/// <summary>
/// Try Take element from cached queue.
/// </summary>
/// <param name="height">Height of block info needed</param>
/// <param name="blockInfo"></param>
/// <param name="isCacheSizeLimited">Use <see cref="_cachedBoundedCapacity"/> as cache count threshold if true.</param>
/// <returns></returns>
public bool TryTake(long height, out IBlockInfo blockInfo, bool isCacheSizeLimited)
{
// clear outdated data
var cachedInQueue = CacheBlockInfoBeforeHeight(height);
// isCacheSizeLimited means minimal caching size limit, so that most nodes have this block.
var lastQueuedHeight = ToBeIndexedBlockInfoQueue.LastOrDefault()?.Height ?? 0;
if (cachedInQueue && !(isCacheSizeLimited && lastQueuedHeight < height + CrossChainConstants.MinimalBlockInfoCacheThreshold))
{
var res = ToBeIndexedBlockInfoQueue.TryTake(out blockInfo,
CrossChainConstants.WaitingIntervalInMillisecond);
if (res)
{
CacheBlockInfo(blockInfo);
}
return(res);
}
blockInfo = LastBlockInfoInCache(height);
if (blockInfo != null)
{
return(!isCacheSizeLimited ||
ToBeIndexedBlockInfoQueue.Count + CachedIndexedBlockInfoQueue.Count(ci => ci.Height >= height)
>= CrossChainConstants.MinimalBlockInfoCacheThreshold);
}
return(false);
}
public bool TryAdd(IBlockInfo blockInfo)
{
if (ToBeIndexedBlockInfoQueue.Count() >= _cachedBoundedCapacity)
{
return(false);
}
// thread unsafe in some extreme cases, but it can be covered with caching mechanism.
if (blockInfo.Height != TargetChainHeight())
{
return(false);
}
var res = ToBeIndexedBlockInfoQueue.TryAdd(blockInfo);
return(res);
}
public long TargetChainHeight()
{
var lastQueuedBlockInfo = ToBeIndexedBlockInfoQueue.LastOrDefault();
if (lastQueuedBlockInfo != null)
{
return(lastQueuedBlockInfo.Height + 1);
}
var lastCachedBlockInfo = CachedIndexedBlockInfoQueue.LastOrDefault();
if (lastCachedBlockInfo != null)
{
return(lastCachedBlockInfo.Height + 1);
}
return(_initTargetHeight);
}
/// <summary>
/// Cache outdated data. The block with height lower than <paramref name="height"/> is outdated.
/// </summary>
/// <param name="height"></param>
private bool CacheBlockInfoBeforeHeight(long height)
{
while (true)
{
var blockInfo = ToBeIndexedBlockInfoQueue.FirstOrDefault();
if (blockInfo == null || blockInfo.Height > height)
{
return(false);
}
if (blockInfo.Height == height)
{
return(true);
}
var res = ToBeIndexedBlockInfoQueue.TryTake(out blockInfo, CrossChainConstants.WaitingIntervalInMillisecond);
if (res)
{
CacheBlockInfo(blockInfo);
}
}
}
