Fix media timeline so that thumb never exceeds buffered data

media/base/clock.cc

 // 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 "media/base/clock.h"
 
 #include "base/logging.h"
 #include "media/base/buffers.h"
 
 namespace media {
@@ skipping 27 matching lines @@
 
 void Clock::SetPlaybackRate(float playback_rate) {
   if (playing_) {
     base::Time time = GetTimeFromProvider();
     media_time_ = ElapsedViaProvidedTime(time);
     reference_ = time;
   }
   playback_rate_ = playback_rate;
 }
 
-void Clock::SetTime(const base::TimeDelta& time) {
-  if (time == kNoTimestamp) {
+void Clock::SetTime(base::TimeDelta current_time, base::TimeDelta max_time) {
+  DCHECK_LE(current_time.ToInternalValue(), max_time.ToInternalValue());

[acolwell GONE FROM CHROMIUM, 2012/01/13 22:51:21]

How about DCHECK(current_time <= max_time)? The ToInternalValue() feels ugly.

[vrk (LEFT CHROMIUM), 2012/01/21 00:54:14]

Done.

+  if (current_time == kNoTimestamp) {
     NOTREACHED();
     return;
   }
   if (playing_) {
     reference_ = GetTimeFromProvider();
   }
-  media_time_ = time;
+  media_time_ = current_time;
+  max_time_ = max_time;
 }
 
 base::TimeDelta Clock::Elapsed() const {
-  if (!playing_) {
-    return media_time_;
-  }
-  return ElapsedViaProvidedTime(GetTimeFromProvider());
+  base::TimeDelta elapsed =
+      playing_ ? ElapsedViaProvidedTime(GetTimeFromProvider()) : media_time_;
+
+  if (max_time_.ToInternalValue() > 0)

[acolwell GONE FROM CHROMIUM, 2012/01/13 22:51:21]

How about using != kNoTimestamp instead of > 0?

[vrk (LEFT CHROMIUM), 2012/01/21 00:54:14]

Done.

+    elapsed = std::min(elapsed, max_time_);
+
+  if (duration_.ToInternalValue() > 0 && elapsed > duration_)

[acolwell GONE FROM CHROMIUM, 2012/01/13 22:51:21]

How about using != kNoTimestamp instead of > 0?

[vrk (LEFT CHROMIUM), 2012/01/21 00:54:14]

Actually, I modified logic of this method to return 0 when duration is not set
(to match the preexisting behavior).

+    return duration_;
+
+  return elapsed;
 }
 
 base::TimeDelta Clock::ElapsedViaProvidedTime(const base::Time& time) const {
   // TODO(scherkus): floating point badness scaling time by playback rate.
   int64 now_us = (time - reference_).InMicroseconds();
   now_us = static_cast<int64>(now_us * playback_rate_);
   return media_time_ + base::TimeDelta::FromMicroseconds(now_us);
 }
 
 base::Time Clock::GetTimeFromProvider() const {
   if (time_provider_) {
     return time_provider_();
   }
   return base::Time();
 }
 
 }  // namespace media