Index: base/profiler/tracked_time.h |
=================================================================== |
--- base/profiler/tracked_time.h (revision 0) |
+++ base/profiler/tracked_time.h (revision 0) |
@@ -0,0 +1,84 @@ |
+// Copyright (c) 2011 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. |
+ |
+#ifndef BASE_PROFILER_TRACKED_TIME_H_ |
+#define BASE_PROFILER_TRACKED_TIME_H_ |
+ |
+ |
+#include "base/base_export.h" |
+#include "base/basictypes.h" |
+#include "base/time.h" |
+ |
+namespace tracked_objects { |
+ |
+//------------------------------------------------------------------------------ |
+ |
+#define USE_FAST_TIME_CLASS_FOR_DURATION_CALCULATIONS |
+ |
+#if defined(USE_FAST_TIME_CLASS_FOR_DURATION_CALCULATIONS) |
+ |
+// TimeTicks maintains a wasteful 64 bits of data (we need less than 32), and on |
+// windows, a 64 bit timer is expensive to even obtain. We use a simple |
+// millisecond counter for most of our time values, as well as millisecond units |
+// of duration between those values. This means we can only handle durations |
+// up to 49 days (range), or 24 days (non-negative time durations). |
+// We only define enough methods to service the needs of the tracking classes, |
+// and our interfaces are modeled after what TimeTicks and TimeDelta use (so we |
+// can swap them into place if we want to use the "real" classes). |
+ |
+class BASE_EXPORT Duration { // Similar to base::TimeDelta. |
+ public: |
+ Duration(); |
+ |
+ Duration& operator+=(const Duration& other); |
+ Duration operator+(const Duration& other) const; |
+ |
+ bool operator==(const Duration& other) const; |
+ bool operator!=(const Duration& other) const; |
+ bool operator>(const Duration& other) const; |
+ |
+ static Duration FromMilliseconds(int ms); |
+ |
+ int32 InMilliseconds() const; |
+ |
+ private: |
+ friend class TrackedTime; |
+ explicit Duration(int32 duration); |
+ |
+ // Internal time is stored directly in milliseconds. |
+ int32 ms_; |
+}; |
+ |
+class BASE_EXPORT TrackedTime { // Similar to base::TimeTicks. |
+ public: |
+ TrackedTime(); |
+ explicit TrackedTime(const base::TimeTicks& time); |
+ |
+ static TrackedTime Now(); |
+ Duration operator-(const TrackedTime& other) const; |
+ TrackedTime operator+(const Duration& other) const; |
+ bool is_null() const; |
+ |
+ private: |
+ friend class Duration; |
+ explicit TrackedTime(int32 ms); |
+ |
+ // Internal duration is stored directly in milliseconds. |
+ uint32 ms_; |
+}; |
+ |
+#else |
+ |
+// Just use full 64 bit time calculations, and the slower TimeTicks::Now(). |
+// This allows us (as an alternative) to test with larger ranges of times, and |
+// with a more thoroughly tested class. |
+ |
+typedef base::TimeTicks TrackedTime; |
+typedef base::TimeDelta Duration; |
+ |
+#endif // USE_FAST_TIME_CLASS_FOR_DURATION_CALCULATIONS |
+ |
+} // namespace tracked_objects |
+ |
+#endif // BASE_PROFILER_TRACKED_TIME_H_ |