Fuchsia port of base/time, with some refactoring of POSIX time modules.

base/time/time_posix.cc

Index: base/time/time_posix.cc
diff --git a/base/time/time_posix.cc b/base/time/time_posix.cc
deleted file mode 100644
index c4138c3b487539a02d19880b72709fd4237f4cba..0000000000000000000000000000000000000000
--- a/base/time/time_posix.cc
+++ /dev/null
@@ -1,471 +0,0 @@
-// 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 "base/numerics/safe_math.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/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::Lock* GetSysTimeToTimeStructLock() {
-  static auto* lock = new base::Lock();
-  return lock;
-}
-
-// 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(*GetSysTimeToTimeStructLock());
-  if (is_local)
-    return mktime64(timestruct);
-  else
-    return timegm64(timestruct);
-}
-
-void SysTimeToTimeStruct(SysTime t, struct tm* timestruct, bool is_local) {
-  base::AutoLock locked(*GetSysTimeToTimeStructLock());
-  if (is_local)
-    localtime64_r(&t, timestruct);
-  else
-    gmtime64_r(&t, timestruct);
-}
-
-#elif defined(OS_AIX)
-
-// The function timegm is not available on AIX.
-time_t aix_timegm(struct tm* tm) {
-  time_t ret;
-  char* tz;
-
-  tz = getenv("TZ");
-  if (tz) {
-    tz = strdup(tz);
-  }
-  setenv("TZ", "GMT0", 1);
-  tzset();
-  ret = mktime(tm);
-  if (tz) {
-    setenv("TZ", tz, 1);
-    free(tz);
-  } else {
-    unsetenv("TZ");
-  }
-  tzset();
-  return ret;
-}
-
-typedef time_t SysTime;
-
-SysTime SysTimeFromTimeStruct(struct tm* timestruct, bool is_local) {
-  base::AutoLock locked(*GetSysTimeToTimeStructLock());
-  if (is_local)
-    return mktime(timestruct);
-  else
-    return aix_timegm(timestruct);
-}
-
-void SysTimeToTimeStruct(SysTime t, struct tm* timestruct, bool is_local) {
-  base::AutoLock locked(*GetSysTimeToTimeStructLock());
-  if (is_local)
-    localtime_r(&t, timestruct);
-  else
-    gmtime_r(&t, timestruct);
-}
-
-#else  // OS_ANDROID && !__LP64__
-typedef time_t SysTime;
-
-SysTime SysTimeFromTimeStruct(struct tm* timestruct, bool is_local) {
-  base::AutoLock locked(*GetSysTimeToTimeStructLock());
-  if (is_local)
-    return mktime(timestruct);
-  else
-    return timegm(timestruct);
-}
-
-void SysTimeToTimeStruct(SysTime t, struct tm* timestruct, bool is_local) {
-  base::AutoLock locked(*GetSysTimeToTimeStructLock());
-  if (is_local)
-    localtime_r(&t, timestruct);
-  else
-    gmtime_r(&t, timestruct);
-}
-#endif  // OS_ANDROID
-
-int64_t ConvertTimespecToMicros(const struct timespec& ts) {
-  // On 32-bit systems, the calculation cannot overflow int64_t.
-  // 2**32 * 1000000 + 2**64 / 1000 < 2**63
-  if (sizeof(ts.tv_sec) <= 4 && sizeof(ts.tv_nsec) <= 8) {
-    int64_t result = ts.tv_sec;
-    result *= base::Time::kMicrosecondsPerSecond;
-    result += (ts.tv_nsec / base::Time::kNanosecondsPerMicrosecond);
-    return result;
-  } else {
-    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 {
-
-// static
-TimeDelta TimeDelta::FromTimeSpec(const timespec& ts) {
-  return TimeDelta(ts.tv_sec * Time::kMicrosecondsPerSecond +
-                   ts.tv_nsec / Time::kNanosecondsPerMicrosecond);
-}
-
-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, &timestruct, 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
-bool Time::FromExploded(bool is_local, const Exploded& exploded, Time* time) {
-  CheckedNumeric<int> month = exploded.month;
-  month--;
-  CheckedNumeric<int> year = exploded.year;
-  year -= 1900;
-  if (!month.IsValid() || !year.IsValid()) {
-    *time = Time(0);
-    return false;
-  }
-
-  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 = month.ValueOrDie();
-  timestruct.tm_year = year.ValueOrDie();
-  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) && !defined(OS_AIX)
-  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
-
-  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(&timestruct, 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(&timestruct, is_local);
-
-    timestruct = timestruct0;
-    timestruct.tm_isdst = 1;
-    int64_t seconds_isdst1 = SysTimeFromTimeStruct(&timestruct, 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.
-  int64_t milliseconds = 0;
-  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 {
-    base::CheckedNumeric<int64_t> checked_millis = seconds;
-    checked_millis *= kMillisecondsPerSecond;
-    checked_millis += exploded.millisecond;
-    if (!checked_millis.IsValid()) {
-      *time = base::Time(0);
-      return false;
-    }
-    milliseconds = checked_millis.ValueOrDie();
-  }
-
-  // Adjust from Unix (1970) to Windows (1601) epoch avoiding overflows.
-  base::CheckedNumeric<int64_t> checked_microseconds_win_epoch = milliseconds;
-  checked_microseconds_win_epoch *= kMicrosecondsPerMillisecond;
-  checked_microseconds_win_epoch += kWindowsEpochDeltaMicroseconds;
-  if (!checked_microseconds_win_epoch.IsValid()) {
-    *time = base::Time(0);
-    return false;
-  }
-  base::Time converted_time(checked_microseconds_win_epoch.ValueOrDie());
-
-  // If |exploded.day_of_month| is set to 31 on a 28-30 day month, it will
-  // return the first day of the next month. Thus round-trip the time and
-  // compare the initial |exploded| with |utc_to_exploded| time.
-  base::Time::Exploded to_exploded;
-  if (!is_local)
-    converted_time.UTCExplode(&to_exploded);
-  else
-    converted_time.LocalExplode(&to_exploded);
-
-  if (ExplodedMostlyEquals(to_exploded, exploded)) {
-    *time = converted_time;
-    return true;
-  }
-
-  *time = Time(0);
-  return false;
-}
-
-// TimeTicks ------------------------------------------------------------------
-// static
-TimeTicks TimeTicks::Now() {
-  return TimeTicks(ClockNow(CLOCK_MONOTONIC));
-}
-
-// static
-TimeTicks::Clock TimeTicks::GetClock() {
-  return Clock::LINUX_CLOCK_MONOTONIC;
-}
-
-// static
-bool TimeTicks::IsHighResolution() {
-  return true;
-}
-
-// static
-bool TimeTicks::IsConsistentAcrossProcesses() {
-  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