shell/common/animator.cc - external/github.com/flutter/engine - Git at Google

 // 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 "flutter/shell/common/animator.h"

 #include "flutter/fml/trace_event.h"
 #include "third_party/dart/runtime/include/dart_tools_api.h"

 namespace flutter {

 namespace {

 // Wait 51 milliseconds (which is 1 more milliseconds than 3 frames at 60hz)
 // before notifying the engine that we are idle.  See comments in |BeginFrame|
 // for further discussion on why this is necessary.
 constexpr fml::TimeDelta kNotifyIdleTaskWaitTime =
     fml::TimeDelta::FromMilliseconds(51);

 }  // namespace

 Animator::Animator(Delegate& delegate,
                    TaskRunners task_runners,
                    std::unique_ptr<VsyncWaiter> waiter)
     : delegate_(delegate),
       task_runners_(std::move(task_runners)),
       waiter_(std::move(waiter)),
       last_frame_begin_time_(),
       last_frame_target_time_(),
       dart_frame_deadline_(0),
 #if FLUTTER_SHELL_ENABLE_METAL
       layer_tree_pipeline_(fml::MakeRefCounted<LayerTreePipeline>(2)),
 #else   // FLUTTER_SHELL_ENABLE_METAL
       // TODO(dnfield): We should remove this logic and set the pipeline depth
       // back to 2 in this case. See
       // https://github.com/flutter/engine/pull/9132 for discussion.
       layer_tree_pipeline_(fml::MakeRefCounted<LayerTreePipeline>(
           task_runners.GetPlatformTaskRunner() ==
                   task_runners.GetRasterTaskRunner()
               ? 1
               : 2)),
 #endif  // FLUTTER_SHELL_ENABLE_METAL
       pending_frame_semaphore_(1),
       frame_number_(1),
       paused_(false),
       regenerate_layer_tree_(false),
       frame_scheduled_(false),
       notify_idle_task_id_(0),
       dimension_change_pending_(false),
       weak_factory_(this) {
 }

 Animator::~Animator() = default;

 float Animator::GetDisplayRefreshRate() const {
   return waiter_->GetDisplayRefreshRate();
 }

 void Animator::Stop() {
   paused_ = true;
 }

 void Animator::Start() {
   if (!paused_) {
     return;
   }

   paused_ = false;
   RequestFrame();
 }

 // Indicate that screen dimensions will be changing in order to force rendering
 // of an updated frame even if the animator is currently paused.
 void Animator::SetDimensionChangePending() {
   dimension_change_pending_ = true;
 }

 void Animator::EnqueueTraceFlowId(uint64_t trace_flow_id) {
   fml::TaskRunner::RunNowOrPostTask(
       task_runners_.GetUITaskRunner(),
       [self = weak_factory_.GetWeakPtr(), trace_flow_id] {
         if (!self) {
           return;
         }
         self->trace_flow_ids_.push_back(trace_flow_id);
       });
 }

 // This Parity is used by the timeline component to correctly align
 // GPU Workloads events with their respective Framework Workload.
 const char* Animator::FrameParity() {
   return (frame_number_ % 2) ? "even" : "odd";
 }

 static int64_t FxlToDartOrEarlier(fml::TimePoint time) {
   int64_t dart_now = Dart_TimelineGetMicros();
   fml::TimePoint fxl_now = fml::TimePoint::Now();
   return (time - fxl_now).ToMicroseconds() + dart_now;
 }

 void Animator::BeginFrame(fml::TimePoint frame_start_time,
                           fml::TimePoint frame_target_time) {
   TRACE_EVENT_ASYNC_END0("flutter", "Frame Request Pending", frame_number_++);

   TRACE_EVENT0("flutter", "Animator::BeginFrame");
   while (!trace_flow_ids_.empty()) {
     uint64_t trace_flow_id = trace_flow_ids_.front();
     TRACE_FLOW_END("flutter", "PointerEvent", trace_flow_id);
     trace_flow_ids_.pop_front();
   }

   frame_scheduled_ = false;
   notify_idle_task_id_++;
   regenerate_layer_tree_ = false;
   pending_frame_semaphore_.Signal();

   if (!producer_continuation_) {
     // We may already have a valid pipeline continuation in case a previous
     // begin frame did not result in an Animation::Render. Simply reuse that
     // instead of asking the pipeline for a fresh continuation.
     producer_continuation_ = layer_tree_pipeline_->Produce();

     if (!producer_continuation_) {
       // If we still don't have valid continuation, the pipeline is currently
       // full because the consumer is being too slow. Try again at the next
       // frame interval.
       RequestFrame();
       return;
     }
   }

