/// <returns>blocks of the file corresponding to the snapshot.</returns>
public virtual BlockInfoContiguous[] GetBlocks(int snapshot)
{
if (snapshot == Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot.CurrentStateId ||
GetDiffs() == null)
{
return(GetBlocks());
}
FileDiff diff = GetDiffs().GetDiffById(snapshot);
BlockInfoContiguous[] snapshotBlocks = diff == null?GetBlocks() : diff.GetBlocks
();
if (snapshotBlocks != null)
{
return(snapshotBlocks);
}
// Blocks are not in the current snapshot
// Find next snapshot with blocks present or return current file blocks
snapshotBlocks = GetDiffs().FindLaterSnapshotBlocks(snapshot);
return((snapshotBlocks == null) ? GetBlocks() : snapshotBlocks);
}
/// <summary>compute the quota usage change for a truncate op</summary>
/// <param name="newLength">the length for truncation</param>
/// <returns>the quota usage delta (not considering replication factor)</returns>
internal virtual long ComputeQuotaDeltaForTruncate(long newLength)
{
BlockInfoContiguous[] blocks = GetBlocks();
if (blocks == null || blocks.Length == 0)
{
return(0);
}
int n = 0;
long size = 0;
for (; n < blocks.Length && newLength > size; n++)
{
size += blocks[n].GetNumBytes();
}
bool onBoundary = size == newLength;
long truncateSize = 0;
for (int i = (onBoundary ? n : n - 1); i < blocks.Length; i++)
{
truncateSize += blocks[i].GetNumBytes();
}
FileWithSnapshotFeature sf = GetFileWithSnapshotFeature();
if (sf != null)
{
FileDiff diff = sf.GetDiffs().GetLast();
BlockInfoContiguous[] sblocks = diff != null?diff.GetBlocks() : null;
if (sblocks != null)
{
for (int i_1 = (onBoundary ? n : n - 1); i_1 < blocks.Length && i_1 < sblocks.Length &&
blocks[i_1].Equals(sblocks[i_1]); i_1++)
{
truncateSize -= blocks[i_1].GetNumBytes();
}
}
}
return(onBoundary ? -truncateSize : (GetPreferredBlockSize() - truncateSize));
}