public IDirectory RegisterDirectory(IDirectory directory)
{
cacheLock.EnterWriteLock();
try
{
var blockId = directory.BlockId;
if (openedDirectories.TryGetValue(blockId, out var directoryWithRefCount))
{
var existingDirectory = Volatile.Read(ref directoryWithRefCount.Directory);
if (existingDirectory != null)
{
throw new InvalidOperationException($"Directory with blockId = {directory.BlockId} has already been registered");
}
}
directoryWithRefCount = new DirectoryWithRefCount
{
Directory = directory,
RefCount = 1
};
openedDirectories[blockId] = directoryWithRefCount;
return(directory);
}
finally
{
cacheLock.ExitWriteLock();
}
}
public IDirectory ReadDirectory(int blockId)
{
cacheLock.EnterUpgradeableReadLock();
try
{
if (openedDirectories.TryGetValue(blockId, out var directoryWithRefCount))
{
var directory = Volatile.Read(ref directoryWithRefCount.Directory);
if (directory != null)
{
Interlocked.Increment(ref directoryWithRefCount.RefCount);
return(directoryWithRefCount.Directory);
}
}
cacheLock.EnterWriteLock();
try
{
if (openedDirectories.TryGetValue(blockId, out directoryWithRefCount))
{
var directory = Volatile.Read(ref directoryWithRefCount.Directory);
if (directory != null)
{
Interlocked.Increment(ref directoryWithRefCount.RefCount);
return(directoryWithRefCount.Directory);
}
}
directoryWithRefCount = new DirectoryWithRefCount
{
Directory = unsafeDirectoryReader.Read(blockId),
RefCount = 1
};
openedDirectories.Add(blockId, directoryWithRefCount);
return(directoryWithRefCount.Directory);
}
finally
{
cacheLock.ExitWriteLock();
}
}
finally
{
cacheLock.ExitUpgradeableReadLock();
}
}
