1 : // Copyright (c) 2006-2008 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 : #include "base/time.h"
6 :
7 : #ifdef OS_MACOSX
8 : #include <mach/mach_time.h>
9 : #endif
10 : #include <sys/time.h>
11 : #ifdef ANDROID
12 : #include <time64.h>
13 : #else
14 : #include <time.h>
15 : #endif
16 : #if defined(ANDROID) || defined(OS_POSIX)
17 : #include <unistd.h>
18 : #endif
19 :
20 : #include <limits>
21 :
22 : #include "base/basictypes.h"
23 : #include "base/logging.h"
24 :
25 : namespace base {
26 :
27 : // The Time routines in this file use standard POSIX routines, or almost-
28 : // standard routines in the case of timegm. We need to use a Mach-specific
29 : // function for TimeTicks::Now() on Mac OS X.
30 :
31 : // Time -----------------------------------------------------------------------
32 :
33 : // Some functions in time.cc use time_t directly, so we provide a zero offset
34 : // for them. The epoch is 1970-01-01 00:00:00 UTC.
35 : // static
36 : const int64 Time::kTimeTToMicrosecondsOffset = GG_INT64_C(0);
37 :
38 : // static
39 5676 : Time Time::Now() {
40 : struct timeval tv;
41 5676 : struct timezone tz = { 0, 0 }; // UTC
42 5676 : if (gettimeofday(&tv, &tz) != 0) {
43 0 : DCHECK(0) << "Could not determine time of day";
44 : }
45 : // Combine seconds and microseconds in a 64-bit field containing microseconds
46 : // since the epoch. That's enough for nearly 600 centuries.
47 5676 : return tv.tv_sec * kMicrosecondsPerSecond + tv.tv_usec;
48 : }
49 :
50 : // static
51 0 : Time Time::NowFromSystemTime() {
52 : // Just use Now() because Now() returns the system time.
53 0 : return Now();
54 : }
55 :
56 : // static
57 0 : Time Time::FromExploded(bool is_local, const Exploded& exploded) {
58 : struct tm timestruct;
59 0 : timestruct.tm_sec = exploded.second;
60 0 : timestruct.tm_min = exploded.minute;
61 0 : timestruct.tm_hour = exploded.hour;
62 0 : timestruct.tm_mday = exploded.day_of_month;
63 0 : timestruct.tm_mon = exploded.month - 1;
64 0 : timestruct.tm_year = exploded.year - 1900;
65 0 : timestruct.tm_wday = exploded.day_of_week; // mktime/timegm ignore this
66 0 : timestruct.tm_yday = 0; // mktime/timegm ignore this
67 0 : timestruct.tm_isdst = -1; // attempt to figure it out
68 0 : timestruct.tm_gmtoff = 0; // not a POSIX field, so mktime/timegm ignore
69 0 : timestruct.tm_zone = NULL; // not a POSIX field, so mktime/timegm ignore
70 :
71 : time_t seconds;
72 : #ifdef ANDROID
73 : seconds = mktime(×truct);
74 : #else
75 0 : if (is_local)
76 0 : seconds = mktime(×truct);
77 : else
78 0 : seconds = timegm(×truct);
79 : #endif
80 :
81 : int64 milliseconds;
82 : // Handle overflow. Clamping the range to what mktime and timegm might
83 : // return is the best that can be done here. It's not ideal, but it's better
84 : // than failing here or ignoring the overflow case and treating each time
85 : // overflow as one second prior to the epoch.
86 0 : if (seconds == -1 &&
87 : (exploded.year < 1969 || exploded.year > 1970)) {
88 : // If exploded.year is 1969 or 1970, take -1 as correct, with the
89 : // time indicating 1 second prior to the epoch. (1970 is allowed to handle
90 : // time zone and DST offsets.) Otherwise, return the most future or past
91 : // time representable. Assumes the time_t epoch is 1970-01-01 00:00:00 UTC.
92 : //
93 : // The minimum and maximum representible times that mktime and timegm could
94 : // return are used here instead of values outside that range to allow for
95 : // proper round-tripping between exploded and counter-type time
96 : // representations in the presence of possible truncation to time_t by
97 : // division and use with other functions that accept time_t.
98 : //
99 : // When representing the most distant time in the future, add in an extra
100 : // 999ms to avoid the time being less than any other possible value that
101 : // this function can return.
