Android Background Platform Channels

ci/licenses_golden/licenses_flutter

@@ -708,6 +708,7 @@ FILE: ../../../flutter/shell/common/persistent_cache_unittests.cc
 FILE: ../../../flutter/shell/common/pipeline.cc
 FILE: ../../../flutter/shell/common/pipeline.h
 FILE: ../../../flutter/shell/common/pipeline_unittests.cc
+FILE: ../../../flutter/shell/common/platform_message_handler.h
 FILE: ../../../flutter/shell/common/platform_view.cc
 FILE: ../../../flutter/shell/common/platform_view.h
 FILE: ../../../flutter/shell/common/pointer_data_dispatcher.cc
@@ -841,6 +842,7 @@ FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/engine/Flutte
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/engine/dart/DartExecutor.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/engine/dart/DartMessenger.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/engine/dart/PlatformMessageHandler.java
+FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/engine/dart/PlatformTaskQueue.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/engine/deferredcomponents/DeferredComponentManager.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/engine/deferredcomponents/PlayStoreDeferredComponentManager.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/engine/loader/ApplicationInfoLoader.java
@@ -938,6 +940,8 @@ FILE: ../../../flutter/shell/platform/android/jni/jni_mock_unittest.cc
 FILE: ../../../flutter/shell/platform/android/jni/platform_view_android_jni.cc
 FILE: ../../../flutter/shell/platform/android/jni/platform_view_android_jni.h
 FILE: ../../../flutter/shell/platform/android/library_loader.cc
+FILE: ../../../flutter/shell/platform/android/platform_message_handler_android.cc
+FILE: ../../../flutter/shell/platform/android/platform_message_handler_android.h
 FILE: ../../../flutter/shell/platform/android/platform_message_response_android.cc
 FILE: ../../../flutter/shell/platform/android/platform_message_response_android.h
 FILE: ../../../flutter/shell/platform/android/platform_view_android.cc

shell/common/BUILD.gn

@@ -73,6 +73,7 @@ source_set("common") {
  "engine.h",
  "pipeline.cc",
  "pipeline.h",
+ "platform_message_handler.h",
  "platform_view.cc",
  "platform_view.h",
  "pointer_data_dispatcher.cc",

shell/common/platform_message_handler.h

@@ -0,0 +1,39 @@
+// 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 SHELL_COMMON_PLATFORM_MESSAGE_HANDLER_H_
+#define SHELL_COMMON_PLATFORM_MESSAGE_HANDLER_H_
+
+#include <memory>
+
+#include "flutter/lib/ui/window/platform_message.h"
+
+namespace flutter {
+
+/// An interface over the ability to handle PlatformMessages that are being sent
+/// from Flutter to the host platform.
+class PlatformMessageHandler {
+ public:
+ virtual ~PlatformMessageHandler() = default;
+
+ /// Ultimately sends the PlatformMessage to the host platform.
+ /// This method is invoked on the ui thread.
+ virtual void HandlePlatformMessage(
+ std::unique_ptr<PlatformMessage> message) = 0;
+
+ /// Performs the return procedure for an associated call to
+ /// HandlePlatformMessage.
+ /// This method should be thread-safe and able to be invoked on any thread.
+ virtual void InvokePlatformMessageResponseCallback(
+ int response_id,
+ std::unique_ptr<fml::Mapping> mapping) = 0;
+
+ /// Performs the return procedure for an associated call to
+ /// HandlePlatformMessage where there is no return value.
+ /// This method should be thread-safe and able to be invoked on any thread.
+ virtual void InvokePlatformMessageEmptyResponseCallback(int response_id) = 0;
+};
+} // namespace flutter
+
+#endif // SHELL_COMMON_PLATFORM_MESSAGE_HANDLER_H_

shell/common/platform_view.cc

@@ -184,4 +184,9 @@ PlatformView::CreateSnapshotSurfaceProducer() {
  return nullptr;
 }
 
+std::shared_ptr<PlatformMessageHandler>
+PlatformView::GetPlatformMessageHandler() const {
+ return nullptr;
+}
+
 } // namespace flutter

shell/common/platform_view.h

@@ -22,6 +22,7 @@
 #include "flutter/lib/ui/window/pointer_data_packet.h"
 #include "flutter/lib/ui/window/pointer_data_packet_converter.h"
 #include "flutter/lib/ui/window/viewport_metrics.h"
+#include "flutter/shell/common/platform_message_handler.h"
 #include "flutter/shell/common/pointer_data_dispatcher.h"
 #include "flutter/shell/common/vsync_waiter.h"
 #include "third_party/skia/include/core/SkSize.h"
@@ -810,6 +811,17 @@ class PlatformView {
  virtual std::unique_ptr<SnapshotSurfaceProducer>
  CreateSnapshotSurfaceProducer();
 
