Allow HTMLMediaElement.currentTime to be set before the transition to HAVE_METADATA

Source/core/html/HTMLMediaElement.cpp

 /*
  * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 306 matching lines @@
     , m_defaultPlaybackRate(1.0f)
     , m_networkState(NETWORK_EMPTY)
     , m_readyState(HAVE_NOTHING)
     , m_readyStateMaximum(HAVE_NOTHING)
     , m_volume(1.0f)
     , m_lastSeekTime(0)
     , m_previousProgressTime(std::numeric_limits<double>::max())
     , m_duration(std::numeric_limits<double>::quiet_NaN())
     , m_lastTimeUpdateEventWallTime(0)
     , m_lastTimeUpdateEventMovieTime(std::numeric_limits<double>::max())
+    , m_defaultPlaybackStartPosition(0)
     , m_loadState(WaitingForSource)
     , m_deferredLoadState(NotDeferred)
     , m_deferredLoadTimer(this, &HTMLMediaElement::deferredLoadTimerFired)
     , m_webLayer(0)
     , m_preload(MediaPlayer::Auto)
     , m_displayMode(Unknown)
     , m_cachedTime(MediaPlayer::invalidTime())
     , m_fragmentStartTime(MediaPlayer::invalidTime())
     , m_fragmentEndTime(MediaPlayer::invalidTime())
     , m_pendingActionFlags(0)
@@ skipping 1473 matching lines @@
         prepareMediaFragmentURI();
 
         selectInitialTracksIfNecessary();
 
         m_duration = duration();
         scheduleEvent(EventTypeNames::durationchange);
 
         if (isHTMLVideoElement())
             scheduleEvent(EventTypeNames::resize);
         scheduleEvent(EventTypeNames::loadedmetadata);
+
+        if (m_defaultPlaybackStartPosition > 0) {
+            seek(m_defaultPlaybackStartPosition);
+            m_defaultPlaybackStartPosition = 0;

[philipj_slow, 2014/09/10 09:57:05]

Either move this out of the if clause, like the spec does, or
ASSERT(m_defaultPlaybackStartPosition == 0) afterwards, so that it's clear that
it can't be a negative number, NaN or anything like that afterwards.

[amogh.bihani, 2014/09/10 11:18:33]

Done.

+        }
+
         if (hasMediaControls())
             mediaControls()->reset();
         if (renderer())
             renderer()->updateFromElement();
     }
 
     bool shouldUpdateDisplayState = false;
 
     if (m_readyState >= HAVE_CURRENT_DATA && oldState < HAVE_CURRENT_DATA && !m_haveFiredLoadedData) {
         m_haveFiredLoadedData = true;
@@ skipping 80 matching lines @@
 {
     WTF_LOG(Media, "HTMLMediaElement::prepareToPlay(%p)", this);
     if (m_havePreparedToPlay)
         return;
     m_havePreparedToPlay = true;
 
     if (loadIsDeferred())
         startDeferredLoad();
 }
 
-void HTMLMediaElement::seek(double time, ExceptionState& exceptionState)
+void HTMLMediaElement::seek(double time)
 {
     WTF_LOG(Media, "HTMLMediaElement::seek(%p, %f)", this, time);
 
-    // 4.8.10.9 Seeking
+    // 4.7.14.9 Seeking

[philipj_slow, 2014/09/10 09:57:05]

Now it's "4.8.14.9 Seeking" in the spec. The section numbers change often, so I
think you can just remove this comment and the one in finishSeek().

[amogh.bihani, 2014/09/10 11:18:33]

Done.

