Adding the ability to use a simulated clock for unit tests.

webrtc/base/timeutils.cc

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 14 matching lines @@
 #include <mmsystem.h>
 #endif
 
 #include "webrtc/base/checks.h"
 #include "webrtc/base/timeutils.h"
 
 namespace rtc {
 
 const uint32_t HALF = 0x80000000;
 
+ClockInterface* clock_ = nullptr;
+
+void SetClock(ClockInterface* clock) {
+  clock_ = clock;
+}
+
 uint64_t TimeNanos() {
+  if (clock_) {

[juberti2, 2016/04/25 20:18:23]

Do we need to mention that this is unsynchronized?

[Taylor Brandstetter, 2016/04/26 01:22:32]

I mention in timeutils.h that SetClock (which is the only thing that modifies
clock_) isn't thread-safe.

+    return clock_->TimeNanos();
+  }
   int64_t ticks = 0;
 #if defined(WEBRTC_MAC)

[juberti2, 2016/04/25 20:18:23]

Should we factor this into a real clock implementation?

[Taylor Brandstetter, 2016/04/26 01:22:32]

Done.

   static mach_timebase_info_data_t timebase;
   if (timebase.denom == 0) {
     // Get the timebase if this is the first time we run.
     // Recommended by Apple's QA1398.
     if (mach_timebase_info(&timebase) != KERN_SUCCESS) {
       RTC_DCHECK(false);
     }
   }
   // Use timebase to convert absolute time tick units into nanoseconds.
   ticks = mach_absolute_time() * timebase.numer / timebase.denom;
@@ skipping 126 matching lines @@
   if (expiry_in_leap_year && month <= 2 - 1) // |month| is zero based.
     day -= 1;
 
   // Combine all variables into seconds from 1970-01-01 00:00 (except |month|
   // which was accumulated into |day| above).
   return (((static_cast<int64_t>
             (year - 1970) * 365 + day) * 24 + hour) * 60 + min) * 60 + sec;
 }
 
 } // namespace rtc