TextTrackCueList* TextTrack::GetActiveCues() { if (mMode == TextTrackMode::Disabled || !mMediaElement) { return nullptr; } // If we are dirty, i.e. an event happened that may cause the sorted mCueList // to have changed like a seek or an insert for a cue, than we need to rebuild // the active cue list from scratch. if (mDirty) { mCuePos = 0; mDirty = true; mActiveCueList->RemoveAll(); } double playbackTime = mMediaElement->CurrentTime(); // Remove all the cues from the active cue list whose end times now occur // earlier then the current playback time. When we reach a cue whose end time // is valid we can safely stop iterating as the list is sorted. for (uint32_t i = 0; i < mActiveCueList->Length() && (*mActiveCueList)[i]->EndTime() < playbackTime; i++) { mActiveCueList->RemoveCueAt(i); } // Add all the cues, starting from the position of the last cue that was // added, that have valid start and end times for the current playback time. // We can stop iterating safely once we encounter a cue that does not have // valid times for the current playback time as the cue list is sorted. for (; mCuePos < mCueList->Length(); mCuePos++) { TextTrackCue* cue = (*mCueList)[mCuePos]; if (cue->StartTime() > playbackTime || cue->EndTime() < playbackTime) { break; } mActiveCueList->AddCue(*cue); } return mActiveCueList; }
// https://html.spec.whatwg.org/multipage/embedded-content.html#time-marches-on void TextTrackManager::TimeMarchesOn() { NS_ASSERTION(NS_IsMainThread(), "Wrong thread!"); WEBVTT_LOG("TimeMarchesOn"); mTimeMarchesOnDispatched = false; // Early return if we don't have any TextTracks or shutting down. if (!mTextTracks || mTextTracks->Length() == 0 || mShutdown) { return; } nsISupports* parentObject = mMediaElement->OwnerDoc()->GetParentObject(); if (NS_WARN_IF(!parentObject)) { return; } nsCOMPtr<nsPIDOMWindowInner> window = do_QueryInterface(parentObject); if (mMediaElement && (!(mMediaElement->GetPlayedOrSeeked()) || mMediaElement->Seeking())) { WEBVTT_LOG("TimeMarchesOn seeking or post return"); return; } // Step 3. double currentPlaybackTime = mMediaElement->CurrentTime(); bool hasNormalPlayback = !mHasSeeked; mHasSeeked = false; WEBVTT_LOG("TimeMarchesOn mLastTimeMarchesOnCalled %lf currentPlaybackTime %lf hasNormalPlayback %d" , mLastTimeMarchesOnCalled, currentPlaybackTime, hasNormalPlayback); // Step 1, 2. RefPtr<TextTrackCueList> currentCues = new TextTrackCueList(window); RefPtr<TextTrackCueList> otherCues = new TextTrackCueList(window); bool dummy; for (uint32_t index = 0; index < mTextTracks->Length(); ++index) { TextTrack* ttrack = mTextTracks->IndexedGetter(index, dummy); if (ttrack && dummy) { // TODO: call GetCueListByTimeInterval on mNewCues? ttrack->UpdateActiveCueList(); TextTrackCueList* activeCueList = ttrack->GetActiveCues(); if (activeCueList) { for (uint32_t i = 0; i < activeCueList->Length(); ++i) { currentCues->AddCue(*((*activeCueList)[i])); } } } } WEBVTT_LOGV("TimeMarchesOn currentCues %d", currentCues->Length()); // Populate otherCues with 'non-active" cues. if (hasNormalPlayback) { if (currentPlaybackTime < mLastTimeMarchesOnCalled) { // TODO: Add log and find the root cause why the // playback position goes backward. mLastTimeMarchesOnCalled = currentPlaybackTime; } media::Interval<double> interval(mLastTimeMarchesOnCalled, currentPlaybackTime); otherCues = mNewCues->GetCueListByTimeInterval(interval);; } else { // Seek case. Put the mLastActiveCues into otherCues. otherCues = mLastActiveCues; } for (uint32_t i = 0; i < currentCues->Length(); ++i) { TextTrackCue* cue = (*currentCues)[i]; otherCues->RemoveCue(*cue); } WEBVTT_LOGV("TimeMarchesOn otherCues %d", otherCues->Length()); // Step 4. RefPtr<TextTrackCueList> missedCues = new TextTrackCueList(window); if (hasNormalPlayback) { for (uint32_t i = 0; i < otherCues->Length(); ++i) { TextTrackCue* cue = (*otherCues)[i]; if (cue->StartTime() >= mLastTimeMarchesOnCalled && cue->EndTime() <= currentPlaybackTime) { missedCues->AddCue(*cue); } } } WEBVTT_LOGV("TimeMarchesOn missedCues %d", missedCues->Length()); // Step 5. Empty now. // TODO: Step 6: fire timeupdate? // Step 7. Abort steps if condition 1, 2, 3 are satisfied. // 1. All of the cues in current cues have their active flag set. // 2. None of the cues in other cues have their active flag set. // 3. Missed cues is empty. bool c1 = true; for (uint32_t i = 0; i < currentCues->Length(); ++i) { if (!