Update Mac implemention of Time to prevent problems with
times later than the UNIX epoch 32 bit rollover in 2038 (such as
cookie expirations). time_t is only 32 bits in MacOS X, so
we can't just use time_posix.cc
Review URL: http://codereview.chromium.org/9249
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@4473 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/base/time_mac.cc b/base/time_mac.cc
new file mode 100644
index 0000000..d71825c
--- /dev/null
+++ b/base/time_mac.cc
@@ -0,0 +1,121 @@
+// Copyright (c) 2008 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.h"
+
+#include <CoreFoundation/CFDate.h>
+#include <CoreFoundation/CFTimeZone.h>
+#include <mach/mach_time.h>
+#include <sys/time.h>
+#include <time.h>
+
+#include "base/basictypes.h"
+#include "base/logging.h"
+#include "base/scoped_cftyperef.h"
+
+namespace base {
+
+// The Time routines in this file use Mach and CoreFoundation APIs, since the
+// POSIX definition of time_t in Mac OS X wraps around after 2038--and
+// there are already cookie expiration dates, etc., past that time out in
+// the field. Using CFDate prevents that problem, and using mach_absolute_time
+// for TimeTicks gives us nice high-resolution interval timing.
+
+// Time -----------------------------------------------------------------------
+
+// The internal representation of Time uses a 64-bit microsecond count
+// from 1970-01-01 00:00:00 UTC. Core Foundation uses a double second count
+// since 2001-01-01 00:00:00 UTC.
+
+// Some functions in time.c use time_t directly, so we provide a zero offset
+// for them. The epoch is 1970-01-01 00:00:00 UTC.
+// static
+const int64 Time::kTimeTToMicrosecondsOffset = GG_INT64_C(0);
+
+// static
+Time Time::Now() {
+ CFAbsoluteTime now =
+ CFAbsoluteTimeGetCurrent() + kCFAbsoluteTimeIntervalSince1970;
+ return Time(static_cast<int64>(now * kMicrosecondsPerSecond));
+}
+
+// static
+Time Time::FromExploded(bool is_local, const Exploded& exploded) {
+ CFGregorianDate date;
+ date.second = exploded.second +
+ exploded.millisecond / static_cast<double>(kMillisecondsPerSecond);
+ date.minute = exploded.minute;
+ date.hour = exploded.hour;
+ date.day = exploded.day_of_month;
+ date.month = exploded.month;
+ date.year = exploded.year;
+
+ scoped_cftyperef<CFTimeZoneRef> time_zone;
+ if (is_local)
+ time_zone.reset(CFTimeZoneCopySystem());
+ CFAbsoluteTime seconds = CFGregorianDateGetAbsoluteTime(date, time_zone) +
+ kCFAbsoluteTimeIntervalSince1970;
+ return Time(static_cast<int64>(seconds * kMicrosecondsPerSecond));
+}
+
+void Time::Explode(bool is_local, Exploded* exploded) const {
+ CFAbsoluteTime seconds =
+ (static_cast<double>(us_) / kMicrosecondsPerSecond) -
+ kCFAbsoluteTimeIntervalSince1970;
+
+ scoped_cftyperef<CFTimeZoneRef> time_zone;
+ if (is_local)
+ time_zone.reset(CFTimeZoneCopySystem());
+ CFGregorianDate date = CFAbsoluteTimeGetGregorianDate(seconds, time_zone);
+
+ exploded->year = date.year;
+ exploded->month = date.month;
+ exploded->day_of_month = date.day;
+ exploded->hour = date.hour;
+ exploded->minute = date.minute;
+ exploded->second = date.second;
+ exploded->millisecond =
+ static_cast<int>(date.second * kMillisecondsPerSecond) %
+ kMillisecondsPerSecond;
+}
+
+// TimeTicks ------------------------------------------------------------------
+
+// static
+TimeTicks TimeTicks::Now() {
+ uint64_t absolute_micro;
+
+ static mach_timebase_info_data_t timebase_info;
+ if (timebase_info.denom == 0) {
+ // Zero-initialization of statics guarantees that denom will be 0 before
+ // calling mach_timebase_info. mach_timebase_info will never set denom to
+ // 0 as that would be invalid, so the zero-check can be used to determine
+ // whether mach_timebase_info has already been called. This is
+ // recommended by Apple's QA1398.
+ kern_return_t kr = mach_timebase_info(&timebase_info);
+ DCHECK(kr == KERN_SUCCESS);
+ }
+
+ // mach_absolute_time is it when it comes to ticks on the Mac. Other calls
+ // with less precision (such as TickCount) just call through to
+ // mach_absolute_time.
+
+ // timebase_info converts absolute time tick units into nanoseconds. Convert
+ // to microseconds up front to stave off overflows.
+ absolute_micro = mach_absolute_time() / Time::kNanosecondsPerMicrosecond *
+ timebase_info.numer / timebase_info.denom;
+
+ // Don't bother with the rollover handling that the Windows version does.
+ // With numer and denom = 1 (the expected case), the 64-bit absolute time
+ // reported in nanoseconds is enough to last nearly 585 years.
+
+ return TimeTicks(absolute_micro);
+}
+
+// static
+TimeTicks TimeTicks::HighResNow() {
+ return Now();
+}
+
+} // namespace base
