1 // Copyright 2013 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef MEDIA_BASE_SCOPED_HISTOGRAM_TIMER_H_ 6 #define MEDIA_BASE_SCOPED_HISTOGRAM_TIMER_H_ 7 8 #include "base/metrics/histogram.h" 9 #include "base/time/time.h" 10 11 // Scoped class which logs its time on this earth as a UMA statistic. Must be 12 // a #define macro since UMA macros prevent variables as names. The nested 13 // macro is necessary to expand __COUNTER__ to an actual value. 14 #define SCOPED_UMA_HISTOGRAM_TIMER(name) \ 15 SCOPED_UMA_HISTOGRAM_TIMER_EXPANDER(name, __COUNTER__) 16 17 #define SCOPED_UMA_HISTOGRAM_TIMER_EXPANDER(name, key) \ 18 SCOPED_UMA_HISTOGRAM_TIMER_UNIQUE(name, key) 19 20 #define SCOPED_UMA_HISTOGRAM_TIMER_UNIQUE(name, key) \ 21 class ScopedHistogramTimer##key { \ 22 public: \ 23 ScopedHistogramTimer##key() : constructed_(base::TimeTicks::Now()) {} \ 24 ~ScopedHistogramTimer##key() { \ 25 base::TimeDelta elapsed = base::TimeTicks::Now() - constructed_; \ 26 UMA_HISTOGRAM_TIMES(name, elapsed); \ 27 } \ 28 private: \ 29 base::TimeTicks constructed_; \ 30 } scoped_histogram_timer_##key 31 32 #endif // MEDIA_BASE_SCOPED_HISTOGRAM_TIMER_H_ 33