+ //--------------------------------------------------------------------------
+ /// @brief Specifies a delegate that will receive PlatformMessages from
+ /// Flutter to the host platform.
+ ///
+ /// @details If this returns `null` that means PlatformMessages should be sent
+ /// to the PlatformView. That is to protect legacy behavior, any embedder
+ /// that wants to support executing Platform Channel handlers on background
+ /// threads should be returing a thread-safe PlatformMessageHandler instead.
+ virtual std::shared_ptr<PlatformMessageHandler> GetPlatformMessageHandler()
+ const;
+
  protected:
  PlatformView::Delegate& delegate_;
  const TaskRunners task_runners_;

shell/common/shell.cc

@@ -625,6 +625,7 @@ bool Shell::Setup(std::unique_ptr<PlatformView> platform_view,
  }
 
  platform_view_ = std::move(platform_view);
+ platform_message_handler_ = platform_view_->GetPlatformMessageHandler();
  engine_ = std::move(engine);
  rasterizer_ = std::move(rasterizer);
  io_manager_ = std::move(io_manager);
@@ -1192,13 +1193,17 @@ void Shell::OnEngineHandlePlatformMessage(
  return;
  }
 
- task_runners_.GetPlatformTaskRunner()->PostTask(
- fml::MakeCopyable([view = platform_view_->GetWeakPtr(),
- message = std::move(message)]() mutable {
- if (view) {
- view->HandlePlatformMessage(std::move(message));
- }
- }));
+ if (platform_message_handler_) {
+ platform_message_handler_->HandlePlatformMessage(std::move(message));
+ } else {
+ task_runners_.GetPlatformTaskRunner()->PostTask(
+ fml::MakeCopyable([view = platform_view_->GetWeakPtr(),
+ message = std::move(message)]() mutable {
+ if (view) {
+ view->HandlePlatformMessage(std::move(message));
+ }
+ }));
+ }
 }
 
 void Shell::HandleEngineSkiaMessage(std::unique_ptr<PlatformMessage> message) {
@@ -1867,4 +1872,9 @@ fml::TimePoint Shell::GetCurrentTimePoint() {
  return fml::TimePoint::Now();
 }
 
+const std::shared_ptr<PlatformMessageHandler>&
+Shell::GetPlatformMessageHandler() const {
+ return platform_message_handler_;
+}
+
 } // namespace flutter

shell/common/shell.h

@@ -395,6 +395,12 @@ class Shell final : public PlatformView::Delegate,
  /// @see `CreateCompatibleGenerator`
  void RegisterImageDecoder(ImageGeneratorFactory factory, int32_t priority);
 
+ //----------------------------------------------------------------------------
+ /// @brief Returns the delegate object that handles PlatformMessage's from
+ /// Flutter to the host platform (and its responses).
+ const std::shared_ptr<PlatformMessageHandler>& GetPlatformMessageHandler()
+ const;
+
  private:
  using ServiceProtocolHandler =
  std::function<bool(const ServiceProtocol::Handler::ServiceProtocolMap&,
@@ -412,6 +418,7 @@ class Shell final : public PlatformView::Delegate,
  std::unique_ptr<ShellIOManager> io_manager_; // on IO task runner
  std::shared_ptr<fml::SyncSwitch> is_gpu_disabled_sync_switch_;
  std::shared_ptr<VolatilePathTracker> volatile_path_tracker_;
+ std::shared_ptr<PlatformMessageHandler> platform_message_handler_;
 
  fml::WeakPtr<Engine> weak_engine_; // to be shared across threads
  fml::TaskRunnerAffineWeakPtr<Rasterizer>

shell/common/shell_test.cc

@@ -325,7 +325,8 @@ std::unique_ptr<Shell> ShellTest::CreateShell(
  std::shared_ptr<ShellTestExternalViewEmbedder>
  shell_test_external_view_embedder,
  bool is_gpu_disabled,
- ShellTestPlatformView::BackendType rendering_backend) {
+ ShellTestPlatformView::BackendType rendering_backend,
+ Shell::CreateCallback<PlatformView> platform_view_create_callback) {
  const auto vsync_clock = std::make_shared<ShellTestVsyncClock>();
 