(*currentCues)[i]->GetActive()) { c1 = false; break; } } bool c2 = true; for (uint32_t i = 0; i < otherCues->Length(); ++i) { if ((*otherCues)[i]->GetActive()) { c2 = false; break; } } bool c3 = (missedCues->Length() == 0); if (c1 && c2 && c3) { mLastTimeMarchesOnCalled = currentPlaybackTime; WEBVTT_LOG("TimeMarchesOn step 7 return, mLastTimeMarchesOnCalled %lf", mLastTimeMarchesOnCalled); return; } // Step 8. Respect PauseOnExit flag if not seek. if (hasNormalPlayback) { for (uint32_t i = 0; i < otherCues->Length(); ++i) { TextTrackCue* cue = (*otherCues)[i]; if (cue && cue->PauseOnExit() && cue->GetActive()) { WEBVTT_LOG("TimeMarchesOn pause the MediaElement"); mMediaElement->Pause(); break; } } for (uint32_t i = 0; i < missedCues->Length(); ++i) { TextTrackCue* cue = (*missedCues)[i]; if (cue && cue->PauseOnExit()) { WEBVTT_LOG("TimeMarchesOn pause the MediaElement"); mMediaElement->Pause(); break; } } } // Step 15. // Sort text tracks in the same order as the text tracks appear // in the media element's list of text tracks, and remove // duplicates. TextTrackListInternal affectedTracks; // Step 13, 14. nsTArray<RefPtr<SimpleTextTrackEvent>> eventList; // Step 9, 10. // For each text track cue in missed cues, prepare an event named // enter for the TextTrackCue object with the cue start time. for (uint32_t i = 0; i < missedCues->Length(); ++i) { TextTrackCue* cue = (*missedCues)[i]; if (cue) { SimpleTextTrackEvent* event = new SimpleTextTrackEvent(NS_LITERAL_STRING("enter"), cue->StartTime(), cue->GetTrack(), cue); eventList.InsertElementSorted(event, CompareSimpleTextTrackEvents(mMediaElement)); affectedTracks.AddTextTrack(cue->GetTrack(), CompareTextTracks(mMediaElement)); } } // Step 11, 17. for (uint32_t i = 0; i < otherCues->Length(); ++i) { TextTrackCue* cue = (*otherCues)[i]; if (cue->GetActive() || missedCues->IsCueExist(cue)) { double time = cue->StartTime() > cue->EndTime() ? cue->StartTime() : cue->EndTime(); SimpleTextTrackEvent* event = new SimpleTextTrackEvent(NS_LITERAL_STRING("exit"), time, cue->GetTrack(), cue); eventList.InsertElementSorted(event, CompareSimpleTextTrackEvents(mMediaElement)); affectedTracks.AddTextTrack(cue->GetTrack(), CompareTextTracks(mMediaElement)); } cue->SetActive(false); } // Step 12, 17. for (uint32_t i = 0; i < currentCues->Length(); ++i) { TextTrackCue* cue = (*currentCues)[i]; if (!cue->GetActive()) { SimpleTextTrackEvent* event = new SimpleTextTrackEvent(NS_LITERAL_STRING("enter"), cue->StartTime(), cue->GetTrack(), cue); eventList.InsertElementSorted(event, CompareSimpleTextTrackEvents(mMediaElement)); affectedTracks.AddTextTrack(cue->GetTrack(), CompareTextTracks(mMediaElement)); } cue->SetActive(true); } // Fire the eventList for (uint32_t i = 0; i < eventList.Length(); ++i) { NS_DispatchToMainThread(eventList[i].forget()); } // Step 16. for (uint32_t i = 0; i < affectedTracks.Length(); ++i) { TextTrack* ttrack = affectedTracks[i]; if (ttrack) { ttrack->DispatchAsyncTrustedEvent(NS_LITERAL_STRING("cuechange")); HTMLTrackElement* trackElement = ttrack->GetTrackElement(); if (trackElement) { trackElement->DispatchTrackRunnable(NS_LITERAL_STRING("cuechange")); } } } mLastTimeMarchesOnCalled = currentPlaybackTime; mLastActiveCues = currentCues; // Step 18. UpdateCueDisplay(); }