WIP: Use worker threads in render

lib/src/node.dart

@@ -27,6 +27,7 @@ import 'node/render_result.dart';
 import 'node/types.dart';
 import 'node/value.dart';
 import 'node/utils.dart';
+import 'node/worker_threads.dart';
 import 'parse/scss.dart';
 import 'syntax.dart';
 import 'value.dart';
@@ -63,56 +64,55 @@ void main() {
 /// [render]: https://github.com/sass/node-sass#options
 void _render(
     RenderOptions options, void callback(JSError error, RenderResult result)) {
-  if (options.fiber != null) {
-    options.fiber.call(allowInterop(() {
-      try {
-        callback(null, _renderSync(options));
-      } catch (error) {
-        callback(error as JSError, null);
-      }
-      return null;
-    })).run();
-  } else {
-    _renderAsync(options).then((result) {
-      callback(null, result);
-    }, onError: (Object error, StackTrace stackTrace) {
-      if (error is SassException) {
-        callback(_wrapException(error), null);
-      } else {
-        callback(_newRenderError(error.toString(), status: 3), null);
-      }
-    });
-  }
+  _renderAsync(options).then((result) {
+    callback(null, result);
+  }, onError: (Object error, StackTrace stackTrace) {
+    if (error is SassException) {
+      callback(_wrapException(error), null);
+    } else {
+      callback(_newRenderError(error.toString(), status: 3), null);
+    }
+  });
 }
 
 /// Converts Sass to CSS asynchronously.
 Future<RenderResult> _renderAsync(RenderOptions options) async {
   var start = DateTime.now();
   var file = options.file == null ? null : p.absolute(options.file);
   CompileResult result;
-  if (options.data != null) {
-    result = await compileStringAsync(options.data,
-        nodeImporter: _parseImporter(options, start),
-        functions: _parseFunctions(options, asynch: true),
-        syntax: isTruthy(options.indentedSyntax) ? Syntax.sass : null,
-        style: _parseOutputStyle(options.outputStyle),
-        useSpaces: options.indentType != 'tab',
-        indentWidth: _parseIndentWidth(options.indentWidth),
-        lineFeed: _parseLineFeed(options.linefeed),
-        url: options.file == null ? 'stdin' : p.toUri(file).toString(),
-        sourceMap: _enableSourceMaps(options));
-  } else if (options.file != null) {
-    result = await compileAsync(file,
-        nodeImporter: _parseImporter(options, start),
-        functions: _parseFunctions(options, asynch: true),
-        syntax: isTruthy(options.indentedSyntax) ? Syntax.sass : null,
-        style: _parseOutputStyle(options.outputStyle),
-        useSpaces: options.indentType != 'tab',
-        indentWidth: _parseIndentWidth(options.indentWidth),
-        lineFeed: _parseLineFeed(options.linefeed),
-        sourceMap: _enableSourceMaps(options));
-  } else {
-    throw ArgumentError("Either options.data or options.file must be set.");
+  if (isMainThread == true) {
+    print(p.current);
+    final worker = Worker(p.current, WorkerOptions(workerData: {options}));
+    worker.on('message', (CompileResult msg) => result = msg);
+    worker.on('error', (JSError error) {
+      jsThrow(_wrapException(error));
+    });
+  } else if (isMainThread == false) {
+    if (options.data != null) {
+      result = await compileStringAsync(options.data,
+          nodeImporter: _parseImporter(options, start),
+          functions: _parseFunctions(options, asynch: true),
+          syntax: isTruthy(options.indentedSyntax) ? Syntax.sass : null,
+          style: _parseOutputStyle(options.outputStyle),
+          useSpaces: options.indentType != 'tab',
+          indentWidth: _parseIndentWidth(options.indentWidth),
+          lineFeed: _parseLineFeed(options.linefeed),
+          url: options.file == null ? 'stdin' : p.toUri(file).toString(),
+          sourceMap: _enableSourceMaps(options));
+    } else if (options.file != null) {
+      result = await compileAsync(file,
+          nodeImporter: _parseImporter(options, start),
+          functions: _parseFunctions(options, asynch: true),
+          syntax: isTruthy(options.indentedSyntax) ? Syntax.sass : null,
+          style: _parseOutputStyle(options.outputStyle),
+          useSpaces: options.indentType != 'tab',
+          indentWidth: _parseIndentWidth(options.indentWidth),
+          lineFeed: _parseLineFeed(options.linefeed),
+          sourceMap: _enableSourceMaps(options));
+    } else {
+      throw ArgumentError("Either options.data or options.file must be set.");
+    }
+    parentPort.postMessage(result, PortOptions());
   }
 
   return _newRenderResult(options, result, start);

