[engine] reland: more consistently flush message loops tasks (#56815)
Changes the following shell callbacks to flush the dart event loop:
* OnPlatformViewSetViewportMetrics
* OnPlatformViewDispatchPointerDataPacket
* OnPlatformViewDispatchPlatformMessage
* OnPlatformViewSetSemanticsEnabled
* OnPlatformViewSetAccessibilityFeatures
Using a new TaskRunner API RunNowAndFlushMessages. If the task runner can run tasks on the current thread, this will immediately invoke a callback and then post an empty task to the event loop to ensure dart listeners fire.
Unlike https://github.com/flutter/engine/pull/56738, does not touch the vsync API - which looks like it depends on scheduling behavior today, at least for iOS.
diff --git a/fml/task_runner.cc b/fml/task_runner.cc
index 5f9dd01..8920a8f 100644
--- a/fml/task_runner.cc
+++ b/fml/task_runner.cc
@@ -52,6 +52,7 @@
loop_queue_id);
}
+// static
void TaskRunner::RunNowOrPostTask(const fml::RefPtr<fml::TaskRunner>& runner,
const fml::closure& task) {
FML_DCHECK(runner);
@@ -62,4 +63,20 @@
}
}
+// static
+void TaskRunner::RunNowAndFlushMessages(
+ const fml::RefPtr<fml::TaskRunner>& runner,
+ const fml::closure& task) {
+ FML_DCHECK(runner);
+ if (runner->RunsTasksOnCurrentThread()) {
+ task();
+ // Post an empty task to make the UI message loop run its task observers.
+ // The observers will execute any Dart microtasks queued by the platform
+ // message handler.
+ runner->PostTask([] {});
+ } else {
+ runner->PostTask(task);
+ }
+}
+
} // namespace fml
diff --git a/fml/task_runner.h b/fml/task_runner.h
index 885c1b3..6bc1c1a 100644
--- a/fml/task_runner.h
+++ b/fml/task_runner.h
@@ -62,6 +62,14 @@
static void RunNowOrPostTask(const fml::RefPtr<fml::TaskRunner>& runner,
const fml::closure& task);
+ /// Like RunNowOrPostTask, except that if the task can be immediately
+ /// executed, an empty task will still be posted to the runner afterwards.
+ ///
+ /// This is used to ensure that messages posted to Dart from the platform
+ /// thread always flush the Dart event loop.
+ static void RunNowAndFlushMessages(const fml::RefPtr<fml::TaskRunner>& runner,
+ const fml::closure& task);
+
protected:
explicit TaskRunner(fml::RefPtr<MessageLoopImpl> loop);
diff --git a/shell/common/fixtures/shell_test.dart b/shell/common/fixtures/shell_test.dart
index 6072756..24dc227 100644
--- a/shell/common/fixtures/shell_test.dart
+++ b/shell/common/fixtures/shell_test.dart
@@ -640,3 +640,13 @@
});
};
}
+
+@pragma('vm:entry-point')
+void testPointerActions() {
+ PlatformDispatcher.instance.onPointerDataPacket = (PointerDataPacket pointer) async {
+ await null;
+ Future<void>.value().then((_) {
+ notifyNative();
+ });
+ };
+}
diff --git a/shell/common/shell.cc b/shell/common/shell.cc
index c6078f7..ba28d8e 100644
--- a/shell/common/shell.cc
+++ b/shell/common/shell.cc
@@ -2,6 +2,7 @@
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
+#include "fml/task_runner.h"
#define RAPIDJSON_HAS_STDSTRING 1
#include "flutter/shell/common/shell.h"
@@ -1036,7 +1037,7 @@
}
});
- fml::TaskRunner::RunNowOrPostTask(
+ fml::TaskRunner::RunNowAndFlushMessages(
task_runners_.GetUITaskRunner(),
[engine = engine_->GetWeakPtr(), view_id, metrics]() {
if (engine) {
@@ -1075,24 +1076,16 @@
}
#endif // FLUTTER_RUNTIME_MODE == FLUTTER_RUNTIME_MODE_DEBUG
- if (task_runners_.GetUITaskRunner()->RunsTasksOnCurrentThread()) {
- engine_->DispatchPlatformMessage(std::move(message));
-
- // Post an empty task to make the UI message loop run its task observers.
