// Copyright (c) 2012 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.
#include "base/time/time.h"
#include <stdint.h>
#include <sys/time.h>
#include <time.h>
#if defined(OS_ANDROID) && !defined(__LP64__)
#include <time64.h>
#endif
#include <unistd.h>
#include <limits>
#include <ostream>
#include "base/logging.h"
#include "build/build_config.h"
#if defined(OS_ANDROID)
#include "base/os_compat_android.h"
#elif defined(OS_NACL)
#include "base/os_compat_nacl.h"
#endif
#if !defined(OS_MACOSX)
#include "base/lazy_instance.h"
#include "base/synchronization/lock.h"
#endif
namespace {
#if !defined(OS_MACOSX)
// This prevents a crash on traversing the environment global and looking up
// the 'TZ' variable in libc. See: crbug.com/390567.
base::LazyInstance<base::Lock>::Leaky
g_sys_time_to_time_struct_lock = LAZY_INSTANCE_INITIALIZER;
// Define a system-specific SysTime that wraps either to a time_t or
// a time64_t depending on the host system, and associated convertion.
// See crbug.com/162007
#if defined(OS_ANDROID) && !defined(__LP64__)
typedef time64_t SysTime;
SysTime SysTimeFromTimeStruct(struct tm* timestruct, bool is_local) {
base::AutoLock locked(g_sys_time_to_time_struct_lock.Get());
if (is_local)
return mktime64(timestruct);
else
return timegm64(timestruct);
}
void SysTimeToTimeStruct(SysTime t, struct tm* timestruct, bool is_local) {
base::AutoLock locked(g_sys_time_to_time_struct_lock.Get());
if (is_local)
localtime64_r(&t, timestruct);
else
gmtime64_r(&t, timestruct);
}
#else // OS_ANDROID && !__LP64__
typedef time_t SysTime;
SysTime SysTimeFromTimeStruct(struct tm* timestruct, bool is_local) {
base::AutoLock locked(g_sys_time_to_time_struct_lock.Get());
if (is_local)
return mktime(timestruct);
else
return timegm(timestruct);
}
void SysTimeToTimeStruct(SysTime t, struct tm* timestruct, bool is_local) {
base::AutoLock locked(g_sys_time_to_time_struct_lock.Get());
if (is_local)
localtime_r(&t, timestruct);
else
gmtime_r(&t, timestruct);
}
#endif // OS_ANDROID
int64_t ConvertTimespecToMicros(const struct timespec& ts) {
base::CheckedNumeric<int64_t> result(ts.tv_sec);
result *= base::Time::kMicrosecondsPerSecond;
result += (ts.tv_nsec / base::Time::kNanosecondsPerMicrosecond);
return result.ValueOrDie();
}
// Helper function to get results from clock_gettime() and convert to a
// microsecond timebase. Minimum requirement is MONOTONIC_CLOCK to be supported
// on the system. FreeBSD 6 has CLOCK_MONOTONIC but defines
// _POSIX_MONOTONIC_CLOCK to -1.
#if (defined(OS_POSIX) && \
defined(_POSIX_MONOTONIC_CLOCK) && _POSIX_MONOTONIC_CLOCK >= 0) || \
defined(OS_BSD) || defined(OS_ANDROID)
int64_t ClockNow(clockid_t clk_id) {
struct timespec ts;
if (clock_gettime(clk_id, &ts) != 0) {
NOTREACHED() << "clock_gettime(" << clk_id << ") failed.";
return 0;
}
return ConvertTimespecToMicros(ts);
}
#else // _POSIX_MONOTONIC_CLOCK
#error No usable tick clock function on this platform.
#endif // _POSIX_MONOTONIC_CLOCK
#endif // !defined(OS_MACOSX)
} // namespace
namespace base {
struct timespec TimeDelta::ToTimeSpec() const {
int64_t microseconds = InMicroseconds();
time_t seconds = 0;
if (microseconds >= Time::kMicrosecondsPerSecond) {
seconds = InSeconds();
microseconds -= seconds * Time::kMicrosecondsPerSecond;
}
struct timespec result =
{seconds,
static_cast<long>(microseconds * Time::kNanosecondsPerMicrosecond)};
return result;
}
#if !defined(OS_MACOSX)
// The Time routines in this file use standard POSIX routines, or almost-
// standard routines in the case of timegm. We need to use a Mach-specific
// function for TimeTicks::Now() on Mac OS X.
// Time -----------------------------------------------------------------------
// Windows uses a Gregorian epoch of 1601. We need to match this internally
// so that our time representations match across all platforms. See bug 14734.