lib/src/node/worker_threads.dart

@@ -0,0 +1,51 @@
+// Copyright 2020 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+@JS("worker_threads")
+library worker_threads;
+
+import 'package:js/js.dart';
+
+@JS("worker_threads")
+external WorkerThreads get worker_threads;
+
+bool isMainThread = worker_threads?.isMainThread;
+ParentPort parentPort = worker_threads?.parentPort;
+
+@JS()
+abstract class WorkerThreads {
+  @JS('Worker')
+  external Worker get worker;
+  external bool get workerData;
+  external bool get isMainThread;
+  external ParentPort get parentPort;
+  external const factory WorkerThreads();
+}
+
+@JS()
+@anonymous
+class WorkerOptions {
+  external factory WorkerOptions(
+      {Object env, bool eval, List<String> execArgv, Object workerData});
+}
+
+@JS()
+class Worker {
+  external void on(String message, Function callback);
+
+  external const factory Worker(String fileName, WorkerOptions options);
+}
+
+@JS("parentPort")
+@anonymous
+class PortOptions {
+  external List get transferList;
+  external factory PortOptions({List<Object> transferList = const []});
+}
+
+@JS("parentPort")
+@anonymous
+abstract class ParentPort {
+  external factory ParentPort({Function postMessage});
+  external void postMessage(Object message, PortOptions options);
+}

package/package.json

@@ -14,7 +14,7 @@
     "url": "https://github.com/nex3"
   },
   "engines": {
-    "node": ">=8.9.0"
+    "node": ">=11.7.0"
   },
   "dependencies": {
     "chokidar": ">=2.0.0 <4.0.0"

test/node_api/function_test.dart

@@ -287,95 +287,6 @@ void main() {
           data: "", functions: jsify({"foo(": allowInterop(neverCalled)})));
       expect(error.toString(), contains('Invalid signature'));
     });
-
-    group("with fibers", () {
-      setUpAll(() {
-        try {
-          fiber;
-        } catch (_) {
-          throw "Can't load fibers package.\n"
-              "Run pub run grinder before-test.";
-        }
-      });
-
-      test("runs a synchronous function", () {
-        expect(
-            render(RenderOptions(
-                data: "a {b: foo()}",
-                functions: jsify({
-                  "foo": allowInterop(
-                      (void _) => callConstructor(sass.types.Number, [1]))
-                }),
-                fiber: fiber)),
-            completion(equalsIgnoringWhitespace("a { b: 1; }")));
-      });
-
-      test("runs an asynchronous function", () {
-        expect(
-            render(RenderOptions(
-                data: "a {b: foo()}",
-                functions: jsify({
-                  "foo": allowInterop((void done(Object result)) {
-                    Timer(Duration.zero, () {
-                      done(callConstructor(sass.types.Number, [1]));
-                    });
-                  })
-                }),
-                fiber: fiber)),
-            completion(equalsIgnoringWhitespace("a { b: 1; }")));
-      });
-
-      test("reports a synchronous error", () async {
-        var error = await renderError(RenderOptions(
-            data: "a {b: foo()}",
-            functions:
-                jsify({"foo": allowInterop((void _) => throw "aw beans")}),
-            fiber: fiber));
-        expect(error.toString(), contains('aw beans'));
-      });
-
-      test("reports an asynchronous error", () async {
-        var error = await renderError(RenderOptions(
-            data: "a {b: foo()}",
-            functions: jsify({
-              "foo": allowInterop((void done(Object result)) {
-                Timer(Duration.zero, () {
-                  done(JSError("aw beans"));
-                });
-              })
-            }),
-            fiber: fiber));
-        expect(error.toString(), contains('aw beans'));
-      });
-
-      test("reports a null return", () async {
-        var error = await renderError(RenderOptions(
-            data: "a {b: foo()}",
-            functions: jsify({
-              "foo": allowInterop((void done(Object result)) {
-                Timer(Duration.zero, () {
-                  done(null);
-                });
-              })
-            }),
-            fiber: fiber));
-        expect(error.toString(), contains('must be a Sass value type'));
-      });
-
-      test("reports a call to done without arguments", () async {
-        var error = await renderError(RenderOptions(
-            data: "a {b: foo()}",
-            functions: jsify({
-              "foo": allowInterop((void done()) {
-                Timer(Duration.zero, () {
-                  done();
-                });
-              })
-            }),
-            fiber: fiber));
-        expect(error.toString(), contains('must be a Sass value type'));
-      });
-    });
   });
 
   // Node Sass currently doesn't provide any representation of first-class

test/node_api/importer_test.dart

@@ -668,6 +668,8 @@ void main() {
                   "  stdin 1:9  root stylesheet")));
     });
 
+    //TODO: Remove these tests
+    /******* Deprecated fibers tests
     group("with fibers", () {
       setUpAll(() {
         try {
@@ -749,5 +751,6 @@ void main() {
                     "  stdin 1:9  root stylesheet")));
       });
     });
+    */
   });
 }

tool/grind.dart

@@ -26,7 +26,12 @@ void main(List<String> args) {
   pkg.chocolateyNuspec = _nuspec;
   pkg.homebrewRepo = "sass/homebrew-sass";
   pkg.homebrewFormula = "sass.rb";
-  pkg.jsRequires = {"fs": "fs", "chokidar": "chokidar", "readline": "readline"};
+  pkg.jsRequires = {
+    "fs": "fs",
+    "chokidar": "chokidar",
+    "readline": "readline",
+    "workerThreads": "worker_threads"
+  };
   pkg.jsModuleMainLibrary = "lib/src/node.dart";
   pkg.npmPackageJson =
       json.decode(File("package/package.json").readAsStringSync())