public void StartSwapOut(ImageCache cache)
{
lock (this)
{
Debug.Assert(Program.EnableSwap);
if (this.outTask != null)
{
return;
}
if (this.holders.Count != 0)
{
return;
}
Stopwatch elapsed = Stopwatch.StartNew();
#if true // TODO: remove hack
EventWaitHandle swapOutDelay = new EventWaitHandle(false, EventResetMode.AutoReset);
#endif
Task <bool> serializationTask = null;
Task <ManagedBitmap> oldBitmap = this.bitmap;
// 'this' is not locked at the time 'cache' is used below in the task delegates
this.outTask = new Task <bool>(
delegate()
{
Profile profile = new Profile("SwapOut {0}", this.id);
#if true // TODO: remove hack
profile.Push("Hack delay for swapins");
// HACK: wait a little to allow swapins to start before swapouts
EventWaitHandle localSwapOutDelay = Interlocked.Exchange(ref swapOutDelay, null);
if (localSwapOutDelay != null) // race: swapin can grab and clear this before we get here
{
localSwapOutDelay.WaitOne(100);
}
profile.Pop();
//
#endif
profile.Push("WaitSwapOutGate");
cache.WaitSwapOutGate(); // defer to in-flight swapins
profile.Pop();
lock (this)
{
Debug.Assert(this.swapFilePath == null);
Debug.Assert(this.swapFileStream == null);
this.swapFilePath = Path.GetTempFileName();
this.swapFileStream = new FileStream(this.swapFilePath, FileMode.Create, FileAccess.ReadWrite, FileShare.ReadWrite, 4096, FileOptions.DeleteOnClose);
}
profile.Push("oldBitmap.Wait()");
oldBitmap.Wait(); // wait for an old in-flight creation to complete
profile.Pop();
profile.Push("Serialize");
serializationTask = new Task <bool>(
delegate()
{
SetIOPriority(this.swapFileStream, PRIORITY_HINT.IoPriorityHintLow);
ManagedBitmap.Serialize(this.swapFileStream, oldBitmap.Result);
SetIOPriority(this.swapFileStream, PRIORITY_HINT.IoPriorityHintNormal);
return(false);
});
SerializationManager.Manager.EnqueueWriteTask(serializationTask);
serializationTask.Wait();
profile.Pop();
profile.Push("Enqueue oldBitmap");
lock (this)
{
this.oldBitmaps.Add(oldBitmap.Result); // remove current bitmap and enqueue for destruction upon zero refs
}
profile.Pop();
profile.Push("Epilog");
cache.Trace("swapout", this, elapsed);
cache.PurgeDisposeList();
profile.Pop();
profile.End();
//Program.Log(LogCat.Perf, profile.ToString());
return(false);
});
this.bitmap = new Task <ManagedBitmap>(
delegate()
{
Profile profile = new Profile("SwapIn {0}", this.id);
profile.Push("outTask.Wait()");
#if true // TODO: remove hack
// HACK: release delay immediately if swapin is requested
EventWaitHandle localSwapOutDelay = Interlocked.Exchange(ref swapOutDelay, null);
if (localSwapOutDelay != null)
{
localSwapOutDelay.Set();
}
//
#endif
SerializationManager.Manager.Prioritize(serializationTask);
Debug.Assert(this.outTask != null);
this.outTask.Wait(); // ensure in-progress swapout finishes
profile.Pop();
profile.Push("cache.BeginSwapIn()");
cache.BeginSwapIn();
profile.Pop();
try
{
Stopwatch elapsed2 = Stopwatch.StartNew();
Debug.Assert(this.swapFilePath != null);
Debug.Assert(this.swapFileStream != null);
profile.Push("Deserialize");
ManagedBitmap bitmap = null;
Task <bool> deserializationTask = new Task <bool>(
delegate()
{
bitmap = ManagedBitmap.Deserialize(this.swapFileStream);
return(false);
});
SerializationManager.Manager.EnqueueReadTask(deserializationTask);
deserializationTask.Wait();
this.swapFilePath = null;
Stream localSwapFileStream = this.swapFileStream;
this.swapFileStream = null;
localSwapFileStream.Dispose();
this.outTask = null;
profile.Pop();
profile.Push("Epilog");
cache.Trace("swapin", this, elapsed2);
cache.PurgeDisposeList();
StartBitmapCompleteWaiter();
return(bitmap);
}
finally
{
cache.EndSwapIn();
#if true // TODO: remove hack
if (localSwapOutDelay != null)
{
localSwapOutDelay.Dispose();
}
#endif
profile.Pop(); // Epilog - here to include cache.EndSwapIn()
profile.End();
//Program.Log(LogCat.Perf, profile.ToString());
}
});
this.outTask.Start();
}
}