  CreateVsyncWaiter create_vsync_waiter = [&]() {
@@ -338,29 +339,29 @@ std::unique_ptr<Shell> ShellTest::CreateShell(
  }
  };
 
- Shell::CreateCallback<PlatformView> platfrom_view_create_callback =
-   [vsync_clock, //
- &create_vsync_waiter, //
- shell_test_external_view_embedder, //
- rendering_backend //
- ](Shell& shell) {
-  return ShellTestPlatformView::Create(
- shell, //
- shell.GetTaskRunners(), //
- vsync_clock, //
- std::move(create_vsync_waiter), //
- rendering_backend, //
-  shell_test_external_view_embedder //
-  );
-  };
+ if (!platform_view_create_callback) {
+ platform_view_create_callback = [vsync_clock, //
+  &create_vsync_waiter, //
+  shell_test_external_view_embedder, //
+  rendering_backend //
+  ](Shell& shell) {
+ return ShellTestPlatformView::Create(shell, //
+  shell.GetTaskRunners(), //
+  vsync_clock,  //
+  std::move(create_vsync_waiter), //
+  rendering_backend,  //
+  shell_test_external_view_embedder //
+ );
+ };
+ }
 
  Shell::CreateCallback<Rasterizer> rasterizer_create_callback =
  [](Shell& shell) { return std::make_unique<Rasterizer>(shell); };
 
  return Shell::Create(flutter::PlatformData(), //
  task_runners, //
  settings, //
- platfrom_view_create_callback, //
+ platform_view_create_callback, //
  rasterizer_create_callback, //
  is_gpu_disabled //
  );

shell/common/shell_test.h

@@ -43,7 +43,9 @@ class ShellTest : public FixtureTest {
  shell_test_external_view_embedder = nullptr,
  bool is_gpu_disabled = false,
  ShellTestPlatformView::BackendType rendering_backend =
- ShellTestPlatformView::BackendType::kDefaultBackend);
+ ShellTestPlatformView::BackendType::kDefaultBackend,
+ Shell::CreateCallback<PlatformView> platform_view_create_callback =
+ nullptr);
  void DestroyShell(std::unique_ptr<Shell> shell);
  void DestroyShell(std::unique_ptr<Shell> shell, TaskRunners task_runners);
  TaskRunners GetTaskRunnersForFixture();

shell/common/shell_unittests.cc

@@ -45,6 +45,10 @@
 
 namespace flutter {
 namespace testing {
+
+using ::testing::_;
+using ::testing::Return;
+
 namespace {
 class MockPlatformViewDelegate : public PlatformView::Delegate {
  MOCK_METHOD1(OnPlatformViewCreated, void(std::unique_ptr<Surface> surface));
@@ -119,6 +123,27 @@ class MockPlatformView : public PlatformView {
  MockPlatformView(MockPlatformViewDelegate& delegate, TaskRunners task_runners)
  : PlatformView(delegate, task_runners) {}
  MOCK_METHOD0(CreateRenderingSurface, std::unique_ptr<Surface>());
+ MOCK_CONST_METHOD0(GetPlatformMessageHandler,
+ std::shared_ptr<PlatformMessageHandler>());
+};
+
+class MockPlatformMessageHandler : public PlatformMessageHandler {
+ public:
+ MOCK_METHOD1(HandlePlatformMessage,
+ void(std::unique_ptr<PlatformMessage> message));
+ MOCK_METHOD2(InvokePlatformMessageResponseCallback,
+ void(int response_id, std::unique_ptr<fml::Mapping> mapping));
+ MOCK_METHOD1(InvokePlatformMessageEmptyResponseCallback,
+ void(int response_id));
+};
+
+class MockPlatformMessageResponse : public PlatformMessageResponse {
+ public:
+ static fml::RefPtr<MockPlatformMessageResponse> Create() {
+ return fml::AdoptRef(new MockPlatformMessageResponse());
+ }
+ MOCK_METHOD1(Complete, void(std::unique_ptr<fml::Mapping> data));
+ MOCK_METHOD0(CompleteEmpty, void());
 };
 } // namespace
 
@@ -3156,7 +3181,52 @@ TEST_F(ShellTest, UIWorkAfterOnPlatformViewDestroyed) {
  ui_flush_latch.Signal();
  });
  ui_flush_latch.Wait();
+ DestroyShell(std::move(shell));
+}
 
