/// <summary>Get the next subdirectory within the block pool slice.</summary>
/// <returns>
/// The next subdirectory within the block pool slice, or
/// null if there are no more.
/// </returns>
/// <exception cref="System.IO.IOException"/>
private string GetNextSubDir(string prev, FilePath dir)
{
IList <string> children = IOUtils.ListDirectory(dir, FsVolumeImpl.SubdirFilter.Instance
);
this.cache = null;
this.cacheMs = 0;
if (children.Count == 0)
{
FsVolumeImpl.Log.Trace("getNextSubDir({}, {}): no subdirectories found in {}", this
._enclosing.storageID, this.bpid, dir.GetAbsolutePath());
return(null);
}
children.Sort();
string nextSubDir = FsVolumeImpl.NextSorted(children, prev);
if (nextSubDir == null)
{
FsVolumeImpl.Log.Trace("getNextSubDir({}, {}): no more subdirectories found in {}"
, this._enclosing.storageID, this.bpid, dir.GetAbsolutePath());
}
else
{
FsVolumeImpl.Log.Trace("getNextSubDir({}, {}): picking next subdirectory {} " + "within {}"
, this._enclosing.storageID, this.bpid, nextSubDir, dir.GetAbsolutePath());
}
return(nextSubDir);
}
/// <summary>
/// Get the next block.<p/>
/// Each volume has a hierarchical structure.<p/>
/// <code>
/// BPID B0
/// finalized/
/// subdir0
/// subdir0
/// blk_000
/// blk_001
/// ...
/// </summary>
/// <remarks>
/// Get the next block.<p/>
/// Each volume has a hierarchical structure.<p/>
/// <code>
/// BPID B0
/// finalized/
/// subdir0
/// subdir0
/// blk_000
/// blk_001
/// ...
/// subdir1
/// subdir0
/// ...
/// rbw/
/// </code>
/// When we run out of entries at one level of the structure, we search
/// progressively higher levels. For example, when we run out of blk_
/// entries in a subdirectory, we search for the next subdirectory.
/// And so on.
/// </remarks>
/// <exception cref="System.IO.IOException"/>
public virtual ExtendedBlock NextBlock()
{
if (this.state.atEnd)
{
return(null);
}
try
{
while (true)
{
IList <string> entries = this.GetSubdirEntries();
if (entries != null)
{
this.state.curEntry = FsVolumeImpl.NextSorted(entries, this.state.curEntry);
if (this.state.curEntry == null)
{
FsVolumeImpl.Log.Trace("nextBlock({}, {}): advancing from {} to next " + "subdirectory."
, this._enclosing.storageID, this.bpid, this.state.curFinalizedSubDir);
}
else
{
ExtendedBlock block = new ExtendedBlock(this.bpid, Block.Filename2id(this.state.curEntry
));
FsVolumeImpl.Log.Trace("nextBlock({}, {}): advancing to {}", this._enclosing.storageID
, this.bpid, block);
return(block);
}
}
this.state.curFinalizedSubDir = this.GetNextFinalizedSubDir();
if (this.state.curFinalizedSubDir == null)
{
this.state.curFinalizedDir = this.GetNextFinalizedDir();
if (this.state.curFinalizedDir == null)
{
this.state.atEnd = true;
return(null);
}
}
}
}
catch (IOException e)
{
this.state.atEnd = true;
FsVolumeImpl.Log.Error("nextBlock({}, {}): I/O error", this._enclosing.storageID,
this.bpid, e);
throw;
}
}