/// <summary>
/// Decrement the reference count of a chunk by its key. If the reference count reaches zero, the chunk is deleted.
/// </summary>
/// <param name="chunkKey">Chunk key.</param>
/// <returns>Boolean indicating if the chunk should be garbage collected.</returns>
public override bool DecrementChunkRefcount(string chunkKey)
{
if (String.IsNullOrEmpty(chunkKey))
{
throw new ArgumentNullException(nameof(chunkKey));
}
chunkKey = DedupeCommon.SanitizeString(chunkKey);
DedupeChunk chunk = GetChunkMetadata(chunkKey);
if (chunk == null)
{
return(false);
}
chunk.RefCount = chunk.RefCount - 1;
if (chunk.RefCount < 1)
{
_ORM.Delete <DedupeChunk>(chunk);
return(true);
}
else
{
_ORM.Update <DedupeChunk>(chunk);
return(false);
}
}
/// <summary>
/// Increment reference count for a chunk by its key. If the chunk does not exist, it is created.
/// </summary>
/// <param name="chunkKey">Chunk key.</param>
/// <param name="length">The chunk length, used when creating the chunk.</param>
public override void IncrementChunkRefcount(string chunkKey, int length)
{
if (String.IsNullOrEmpty(chunkKey))
{
throw new ArgumentNullException(nameof(chunkKey));
}
chunkKey = DedupeCommon.SanitizeString(chunkKey);
lock (_ChunkLock)
{
DedupeChunk chunk = GetChunkMetadata(chunkKey);
if (chunk != null)
{
chunk.RefCount = chunk.RefCount + 1;
_ORM.Update <DedupeChunk>(chunk);
}
else
{
chunk = new DedupeChunk(chunkKey, length, 1);
_ORM.Insert <DedupeChunk>(chunk);
}
}
}
static void WriteChunk(DedupeChunk data)
{
using (var fs = new FileStream(
_ChunkDir + data.Key,
FileMode.Create,
FileAccess.Write,
FileShare.None,
0x1000,
FileOptions.WriteThrough))
{
fs.Write(data.Data, 0, data.Data.Length);
}
}
static void WriteChunk(DedupeChunk data)
{
// File.WriteAllBytes("Chunks\\" + data.Key, data.Value);
using (var fs = new FileStream(
"Chunks\\" + data.Key,
FileMode.Create,
FileAccess.Write,
FileShare.None,
0x1000,
FileOptions.WriteThrough))
{
fs.Write(data.Data, 0, data.Data.Length);
}
}
/// <summary>
/// Retrieve metadata for a given chunk by its key.
/// </summary>
/// <param name="chunkKey">Chunk key.</param>
/// <returns>Chunk metadata.</returns>
public override DedupeChunk GetChunkMetadata(string chunkKey)
{
if (String.IsNullOrEmpty(chunkKey))
{
throw new ArgumentNullException(nameof(chunkKey));
}
chunkKey = DedupeCommon.SanitizeString(chunkKey);
DbExpression e = new DbExpression(
_ORM.GetColumnName <DedupeChunk>(nameof(DedupeChunk.Key)),
DbOperators.Equals,
chunkKey);
DedupeChunk ret = _ORM.SelectFirst <DedupeChunk>(e);
return(ret);
}
// Called during store operations, consider using FileStream with FileOptions.WriteThrough to ensure crash consistency
static void WriteChunk(DedupeChunk data)
{
File.WriteAllBytes("Chunks\\" + data.Key, data.Data);
}