// irb(main):010:0> Time.at(0).getutc()
// => Thu Jan 01 00:00:00 UTC 1970
// irb(main):011:0> Time.at(-11644473600).getutc()
// => Mon Jan 01 00:00:00 UTC 1601
static const int64_t kWindowsEpochDeltaSeconds = INT64_C(11644473600);
// static
const int64_t Time::kWindowsEpochDeltaMicroseconds =
kWindowsEpochDeltaSeconds * Time::kMicrosecondsPerSecond;
// Some functions in time.cc use time_t directly, so we provide an offset
// to convert from time_t (Unix epoch) and internal (Windows epoch).
// static
const int64_t Time::kTimeTToMicrosecondsOffset = kWindowsEpochDeltaMicroseconds;
// static
Time Time::Now() {
struct timeval tv;
struct timezone tz = { 0, 0 }; // UTC
if (gettimeofday(&tv, &tz) != 0) {
DCHECK(0) << "Could not determine time of day";
PLOG(ERROR) << "Call to gettimeofday failed.";
// Return null instead of uninitialized |tv| value, which contains random
// garbage data. This may result in the crash seen in crbug.com/147570.
return Time();
}
// Combine seconds and microseconds in a 64-bit field containing microseconds
// since the epoch. That's enough for nearly 600 centuries. Adjust from
// Unix (1970) to Windows (1601) epoch.
return Time((tv.tv_sec * kMicrosecondsPerSecond + tv.tv_usec) +
kWindowsEpochDeltaMicroseconds);
}
// static
Time Time::NowFromSystemTime() {
// Just use Now() because Now() returns the system time.
return Now();
}
void Time::Explode(bool is_local, Exploded* exploded) const {
// Time stores times with microsecond resolution, but Exploded only carries
// millisecond resolution, so begin by being lossy. Adjust from Windows
// epoch (1601) to Unix epoch (1970);
int64_t microseconds = us_ - kWindowsEpochDeltaMicroseconds;
// The following values are all rounded towards -infinity.
int64_t milliseconds; // Milliseconds since epoch.
SysTime seconds; // Seconds since epoch.
int millisecond; // Exploded millisecond value (0-999).
if (microseconds >= 0) {
// Rounding towards -infinity <=> rounding towards 0, in this case.
milliseconds = microseconds / kMicrosecondsPerMillisecond;
seconds = milliseconds / kMillisecondsPerSecond;
millisecond = milliseconds % kMillisecondsPerSecond;
} else {
// Round these *down* (towards -infinity).
milliseconds = (microseconds - kMicrosecondsPerMillisecond + 1) /
kMicrosecondsPerMillisecond;
seconds = (milliseconds - kMillisecondsPerSecond + 1) /
kMillisecondsPerSecond;
// Make this nonnegative (and between 0 and 999 inclusive).
millisecond = milliseconds % kMillisecondsPerSecond;
if (millisecond < 0)
millisecond += kMillisecondsPerSecond;
}
struct tm timestruct;
SysTimeToTimeStruct(seconds, ×truct, is_local);
exploded->year = timestruct.tm_year + 1900;
exploded->month = timestruct.tm_mon + 1;
exploded->day_of_week = timestruct.tm_wday;
exploded->day_of_month = timestruct.tm_mday;
exploded->hour = timestruct.tm_hour;
exploded->minute = timestruct.tm_min;
exploded->second = timestruct.tm_sec;
exploded->millisecond = millisecond;
}
// static
Time Time::FromExploded(bool is_local, const Exploded& exploded) {
struct tm timestruct;
timestruct.tm_sec = exploded.second;
timestruct.tm_min = exploded.minute;
timestruct.tm_hour = exploded.hour;
timestruct.tm_mday = exploded.day_of_month;
timestruct.tm_mon = exploded.month - 1;
timestruct.tm_year = exploded.year - 1900;
timestruct.tm_wday = exploded.day_of_week; // mktime/timegm ignore this
timestruct.tm_yday = 0; // mktime/timegm ignore this
timestruct.tm_isdst = -1; // attempt to figure it out
#if !defined(OS_NACL) && !defined(OS_SOLARIS)
timestruct.tm_gmtoff = 0; // not a POSIX field, so mktime/timegm ignore
timestruct.tm_zone = NULL; // not a POSIX field, so mktime/timegm ignore
#endif
int64_t milliseconds;
SysTime seconds;
// Certain exploded dates do not really exist due to daylight saving times,
// and this causes mktime() to return implementation-defined values when
// tm_isdst is set to -1. On Android, the function will return -1, while the
// C libraries of other platforms typically return a liberally-chosen value.
// Handling this requires the special code below.
