Use base/time/time_posix.cc on OS X and iOS.

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
index 4aadee618a0fb3a452edf945ab4b7e9fc3ac8a14..caa7ea9927a3cd65984529181d60be0bb0ffe80c 100644
--- a/base/time/time_posix.cc
+++ b/base/time/time_posix.cc
@@ -15,23 +15,25 @@
 #include <limits>
 #include <ostream>
 
+#include "base/lazy_instance.h"
 #include "base/logging.h"
+#include "base/synchronization/lock.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"
+#elif defined(OS_MACOSX)
+#include <mach/mach.h>
+#include <mach/mach_time.h>
+#include <sys/sysctl.h>
+#include "base/mac/mach_logging.h"
+#include "base/mac/scoped_mach_port.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
@@ -79,6 +81,7 @@ void SysTimeToTimeStruct(SysTime t, struct tm* timestruct, bool is_local) {
 }
 #endif  // OS_ANDROID
 
+#if !defined(OS_MACOSX)
 int64_t ConvertTimespecToMicros(const struct timespec& ts) {
   base::CheckedNumeric<int64_t> result(ts.tv_sec);
   result *= base::Time::kMicrosecondsPerSecond;
@@ -104,7 +107,89 @@ int64_t ClockNow(clockid_t clk_id) {
 #else  // _POSIX_MONOTONIC_CLOCK
 #error No usable tick clock function on this platform.
 #endif  // _POSIX_MONOTONIC_CLOCK
-#endif  // !defined(OS_MACOSX)
+#endif
+
+int64_t ComputeCurrentTicks() {
+#if defined(OS_IOS)
+  // On iOS mach_absolute_time stops while the device is sleeping. Instead use
+  // now - KERN_BOOTTIME to get a time difference that is not impacted by clock
+  // changes. KERN_BOOTTIME will be updated by the system whenever the system
+  // clock change.
+  struct timeval boottime;
+  int mib[2] = {CTL_KERN, KERN_BOOTTIME};
+  size_t size = sizeof(boottime);
+  int kr = sysctl(mib, arraysize(mib), &boottime, &size, NULL, 0);
+  DCHECK_EQ(KERN_SUCCESS, kr);
+  base::TimeDelta time_difference = base::Time::Now() -
+      (base::Time::FromTimeT(boottime.tv_sec) +
+       base::TimeDelta::FromMicroseconds(boottime.tv_usec));
+  return time_difference.InMicroseconds();
+#elif defined(OS_MACOSX)
+  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);
+    MACH_DCHECK(kr == KERN_SUCCESS, kr) << "mach_timebase_info";
+  }
+
+  // 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.
+  base::CheckedNumeric<uint64_t> result(
+      mach_absolute_time() / base::Time::kNanosecondsPerMicrosecond);
+  result *= timebase_info.numer;
+  result /= 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 base::checked_cast<int64_t>(result.ValueOrDie());
+#else
+  return ClockNow(CLOCK_MONOTONIC);
+#endif
+}
+
+int64_t ComputeThreadTicks() {
+#if defined(OS_IOS)
+  NOTREACHED();
+  return 0;
+#elif defined(OS_MACOSX)
+  base::mac::ScopedMachSendRight thread(mach_thread_self());
+  mach_msg_type_number_t thread_info_count = THREAD_BASIC_INFO_COUNT;
+  thread_basic_info_data_t thread_info_data;
+
+  if (thread.get() == MACH_PORT_NULL) {
+    DLOG(ERROR) << "Failed to get mach_thread_self()";
+    return 0;
+  }
+
+  kern_return_t kr = thread_info(
+      thread.get(),
+      THREAD_BASIC_INFO,
+      reinterpret_cast<thread_info_t>(&thread_info_data),
+      &thread_info_count);
+  MACH_DCHECK(kr == KERN_SUCCESS, kr) << "thread_info";
+
+  base::CheckedNumeric<int64_t> absolute_micros(
+      thread_info_data.user_time.seconds);
+  absolute_micros *= base::Time::kMicrosecondsPerSecond;
+  absolute_micros += thread_info_data.user_time.microseconds;
+  return absolute_micros.ValueOrDie();
+#elif (defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)) || \
+    defined(OS_ANDROID)
+  return ThreadTicks(ClockNow(CLOCK_THREAD_CPUTIME_ID));
+#else
+  NOTREACHED();
+  return 0;
+#endif
+}
 
 }  // namespace
 
@@ -123,7 +208,6 @@ struct timespec TimeDelta::ToTimeSpec() const {
   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.
@@ -308,7 +392,7 @@ Time Time::FromExploded(bool is_local, const Exploded& exploded) {
 // TimeTicks ------------------------------------------------------------------
 // static
 TimeTicks TimeTicks::Now() {
-  return TimeTicks(ClockNow(CLOCK_MONOTONIC));
+  return TimeTicks(ComputeCurrentTicks());
 }
 
 // static
@@ -318,17 +402,9 @@ bool TimeTicks::IsHighResolution() {
 
 // 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
+  return ThreadTicks(ComputeThreadTicks());
 }
 
-#endif  // !OS_MACOSX
-
 // static
 Time Time::FromTimeVal(struct timeval t) {
   DCHECK_LT(t.tv_usec, static_cast<int>(Time::kMicrosecondsPerSecond));
@@ -360,4 +436,30 @@ struct timeval Time::ToTimeVal() const {
   return result;
 }
 
+#if defined(OS_MACOSX)
+// static
+Time Time::FromCFAbsoluteTime(CFAbsoluteTime t) {
+  static_assert(std::numeric_limits<CFAbsoluteTime>::has_infinity,
+                "CFAbsoluteTime must have an infinity value");
+  if (t == 0)
+    return Time();  // Consider 0 as a null Time.
+  if (t == std::numeric_limits<CFAbsoluteTime>::infinity())
+    return Max();
+  return Time(static_cast<int64_t>((t + kCFAbsoluteTimeIntervalSince1970) *
+                                   kMicrosecondsPerSecond) +
+              kWindowsEpochDeltaMicroseconds);
+}
+
+CFAbsoluteTime Time::ToCFAbsoluteTime() const {
+  static_assert(std::numeric_limits<CFAbsoluteTime>::has_infinity,
+                "CFAbsoluteTime must have an infinity value");
+  if (is_null())
+    return 0;  // Consider 0 as a null Time.
+  if (is_max())
+    return std::numeric_limits<CFAbsoluteTime>::infinity();
+  return (static_cast<CFAbsoluteTime>(us_ - kWindowsEpochDeltaMicroseconds) /
+      kMicrosecondsPerSecond) - kCFAbsoluteTimeIntervalSince1970;
+}
+#endif  // OS_MACOSX
+
 }  // namespace base