private Stream CacheAndCreateEntryStream(string filename, string entryName)
{
Stream stream = null;
var dataStream = _dataProvider.Fetch(filename);
if (dataStream != null)
{
try
{
var newItem = new CachedZipFile(dataStream, DateTime.UtcNow, filename);
// here we don't need to lock over the cache item
// because it was still not added in the cache
stream = CreateEntryStream(newItem, entryName, filename);
if (!_zipFileCache.TryAdd(filename, newItem))
{
// some other thread could of added it already, lets dispose ours
newItem.Dispose();
}
}
catch (Exception exception)
{
if (exception is ZipException || exception is ZlibException)
{
Log.Error("ZipDataCacheProvider.Fetch(): Corrupt zip file/entry: " + filename + "#" + entryName + " Error: " + exception);
}
else
{
throw;
}
}
}
return(stream);
}
/// <summary>
/// Cache a Zip
/// </summary>
/// <param name="filename">Zip to cache</param>
/// <param name="cachedZip">The resulting CachedZipFile</param>
/// <returns></returns>
private bool Cache(string filename, out CachedZipFile cachedZip)
{
cachedZip = null;
var dataStream = _dataProvider.Fetch(filename);
if (dataStream != null)
{
try
{
cachedZip = new CachedZipFile(dataStream, DateTime.UtcNow, filename);
if (!_zipFileCache.TryAdd(filename, cachedZip))
{
// some other thread could of added it already, lets dispose ours
cachedZip.Dispose();
return(_zipFileCache.TryGetValue(filename, out cachedZip));
}
return(true);
}
catch (Exception exception)
{
if (exception is ZipException || exception is ZlibException)
{
Log.Error("ZipDataCacheProvider.Fetch(): Corrupt zip file/entry: " + filename + " Error: " + exception);
}
else
{
throw;
}
}
dataStream.Dispose();
}
return(false);
}
/// <summary>
/// Does not attempt to retrieve any data
/// </summary>
public Stream Fetch(string key)
{
string entryName = null; // default to all entries
var filename = key;
var hashIndex = key.LastIndexOf("#", StringComparison.Ordinal);
if (hashIndex != -1)
{
entryName = key.Substring(hashIndex + 1);
filename = key.Substring(0, hashIndex);
}
// handles zip files
if (filename.GetExtension() == ".zip")
{
Stream stream = null;
// scan the cache once every 3 seconds
if (_lastCacheScan == DateTime.MinValue || _lastCacheScan < DateTime.Now.AddSeconds(-3))
{
CleanCache();
}
try
{
CachedZipFile existingEntry;
if (!_zipFileCache.TryGetValue(filename, out existingEntry))
{
var dataStream = _dataProvider.Fetch(filename);
if (dataStream != null)
{
try
{
var newItem = new CachedZipFile(dataStream, filename);
stream = CreateStream(newItem, entryName, filename);
if (!_zipFileCache.TryAdd(filename, newItem))
{
newItem.Dispose();
}
}
catch (Exception exception)
{
if (exception is ZipException || exception is ZlibException)
{
Log.Error("ZipDataCacheProvider.Fetch(): Corrupt zip file/entry: " + filename + "#" + entryName + " Error: " + exception);
}
else
{
throw;
}
}
}
}
else
{
try
{
lock (existingEntry)
{
stream = CreateStream(existingEntry, entryName, filename);
}
}
catch (Exception exception)
{
if (exception is ZipException || exception is ZlibException)
{
Log.Error("ZipDataCacheProvider.Fetch(): Corrupt zip file/entry: " + filename + "#" + entryName + " Error: " + exception);
}
else
{
throw;
}
}
}
return(stream);
}
catch (Exception err)
{
Log.Error(err, "Inner try/catch");
stream?.DisposeSafely();
return(null);
}
}
else
{
// handles text files
return(_dataProvider.Fetch(filename));
}
}