// SysTimeFromTimeStruct() modifies the input structure, save current value.
struct tm timestruct0 = timestruct;
seconds = SysTimeFromTimeStruct(×truct, is_local);
if (seconds == -1) {
// Get the time values with tm_isdst == 0 and 1, then select the closest one
// to UTC 00:00:00 that isn't -1.
timestruct = timestruct0;
timestruct.tm_isdst = 0;
int64_t seconds_isdst0 = SysTimeFromTimeStruct(×truct, is_local);
timestruct = timestruct0;
timestruct.tm_isdst = 1;
int64_t seconds_isdst1 = SysTimeFromTimeStruct(×truct, is_local);
// seconds_isdst0 or seconds_isdst1 can be -1 for some timezones.
// E.g. "CLST" (Chile Summer Time) returns -1 for 'tm_isdt == 1'.
if (seconds_isdst0 < 0)
seconds = seconds_isdst1;
else if (seconds_isdst1 < 0)
seconds = seconds_isdst0;
else
seconds = std::min(seconds_isdst0, seconds_isdst1);
}
// Handle overflow. Clamping the range to what mktime and timegm might
// return is the best that can be done here. It's not ideal, but it's better
// than failing here or ignoring the overflow case and treating each time
// overflow as one second prior to the epoch.
if (seconds == -1 &&
(exploded.year < 1969 || exploded.year > 1970)) {
// If exploded.year is 1969 or 1970, take -1 as correct, with the
// time indicating 1 second prior to the epoch. (1970 is allowed to handle
// time zone and DST offsets.) Otherwise, return the most future or past
// time representable. Assumes the time_t epoch is 1970-01-01 00:00:00 UTC.
//
// The minimum and maximum representible times that mktime and timegm could
// return are used here instead of values outside that range to allow for
// proper round-tripping between exploded and counter-type time
// representations in the presence of possible truncation to time_t by
// division and use with other functions that accept time_t.
//
// When representing the most distant time in the future, add in an extra
// 999ms to avoid the time being less than any other possible value that
// this function can return.
// On Android, SysTime is int64_t, special care must be taken to avoid
// overflows.
const int64_t min_seconds = (sizeof(SysTime) < sizeof(int64_t))
? std::numeric_limits<SysTime>::min()
: std::numeric_limits<int32_t>::min();
const int64_t max_seconds = (sizeof(SysTime) < sizeof(int64_t))
? std::numeric_limits<SysTime>::max()
: std::numeric_limits<int32_t>::max();
if (exploded.year < 1969) {
milliseconds = min_seconds * kMillisecondsPerSecond;
} else {
milliseconds = max_seconds * kMillisecondsPerSecond;
milliseconds += (kMillisecondsPerSecond - 1);
}
} else {
milliseconds = seconds * kMillisecondsPerSecond + exploded.millisecond;
}
// Adjust from Unix (1970) to Windows (1601) epoch.
return Time((milliseconds * kMicrosecondsPerMillisecond) +
kWindowsEpochDeltaMicroseconds);
}
// TimeTicks ------------------------------------------------------------------
// static
TimeTicks TimeTicks::Now() {
return TimeTicks(ClockNow(CLOCK_MONOTONIC));
}
// static
bool TimeTicks::IsHighResolution() {
return true;
}
// static
ThreadTicks ThreadTicks::Now() {
#if (defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)) || \
defined(OS_ANDROID)
return ThreadTicks(ClockNow(CLOCK_THREAD_CPUTIME_ID));
#else
NOTREACHED();
return ThreadTicks();
#endif
}
#endif // !OS_MACOSX
// static
Time Time::FromTimeVal(struct timeval t) {
DCHECK_LT(t.tv_usec, static_cast<int>(Time::kMicrosecondsPerSecond));
DCHECK_GE(t.tv_usec, 0);
if (t.tv_usec == 0 && t.tv_sec == 0)
return Time();
if (t.tv_usec == static_cast<suseconds_t>(Time::kMicrosecondsPerSecond) - 1 &&
t.tv_sec == std::numeric_limits<time_t>::max())
return Max();
return Time((static_cast<int64_t>(t.tv_sec) * Time::kMicrosecondsPerSecond) +
t.tv_usec + kTimeTToMicrosecondsOffset);
}
struct timeval Time::ToTimeVal() const {
struct timeval result;
if (is_null()) {
result.tv_sec = 0;
result.tv_usec = 0;
return result;
}
if (is_max()) {
result.tv_sec = std::numeric_limits<time_t>::max();
result.tv_usec = static_cast<suseconds_t>(Time::kMicrosecondsPerSecond) - 1;
return result;
}
int64_t us = us_ - kTimeTToMicrosecondsOffset;
result.tv_sec = us / Time::kMicrosecondsPerSecond;
result.tv_usec = us % Time::kMicrosecondsPerSecond;
return result;
}
} // namespace base