 +1298,12 @@ class TerminalHandler {
           return true;
         }
         return false;
+      case 'M':
+        if (residentRunner.supportsWriteSkSL) {
+          await residentRunner.writeSkSL();
+          return true;
+        }
+        return false;
       case 'p':
         if (residentRunner.supportsServiceProtocol && residentRunner.isRunningDebug) {
           await residentRunner.debugToggleDebugPaintSizeEnabled();

packages/flutter_tools/lib/src/vmservice.dart

@@ -1530,6 +1530,16 @@ class FlutterView extends ServiceObject {
         });
   }
 
+  Future<Map<String, Object>> getSkSLs() async {
+    final Map<String, dynamic> response = await owner.vmService.vm.invokeRpcRaw(
+      '_flutter.getSkSLs',
+      params: <String, dynamic>{
+        'viewId': id,
+      },
+    );
+    return response['SkSLs'] as Map<String, Object>;
+  }
+
   bool get hasIsolate => _uiIsolate != null;
 
   Future<void> flushUIThreadTasks() async {

packages/flutter_tools/test/general.shard/resident_runner_test.dart

@@ -14,6 +14,7 @@ import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/io.dart' as io;
 import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/compile.dart';
+import 'package:flutter_tools/src/convert.dart';
 import 'package:flutter_tools/src/devfs.dart';
 import 'package:flutter_tools/src/device.dart';
 import 'package:flutter_tools/src/globals.dart' as globals;
@@ -387,6 +388,8 @@ void main() {
     expect(residentRunner.isRunningDebug, true);
     // does not support CanvasKit
     expect(residentRunner.supportsCanvasKit, false);
+    // does support SkSL
+    expect(residentRunner.supportsWriteSkSL, true);
     // commands
     expect(testLogger.statusText, equals(
         <dynamic>[
@@ -406,6 +409,7 @@ void main() {
           commandHelp.p,
           commandHelp.o,
           commandHelp.z,
+          commandHelp.M,
           commandHelp.v,
           commandHelp.P,
           commandHelp.a,
@@ -415,11 +419,42 @@ void main() {
     ));
   }));
 
-  test('ResidentRunner does not support CanvasKit', () => testbed.run(() async {
+  test('ResidentRunner does support CanvasKit', () => testbed.run(() async {
     expect(() => residentRunner.toggleCanvaskit(),
       throwsA(isA<Exception>()));
   }));
 
+  test('ResidentRunner handles writeSkSL returning no data', () => testbed.run(() async {
+    when(mockFlutterView.getSkSLs()).thenAnswer((Invocation invocation) async {
+      return <String, Object>{};
+    });
+    await residentRunner.writeSkSL();
+
+    expect(testLogger.statusText, contains('No data was receieved'));
+  }));
+
+  test('ResidentRunner can write SkSL data to a unique file with engine revision, platform, and device name', () => testbed.run(() async {
+    when(mockDevice.targetPlatform).thenAnswer((Invocation invocation) async {
+      return TargetPlatform.android_arm;
+    });
+    when(mockDevice.name).thenReturn('test device');
+    when(mockFlutterView.getSkSLs()).thenAnswer((Invocation invocation) async {
+      return <String, Object>{
+        'A': 'B',
+      };
+    });
+    await residentRunner.writeSkSL();
+
+    expect(testLogger.statusText, contains('flutter_01.sksl'));
+    expect(globals.fs.file('flutter_01.sksl'), exists);
+    expect(json.decode(globals.fs.file('flutter_01.sksl').readAsStringSync()), <String, Object>{
+      'platform': 'android-arm',
+      'name': 'test device',
+      'engineRevision': '42.2', // From FakeFlutterVersion
+      'data': <String, Object>{'A': 'B'}
+    });
+  }));
+
   test('ResidentRunner can take screenshot on debug device', () => testbed.run(() async {
     when(mockDevice.supportsScreenshot).thenReturn(true);
     when(mockDevice.takeScreenshot(any))