   // We have acquired a valid continuation from the pipeline and are ready
   // to service potential frame.
   FML_DCHECK(producer_continuation_);

   last_frame_begin_time_ = frame_start_time;
   last_frame_target_time_ = frame_target_time;
   dart_frame_deadline_ = FxlToDartOrEarlier(frame_target_time);
   {
     TRACE_EVENT2("flutter", "Framework Workload", "mode", "basic", "frame",
                  FrameParity());
     delegate_.OnAnimatorBeginFrame(frame_target_time);
   }

   if (!frame_scheduled_) {
     // Under certain workloads (such as our parent view resizing us, which is
     // communicated to us by repeat viewport metrics events), we won't
     // actually have a frame scheduled yet, despite the fact that we *will* be
     // producing a frame next vsync (it will be scheduled once we receive the
     // viewport event).  Because of this, we hold off on calling
     // |OnAnimatorNotifyIdle| for a little bit, as that could cause garbage
     // collection to trigger at a highly undesirable time.
     task_runners_.GetUITaskRunner()->PostDelayedTask(
         [self = weak_factory_.GetWeakPtr(),
          notify_idle_task_id = notify_idle_task_id_]() {
           if (!self.get()) {
             return;
           }
           // If our (this task's) task id is the same as the current one
           // (meaning there were no follow up frames to the |BeginFrame| call
           // that posted this task) and no frame is currently scheduled, then
           // assume that we are idle, and notify the engine of this.
           if (notify_idle_task_id == self->notify_idle_task_id_ &&
               !self->frame_scheduled_) {
             TRACE_EVENT0("flutter", "BeginFrame idle callback");
             self->delegate_.OnAnimatorNotifyIdle(Dart_TimelineGetMicros() +
                                                  100000);
           }
         },
         kNotifyIdleTaskWaitTime);
   }
 }

 void Animator::Render(std::unique_ptr<flutter::LayerTree> layer_tree) {
   if (dimension_change_pending_ &&
       layer_tree->frame_size() != last_layer_tree_size_) {
     dimension_change_pending_ = false;
   }
   last_layer_tree_size_ = layer_tree->frame_size();

   if (layer_tree) {
     // Note the frame time for instrumentation.
     layer_tree->RecordBuildTime(last_frame_begin_time_,
                                 last_frame_target_time_);
   }

   // Commit the pending continuation.
   bool result = producer_continuation_.Complete(std::move(layer_tree));
   if (!result) {
     FML_DLOG(INFO) << "No pending continuation to commit";
   }

   delegate_.OnAnimatorDraw(layer_tree_pipeline_, last_frame_target_time_);
 }

 bool Animator::CanReuseLastLayerTree() {
   return !regenerate_layer_tree_;
 }

 void Animator::DrawLastLayerTree() {
   pending_frame_semaphore_.Signal();
   delegate_.OnAnimatorDrawLastLayerTree();
 }

 void Animator::RequestFrame(bool regenerate_layer_tree) {
   if (regenerate_layer_tree) {
     regenerate_layer_tree_ = true;
   }
   if (paused_ && !dimension_change_pending_) {
     return;
   }

   if (!pending_frame_semaphore_.TryWait()) {
     // Multiple calls to Animator::RequestFrame will still result in a
     // single request to the VsyncWaiter.
     return;
   }

   // The AwaitVSync is going to call us back at the next VSync. However, we want
   // to be reasonably certain that the UI thread is not in the middle of a
   // particularly expensive callout. We post the AwaitVSync to run right after
   // an idle. This does NOT provide a guarantee that the UI thread has not
   // started an expensive operation right after posting this message however.
   // To support that, we need edge triggered wakes on VSync.

   task_runners_.GetUITaskRunner()->PostTask([self = weak_factory_.GetWeakPtr(),
                                              frame_number = frame_number_]() {
     if (!self.get()) {
       return;
     }
     TRACE_EVENT_ASYNC_BEGIN0("flutter", "Frame Request Pending", frame_number);
     self->AwaitVSync();
   });
   frame_scheduled_ = true;
 }

 void Animator::AwaitVSync() {
   waiter_->AsyncWaitForVsync(
       [self = weak_factory_.GetWeakPtr()](fml::TimePoint frame_start_time,
                                           fml::TimePoint frame_target_time) {
         if (self) {
           if (self->CanReuseLastLayerTree()) {
             self->DrawLastLayerTree();
           } else {
             self->BeginFrame(frame_start_time, frame_target_time);
           }
         }
       });

   delegate_.OnAnimatorNotifyIdle(dart_frame_deadline_);
 }

 void Animator::ScheduleSecondaryVsyncCallback(const fml::closure& callback) {
   waiter_->ScheduleSecondaryCallback(callback);
 }