- // The observers will execute any Dart microtasks queued by the platform
- // message handler.
- task_runners_.GetUITaskRunner()->PostTask([] {});
- } else {
- // The static leak checker gets confused by the use of fml::MakeCopyable.
- // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks)
- task_runners_.GetUITaskRunner()->PostTask(
- fml::MakeCopyable([engine = engine_->GetWeakPtr(),
- message = std::move(message)]() mutable {
- if (engine) {
- engine->DispatchPlatformMessage(std::move(message));
- }
- }));
- }
+ // The static leak checker gets confused by the use of fml::MakeCopyable.
+ // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks)
+ fml::TaskRunner::RunNowAndFlushMessages(
+ task_runners_.GetUITaskRunner(),
+ fml::MakeCopyable([engine = engine_->GetWeakPtr(),
+ message = std::move(message)]() mutable {
+ if (engine) {
+ engine->DispatchPlatformMessage(std::move(message));
+ }
+ }));
}
// |PlatformView::Delegate|
@@ -1104,7 +1097,7 @@
TRACE_FLOW_BEGIN("flutter", "PointerEvent", next_pointer_flow_id_);
FML_DCHECK(is_set_up_);
FML_DCHECK(task_runners_.GetPlatformTaskRunner()->RunsTasksOnCurrentThread());
- fml::TaskRunner::RunNowOrPostTask(
+ fml::TaskRunner::RunNowAndFlushMessages(
task_runners_.GetUITaskRunner(),
fml::MakeCopyable([engine = weak_engine_, packet = std::move(packet),
flow_id = next_pointer_flow_id_]() mutable {
@@ -1122,7 +1115,8 @@
FML_DCHECK(is_set_up_);
FML_DCHECK(task_runners_.GetPlatformTaskRunner()->RunsTasksOnCurrentThread());
- task_runners_.GetUITaskRunner()->PostTask(
+ fml::TaskRunner::RunNowAndFlushMessages(
+ task_runners_.GetUITaskRunner(),
fml::MakeCopyable([engine = engine_->GetWeakPtr(), node_id, action,
args = std::move(args)]() mutable {
if (engine) {
@@ -1136,12 +1130,13 @@
FML_DCHECK(is_set_up_);
FML_DCHECK(task_runners_.GetPlatformTaskRunner()->RunsTasksOnCurrentThread());
- fml::TaskRunner::RunNowOrPostTask(task_runners_.GetUITaskRunner(),
- [engine = engine_->GetWeakPtr(), enabled] {
- if (engine) {
- engine->SetSemanticsEnabled(enabled);
- }
- });
+ fml::TaskRunner::RunNowAndFlushMessages(
+ task_runners_.GetUITaskRunner(),
+ [engine = engine_->GetWeakPtr(), enabled] {
+ if (engine) {
+ engine->SetSemanticsEnabled(enabled);
+ }
+ });
}
// |PlatformView::Delegate|
@@ -1149,12 +1144,12 @@
FML_DCHECK(is_set_up_);
FML_DCHECK(task_runners_.GetPlatformTaskRunner()->RunsTasksOnCurrentThread());
- fml::TaskRunner::RunNowOrPostTask(task_runners_.GetUITaskRunner(),
- [engine = engine_->GetWeakPtr(), flags] {
- if (engine) {
- engine->SetAccessibilityFeatures(flags);
- }
- });
+ fml::TaskRunner::RunNowAndFlushMessages(
+ task_runners_.GetUITaskRunner(), [engine = engine_->GetWeakPtr(), flags] {
+ if (engine) {
+ engine->SetAccessibilityFeatures(flags);
+ }
+ });
}
// |PlatformView::Delegate|
diff --git a/shell/common/shell_unittests.cc b/shell/common/shell_unittests.cc
index ba56e9f..8c6a0c2 100644
--- a/shell/common/shell_unittests.cc
+++ b/shell/common/shell_unittests.cc
@@ -4312,7 +4312,8 @@
ASSERT_FALSE(DartVMRef::IsInstanceRunning());
}
-TEST_F(ShellTest, SemanticsActionsPostTask) {
+// Verifies a semantics Action will flush the dart event loop.
