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
3// found in the LICENSE file.
4
5#ifndef V8_BASE_PLATFORM_TIME_H_
6#define V8_BASE_PLATFORM_TIME_H_
7
8#include <ctime>
9#include <iosfwd>
10#include <limits>
11
12#include "src/base/macros.h"
13
14// Forward declarations.
15extern "C" {
16struct _FILETIME;
17struct mach_timespec;
18struct timespec;
19struct timeval;
20}
21
22namespace v8 {
23namespace base {
24
25class Time;
26class TimeTicks;
27
28// -----------------------------------------------------------------------------
29// TimeDelta
30//
31// This class represents a duration of time, internally represented in
32// microseonds.
33
34class TimeDelta final {
35 public:
36  TimeDelta() : delta_(0) {}
37
38  // Converts units of time to TimeDeltas.
39  static TimeDelta FromDays(int days);
40  static TimeDelta FromHours(int hours);
41  static TimeDelta FromMinutes(int minutes);
42  static TimeDelta FromSeconds(int64_t seconds);
43  static TimeDelta FromMilliseconds(int64_t milliseconds);
44  static TimeDelta FromMicroseconds(int64_t microseconds) {
45    return TimeDelta(microseconds);
46  }
47  static TimeDelta FromNanoseconds(int64_t nanoseconds);
48
49  // Returns the time delta in some unit. The F versions return a floating
50  // point value, the "regular" versions return a rounded-down value.
51  //
52  // InMillisecondsRoundedUp() instead returns an integer that is rounded up
53  // to the next full millisecond.
54  int InDays() const;
55  int InHours() const;
56  int InMinutes() const;
57  double InSecondsF() const;
58  int64_t InSeconds() const;
59  double InMillisecondsF() const;
60  int64_t InMilliseconds() const;
61  int64_t InMillisecondsRoundedUp() const;
62  int64_t InMicroseconds() const { return delta_; }
63  int64_t InNanoseconds() const;
64
65  // Converts to/from Mach time specs.
66  static TimeDelta FromMachTimespec(struct mach_timespec ts);
67  struct mach_timespec ToMachTimespec() const;
68
69  // Converts to/from POSIX time specs.
70  static TimeDelta FromTimespec(struct timespec ts);
71  struct timespec ToTimespec() const;
72
73  TimeDelta& operator=(const TimeDelta& other) {
74    delta_ = other.delta_;
75    return *this;
76  }
77
78  // Computations with other deltas.
79  TimeDelta operator+(const TimeDelta& other) const {
80    return TimeDelta(delta_ + other.delta_);
81  }
82  TimeDelta operator-(const TimeDelta& other) const {
83    return TimeDelta(delta_ - other.delta_);
84  }
85
86  TimeDelta& operator+=(const TimeDelta& other) {
87    delta_ += other.delta_;
88    return *this;
89  }
90  TimeDelta& operator-=(const TimeDelta& other) {
91    delta_ -= other.delta_;
92    return *this;
93  }
94  TimeDelta operator-() const {
95    return TimeDelta(-delta_);
96  }
97
98  double TimesOf(const TimeDelta& other) const {
99    return static_cast<double>(delta_) / static_cast<double>(other.delta_);
100  }
101  double PercentOf(const TimeDelta& other) const {
102    return TimesOf(other) * 100.0;
103  }
104
105  // Computations with ints, note that we only allow multiplicative operations
106  // with ints, and additive operations with other deltas.
107  TimeDelta operator*(int64_t a) const {
108    return TimeDelta(delta_ * a);
109  }
110  TimeDelta operator/(int64_t a) const {
111    return TimeDelta(delta_ / a);
112  }
113  TimeDelta& operator*=(int64_t a) {
114    delta_ *= a;
115    return *this;
116  }
117  TimeDelta& operator/=(int64_t a) {
118    delta_ /= a;
119    return *this;
120  }
121  int64_t operator/(const TimeDelta& other) const {
122    return delta_ / other.delta_;
123  }
124
125  // Comparison operators.
126  bool operator==(const TimeDelta& other) const {
127    return delta_ == other.delta_;
128  }
129  bool operator!=(const TimeDelta& other) const {
130    return delta_ != other.delta_;
131  }
132  bool operator<(const TimeDelta& other) const {
133    return delta_ < other.delta_;
134  }
135  bool operator<=(const TimeDelta& other) const {
136    return delta_ <= other.delta_;
137  }
138  bool operator>(const TimeDelta& other) const {
139    return delta_ > other.delta_;
140  }
141  bool operator>=(const TimeDelta& other) const {
142    return delta_ >= other.delta_;
143  }
144
145 private:
146  // Constructs a delta given the duration in microseconds. This is private
147  // to avoid confusion by callers with an integer constructor. Use
148  // FromSeconds, FromMilliseconds, etc. instead.
