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// Copyright 2014 The Chromium 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 <map>
#include <QuartzCore/CVDisplayLink.h>
#include "base/lazy_instance.h"
#include "base/mac/scoped_typeref.h"
#include "base/memory/ref_counted.h"
#include "base/synchronization/lock.h"
#include "base/time/time.h"
#include "base/timer/timer.h"
#include "ui/accelerated_widget_mac/accelerated_widget_mac_export.h"
namespace base {
class SingleThreadTaskRunner;
namespace ui {
: public base::RefCountedThreadSafe<DisplayLinkMac> {
static scoped_refptr<DisplayLinkMac> GetForDisplay(
CGDirectDisplayID display_id);
// Get vsync scheduling parameters.
bool GetVSyncParameters(
base::TimeTicks* timebase,
base::TimeDelta* interval);
// The vsync parameters are cached, because re-computing them is expensive.
// The parameters also skew over time (astonishingly quickly -- 0.1 msec per
// second), so, use this method to tell the display link the current time.
// If too much time has elapsed since the last time the vsync parameters were
// calculated, re-calculate them.
void NotifyCurrentTime(const base::TimeTicks& now);
friend class base::RefCountedThreadSafe<DisplayLinkMac>;
CGDirectDisplayID display_id,
base::ScopedTypeRef<CVDisplayLinkRef> display_link);
virtual ~DisplayLinkMac();
void StartOrContinueDisplayLink();
void StopDisplayLink();
void Tick(const CVTimeStamp& time);
// Called by the system on the display link thread, and posts a call to Tick
// to the UI thread.
static CVReturn DisplayLinkCallback(
CVDisplayLinkRef display_link,
const CVTimeStamp* now,
const CVTimeStamp* output_time,
CVOptionFlags flags_in,
CVOptionFlags* flags_out,
void* context);
// This is called whenever the display is reconfigured, and marks that the
// vsync parameters must be recalculated.
static void DisplayReconfigurationCallBack(
CGDirectDisplayID display,
CGDisplayChangeSummaryFlags flags,
void* user_info);
// The task runner to post tasks to from the display link thread.
scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
// The display that this display link is attached to.
CGDirectDisplayID display_id_;
// CVDisplayLink for querying VSync timing info.
base::ScopedTypeRef<CVDisplayLinkRef> display_link_;
// VSync parameters computed during Tick.
bool timebase_and_interval_valid_;
base::TimeTicks timebase_;
base::TimeDelta interval_;
// The time after which we should re-start the display link to get fresh
// parameters.
base::TimeTicks recalculate_time_;
// Each display link instance consumes a non-negligible number of cycles, so
// make all display links on the same screen share the same object.
typedef std::map<CGDirectDisplayID, DisplayLinkMac*> DisplayMap;
static base::LazyInstance<DisplayMap> display_map_;
} // ui