 
-    // 1 - If the media element's readyState is HAVE_NOTHING, then raise an InvalidStateError exception.
-    if (m_readyState == HAVE_NOTHING) {
-        exceptionState.throwDOMException(InvalidStateError, "The element's readyState is HAVE_NOTHING.");
+    // 2 - If the media element's readyState is HAVE_NOTHING, abort these steps.
+    if (m_readyState == HAVE_NOTHING)
         return;
-    }
 
     // If the media engine has been told to postpone loading data, let it go ahead now.
     if (m_preload < MediaPlayer::Auto && m_readyState < HAVE_FUTURE_DATA)
         prepareToPlay();
 
     // Get the current time before setting m_seeking, m_lastSeekTime is returned once it is set.
     refreshCachedTime();
-    double now = currentTime();
+    // This is needed to avoid getting default playback start position from currentTime().
+    double now = m_cachedTime;
 
-    // 2 - If the element's seeking IDL attribute is true, then another instance of this algorithm is
+    // 3 - If the element's seeking IDL attribute is true, then another instance of this algorithm is
     // already running. Abort that other instance of the algorithm without waiting for the step that
     // it is running to complete.
     // Nothing specific to be done here.
 
-    // 3 - Set the seeking IDL attribute to true.
+    // 4 - Set the seeking IDL attribute to true.
     // The flag will be cleared when the engine tells us the time has actually changed.
     bool previousSeekStillPending = m_seeking;
     m_seeking = true;
 
-    // 5 - If the new playback position is later than the end of the media resource, then let it be the end
+    // 6 - If the new playback position is later than the end of the media resource, then let it be the end
     // of the media resource instead.
     time = std::min(time, duration());
 
-    // 6 - If the new playback position is less than the earliest possible position, let it be that position instead.
+    // 7 - If the new playback position is less than the earliest possible position, let it be that position instead.
     time = std::max(time, 0.0);
 
     // Ask the media engine for the time value in the movie's time scale before comparing with current time. This
     // is necessary because if the seek time is not equal to currentTime but the delta is less than the movie's
     // time scale, we will ask the media engine to "seek" to the current movie time, which may be a noop and
     // not generate a timechanged callback. This means m_seeking will never be cleared and we will never
     // fire a 'seeked' event.
     double mediaTime = webMediaPlayer()->mediaTimeForTimeValue(time);
     if (time != mediaTime) {
         WTF_LOG(Media, "HTMLMediaElement::seek(%p, %f) - media timeline equivalent is %f", this, time, mediaTime);
         time = mediaTime;
     }
 
-    // 7 - If the (possibly now changed) new playback position is not in one of the ranges given in the
+    // 8 - If the (possibly now changed) new playback position is not in one of the ranges given in the
     // seekable attribute, then let it be the position in one of the ranges given in the seekable attribute
     // that is the nearest to the new playback position. ... If there are no ranges given in the seekable
     // attribute then set the seeking IDL attribute to false and abort these steps.
     RefPtrWillBeRawPtr<TimeRanges> seekableRanges = seekable();
 
     // Short circuit seeking to the current time by just firing the events if no seek is required.
     // Don't skip calling the media engine if we are in poster mode because a seek should always
     // cancel poster display.
     bool noSeekRequired = !seekableRanges->length() || (time == now && displayMode() != Poster);
 
@@ skipping 12 matching lines @@
     }
     time = seekableRanges->nearest(time);
 
     if (m_playing) {
         if (m_lastSeekTime < now)
             addPlayedRange(m_lastSeekTime, now);
     }
     m_lastSeekTime = time;
     m_sentEndEvent = false;
 
-    // 8 - Queue a task to fire a simple event named seeking at the element.
+    // 10 - Queue a task to fire a simple event named seeking at the element.
     scheduleEvent(EventTypeNames::seeking);
 
-    // 9 - Set the current playback position to the given new playback position
+    // 11 - Set the current playback position to the given new playback position

[philipj_slow, 2014/09/10 09:57:06]

Can you add the missing period here?

