public StreamBlockProxy TryRentIndexedStreamBlockProxy(StreamLog streamLog, StreamBlockRecord record)
{
StreamBlockProxy p = null;
while (p == null)
{
var blockKey = new BlockKey(streamLog.Slid, record.Version);
// ReSharper disable once InconsistentlySynchronizedField
if (_blocks.TryGetValue(blockKey, out var handle))
{
p = handle.Target as StreamBlockProxy;
}
else
{
// CD.GetOrAdd factory is not atomic, lock manually.
// Lock on SL, not a global object. This also helps
// to avoid a capturing lambda and the risk of collecting
// an object held only by a weak reference during that lambda return.
lock (streamLog)
{
if (_blocks.TryGetValue(blockKey, out handle))
{
p = handle.Target as StreamBlockProxy;
}
else
{
p = StreamBlockProxy.Create(blockKey, this);
var sb = streamLog.GetBlockFromRecord(record);
// Could set directly without SetStreamBlock
p.Block = sb;
handle = GCHandle.Alloc(p, GCHandleType.Weak);
if (!_blocks.TryAdd(blockKey, handle))
{
// this should never happen unless there are different streamLog instances for the same slid,
// which in turn should never happen because SLs are stored in SLM dictionary.
ThrowHelper.FailFast("Cannot add newly created StreamBlockProxy to cache from inside a lock.");
}
}
}
}
// will be null if cannot retain, then will start over
p = p?.TryRetain();
}
return(p);
}
public bool GetIsCompleted(StreamLogId streamLogId)
{
var streamId = (long)streamLogId;
using (var txn = Environment.BeginReadOnlyTransaction())
using (var c = _blocksDb.OpenReadOnlyCursor(txn))
{
StreamBlockRecord value = default;
if (c.TryGet(ref streamId, ref value, CursorGetOption.Set) &&
c.TryGet(ref streamId, ref value, CursorGetOption.LastDuplicate))
{
return(value.Version == CompletedVersion);
}
return(false);
}
}
internal StreamBlock GetBlockFromRecord(StreamBlockRecord record)
{
StreamBlock block;
// we cannot touch a block when it is stored
if (record.BufferRef != default)
{
#pragma warning disable 618
block = StreamLogManager.BlockIndex.TryRentIndexedStreamBlock(this, record.BufferRef);
#pragma warning restore 618
if (block.IsValid || record.Version == StreamBlockIndex.ReadyBlockVersion)
{
return(block);
}
// TODO (!) review why this was needed, sometimes we get "cannot get block that should exists", probably this is the fix
//if (_streamLog.StreamLogManager.BlockIndex.TryGetValue(StreamLogId, record.Version, out record)
// && record.BufferRef != default && !record.BufferRef.Flag
//)
//{
// FailCannotGetChunk(record);
//}
}
// throw new NotImplementedException(); // TODO Storage
block =
StreamLogManager
.BlockIndex
.BlockStorage
.TryGetStreamBlock((long)Slid, record.Version);
if (block.IsValid)
{
return(block);
}
FailCannotGetBlock();
return(default);