+TEST_F(ShellTest, SemanticsActionsFlushMessageLoop) {
Settings settings = CreateSettingsForFixture();
ThreadHost thread_host("io.flutter.test." + GetCurrentTestName() + ".",
ThreadHost::Type::kPlatform);
@@ -4327,13 +4328,6 @@
configuration.SetEntrypoint("testSemanticsActions");
RunEngine(shell.get(), std::move(configuration));
-
- task_runners.GetPlatformTaskRunner()->PostTask([&] {
- SendSemanticsAction(shell.get(), 0, SemanticsAction::kTap,
- fml::MallocMapping(nullptr, 0));
- });
-
- // Fulfill native function for the second Shell's entrypoint.
fml::CountDownLatch latch(1);
AddNativeCallback(
// The Dart native function names aren't very consistent but this is
@@ -4341,6 +4335,42 @@
// fixture.
"NotifyNative",
CREATE_NATIVE_ENTRY([&](auto args) { latch.CountDown(); }));
+
+ task_runners.GetPlatformTaskRunner()->PostTask([&] {
+ SendSemanticsAction(shell.get(), 0, SemanticsAction::kTap,
+ fml::MallocMapping(nullptr, 0));
+ });
+ latch.Wait();
+
+ DestroyShell(std::move(shell), task_runners);
+ ASSERT_FALSE(DartVMRef::IsInstanceRunning());
+}
+
+// Verifies a pointer event will flush the dart event loop.
+TEST_F(ShellTest, PointerPacketFlushMessageLoop) {
+ Settings settings = CreateSettingsForFixture();
+ ThreadHost thread_host("io.flutter.test." + GetCurrentTestName() + ".",
+ ThreadHost::Type::kPlatform);
+ auto task_runner = thread_host.platform_thread->GetTaskRunner();
+ TaskRunners task_runners("test", task_runner, task_runner, task_runner,
+ task_runner);
+
+ EXPECT_EQ(task_runners.GetPlatformTaskRunner(),
+ task_runners.GetUITaskRunner());
+ auto shell = CreateShell(settings, task_runners);
+ auto configuration = RunConfiguration::InferFromSettings(settings);
+ configuration.SetEntrypoint("testPointerActions");
+
+ RunEngine(shell.get(), std::move(configuration));
+ fml::CountDownLatch latch(1);
+ AddNativeCallback(
+ // The Dart native function names aren't very consistent but this is
+ // just the native function name of the second vm entrypoint in the
+ // fixture.
+ "NotifyNative",
+ CREATE_NATIVE_ENTRY([&](auto args) { latch.CountDown(); }));
+
+ DispatchFakePointerData(shell.get(), 23);
latch.Wait();
DestroyShell(std::move(shell), task_runners);
diff --git a/shell/common/vsync_waiter.cc b/shell/common/vsync_waiter.cc
index 80074fa..fdc8c64 100644
--- a/shell/common/vsync_waiter.cc
+++ b/shell/common/vsync_waiter.cc
@@ -127,7 +127,6 @@
fml::TaskQueueId ui_task_queue_id =
task_runners_.GetUITaskRunner()->GetTaskQueueId();
-
task_runners_.GetUITaskRunner()->PostTask(
[ui_task_queue_id, callback, flow_identifier, frame_start_time,
frame_target_time, pause_secondary_tasks]() {