149  explicit TimeDelta(int64_t delta) : delta_(delta) {}
150
151  // Delta in microseconds.
152  int64_t delta_;
153};
154
155
156// -----------------------------------------------------------------------------
157// Time
158//
159// This class represents an absolute point in time, internally represented as
160// microseconds (s/1,000,000) since 00:00:00 UTC, January 1, 1970.
161
162class Time final {
163 public:
164  static const int64_t kMillisecondsPerSecond = 1000;
165  static const int64_t kMicrosecondsPerMillisecond = 1000;
166  static const int64_t kMicrosecondsPerSecond = kMicrosecondsPerMillisecond *
167                                                kMillisecondsPerSecond;
168  static const int64_t kMicrosecondsPerMinute = kMicrosecondsPerSecond * 60;
169  static const int64_t kMicrosecondsPerHour = kMicrosecondsPerMinute * 60;
170  static const int64_t kMicrosecondsPerDay = kMicrosecondsPerHour * 24;
171  static const int64_t kMicrosecondsPerWeek = kMicrosecondsPerDay * 7;
172  static const int64_t kNanosecondsPerMicrosecond = 1000;
173  static const int64_t kNanosecondsPerSecond = kNanosecondsPerMicrosecond *
174                                               kMicrosecondsPerSecond;
175
176  // Contains the NULL time. Use Time::Now() to get the current time.
177  Time() : us_(0) {}
178
179  // Returns true if the time object has not been initialized.
180  bool IsNull() const { return us_ == 0; }
181
182  // Returns true if the time object is the maximum time.
183  bool IsMax() const { return us_ == std::numeric_limits<int64_t>::max(); }
184
185  // Returns the current time. Watch out, the system might adjust its clock
186  // in which case time will actually go backwards. We don't guarantee that
187  // times are increasing, or that two calls to Now() won't be the same.
188  static Time Now();
189
190  // Returns the current time. Same as Now() except that this function always
191  // uses system time so that there are no discrepancies between the returned
192  // time and system time even on virtual environments including our test bot.
193  // For timing sensitive unittests, this function should be used.
194  static Time NowFromSystemTime();
195
196  // Returns the time for epoch in Unix-like system (Jan 1, 1970).
197  static Time UnixEpoch() { return Time(0); }
198
199  // Returns the maximum time, which should be greater than any reasonable time
200  // with which we might compare it.
201  static Time Max() { return Time(std::numeric_limits<int64_t>::max()); }
202
203  // Converts to/from internal values. The meaning of the "internal value" is
204  // completely up to the implementation, so it should be treated as opaque.
205  static Time FromInternalValue(int64_t value) {
206    return Time(value);
207  }
208  int64_t ToInternalValue() const {
209    return us_;
210  }
211
212  // Converts to/from POSIX time specs.
213  static Time FromTimespec(struct timespec ts);
214  struct timespec ToTimespec() const;
215
216  // Converts to/from POSIX time values.
217  static Time FromTimeval(struct timeval tv);
218  struct timeval ToTimeval() const;
219
220  // Converts to/from Windows file times.
221  static Time FromFiletime(struct _FILETIME ft);
222  struct _FILETIME ToFiletime() const;
223
224  // Converts to/from the Javascript convention for times, a number of
225  // milliseconds since the epoch:
226  static Time FromJsTime(double ms_since_epoch);
227  double ToJsTime() const;
228
229  Time& operator=(const Time& other) {
230    us_ = other.us_;
231    return *this;
232  }
233
234  // Compute the difference between two times.
235  TimeDelta operator-(const Time& other) const {
236    return TimeDelta::FromMicroseconds(us_ - other.us_);
237  }
238
239  // Modify by some time delta.
240  Time& operator+=(const TimeDelta& delta) {
241    us_ += delta.InMicroseconds();
242    return *this;
243  }
244  Time& operator-=(const TimeDelta& delta) {
245    us_ -= delta.InMicroseconds();
246    return *this;
247  }
248
249  // Return a new time modified by some delta.
250  Time operator+(const TimeDelta& delta) const {
251    return Time(us_ + delta.InMicroseconds());
252  }
253  Time operator-(const TimeDelta& delta) const {
254    return Time(us_ - delta.InMicroseconds());
255  }
256
257  // Comparison operators
258  bool operator==(const Time& other) const {
259    return us_ == other.us_;
260  }
261  bool operator!=(const Time& other) const {
262    return us_ != other.us_;
263  }
264  bool operator<(const Time& other) const {
265    return us_ < other.us_;
266  }
267  bool operator<=(const Time& other) const {
268    return us_ <= other.us_;
269  }
270  bool operator>(const Time& other) const {
271    return us_ > other.us_;
272  }
273  bool operator>=(const Time& other) const {
274    return us_ >= other.us_;
275  }
276
277 private:
278  explicit Time(int64_t us) : us_(us) {}
279
280  // Time in microseconds in UTC.
