async Task <Stream> GetStreamFromCacheAsync(Uri uri, CancellationToken cancellationToken)
{
string key = GetCacheKey(uri);
LockingSemaphore sem;
lock (s_syncHandle)
{
if (s_semaphores.ContainsKey(key))
{
sem = s_semaphores[key];
}
else
{
s_semaphores.Add(key, sem = new LockingSemaphore(1));
}
}
try
{
await sem.WaitAsync(cancellationToken);
Stream stream = await GetStreamAsyncUnchecked(key, uri, cancellationToken);
if (stream == null)
{
sem.Release();
return(null);
}
var wrapped = new StreamWrapper(stream);
wrapped.Disposed += (o, e) => sem.Release();
return(wrapped);
}
catch (OperationCanceledException)
{
sem.Release();
throw;
}
}
async Task<Stream> GetStreamFromCacheAsync(Uri uri, CancellationToken cancellationToken)
{
string key = GetCacheKey(uri);
LockingSemaphore sem;
lock (s_syncHandle)
{
if (s_semaphores.ContainsKey(key))
sem = s_semaphores[key];
else
s_semaphores.Add(key, sem = new LockingSemaphore(1));
}
try
{
await sem.WaitAsync(cancellationToken);
Stream stream = await GetStreamAsyncUnchecked(key, uri, cancellationToken);
if (stream == null)
{
sem.Release();
return null;
}
var wrapped = new StreamWrapper(stream);
wrapped.Disposed += (o, e) => sem.Release();
return wrapped;
}
catch (OperationCanceledException)
{
sem.Release();
throw;
}
}