/// <summary>
/// Create a AsyncDiskServices with a set of volumes (specified by their
/// root directories).
/// </summary>
/// <remarks>
/// Create a AsyncDiskServices with a set of volumes (specified by their
/// root directories).
/// The AsyncDiskServices uses one ThreadPool per volume to do the async disk
/// operations.
/// </remarks>
/// <param name="localFileSystem">The localFileSystem used for deletions.</param>
/// <param name="nonCanonicalVols">
/// The roots of the file system volumes, which may
/// be absolte paths, or paths relative to the ${user.dir} system property
/// ("cwd").
/// </param>
/// <exception cref="System.IO.IOException"/>
public MRAsyncDiskService(FileSystem localFileSystem, params string[] nonCanonicalVols
)
{
this.localFileSystem = localFileSystem;
this.volumes = new string[nonCanonicalVols.Length];
for (int v = 0; v < nonCanonicalVols.Length; v++)
{
this.volumes[v] = NormalizePath(nonCanonicalVols[v]);
Log.Debug("Normalized volume: " + nonCanonicalVols[v] + " -> " + this.volumes[v]);
}
asyncDiskService = new AsyncDiskService(this.volumes);
// Create one ThreadPool per volume
for (int v_1 = 0; v_1 < volumes.Length; v_1++)
{
// Create the root for file deletion
Path absoluteSubdir = new Path(volumes[v_1], Tobedeleted);
if (!localFileSystem.Mkdirs(absoluteSubdir))
{
// We should tolerate missing volumes.
Log.Warn("Cannot create " + Tobedeleted + " in " + volumes[v_1] + ". Ignored.");
}
}
// Create tasks to delete the paths inside the volumes
for (int v_2 = 0; v_2 < volumes.Length; v_2++)
{
Path absoluteSubdir = new Path(volumes[v_2], Tobedeleted);
FileStatus[] files = null;
try
{
// List all files inside the volumes TOBEDELETED sub directory
files = localFileSystem.ListStatus(absoluteSubdir);
}
catch (Exception)
{
}
// Ignore exceptions in listStatus
// We tolerate missing sub directories.
if (files != null)
{
for (int f = 0; f < files.Length; f++)
{
// Get the relative file name to the root of the volume
string absoluteFilename = files[f].GetPath().ToUri().GetPath();
string relative = Tobedeleted + Path.SeparatorChar + files[f].GetPath().GetName();
MRAsyncDiskService.DeleteTask task = new MRAsyncDiskService.DeleteTask(this, volumes
[v_2], absoluteFilename, relative);
Execute(volumes[v_2], task);
}
}
}
}
/// <summary>
/// Move the path name on one volume to a temporary location and then
/// delete them.
/// </summary>
/// <remarks>
/// Move the path name on one volume to a temporary location and then
/// delete them.
/// This functions returns when the moves are done, but not necessarily all
/// deletions are done. This is usually good enough because applications
/// won't see the path name under the old name anyway after the move.
/// </remarks>
/// <param name="volume">The disk volume</param>
/// <param name="pathName">The path name relative to volume root.</param>
/// <exception cref="System.IO.IOException">If the move failed</exception>
/// <returns>false if the file is not found</returns>
public virtual bool MoveAndDeleteRelativePath(string volume, string pathName)
{
volume = NormalizePath(volume);
// Move the file right now, so that it can be deleted later
string newPathName = format.Format(new DateTime()) + "_" + uniqueId.GetAndIncrement
();
newPathName = Tobedeleted + Path.SeparatorChar + newPathName;
Path source = new Path(volume, pathName);
Path target = new Path(volume, newPathName);
try
{
if (!localFileSystem.Rename(source, target))
{
// If the source does not exists, return false.
// This is necessary because rename can return false if the source
// does not exists.
if (!localFileSystem.Exists(source))
{
return(false);
}
// Try to recreate the parent directory just in case it gets deleted.
if (!localFileSystem.Mkdirs(new Path(volume, Tobedeleted)))
{
throw new IOException("Cannot create " + Tobedeleted + " under " + volume);
}
// Try rename again. If it fails, return false.
if (!localFileSystem.Rename(source, target))
{
throw new IOException("Cannot rename " + source + " to " + target);
}
}
}
catch (FileNotFoundException)
{
// Return false in case that the file is not found.
return(false);
}
MRAsyncDiskService.DeleteTask task = new MRAsyncDiskService.DeleteTask(this, volume
, pathName, newPathName);
Execute(volume, task);
return(true);
}