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1 // Copyright 2013 the V8 project authors. All rights reserved. | 1 // Copyright 2013 the V8 project authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef V8_BASE_PLATFORM_ELAPSED_TIMER_H_ | 5 #ifndef V8_BASE_PLATFORM_ELAPSED_TIMER_H_ |
6 #define V8_BASE_PLATFORM_ELAPSED_TIMER_H_ | 6 #define V8_BASE_PLATFORM_ELAPSED_TIMER_H_ |
7 | 7 |
8 #include "src/base/logging.h" | 8 #include "src/base/logging.h" |
9 #include "src/base/platform/time.h" | 9 #include "src/base/platform/time.h" |
10 | 10 |
11 namespace v8 { | 11 namespace v8 { |
12 namespace base { | 12 namespace base { |
13 | 13 |
14 class ElapsedTimer V8_FINAL { | 14 class ElapsedTimer V8_FINAL { |
15 public: | 15 public: |
16 #ifdef DEBUG | 16 #ifdef DEBUG |
17 ElapsedTimer() : started_(false) {} | 17 ElapsedTimer() : started_(false) {} |
18 #endif | 18 #endif |
19 | 19 |
20 // Starts this timer. Once started a timer can be checked with | 20 // Starts this timer. Once started a timer can be checked with |
21 // |Elapsed()| or |HasExpired()|, and may be restarted using |Restart()|. | 21 // |Elapsed()| or |HasExpired()|, and may be restarted using |Restart()|. |
22 // This method must not be called on an already started timer. | 22 // This method must not be called on an already started timer. |
23 void Start() { | 23 void Start() { |
24 ASSERT(!IsStarted()); | 24 DCHECK(!IsStarted()); |
25 start_ticks_ = Now(); | 25 start_ticks_ = Now(); |
26 #ifdef DEBUG | 26 #ifdef DEBUG |
27 started_ = true; | 27 started_ = true; |
28 #endif | 28 #endif |
29 ASSERT(IsStarted()); | 29 DCHECK(IsStarted()); |
30 } | 30 } |
31 | 31 |
32 // Stops this timer. Must not be called on a timer that was not | 32 // Stops this timer. Must not be called on a timer that was not |
33 // started before. | 33 // started before. |
34 void Stop() { | 34 void Stop() { |
35 ASSERT(IsStarted()); | 35 DCHECK(IsStarted()); |
36 start_ticks_ = TimeTicks(); | 36 start_ticks_ = TimeTicks(); |
37 #ifdef DEBUG | 37 #ifdef DEBUG |
38 started_ = false; | 38 started_ = false; |
39 #endif | 39 #endif |
40 ASSERT(!IsStarted()); | 40 DCHECK(!IsStarted()); |
41 } | 41 } |
42 | 42 |
43 // Returns |true| if this timer was started previously. | 43 // Returns |true| if this timer was started previously. |
44 bool IsStarted() const { | 44 bool IsStarted() const { |
45 ASSERT(started_ || start_ticks_.IsNull()); | 45 DCHECK(started_ || start_ticks_.IsNull()); |
46 ASSERT(!started_ || !start_ticks_.IsNull()); | 46 DCHECK(!started_ || !start_ticks_.IsNull()); |
47 return !start_ticks_.IsNull(); | 47 return !start_ticks_.IsNull(); |
48 } | 48 } |
49 | 49 |
50 // Restarts the timer and returns the time elapsed since the previous start. | 50 // Restarts the timer and returns the time elapsed since the previous start. |
51 // This method is equivalent to obtaining the elapsed time with |Elapsed()| | 51 // This method is equivalent to obtaining the elapsed time with |Elapsed()| |
52 // and then starting the timer again, but does so in one single operation, | 52 // and then starting the timer again, but does so in one single operation, |
53 // avoiding the need to obtain the clock value twice. It may only be called | 53 // avoiding the need to obtain the clock value twice. It may only be called |
54 // on a previously started timer. | 54 // on a previously started timer. |
55 TimeDelta Restart() { | 55 TimeDelta Restart() { |
56 ASSERT(IsStarted()); | 56 DCHECK(IsStarted()); |
57 TimeTicks ticks = Now(); | 57 TimeTicks ticks = Now(); |
58 TimeDelta elapsed = ticks - start_ticks_; | 58 TimeDelta elapsed = ticks - start_ticks_; |
59 ASSERT(elapsed.InMicroseconds() >= 0); | 59 DCHECK(elapsed.InMicroseconds() >= 0); |
60 start_ticks_ = ticks; | 60 start_ticks_ = ticks; |
61 ASSERT(IsStarted()); | 61 DCHECK(IsStarted()); |
62 return elapsed; | 62 return elapsed; |
63 } | 63 } |
64 | 64 |
65 // Returns the time elapsed since the previous start. This method may only | 65 // Returns the time elapsed since the previous start. This method may only |
66 // be called on a previously started timer. | 66 // be called on a previously started timer. |
67 TimeDelta Elapsed() const { | 67 TimeDelta Elapsed() const { |
68 ASSERT(IsStarted()); | 68 DCHECK(IsStarted()); |
69 TimeDelta elapsed = Now() - start_ticks_; | 69 TimeDelta elapsed = Now() - start_ticks_; |
70 ASSERT(elapsed.InMicroseconds() >= 0); | 70 DCHECK(elapsed.InMicroseconds() >= 0); |
71 return elapsed; | 71 return elapsed; |
72 } | 72 } |
73 | 73 |
74 // Returns |true| if the specified |time_delta| has elapsed since the | 74 // Returns |true| if the specified |time_delta| has elapsed since the |
75 // previous start, or |false| if not. This method may only be called on | 75 // previous start, or |false| if not. This method may only be called on |
76 // a previously started timer. | 76 // a previously started timer. |
77 bool HasExpired(TimeDelta time_delta) const { | 77 bool HasExpired(TimeDelta time_delta) const { |
78 ASSERT(IsStarted()); | 78 DCHECK(IsStarted()); |
79 return Elapsed() >= time_delta; | 79 return Elapsed() >= time_delta; |
80 } | 80 } |
81 | 81 |
82 private: | 82 private: |
83 static V8_INLINE TimeTicks Now() { | 83 static V8_INLINE TimeTicks Now() { |
84 TimeTicks now = TimeTicks::HighResolutionNow(); | 84 TimeTicks now = TimeTicks::HighResolutionNow(); |
85 ASSERT(!now.IsNull()); | 85 DCHECK(!now.IsNull()); |
86 return now; | 86 return now; |
87 } | 87 } |
88 | 88 |
89 TimeTicks start_ticks_; | 89 TimeTicks start_ticks_; |
90 #ifdef DEBUG | 90 #ifdef DEBUG |
91 bool started_; | 91 bool started_; |
92 #endif | 92 #endif |
93 }; | 93 }; |
94 | 94 |
95 } } // namespace v8::base | 95 } } // namespace v8::base |
96 | 96 |
97 #endif // V8_BASE_PLATFORM_ELAPSED_TIMER_H_ | 97 #endif // V8_BASE_PLATFORM_ELAPSED_TIMER_H_ |
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