 }  // namespace flutter
	// 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 "flutter/shell/common/animator.h"

	#include "flutter/fml/trace_event.h"
	#include "third_party/dart/runtime/include/dart_tools_api.h"

	namespace flutter {

	namespace {

	// Wait 51 milliseconds (which is 1 more milliseconds than 3 frames at 60hz)
	// before notifying the engine that we are idle. See comments in \|BeginFrame\|
	// for further discussion on why this is necessary.
	constexpr fml::TimeDelta kNotifyIdleTaskWaitTime =
	fml::TimeDelta::FromMilliseconds(51);

	} // namespace

	Animator::Animator(Delegate& delegate,
	TaskRunners task_runners,
	std::unique_ptr<VsyncWaiter> waiter)
	: delegate_(delegate),
	task_runners_(std::move(task_runners)),
	waiter_(std::move(waiter)),
	last_frame_begin_time_(),
	last_frame_target_time_(),
	dart_frame_deadline_(0),
	#if FLUTTER_SHELL_ENABLE_METAL
	layer_tree_pipeline_(fml::MakeRefCounted<LayerTreePipeline>(2)),
	#else // FLUTTER_SHELL_ENABLE_METAL
	// TODO(dnfield): We should remove this logic and set the pipeline depth
	// back to 2 in this case. See
	// https://github.com/flutter/engine/pull/9132 for discussion.
	layer_tree_pipeline_(fml::MakeRefCounted<LayerTreePipeline>(
	task_runners.GetPlatformTaskRunner() ==
	task_runners.GetRasterTaskRunner()
	? 1
	: 2)),
	#endif // FLUTTER_SHELL_ENABLE_METAL
	pending_frame_semaphore_(1),
	frame_number_(1),
	paused_(false),
	regenerate_layer_tree_(false),
	frame_scheduled_(false),
	notify_idle_task_id_(0),
	dimension_change_pending_(false),
	weak_factory_(this) {
	}

	Animator::~Animator() = default;

	float Animator::GetDisplayRefreshRate() const {
	return waiter_->GetDisplayRefreshRate();
	}

	void Animator::Stop() {
	paused_ = true;
	}

	void Animator::Start() {
	if (!paused_) {
	return;
	}

	paused_ = false;
	RequestFrame();
	}

	// Indicate that screen dimensions will be changing in order to force rendering
	// of an updated frame even if the animator is currently paused.
	void Animator::SetDimensionChangePending() {
	dimension_change_pending_ = true;
	}

	void Animator::EnqueueTraceFlowId(uint64_t trace_flow_id) {
	fml::TaskRunner::RunNowOrPostTask(
	task_runners_.GetUITaskRunner(),
	[self = weak_factory_.GetWeakPtr(), trace_flow_id] {
	if (!self) {
	return;
	}
	self->trace_flow_ids_.push_back(trace_flow_id);
	});
	}

	// This Parity is used by the timeline component to correctly align
	// GPU Workloads events with their respective Framework Workload.
	const char* Animator::FrameParity() {
	return (frame_number_ % 2) ? "even" : "odd";
	}

	static int64_t FxlToDartOrEarlier(fml::TimePoint time) {
	int64_t dart_now = Dart_TimelineGetMicros();
	fml::TimePoint fxl_now = fml::TimePoint::Now();
	return (time - fxl_now).ToMicroseconds() + dart_now;
	}

	void Animator::BeginFrame(fml::TimePoint frame_start_time,
	fml::TimePoint frame_target_time) {
	TRACE_EVENT_ASYNC_END0("flutter", "Frame Request Pending", frame_number_++);

	TRACE_EVENT0("flutter", "Animator::BeginFrame");
	while (!trace_flow_ids_.empty()) {
	uint64_t trace_flow_id = trace_flow_ids_.front();
	TRACE_FLOW_END("flutter", "PointerEvent", trace_flow_id);
	trace_flow_ids_.pop_front();
	}

	frame_scheduled_ = false;
	notify_idle_task_id_++;
	regenerate_layer_tree_ = false;
	pending_frame_semaphore_.Signal();

	if (!producer_continuation_) {
	// We may already have a valid pipeline continuation in case a previous
	// begin frame did not result in an Animation::Render. Simply reuse that
	// instead of asking the pipeline for a fresh continuation.
	producer_continuation_ = layer_tree_pipeline_->Produce();

	if (!producer_continuation_) {
	// If we still don't have valid continuation, the pipeline is currently
	// full because the consumer is being too slow. Try again at the next
	// frame interval.
	RequestFrame();
	return;
	}
	}