102 0 : if (exploded.year < 1969) {
103 0 : milliseconds = std::numeric_limits<time_t>::min() *
104 0 : kMillisecondsPerSecond;
105 : } else {
106 0 : milliseconds = (std::numeric_limits<time_t>::max() *
107 : kMillisecondsPerSecond) +
108 0 : kMillisecondsPerSecond - 1;
109 : }
110 : } else {
111 0 : milliseconds = seconds * kMillisecondsPerSecond + exploded.millisecond;
112 : }
113 :
114 0 : return Time(milliseconds * kMicrosecondsPerMillisecond);
115 : }
116 :
117 0 : void Time::Explode(bool is_local, Exploded* exploded) const {
118 : // Time stores times with microsecond resolution, but Exploded only carries
119 : // millisecond resolution, so begin by being lossy.
120 0 : int64 milliseconds = us_ / kMicrosecondsPerMillisecond;
121 0 : time_t seconds = milliseconds / kMillisecondsPerSecond;
122 :
123 : struct tm timestruct;
124 0 : if (is_local)
125 0 : localtime_r(&seconds, ×truct);
126 : else
127 0 : gmtime_r(&seconds, ×truct);
128 :
129 0 : exploded->year = timestruct.tm_year + 1900;
130 0 : exploded->month = timestruct.tm_mon + 1;
131 0 : exploded->day_of_week = timestruct.tm_wday;
132 0 : exploded->day_of_month = timestruct.tm_mday;
133 0 : exploded->hour = timestruct.tm_hour;
134 0 : exploded->minute = timestruct.tm_min;
135 0 : exploded->second = timestruct.tm_sec;
136 0 : exploded->millisecond = milliseconds % kMillisecondsPerSecond;
137 0 : }
138 :
139 : // TimeTicks ------------------------------------------------------------------
140 :
141 : // static
142 0 : TimeTicks TimeTicks::Now() {
143 : uint64_t absolute_micro;
144 :
145 : #if defined(OS_MACOSX)
146 : static mach_timebase_info_data_t timebase_info;
147 : if (timebase_info.denom == 0) {
148 : // Zero-initialization of statics guarantees that denom will be 0 before
149 : // calling mach_timebase_info. mach_timebase_info will never set denom to
150 : // 0 as that would be invalid, so the zero-check can be used to determine
151 : // whether mach_timebase_info has already been called. This is
152 : // recommended by Apple's QA1398.
153 : kern_return_t kr = mach_timebase_info(&timebase_info);
154 : DCHECK(kr == KERN_SUCCESS);
155 : }
156 :
157 : // mach_absolute_time is it when it comes to ticks on the Mac. Other calls
158 : // with less precision (such as TickCount) just call through to
159 : // mach_absolute_time.
160 :
161 : // timebase_info converts absolute time tick units into nanoseconds. Convert
162 : // to microseconds up front to stave off overflows.
163 : absolute_micro = mach_absolute_time() / Time::kNanosecondsPerMicrosecond *
164 : timebase_info.numer / timebase_info.denom;
165 :
166 : // Don't bother with the rollover handling that the Windows version does.
167 : // With numer and denom = 1 (the expected case), the 64-bit absolute time
168 : // reported in nanoseconds is enough to last nearly 585 years.
169 :
170 : #elif defined(__OpenBSD__) || defined(OS_POSIX) && \
171 : defined(_POSIX_MONOTONIC_CLOCK) && _POSIX_MONOTONIC_CLOCK >= 0
172 :
173 : struct timespec ts;
174 0 : if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0) {
175 0 : NOTREACHED() << "clock_gettime(CLOCK_MONOTONIC) failed.";
176 0 : return TimeTicks();
177 : }
178 :
179 : absolute_micro =
180 : (static_cast<int64>(ts.tv_sec) * Time::kMicrosecondsPerSecond) +
181 0 : (static_cast<int64>(ts.tv_nsec) / Time::kNanosecondsPerMicrosecond);
182 :
183 : #else // _POSIX_MONOTONIC_CLOCK
184 : #error No usable tick clock function on this platform.
185 : #endif // _POSIX_MONOTONIC_CLOCK
186 :
187 0 : return TimeTicks(absolute_micro);
188 : }
189 :
190 : // static
191 0 : TimeTicks TimeTicks::HighResNow() {
192 0 : return Now();
193 : }
194 :
195 : } // namespace base
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