Windows: Client Wrapper: Expose TaskRunner

Author: jnschulze

ci/licenses_golden/licenses_flutter

@@ -1740,11 +1740,13 @@ FILE: ../../../flutter/shell/platform/windows/angle_surface_manager.h
 FILE: ../../../flutter/shell/platform/windows/client_wrapper/dart_project_unittests.cc
 FILE: ../../../flutter/shell/platform/windows/client_wrapper/flutter_engine.cc
 FILE: ../../../flutter/shell/platform/windows/client_wrapper/flutter_engine_unittests.cc
+FILE: ../../../flutter/shell/platform/windows/client_wrapper/flutter_task_runner_unittests.cc
 FILE: ../../../flutter/shell/platform/windows/client_wrapper/flutter_view_controller.cc
 FILE: ../../../flutter/shell/platform/windows/client_wrapper/flutter_view_controller_unittests.cc
 FILE: ../../../flutter/shell/platform/windows/client_wrapper/flutter_view_unittests.cc
 FILE: ../../../flutter/shell/platform/windows/client_wrapper/include/flutter/dart_project.h
 FILE: ../../../flutter/shell/platform/windows/client_wrapper/include/flutter/flutter_engine.h
+FILE: ../../../flutter/shell/platform/windows/client_wrapper/include/flutter/flutter_task_runner.h
 FILE: ../../../flutter/shell/platform/windows/client_wrapper/include/flutter/flutter_view.h
 FILE: ../../../flutter/shell/platform/windows/client_wrapper/include/flutter/flutter_view_controller.h
 FILE: ../../../flutter/shell/platform/windows/client_wrapper/include/flutter/plugin_registrar_windows.h

shell/platform/windows/client_wrapper/BUILD.gn

@@ -8,6 +8,7 @@ import("//flutter/testing/testing.gni")
 _wrapper_includes = [
  "include/flutter/dart_project.h",
  "include/flutter/flutter_engine.h",
+ "include/flutter/flutter_task_runner.h",
  "include/flutter/flutter_view_controller.h",
  "include/flutter/flutter_view.h",
  "include/flutter/plugin_registrar_windows.h",
@@ -76,6 +77,7 @@ executable("client_wrapper_windows_unittests") {
  sources = [
  "dart_project_unittests.cc",
  "flutter_engine_unittests.cc",
+ "flutter_task_runner_unittests.cc",
  "flutter_view_controller_unittests.cc",
  "flutter_view_unittests.cc",
  "plugin_registrar_windows_unittests.cc",

