Method updateCacheQueue

YUViewLib/src/video/VideoCache.cpp:518–956

}

void VideoCache::updateCacheQueue()
{
  if (!cachingEnabled)
    return; // Caching disabled

  // Now calculate the new list of frames to cache and run the cacher
  DEBUG_CACHING("VideoCache::updateCacheQueue");

  // Firstly clear the old cache queues
  cacheQueue.clear();
  cacheDeQueue.clear();

  // Get all items from the playlist. There are two lists. For the caching status (how full is the
  // cache) we have to consider all items in the playlist. However, we only cache top level items
  // and no child items.
  QList<playlistItem *> allItems    = playlist->getAllPlaylistItems();
  QList<playlistItem *> allItemsTop = playlist->getAllPlaylistItems(true);

  if (allItemsTop.count() == 0)
    // No cachable items in the playlist.
    return;

  const bool play = playback->playing();
  DEBUG_CACHING("VideoCache::updateCacheQueue Playback is %srunning", play ? "" : "not ");

  // Our caching priority list is like this:
  // 1: Cache all the frames in the item that is currently selected. In order to achieve this, we
  // will aggressively
  //    delete other frames from other sequences in the cache. This has highest priority.
  // 2: Cache all the frames from the following items (while there is space left in the cache). If
  // case of playback
  //    we will remove all frames from items that were already played back (are before the current
  //    item in the playlist). If playback is not running, we will not remove any frames from other
  //    items from the cache to achieve this.
  //
  // When frames have to be removed to fit the selected sequence into the cache, the following
  // priorities apply to frames from other sequences. (The ones with highest priority get removed
  // last). This priority list differs depending if playback is currently running or not.
  //
  // Playback is not running:
  // 1: The frames from the previous item have highest priority and are removed last. It is very
  // likely that in 'interactive'
  //    (playback is not running) mode, the user will go back to the previous item.
  // 2: The item after this item is next in the priority list.
  // 3: The item after 2 is next and so on (wrap around in the playlist) until the previous item is
  // reached.
  //
  // Playback is running:
  // 1: The item after this item has the highest priority (it will be played next)
  // 2: The item after 2 is next and so on (wrap around in the playlist) until the previous item is
  // reached.

  // Let's start with the currently selected item (if no item is selected, the first item in the
  // playlist is considered as being selected)
  auto selection = playlist->getSelectedItems();
  if (selection[0] == nullptr)
    selection[0] = allItems[0];
  // Get the position of the curretnly selected item