281  int64_t us_;
282};
283
284std::ostream& operator<<(std::ostream&, const Time&);
285
286inline Time operator+(const TimeDelta& delta, const Time& time) {
287  return time + delta;
288}
289
290
291// -----------------------------------------------------------------------------
292// TimeTicks
293//
294// This class represents an abstract time that is most of the time incrementing
295// for use in measuring time durations. It is internally represented in
296// microseconds.  It can not be converted to a human-readable time, but is
297// guaranteed not to decrease (if the user changes the computer clock,
298// Time::Now() may actually decrease or jump).  But note that TimeTicks may
299// "stand still", for example if the computer suspended.
300
301class TimeTicks final {
302 public:
303  TimeTicks() : ticks_(0) {}
304
305  // Platform-dependent tick count representing "right now."
306  // The resolution of this clock is ~1-15ms.  Resolution varies depending
307  // on hardware/operating system configuration.
308  // This method never returns a null TimeTicks.
309  static TimeTicks Now();
310
311  // Returns a platform-dependent high-resolution tick count. Implementation
312  // is hardware dependent and may or may not return sub-millisecond
313  // resolution.  THIS CALL IS GENERALLY MUCH MORE EXPENSIVE THAN Now() AND
314  // SHOULD ONLY BE USED WHEN IT IS REALLY NEEDED.
315  // This method never returns a null TimeTicks.
316  static TimeTicks HighResolutionNow();
317
318  // Returns true if the high-resolution clock is working on this system.
319  static bool IsHighResolutionClockWorking();
320
321  // Returns Linux kernel timestamp for generating profiler events. This method
322  // returns null TimeTicks if the kernel cannot provide the timestamps (e.g.,
323  // on non-Linux OS or if the kernel module for timestamps is not loaded).
324
325  static TimeTicks KernelTimestampNow();
326  static bool KernelTimestampAvailable();
327
328  // Returns true if this object has not been initialized.
329  bool IsNull() const { return ticks_ == 0; }
330
331  // Converts to/from internal values. The meaning of the "internal value" is
332  // completely up to the implementation, so it should be treated as opaque.
333  static TimeTicks FromInternalValue(int64_t value) {
334    return TimeTicks(value);
335  }
336  int64_t ToInternalValue() const {
337    return ticks_;
338  }
339
340  TimeTicks& operator=(const TimeTicks other) {
341    ticks_ = other.ticks_;
342    return *this;
343  }
344
345  // Compute the difference between two times.
346  TimeDelta operator-(const TimeTicks other) const {
347    return TimeDelta::FromMicroseconds(ticks_ - other.ticks_);
348  }
349
350  // Modify by some time delta.
351  TimeTicks& operator+=(const TimeDelta& delta) {
352    ticks_ += delta.InMicroseconds();
353    return *this;
354  }
355  TimeTicks& operator-=(const TimeDelta& delta) {
356    ticks_ -= delta.InMicroseconds();
357    return *this;
358  }
359
360  // Return a new TimeTicks modified by some delta.
361  TimeTicks operator+(const TimeDelta& delta) const {
362    return TimeTicks(ticks_ + delta.InMicroseconds());
363  }
364  TimeTicks operator-(const TimeDelta& delta) const {
365    return TimeTicks(ticks_ - delta.InMicroseconds());
366  }
367
368  // Comparison operators
369  bool operator==(const TimeTicks& other) const {
370    return ticks_ == other.ticks_;
371  }
372  bool operator!=(const TimeTicks& other) const {
373    return ticks_ != other.ticks_;
374  }
375  bool operator<(const TimeTicks& other) const {
376    return ticks_ < other.ticks_;
377  }
378  bool operator<=(const TimeTicks& other) const {
379    return ticks_ <= other.ticks_;
380  }
381  bool operator>(const TimeTicks& other) const {
382    return ticks_ > other.ticks_;
383  }
384  bool operator>=(const TimeTicks& other) const {
385    return ticks_ >= other.ticks_;
386  }
387
388 private:
389  // Please use Now() to create a new object. This is for internal use
390  // and testing. Ticks is in microseconds.
391  explicit TimeTicks(int64_t ticks) : ticks_(ticks) {}
392
393  // Tick count in microseconds.
394  int64_t ticks_;
395};
396
397inline TimeTicks operator+(const TimeDelta& delta, const TimeTicks& ticks) {
398  return ticks + delta;
399}
400
401}  // namespace base
402}  // namespace v8
403
404#endif  // V8_BASE_PLATFORM_TIME_H_
405