shell/platform/windows/client_wrapper/flutter_task_runner_unittests.cc

@@ -0,0 +1,79 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <memory>
+#include <string>
+
+#include "flutter/shell/platform/windows/client_wrapper/include/flutter/flutter_task_runner.h"
+#include "flutter/shell/platform/windows/client_wrapper/testing/stub_flutter_windows_api.h"
+#include "gtest/gtest.h"
+
+namespace flutter {
+namespace {
+
+// Stub implementation to validate calls to the API.
+class TestWindowsApi : public testing::StubFlutterWindowsApi {
+ public:
+ TestWindowsApi(bool runs_tasks_on_current_thread)
+ : runs_tasks_on_current_thread_(runs_tasks_on_current_thread) {}
+
+ void TaskRunnerPostTask(VoidCallback callback, void* user_data) override {
+ post_task_called_ = true;
+ callback(user_data);
+ }
+
+ bool TaskRunnerRunsTasksOnCurrentThread() override {
+ return runs_tasks_on_current_thread_;
+ }
+
+ bool post_task_called() { return post_task_called_; }
+
+ private:
+ bool runs_tasks_on_current_thread_;
+ bool post_task_called_ = false;
+};
+
+} // namespace
+
+TEST(FlutterTaskRunnerTest, RunsTasksOnCurrentThreadPassesThrough) {
+ testing::ScopedStubFlutterWindowsApi scoped_api_stub(
+ std::make_unique<TestWindowsApi>(false));
+ auto test_api = static_cast<TestWindowsApi*>(scoped_api_stub.stub());
+ FlutterTaskRunner task_runner(
+ reinterpret_cast<FlutterDesktopTaskRunnerRef>(2));
+
+ EXPECT_FALSE(task_runner.RunsTasksOnCurrentThread());
+}
+
+TEST(FlutterTaskRunnerTest, PostTaskInline) {
+ testing::ScopedStubFlutterWindowsApi scoped_api_stub(
+ std::make_unique<TestWindowsApi>(true));
+ auto test_api = static_cast<TestWindowsApi*>(scoped_api_stub.stub());
+ FlutterTaskRunner task_runner(
+ reinterpret_cast<FlutterDesktopTaskRunnerRef>(2));
+
+ bool task_executed = false;
+ task_runner.PostTask([&task_executed]() { task_executed = true; });
+
+ EXPECT_TRUE(task_runner.RunsTasksOnCurrentThread());
+ EXPECT_TRUE(task_executed);
+ EXPECT_FALSE(test_api->post_task_called());
+}
+
+TEST(FlutterTaskRunnerTest, PostTaskFromOtherThread) {
+ testing::ScopedStubFlutterWindowsApi scoped_api_stub(
+ std::make_unique<TestWindowsApi>(false));
+ auto test_api = static_cast<TestWindowsApi*>(scoped_api_stub.stub());
+ FlutterTaskRunner task_runner(
+ reinterpret_cast<FlutterDesktopTaskRunnerRef>(2));
+
+ bool task_executed = false;
+ task_runner.PostTask([&task_executed]() { task_executed = true; });
+
+ EXPECT_FALSE(task_runner.RunsTasksOnCurrentThread());
+ EXPECT_TRUE(task_executed);
+ EXPECT_TRUE(test_api->post_task_called());
+}
+
+} // namespace flutter

shell/platform/windows/client_wrapper/flutter_view_unittests.cc

@@ -28,4 +28,12 @@ TEST(FlutterViewTest, HwndAccessPassesThrough) {
  EXPECT_EQ(view.GetNativeWindow(), reinterpret_cast<HWND>(7));
 }
 
+TEST(FlutterViewTest, GetPlatformTaskRunner) {
+ testing::ScopedStubFlutterWindowsApi scoped_api_stub(
+ std::make_unique<TestWindowsApi>());
+ auto test_api = static_cast<TestWindowsApi*>(scoped_api_stub.stub());
+ FlutterView view(reinterpret_cast<FlutterDesktopViewRef>(2));
+ EXPECT_NE(view.GetPlatformTaskRunner(), nullptr);
+}
+
 } // namespace flutter

shell/platform/windows/client_wrapper/include/flutter/flutter_task_runner.h

@@ -0,0 +1,55 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_SHELL_PLATFORM_WINDOWS_CLIENT_WRAPPER_INCLUDE_FLUTTER_TASK_RUNNER_H_
+#define FLUTTER_SHELL_PLATFORM_WINDOWS_CLIENT_WRAPPER_INCLUDE_FLUTTER_TASK_RUNNER_H_
+
+#include <flutter_windows.h>
+
+#include <functional>
+
+namespace flutter {
+
+// An interface for scheduling tasks on the associated thread.
+class FlutterTaskRunner {
+ public:
+ typedef std::function<void()> VoidCallback;
+ explicit FlutterTaskRunner(FlutterDesktopTaskRunnerRef task_runner)
+ : task_runner_(task_runner) {}
+
+ // Schedules the task for execution by the associated thread.
+ void PostTask(VoidCallback callback) {
+ if (RunsTasksOnCurrentThread()) {
+ callback();
+ return;
+ }
+
+ struct Captures {
+ VoidCallback callback;
+ };
+ auto captures = new Captures();
+ captures->callback = callback;
+ FlutterDesktopTaskRunnerPostTask(
+ task_runner_,
+ [](void* opaque) {
+ auto captures = reinterpret_cast<Captures*>(opaque);
+ captures->callback();
+ delete captures;
+ },
+ captures);
+ }
+
+ // Returns `true` if the associated thread is the current thread.
+ bool RunsTasksOnCurrentThread() {
+ return FlutterDesktopTaskRunnerRunsTasksOnCurrentThread(task_runner_);
+ }
+
+ private:
+ // Handle for interacting with the C API's task runner.
+ FlutterDesktopTaskRunnerRef task_runner_;
+};
+
+} // namespace flutter
+
+#endif // FLUTTER_SHELL_PLATFORM_WINDOWS_CLIENT_WRAPPER_INCLUDE_FLUTTER_TASK_RUNNER_H_

