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/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
*/
#include "SoftwareVsyncSource.h"
#include "base/task.h"
#include "gfxPlatform.h"
#include "nsThreadUtils.h"
namespace mozilla::gfx {
SoftwareVsyncSource::SoftwareVsyncSource(const TimeDuration& aInitialVsyncRate)
: mVsyncEnabled(false),
mVsyncRate(TimeDuration{aInitialVsyncRate},
"SoftwareVsyncSource::mVsyncRate") {
MOZ_ASSERT(NS_IsMainThread());
mVsyncThread = new base::Thread("SoftwareVsyncThread");
MOZ_RELEASE_ASSERT(mVsyncThread->Start(),
"GFX: Could not start software vsync thread");
}
SoftwareVsyncSource::~SoftwareVsyncSource() {
MOZ_ASSERT(NS_IsMainThread());
if (mVsyncThread) {
mVsyncThread->Stop();
delete mVsyncThread;
}
};
void SoftwareVsyncSource::EnableVsync() {
MOZ_ASSERT(mVsyncThread->IsRunning());
if (NS_IsMainThread()) {
if (mVsyncEnabled) {
return;
}
mVsyncEnabled = true;
mVsyncThread->message_loop()->PostTask(
NewRunnableMethod("SoftwareVsyncSource::EnableVsync", this,
&SoftwareVsyncSource::EnableVsync));
return;
}
MOZ_ASSERT(IsInSoftwareVsyncThread());
TimeStamp vsyncTime = TimeStamp::Now();
TimeStamp outputTime = vsyncTime + GetVsyncRate();
NotifyVsync(vsyncTime, outputTime);
}
void SoftwareVsyncSource::DisableVsync() {
MOZ_ASSERT(mVsyncThread->IsRunning());
if (NS_IsMainThread()) {
if (!mVsyncEnabled) {
return;
}
mVsyncEnabled = false;
mVsyncThread->message_loop()->PostTask(
NewRunnableMethod("SoftwareVsyncSource::DisableVsync", this,
&SoftwareVsyncSource::DisableVsync));
return;
}
MOZ_ASSERT(IsInSoftwareVsyncThread());
if (mCurrentVsyncTask) {
mCurrentVsyncTask->Cancel();
mCurrentVsyncTask = nullptr;
}
}
bool SoftwareVsyncSource::IsVsyncEnabled() {
MOZ_ASSERT(NS_IsMainThread());
return mVsyncEnabled;
}
bool SoftwareVsyncSource::IsInSoftwareVsyncThread() {
return mVsyncThread->thread_id() == PlatformThread::CurrentId();
}
void SoftwareVsyncSource::NotifyVsync(const TimeStamp& aVsyncTimestamp,
const TimeStamp& aOutputTimestamp) {
MOZ_ASSERT(IsInSoftwareVsyncThread());
TimeStamp displayVsyncTime = aVsyncTimestamp;
TimeStamp now = TimeStamp::Now();
// Posted tasks can only have integer millisecond delays
// whereas TimeDurations can have floating point delays.
// Thus the vsync timestamp can be in the future, which large parts
// of the system can't handle, including animations. Force the timestamp to be
// now.
if (aVsyncTimestamp > now) {
displayVsyncTime = now;
}
VsyncSource::NotifyVsync(displayVsyncTime, aOutputTimestamp);
// Prevent skew by still scheduling based on the original
// vsync timestamp
ScheduleNextVsync(aVsyncTimestamp);
}
TimeDuration SoftwareVsyncSource::GetVsyncRate() {
auto rate = mVsyncRate.Lock();
return *rate;
}
void SoftwareVsyncSource::SetVsyncRate(const TimeDuration& aNewRate) {
auto rate = mVsyncRate.Lock();
*rate = aNewRate;
}
void SoftwareVsyncSource::ScheduleNextVsync(TimeStamp aVsyncTimestamp) {
MOZ_ASSERT(IsInSoftwareVsyncThread());
TimeDuration vsyncRate = GetVsyncRate();
TimeStamp nextVsync = aVsyncTimestamp + vsyncRate;
TimeDuration delay = nextVsync - TimeStamp::Now();
if (delay.ToMilliseconds() < 0) {
delay = TimeDuration::FromMilliseconds(0);
nextVsync = TimeStamp::Now();
}
TimeStamp outputTime = nextVsync + vsyncRate;
mCurrentVsyncTask = NewCancelableRunnableMethod<TimeStamp, TimeStamp>(
"SoftwareVsyncSource::NotifyVsync", this,
&SoftwareVsyncSource::NotifyVsync, nextVsync, outputTime);
RefPtr<Runnable> addrefedTask = mCurrentVsyncTask;
mVsyncThread->message_loop()->PostDelayedTask(addrefedTask.forget(),
delay.ToMilliseconds());
}
void SoftwareVsyncSource::Shutdown() {
MOZ_ASSERT(NS_IsMainThread());
DisableVsync();
mVsyncThread->Stop();
delete mVsyncThread;
mVsyncThread = nullptr;
}
} // namespace mozilla::gfx