[amogh.bihani, 2014/09/10 11:18:33]

Done.

     webMediaPlayer()->seek(time);
 
-    // 10-14 are handled, if necessary, when the engine signals a readystate change or otherwise
+    // 12-17 are handled, if necessary, when the engine signals a readystate change or otherwise

[philipj_slow, 2014/09/10 09:57:06]

It's step 14-17 that's handled in finishSeek(). Can you update the numbering
there as well?

[amogh.bihani, 2014/09/10 11:18:33]

Done.

     // satisfies seek completion and signals a time change.
 }
 
 void HTMLMediaElement::finishSeek()
 {
     WTF_LOG(Media, "HTMLMediaElement::finishSeek(%p)", this);
 
     // 4.8.10.9 Seeking completion
     // 12 - Set the seeking IDL attribute to false.
     m_seeking = false;
@@ skipping 32 matching lines @@
 
 void HTMLMediaElement::invalidateCachedTime()
 {
     WTF_LOG(Media, "HTMLMediaElement::invalidateCachedTime(%p)", this);
     m_cachedTime = MediaPlayer::invalidTime();
 }
 
 // playback state
 double HTMLMediaElement::currentTime() const
 {
+    if (m_defaultPlaybackStartPosition)
+        return m_defaultPlaybackStartPosition;
+
     if (m_readyState == HAVE_NOTHING)
         return 0;
 
     if (m_seeking) {
         WTF_LOG(Media, "HTMLMediaElement::currentTime(%p) - seeking, returning %f", this, m_lastSeekTime);
         return m_lastSeekTime;
     }
 
     if (m_cachedTime != MediaPlayer::invalidTime() && m_paused) {
 #if LOG_CACHED_TIME_WARNINGS
         static const double minCachedDeltaForWarning = 0.01;
         double delta = m_cachedTime - webMediaPlayer()->currentTime();
         if (delta > minCachedDeltaForWarning)
             WTF_LOG(Media, "HTMLMediaElement::currentTime(%p) - WARNING, cached time is %f seconds off of media time when paused", this, delta);
 #endif
         return m_cachedTime;
     }
 
     refreshCachedTime();
 
     return m_cachedTime;
 }
 
 void HTMLMediaElement::setCurrentTime(double time, ExceptionState& exceptionState)
 {
     if (m_mediaController) {
         exceptionState.throwDOMException(InvalidStateError, "The element is slaved to a MediaController.");
         return;
     }
-    seek(time, exceptionState);
+
+    // If the media element's readyState is HAVE_NOTHING, then set the default
+    // playback start position to that time.
+    if (m_readyState == HAVE_NOTHING) {
+        m_defaultPlaybackStartPosition = time;
+        return;
+    }
+
+    seek(time);
 }
 
 double HTMLMediaElement::duration() const
 {
     // FIXME: remove m_player check once we figure out how m_player is going
     // out of sync with readystate. m_player is cleared but readystate is not set
     // to HAVE_NOTHING
     if (!m_player || m_readyState < HAVE_METADATA)
         return std::numeric_limits<double>::quiet_NaN();
 
@@ skipping 118 matching lines @@
 
 void HTMLMediaElement::playInternal()
 {
     WTF_LOG(Media, "HTMLMediaElement::playInternal(%p)", this);
 
     // 4.8.10.9. Playing the media resource
     if (!m_player || m_networkState == NETWORK_EMPTY)
         scheduleDelayedAction(LoadMediaResource);
 
     if (endedPlayback())
-        seek(0, IGNORE_EXCEPTION);
+        seek(0);
 
     if (m_mediaController)
         m_mediaController->bringElementUpToSpeed(this);
 
     if (m_paused) {
         m_paused = false;
         invalidateCachedTime();
         scheduleEvent(EventTypeNames::play);
 
         if (m_readyState <= HAVE_CURRENT_DATA)
@@ skipping 837 matching lines @@
     double now = currentTime();
     double dur = duration();
 
