public IObservable <Stream> SafeOpenFileAsync(string path, FileMode mode, FileAccess access, FileShare share, IScheduler scheduler)
{
if (mode == FileMode.Create ||
mode == FileMode.CreateNew ||
(mode == FileMode.OpenOrCreate && !File.Exists(path)))
{
return(Observable.Throw <Stream>(new Exception("Read only mode")));
}
return(_inner.SafeOpenFileAsync(path, mode, FileAccess.Read, share, scheduler));
}
AsyncSubject <byte[]> FetchOrWriteBlobFromDisk(string key, object byteData, bool synchronous)
{
// If this is secretly a write, dispatch to WriteBlobToDisk (we're
// kind of abusing the 'context' variable from MemoizingMRUCache
// here a bit)
if (byteData != null)
{
return(WriteBlobToDisk(key, (byte[])byteData, synchronous));
}
var ret = new AsyncSubject <byte[]>();
var ms = new MemoryStream();
var scheduler = synchronous ? System.Reactive.Concurrency.Scheduler.Immediate : Scheduler;
if (disposed)
{
Observable.Throw <byte[]>(new ObjectDisposedException("PersistentBlobCache"))
.Multicast(ret)
.PermaRef();
return(ret);
}
Func <IObservable <byte[]> > readResult = () =>
Observable.Defer(() =>
filesystem.SafeOpenFileAsync(GetPathForKey(key), FileMode.Open, FileAccess.Read, FileShare.Read, scheduler))
.Retry(1)
.SelectMany(x => x.CopyToAsync(ms, scheduler))
.SelectMany(x => AfterReadFromDiskFilter(ms.ToArray(), scheduler))
.Catch <byte[], FileNotFoundException>(ex => ObservableThrowKeyNotFoundException(key, ex))
.Catch <byte[], IsolatedStorageException>(ex => ObservableThrowKeyNotFoundException(key, ex))
.Do(_ =>
{
if (!synchronous && key != BlobCacheIndexKey)
{
actionTaken.OnNext(Unit.Default);
}
});
readResult().Multicast(ret).PermaRef();
return(ret);
}