	// We have acquired a valid continuation from the pipeline and are ready
	// to service potential frame.
	FML_DCHECK(producer_continuation_);

	last_frame_begin_time_ = frame_start_time;
	last_frame_target_time_ = frame_target_time;
	dart_frame_deadline_ = FxlToDartOrEarlier(frame_target_time);
	{
	TRACE_EVENT2("flutter", "Framework Workload", "mode", "basic", "frame",
	FrameParity());
	delegate_.OnAnimatorBeginFrame(frame_target_time);
	}

	if (!frame_scheduled_) {
	// Under certain workloads (such as our parent view resizing us, which is
	// communicated to us by repeat viewport metrics events), we won't
	// actually have a frame scheduled yet, despite the fact that we will be
	// producing a frame next vsync (it will be scheduled once we receive the
	// viewport event). Because of this, we hold off on calling
	// \|OnAnimatorNotifyIdle\| for a little bit, as that could cause garbage
	// collection to trigger at a highly undesirable time.
	task_runners_.GetUITaskRunner()->PostDelayedTask(
	[self = weak_factory_.GetWeakPtr(),
	notify_idle_task_id = notify_idle_task_id_]() {
	if (!self.get()) {
	return;
	}
	// If our (this task's) task id is the same as the current one
	// (meaning there were no follow up frames to the \|BeginFrame\| call
	// that posted this task) and no frame is currently scheduled, then
	// assume that we are idle, and notify the engine of this.
	if (notify_idle_task_id == self->notify_idle_task_id_ &&
	!self->frame_scheduled_) {
	TRACE_EVENT0("flutter", "BeginFrame idle callback");
	self->delegate_.OnAnimatorNotifyIdle(Dart_TimelineGetMicros() +
	100000);
	}
	},
	kNotifyIdleTaskWaitTime);
	}
	}

	void Animator::Render(std::unique_ptr<flutter::LayerTree> layer_tree) {
	if (dimension_change_pending_ &&
	layer_tree->frame_size() != last_layer_tree_size_) {
	dimension_change_pending_ = false;
	}
	last_layer_tree_size_ = layer_tree->frame_size();

	if (layer_tree) {
	// Note the frame time for instrumentation.
	layer_tree->RecordBuildTime(last_frame_begin_time_,
	last_frame_target_time_);
	}

	// Commit the pending continuation.
	bool result = producer_continuation_.Complete(std::move(layer_tree));
	if (!result) {
	FML_DLOG(INFO) << "No pending continuation to commit";
	}

	delegate_.OnAnimatorDraw(layer_tree_pipeline_, last_frame_target_time_);
	}

	bool Animator::CanReuseLastLayerTree() {
	return !regenerate_layer_tree_;
	}

	void Animator::DrawLastLayerTree() {
	pending_frame_semaphore_.Signal();
	delegate_.OnAnimatorDrawLastLayerTree();
	}

	void Animator::RequestFrame(bool regenerate_layer_tree) {
	if (regenerate_layer_tree) {
	regenerate_layer_tree_ = true;
	}
	if (paused_ && !dimension_change_pending_) {
	return;
	}

	if (!pending_frame_semaphore_.TryWait()) {
	// Multiple calls to Animator::RequestFrame will still result in a
	// single request to the VsyncWaiter.
	return;
	}

	// The AwaitVSync is going to call us back at the next VSync. However, we want
	// to be reasonably certain that the UI thread is not in the middle of a
	// particularly expensive callout. We post the AwaitVSync to run right after
	// an idle. This does NOT provide a guarantee that the UI thread has not
	// started an expensive operation right after posting this message however.
	// To support that, we need edge triggered wakes on VSync.

	task_runners_.GetUITaskRunner()->PostTask([self = weak_factory_.GetWeakPtr(),
	frame_number = frame_number_]() {
	if (!self.get()) {
	return;
	}
	TRACE_EVENT_ASYNC_BEGIN0("flutter", "Frame Request Pending", frame_number);
	self->AwaitVSync();
	});
	frame_scheduled_ = true;
	}

	void Animator::AwaitVSync() {
	waiter_->AsyncWaitForVsync(
	[self = weak_factory_.GetWeakPtr()](fml::TimePoint frame_start_time,
	fml::TimePoint frame_target_time) {
	if (self) {
	if (self->CanReuseLastLayerTree()) {
	self->DrawLastLayerTree();
	} else {
	self->BeginFrame(frame_start_time, frame_target_time);
	}
	}
	});

	delegate_.OnAnimatorNotifyIdle(dart_frame_deadline_);
	}

	void Animator::ScheduleSecondaryVsyncCallback(const fml::closure& callback) {
	waiter_->ScheduleSecondaryCallback(callback);
	}

	} // namespace flutter