     // When the current playback position reaches the end of the media resource when the direction of
     // playback is forwards, then the user agent must follow these steps:
     if (!std::isnan(dur) && dur && now >= dur && directionOfPlayback() == Forward) {
         // If the media element has a loop attribute specified and does not have a current media controller,
         if (loop() && !m_mediaController) {
             m_sentEndEvent = false;
             //  then seek to the earliest possible position of the media resource and abort these steps.
-            seek(0, IGNORE_EXCEPTION);
+            seek(0);
         } else {
             // If the media element does not have a current media controller, and the media element
             // has still ended playback, and the direction of playback is still forwards, and paused
             // is false,
             if (!m_mediaController && !m_paused) {
                 // changes paused to true and fires a simple event named pause at the media element.
                 m_paused = true;
                 scheduleEvent(EventTypeNames::pause);
             }
             // Queue a task to fire a simple event named ended at the media element.
@@ skipping 33 matching lines @@
     WTF_LOG(Media, "HTMLMediaElement::durationChanged(%p) : %f -> %f", this, m_duration, duration);
     m_duration = duration;
     scheduleEvent(EventTypeNames::durationchange);
 
     if (hasMediaControls())
         mediaControls()->reset();
     if (renderer())
         renderer()->updateFromElement();
 
     if (requestSeek)
-        seek(duration, IGNORE_EXCEPTION);
+        seek(duration);
 }
 
 void HTMLMediaElement::mediaPlayerPlaybackStateChanged()
 {
     WTF_LOG(Media, "HTMLMediaElement::mediaPlayerPlaybackStateChanged(%p)", this);
 
     if (!m_player || m_pausedInternal)
         return;
 
     if (webMediaPlayer()->paused())
@@ skipping 10 matching lines @@
     // user interaction or when it is technically required to play the video.
     UserGestureIndicator gestureIndicator(DefinitelyProcessingNewUserGesture);
 
     enterFullscreen();
 }
 
 void HTMLMediaElement::mediaPlayerRequestSeek(double time)
 {
     // The player is the source of this seek request.
     if (m_mediaController) {
-        m_mediaController->setCurrentTime(time, IGNORE_EXCEPTION);
+        m_mediaController->setCurrentTime(time);
         return;
     }
-    setCurrentTime(time, IGNORE_EXCEPTION);
+    setCurrentTime(time, ASSERT_NO_EXCEPTION);
 }
 
 // MediaPlayerPresentation methods
 void HTMLMediaElement::mediaPlayerRepaint()
 {
     if (m_webLayer)
         m_webLayer->invalidate();
 
     updateDisplayState();
     if (renderer())
@@ skipping 678 matching lines @@
 
     if (m_fragmentStartTime != MediaPlayer::invalidTime() && m_readyState < HAVE_FUTURE_DATA)
         prepareToPlay();
 }
 
 void HTMLMediaElement::applyMediaFragmentURI()
 {
     if (m_fragmentStartTime != MediaPlayer::invalidTime()) {
         m_sentEndEvent = false;
         UseCounter::count(document(), UseCounter::HTMLMediaElementSeekToFragmentStart);
-        seek(m_fragmentStartTime, IGNORE_EXCEPTION);
+        seek(m_fragmentStartTime);
     }
 }
 
 WebMediaPlayer::CORSMode HTMLMediaElement::corsMode() const
 {
     const AtomicString& crossOriginMode = fastGetAttribute(crossoriginAttr);
     if (crossOriginMode.isNull())
         return WebMediaPlayer::CORSModeUnspecified;
     if (equalIgnoringCase(crossOriginMode, "use-credentials"))
         return WebMediaPlayer::CORSModeUseCredentials;
@@ skipping 86 matching lines @@
 
 #if ENABLE(WEB_AUDIO)
 void HTMLMediaElement::clearWeakMembers(Visitor* visitor)
 {
     if (!visitor->isAlive(m_audioSourceNode) && audioSourceProvider())
         audioSourceProvider()->setClient(0);
 }
 #endif
 
 }