shell/platform/windows/client_wrapper/include/flutter/flutter_view.h

@@ -7,12 +7,17 @@
 
 #include <flutter_windows.h>
 
+#include "flutter_task_runner.h"
+
 namespace flutter {
 
 // A view displaying Flutter content.
 class FlutterView {
  public:
- explicit FlutterView(FlutterDesktopViewRef view) : view_(view) {}
+ explicit FlutterView(FlutterDesktopViewRef view)
+ : view_(view),
+ platform_task_runner_(std::make_unique<FlutterTaskRunner>(
+ FlutterDesktopViewGetTaskRunner(view))) {}
 
  virtual ~FlutterView() = default;
 
@@ -30,9 +35,17 @@ class FlutterView {
  HWND GetNativeWindow() { return FlutterDesktopViewGetHWND(view_); }
 #endif
 
+ // Gets the platform task runner.
+ FlutterTaskRunner* GetPlatformTaskRunner() {
+ return platform_task_runner_.get();
+ }
+
  private:
  // Handle for interacting with the C API's view.
  FlutterDesktopViewRef view_ = nullptr;
+
+ // The task runner for this view.
+ std::unique_ptr<FlutterTaskRunner> platform_task_runner_;
 };
 
 } // namespace flutter

shell/platform/windows/client_wrapper/testing/stub_flutter_windows_api.cc

@@ -150,6 +150,28 @@ HWND FlutterDesktopViewGetHWND(FlutterDesktopViewRef controller) {
  return reinterpret_cast<HWND>(-1);
 }
 
+FlutterDesktopTaskRunnerRef FlutterDesktopViewGetTaskRunner(
+ FlutterDesktopViewRef view) {
+ // The stub ignores this, so just return an arbitrary non-zero value.
+ return reinterpret_cast<FlutterDesktopTaskRunnerRef>(1);
+}
+
+void FlutterDesktopTaskRunnerPostTask(FlutterDesktopTaskRunnerRef task_runner,
+ VoidCallback callback,
+ void* user_data) {
+ if (s_stub_implementation) {
+ return s_stub_implementation->TaskRunnerPostTask(callback, user_data);
+ }
+}
+
+bool FlutterDesktopTaskRunnerRunsTasksOnCurrentThread(
+ FlutterDesktopTaskRunnerRef task_runner) {
+ if (s_stub_implementation) {
+ return s_stub_implementation->TaskRunnerRunsTasksOnCurrentThread();
+ }
+ return true;
+}
+
 FlutterDesktopViewRef FlutterDesktopPluginRegistrarGetView(
  FlutterDesktopPluginRegistrarRef controller) {
  // The stub ignores this, so just return an arbitrary non-zero value.

shell/platform/windows/client_wrapper/testing/stub_flutter_windows_api.h

@@ -71,6 +71,17 @@ class StubFlutterWindowsApi {
  // Called for FlutterDesktopViewGetHWND.
  virtual HWND ViewGetHWND() { return reinterpret_cast<HWND>(1); }
 
+ // Called for FlutterDesktopViewGetTaskRunner.
+ virtual FlutterDesktopTaskRunnerRef ViewGetTaskRunner() {
+ return reinterpret_cast<FlutterDesktopTaskRunnerRef>(1);
+ }
+
+ // Called for FlutterDesktopTaskRunnerPostTask.
+ virtual void TaskRunnerPostTask(VoidCallback callback, void* user_data) {}
+
+ // Called for FlutterDesktopTaskRunnerRunsTasksOnCurrentThread.
+ virtual bool TaskRunnerRunsTasksOnCurrentThread() { return true; }
+
  // Called for FlutterDesktopPluginRegistrarRegisterTopLevelWindowProcDelegate.
  virtual void PluginRegistrarRegisterTopLevelWindowProcDelegate(
  FlutterDesktopWindowProcCallback delegate,

shell/platform/windows/flutter_windows.cc

@@ -61,6 +61,18 @@ static FlutterDesktopTextureRegistrarRef HandleForTextureRegistrar(
  return reinterpret_cast<FlutterDesktopTextureRegistrarRef>(registrar);
 }
 
