public bool Exists(FileSystemCacheKey key)
{
lock (KeyLockFor(key))
{
return(_fileSystemAccess.Exists(CachePathForKey(key)));
}
}
public void Add(FileSystemCacheKey key, Stream contents, CancellationToken cancellationToken = default, bool ensureFolderExists = false)
{
string cachePathForKey = CachePathForKey(key);
try
{
lock (KeyLockFor(key))
{
if (ensureFolderExists)
{
EnsureFolderExists(Path.GetDirectoryName(cachePathForKey));
}
_fileSystemAccess.Write(cachePathForKey, contents, cancellationToken)
.GetAwaiter()
.GetResult();
}
}
catch (IOException) when(_fileSystemAccess.Exists(cachePathForKey))
{
_logger.Warning($"Detected file collision for {CachePathForKey(key)}. Swallowing exception");
}
catch (Exception exception)
{
string message = $"Unable to write content for file system cache item with key {key.Key}";
_logger.Error(exception, message);
throw new Exception(message, exception);
}
}
private string CachePathForKey(FileSystemCacheKey key)
{
string cachePath = key.Path;
string fileName = Path.GetFileName(cachePath);
string folder = Path.GetDirectoryName(cachePath);
return(Path.Combine(_settings.Path, folder, $"{_settings.Prefix}_{fileName}"));
}
private object KeyLockFor(FileSystemCacheKey key)
{
if (!_evictionInProgress)
{
return(KeyLocks.GetOrAdd(key.Key, new object()));
}
lock (EvictionLock)
{
return(KeyLocks.GetOrAdd(key.Key, new object()));
}
}
public Stream Get(FileSystemCacheKey key)
{
try
{
lock (KeyLockFor(key))
{
return(_fileSystemAccess.OpenRead(CachePathForKey(key)));
}
}
catch (Exception exception)
{
string errorMessage = $"Unable to read content for file system cache item with key {key.Key}";
_logger.Error(errorMessage, exception);
throw new Exception(errorMessage, exception);
}
}