| // Copyright 2013 the V8 project authors. All rights reserved. |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following |
| // disclaimer in the documentation and/or other materials provided |
| // with the distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived |
| // from this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #ifndef V8_PLATFORM_ELAPSED_TIMER_H_ |
| #define V8_PLATFORM_ELAPSED_TIMER_H_ |
| |
| #include "../checks.h" |
| #include "time.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| class ElapsedTimer V8_FINAL BASE_EMBEDDED { |
| public: |
| #ifdef DEBUG |
| ElapsedTimer() : started_(false) {} |
| #endif |
| |
| // 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() { |
| ASSERT(!IsStarted()); |
| start_ticks_ = Now(); |
| #ifdef DEBUG |
| started_ = true; |
| #endif |
| ASSERT(IsStarted()); |
| } |
| |
| // Stops this timer. Must not be called on a timer that was not |
| // started before. |
| void Stop() { |
| ASSERT(IsStarted()); |
| start_ticks_ = TimeTicks(); |
| #ifdef DEBUG |
| started_ = false; |
| #endif |
| ASSERT(!IsStarted()); |
| } |
| |
| // Returns |true| if this timer was started previously. |
| bool IsStarted() const { |
| ASSERT(started_ || start_ticks_.IsNull()); |
| ASSERT(!started_ || !start_ticks_.IsNull()); |
| return !start_ticks_.IsNull(); |
| } |
| |
| // 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() { |
| ASSERT(IsStarted()); |
| TimeTicks ticks = Now(); |
| TimeDelta elapsed = ticks - start_ticks_; |
| ASSERT(elapsed.InMicroseconds() >= 0); |
| start_ticks_ = ticks; |
| ASSERT(IsStarted()); |
| return elapsed; |
| } |
| |
| // Returns the time elapsed since the previous start. This method may only |
| // be called on a previously started timer. |
| TimeDelta Elapsed() const { |
| ASSERT(IsStarted()); |
| TimeDelta elapsed = Now() - start_ticks_; |
| ASSERT(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 { |
| ASSERT(IsStarted()); |
| return Elapsed() >= time_delta; |
| } |
| |
| private: |
| static V8_INLINE TimeTicks Now() { |
| TimeTicks now = TimeTicks::HighResolutionNow(); |
| ASSERT(!now.IsNull()); |
| return now; |
| } |
| |
| TimeTicks start_ticks_; |
| #ifdef DEBUG |
| bool started_; |
| #endif |
| }; |
| |
| } } // namespace v8::internal |
| |
| #endif // V8_PLATFORM_ELAPSED_TIMER_H_ |