/// <summary>
/// Handles the DoWork event of the queued background worker.
/// </summary>
/// <param name="sender">The source of the event.</param>
/// <param name="e">The <see cref="PanoClient.ImageListView.QueuedWorkerDoWorkEventArgs"/> instance
/// containing the event data.</param>
void bw_DoWork(object sender, QueuedWorkerDoWorkEventArgs e)
{
string extension = e.Argument as string;
// Should we continue processing this item?
// The callback checks if the item is already cached.
if (!OnCanContinueProcessing(extension))
{
e.Cancel = true;
return;
}
// Read shell info
ShellInfoExtractor info = ShellInfoExtractor.FromFile(extension);
// Return the info
CacheItem result = null;
if ((info.SmallIcon == null || info.LargeIcon == null) && !RetryOnError)
{
result = new CacheItem(extension, info.SmallIcon, info.LargeIcon, info.FileType, CacheState.Error);
}
else
{
result = new CacheItem(extension, info.SmallIcon, info.LargeIcon, info.FileType, CacheState.Cached);
}
e.Result = result;
}
/// <summary>
/// Raises the DoWork event.
/// </summary>
/// <param name="e">A <see cref="QueuedWorkerDoWorkEventArgs"/> that contains event data.</param>
protected virtual void OnDoWork(QueuedWorkerDoWorkEventArgs e)
{
if (DoWork != null)
{
DoWork(this, e);
}
}
/// <summary>
/// Handles the DoWork event of the queued background worker.
/// </summary>
/// <param name="sender">The source of the event.</param>
/// <param name="e">The <see cref="PanoClient.ImageListView.QueuedWorkerDoWorkEventArgs"/> instance
/// containing the event data.</param>
void bw_DoWork(object sender, QueuedWorkerDoWorkEventArgs e)
{
CacheRequest request = e.Argument as CacheRequest;
// Should we continue processing this item?
// The callback checks the following and returns false if
// the item is already cached -OR-
// the item is in the edit cache -OR-
// the item is outside the visible area (only if the CacheMode is OnDemand).
if (!OnCanContinueProcessing(request))
{
e.Cancel = true;
return;
}
Image thumb = null;
string diskCacheKey = request.Adaptor.GetUniqueIdentifier(request.VirtualItemKey, request.Size, request.UseEmbeddedThumbnails, request.AutoRotate, request.UseWIC);
// Check the disk cache
using (Stream stream = diskCache.Read(diskCacheKey))
{
if (stream.Length > 0)
{
thumb = new Bitmap(stream);
}
}
// Extract the thumbnail from the source image.
if (thumb == null)
{
thumb = request.Adaptor.GetThumbnail(request.VirtualItemKey, request.Size, request.UseEmbeddedThumbnails, request.AutoRotate, request.UseWIC);
// Save to disk cache
if (thumb != null)
{
using (MemoryStream stream = new MemoryStream())
{
thumb.Save(stream, System.Drawing.Imaging.ImageFormat.Png);
diskCache.Write(diskCacheKey, stream);
}
}
}
// Return the thumbnail
CacheItem result = null;
if (thumb == null && !RetryOnError)
{
result = new CacheItem(request.Guid, request.Size, null, CacheState.Error, request.UseEmbeddedThumbnails, request.AutoRotate, request.UseWIC);
}
else
{
result = new CacheItem(request.Guid, request.Size, thumb, CacheState.Cached, request.UseEmbeddedThumbnails, request.AutoRotate, request.UseWIC);
}
e.Result = result;
}
/// <summary>
/// Handles the DoWork event of the queued background worker.
/// </summary>
/// <param name="sender">The source of the event.</param>
/// <param name="e">The <see cref="PanoClient.ImageListView.QueuedWorkerDoWorkEventArgs"/> instance
/// containing the event data.</param>
void bw_DoWork(object sender, QueuedWorkerDoWorkEventArgs e)
{
CacheRequest request = e.Argument as CacheRequest;
// Should we continue processing this item?
// The callback checks the following and returns false if
// the item is in the edit cache -OR-
// the item was fetched by the UI thread before.
if (!OnCanContinueProcessing(request))
{
e.Cancel = true;
return;
}
// Get item details
e.Result = request.Adaptor.GetDetails(request.VirtualItemKey, request.UseWIC);
}
/// <summary>
/// Used by the worker thread to process items.
/// </summary>
private void Run()
{
while (!Stopping)
{
lock (lockObject)
{
// Wait until we have pending work items
if (paused || IsWorkQueueEmpty())
{
Monitor.Wait(lockObject);
}
}
// Loop until we exhaust the queue
bool queueFull = true;
while (queueFull && !Stopping && !Paused)
{
// Get an item from the queue
AsyncOperation asyncOp = null;
object request = null;
int priority = 0;
lock (lockObject)
{
// Check queues
Utility.Tuple <AsyncOperation, int> work = GetWork();
asyncOp = work.Item1;
priority = work.Item2;
if (asyncOp != null)
{
request = asyncOp.UserSuppliedState;
}
// Check if the item was removed
if (request != null && cancelledItems.ContainsKey(request))
{
request = null;
}
}
if (request != null)
{
Exception error = null;
object result = null;
bool cancel = false;
// Start the work
try
{
// Raise the do work event
QueuedWorkerDoWorkEventArgs doWorkArg = new QueuedWorkerDoWorkEventArgs(request, priority);
OnDoWork(doWorkArg);
result = doWorkArg.Result;
cancel = doWorkArg.Cancel;
}
catch (Exception e)
{
error = e;
}
// Raise the work complete event
QueuedWorkerCompletedEventArgs workCompletedArg = new QueuedWorkerCompletedEventArgs(request, result, priority, error, cancel);
if (!Stopping)
{
asyncOp.PostOperationCompleted(workCompletedCallback, workCompletedArg);
}
}
else if (asyncOp != null)
{
asyncOp.OperationCompleted();
}
// Check if the cache is exhausted
lock (lockObject)
{
queueFull = !IsWorkQueueEmpty();
}
}
}
}