/// <summary>
/// return true cache is needed, otherwise false
/// </summary>
/// <param name="data"></param>
/// <returns></returns>
private bool CacheData(PictureData data)
{
lock (_cacheLock)
{
bool isCached = _cachedData.ToList().Exists(c => c.PageUrl == data.PageUrl);
if (!isCached)
{
_cachedData.Enqueue(data);
}
if (_cachedData.Count > CacheLimit)
{
_cachedData.Dequeue();
}
return(!isCached);
}
}
//download and display cell
private async Task DisplayAnImage(PictureData pictureData, Queue <ImageCell> queue, IPictureDataProvider provider)
{
var bitmap = pictureData.ThumbBitmap ?? await pictureData.GetThumbBitmap().ConfigureAwait(false);
if (bitmap == null)
{
Debug.WriteLine("Thumb download failed, scraper: " + pictureData.Scraper.SiteName);
if (provider.CanSupplyWhenFail)
//replace with another image
{
Debug.WriteLine("Replace fail thumb...");
await FillImages(1, queue, provider).ConfigureAwait(false);
}
else
{
//fixed set, cant replace, displays default error image
UiInvoke(() => { throw new NotImplementedException(); });
}
return;
}
bool needCached = CacheData(pictureData);
if (queue.Count == 0)
{
Debug.WriteLine("Queue is empty, can not display image.");
return;
}
var cell = queue.Dequeue();
//when a favorited data is randomly loaded marks it as so
pictureData.IsFavorite = _favoriteSaver.CheckFavorite(pictureData);
UiInvoke(() =>
{
//cell.SetValue(ImageCell.IsImageDownloaded, true);
cell.SetData(pictureData);
//no effect when data is taken from cached
if (needCached)
{
cell.BeginStoryboard((Storyboard)TryFindResource("fadeInEffect"));
}
});
RaiseThumbDowloaded();
}
private PictureData GetCachedData(PictureData data)
{
lock (_cacheLock)
{
var cachedData = _cachedData.ToList().FirstOrDefault(d => d.PageUrl == data.PageUrl);
if (cachedData == null)
{
//download new bitmap, delays throttle rq
_thumbDownloadDelay = DefaultThumbDownloadDelay;
cachedData = data;
}
else
{
//load from cache
_thumbDownloadDelay = 0;
}
return(cachedData);
}
}