+TEST_F(ShellTest, UsesPlatformMessageHandler) {
+ TaskRunners task_runners = GetTaskRunnersForFixture();
+ auto settings = CreateSettingsForFixture();
+ MockPlatformViewDelegate platform_view_delegate;
+ auto platform_message_handler =
+ std::make_shared<MockPlatformMessageHandler>();
+ int message_id = 1;
+ EXPECT_CALL(*platform_message_handler, HandlePlatformMessage(_));
+ EXPECT_CALL(*platform_message_handler,
+ InvokePlatformMessageEmptyResponseCallback(message_id));
+ Shell::CreateCallback<PlatformView> platform_view_create_callback =
+ [&platform_view_delegate, task_runners,
+ platform_message_handler](flutter::Shell& shell) {
+ auto result = std::make_unique<MockPlatformView>(platform_view_delegate,
+ task_runners);
+ EXPECT_CALL(*result, GetPlatformMessageHandler())
+ .WillOnce(Return(platform_message_handler));
+ return result;
+ };
+ auto shell = CreateShell(
+ /*settings=*/std::move(settings),
+ /*task_runners=*/task_runners,
+ /*simulate_vsync=*/false,
+ /*shell_test_external_view_embedder=*/nullptr,
+ /*is_gpu_disabled=*/false,
+ /*rendering_backend=*/
+ ShellTestPlatformView::BackendType::kDefaultBackend,
+ /*platform_view_create_callback=*/platform_view_create_callback);
+
+ EXPECT_EQ(platform_message_handler, shell->GetPlatformMessageHandler());
+ PostSync(task_runners.GetUITaskRunner(), [&shell]() {
+ size_t data_size = 4;
+ fml::MallocMapping bytes =
+ fml::MallocMapping(static_cast<uint8_t*>(malloc(data_size)), data_size);
+ fml::RefPtr<MockPlatformMessageResponse> response =
+ MockPlatformMessageResponse::Create();
+ auto message = std::make_unique<PlatformMessage>(
+ /*channel=*/"foo", /*data=*/std::move(bytes), /*response=*/response);
+ (static_cast<Engine::Delegate*>(shell.get()))
+ ->OnEngineHandlePlatformMessage(std::move(message));
+ });
+ shell->GetPlatformMessageHandler()
+ ->InvokePlatformMessageEmptyResponseCallback(message_id);
  DestroyShell(std::move(shell));
 }
 

shell/platform/android/BUILD.gn

@@ -79,6 +79,8 @@ source_set("flutter_shell_native_src") {
  "flutter_main.cc",
  "flutter_main.h",
  "library_loader.cc",
+ "platform_message_handler_android.cc",
+ "platform_message_handler_android.h",
  "platform_message_response_android.cc",
  "platform_message_response_android.h",
  "platform_view_android.cc",
@@ -186,6 +188,7 @@ android_java_sources = [
  "io/flutter/embedding/engine/dart/DartExecutor.java",
  "io/flutter/embedding/engine/dart/DartMessenger.java",
  "io/flutter/embedding/engine/dart/PlatformMessageHandler.java",
+ "io/flutter/embedding/engine/dart/PlatformTaskQueue.java",
  "io/flutter/embedding/engine/deferredcomponents/DeferredComponentManager.java",
  "io/flutter/embedding/engine/deferredcomponents/PlayStoreDeferredComponentManager.java",
  "io/flutter/embedding/engine/loader/ApplicationInfoLoader.java",

shell/platform/android/android_shell_holder.h

@@ -16,6 +16,7 @@
 #include "flutter/shell/common/shell.h"
 #include "flutter/shell/common/thread_host.h"
 #include "flutter/shell/platform/android/jni/platform_view_android_jni.h"
+#include "flutter/shell/platform/android/platform_message_handler_android.h"
 #include "flutter/shell/platform/android/platform_view_android.h"
 
 namespace flutter {
@@ -96,6 +97,11 @@ class AndroidShellHolder {
 
  void NotifyLowMemoryWarning();
 
+ const std::shared_ptr<PlatformMessageHandler>& GetPlatformMessageHandler()
+ const {
+ return shell_->GetPlatformMessageHandler();
+ }
+
  private:
  const flutter::Settings settings_;
  const std::shared_ptr<PlatformViewAndroidJNI> jni_facade_;