+// Returns the task runner corresponding to the given opaque API handle.
+static flutter::TaskRunner* TaskRunnerFromHandle(
+ FlutterDesktopTaskRunnerRef ref) {
+ return reinterpret_cast<flutter::TaskRunner*>(ref);
+}
+
+// Returns the opaque API handle for the given task runner instance.
+static FlutterDesktopTaskRunnerRef HandleForTaskRunner(
+ flutter::TaskRunner* task_runner) {
+ return reinterpret_cast<FlutterDesktopTaskRunnerRef>(task_runner);
+}
+
 void FlutterDesktopViewControllerDestroy(
  FlutterDesktopViewControllerRef controller) {
  delete controller;
@@ -153,6 +165,18 @@ FlutterDesktopViewRef FlutterDesktopPluginRegistrarGetView(
  return HandleForView(registrar->engine->view());
 }
 
+void FlutterDesktopTaskRunnerPostTask(FlutterDesktopTaskRunnerRef task_runner,
+ VoidCallback callback,
+ void* user_data) {
+ return TaskRunnerFromHandle(task_runner)
+ ->RunNowOrPostTask([user_data, callback]() { callback(user_data); });
+}
+
+bool FlutterDesktopTaskRunnerRunsTasksOnCurrentThread(
+ FlutterDesktopTaskRunnerRef task_runner) {
+ return TaskRunnerFromHandle(task_runner)->RunsTasksOnCurrentThread();
+}
+
 void FlutterDesktopResyncOutputStreams() {
  FILE* unused;
  if (freopen_s(&unused, "CONOUT$", "w", stdout)) {

shell/platform/windows/public/flutter_windows.h

@@ -34,6 +34,10 @@ typedef struct FlutterDesktopView* FlutterDesktopViewRef;
 struct FlutterDesktopEngine;
 typedef struct FlutterDesktopEngine* FlutterDesktopEngineRef;
 
+// Opaque reference to a Flutter platform task runner.
+struct FlutterDesktopTaskRunner;
+typedef struct FlutterDesktopTaskRunner* FlutterDesktopTaskRunnerRef;
+
 // Properties for configuring a Flutter engine instance.
 typedef struct {
  // The path to the flutter_assets folder for the application to be run.
@@ -105,8 +109,8 @@ FLUTTER_EXPORT void FlutterDesktopViewControllerDestroy(
 // Its lifetime is the same as the |controller|'s.
 FLUTTER_EXPORT FlutterDesktopEngineRef FlutterDesktopViewControllerGetEngine(
  FlutterDesktopViewControllerRef controller);
-// Returns the view managed by the given controller.
 
+// Returns the view managed by the given controller.
 FLUTTER_EXPORT FlutterDesktopViewRef
 FlutterDesktopViewControllerGetView(FlutterDesktopViewControllerRef controller);
 
@@ -205,6 +209,24 @@ FlutterDesktopViewGetCoreApplicationView(FlutterDesktopViewRef view);
 FLUTTER_EXPORT HWND FlutterDesktopViewGetHWND(FlutterDesktopViewRef view);
 #endif
 
+// Returns the task runner associated with the view.
+FLUTTER_EXPORT FlutterDesktopTaskRunnerRef
+FlutterDesktopViewGetTaskRunner(FlutterDesktopViewRef view);
+
+// ========== Task Runner ==========
+typedef void (*VoidCallback)(void* user_data);
+
+// Posts a task to the runner.
+FLUTTER_EXPORT void FlutterDesktopTaskRunnerPostTask(
+ FlutterDesktopTaskRunnerRef task_runner,
+ VoidCallback callback,
+ void* user_data);
+
+// Gets a flag indicating whether the task runner executes tasks on the current
+// thread.
+FLUTTER_EXPORT bool FlutterDesktopTaskRunnerRunsTasksOnCurrentThread(
+ FlutterDesktopTaskRunnerRef task_runner);
+
 // ========== Plugin Registrar (extensions) ==========
 // These are Windows-specific extensions to flutter_plugin_registrar.h