Current File : /home/vacivi36/vittasync.vacivitta.com.br/vittasync/node/deps/v8/src/base/platform/elapsed-timer.h
// Copyright 2013 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_BASE_PLATFORM_ELAPSED_TIMER_H_
#define V8_BASE_PLATFORM_ELAPSED_TIMER_H_
#include "src/base/logging.h"
#include "src/base/platform/time.h"
namespace v8 {
namespace base {
class ElapsedTimer final {
public:
ElapsedTimer() : start_ticks_() {}
// Starts this timer. Once started a timer can be checked with
// |Elapsed()| or |HasExpired()|, and may be restarted using |Restart()|.
// This method must not be called on an already started timer.
void Start() { Start(Now()); }
void Start(TimeTicks now) {
DCHECK(!now.IsNull());
DCHECK(!IsStarted());
set_start_ticks(now);
#ifdef DEBUG
started_ = true;
#endif
DCHECK(IsStarted());
}
// Stops this timer. Must not be called on a timer that was not
// started before.
void Stop() {
DCHECK(IsStarted());
set_start_ticks(TimeTicks());
#ifdef DEBUG
started_ = false;
#endif
DCHECK(!IsStarted());
}
// Returns |true| if this timer was started previously.
bool IsStarted() const {
DCHECK(!paused_);
DCHECK_NE(started_, start_ticks_.IsNull());
return !start_ticks_.IsNull();
}
#if DEBUG
bool IsPaused() const { return paused_; }
#endif
// Restarts the timer and returns the time elapsed since the previous start.
// This method is equivalent to obtaining the elapsed time with |Elapsed()|
// and then starting the timer again, but does so in one single operation,
// avoiding the need to obtain the clock value twice. It may only be called
// on a previously started timer.
TimeDelta Restart() { return Restart(Now()); }
TimeDelta Restart(TimeTicks now) {
DCHECK(!now.IsNull());
DCHECK(IsStarted());
TimeDelta elapsed = now - start_ticks_;
DCHECK_GE(elapsed.InMicroseconds(), 0);
set_start_ticks(now);
DCHECK(IsStarted());
return elapsed;
}
void Pause() { Pause(Now()); }
void Pause(TimeTicks now) {
TimeDelta elapsed = Elapsed(now);
DCHECK(IsStarted());
#ifdef DEBUG
paused_ = true;
#endif
set_paused_elapsed(elapsed);
}
void Resume() { Resume(Now()); }
void Resume(TimeTicks now) {
DCHECK(!now.IsNull());
DCHECK(started_);
DCHECK(paused_);
TimeDelta elapsed = paused_elapsed();
#ifdef DEBUG
paused_ = false;
#endif
set_start_ticks(now - elapsed);
DCHECK(IsStarted());
}
// Returns the time elapsed since the previous start. This method may only
// be called on a previously started timer.
TimeDelta Elapsed() const { return Elapsed(Now()); }
TimeDelta Elapsed(TimeTicks now) const {
DCHECK(!now.IsNull());
DCHECK(IsStarted());
TimeDelta elapsed = now - start_ticks();
DCHECK_GE(elapsed.InMicroseconds(), 0);
return elapsed;
}
// Returns |true| if the specified |time_delta| has elapsed since the
// previous start, or |false| if not. This method may only be called on
// a previously started timer.
bool HasExpired(TimeDelta time_delta) const {
DCHECK(IsStarted());
return Elapsed() >= time_delta;
}
private:
static V8_INLINE TimeTicks Now() {
TimeTicks now = TimeTicks::Now();
DCHECK(!now.IsNull());
return now;
}
TimeDelta paused_elapsed() {
// Only used started_ since paused_elapsed_ can be 0.
DCHECK(paused_);
DCHECK(started_);
return paused_elapsed_;
}
void set_paused_elapsed(TimeDelta delta) {
DCHECK(paused_);
DCHECK(started_);
paused_elapsed_ = delta;
}
TimeTicks start_ticks() const {
DCHECK(!paused_);
return start_ticks_;
}
void set_start_ticks(TimeTicks start_ticks) {
DCHECK(!paused_);
start_ticks_ = start_ticks;
}
union {
TimeTicks start_ticks_;
TimeDelta paused_elapsed_;
};
#ifdef DEBUG
bool started_ = false;
bool paused_ = false;
#endif
};
// Helper that times a scoped region and records the elapsed time.
struct ScopedTimer {
explicit ScopedTimer(TimeDelta* location) : location_(location) {
if (location_) {
timer_.Start();
}
}
~ScopedTimer() {
if (location_) {
*location_ += timer_.Elapsed();
}
}
ElapsedTimer timer_;
TimeDelta* location_;
};
} // namespace base
} // namespace v8
#endif // V8_BASE_PLATFORM_ELAPSED_TIMER_H_
Mini Shell