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[engine] reland: more consistently flush message loops tasks (flutter/engine#56815)

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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.
This commit is contained in:
Jonah Williams 2024-11-26 14:34:00 -08:00 committed by GitHub
parent 26dd7e27cf
commit fb62aa5d47
6 changed files with 101 additions and 42 deletions
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17
engine/src/flutter/fml/task_runner.cc
View File

@ -52,6 +52,7 @@ bool TaskRunner::RunsTasksOnCurrentThread() {
loop_queue_id);
}
// static
void TaskRunner::RunNowOrPostTask(const fml::RefPtr<fml::TaskRunner>& runner,
const fml::closure& task) {
FML_DCHECK(runner);
@ -62,4 +63,20 @@ void TaskRunner::RunNowOrPostTask(const fml::RefPtr<fml::TaskRunner>& runner,
}
}
// 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

8
engine/src/flutter/fml/task_runner.h
View File

@ -62,6 +62,14 @@ class TaskRunner : public fml::RefCountedThreadSafe<TaskRunner>,
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);

10
engine/src/flutter/shell/common/fixtures/shell_test.dart
View File

@ -640,3 +640,13 @@ void testSemanticsActions() {
});
};
}
@pragma('vm:entry-point')
void testPointerActions() {
PlatformDispatcher.instance.onPointerDataPacket = (PointerDataPacket pointer) async {
await null;
Future<void>.value().then((_) {
notifyNative();
});
};
}

61
engine/src/flutter/shell/common/shell.cc
View File

@ -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 @@ void Shell::OnPlatformViewSetViewportMetrics(int64_t view_id,
}
});
fml::TaskRunner::RunNowOrPostTask(
fml::TaskRunner::RunNowAndFlushMessages(
task_runners_.GetUITaskRunner(),
[engine = engine_->GetWeakPtr(), view_id, metrics]() {
if (engine) {
@ -1075,24 +1076,16 @@ void Shell::OnPlatformViewDispatchPlatformMessage(
}
#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 @@ void Shell::OnPlatformViewDispatchPointerDataPacket(
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 @@ void Shell::OnPlatformViewDispatchSemanticsAction(int32_t node_id,
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 @@ void Shell::OnPlatformViewSetSemanticsEnabled(bool enabled) {
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 @@ void Shell::OnPlatformViewSetAccessibilityFeatures(int32_t flags) {
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|

46
engine/src/flutter/shell/common/shell_unittests.cc
View File

@ -4312,7 +4312,8 @@ TEST_F(ShellTest, NavigationMessageDispachedImmediately) {
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 @@ TEST_F(ShellTest, SemanticsActionsPostTask) {
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 @@ TEST_F(ShellTest, SemanticsActionsPostTask) {
// 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);

1
engine/src/flutter/shell/common/vsync_waiter.cc
View File

@ -127,7 +127,6 @@ void VsyncWaiter::FireCallback(fml::TimePoint frame_start_time,
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]() {