/// <summary>Retrieve existing INodes from a path.</summary>
/// <remarks>
/// Retrieve existing INodes from a path. For non-snapshot path,
/// the number of INodes is equal to the number of path components. For
/// snapshot path (e.g., /foo/.snapshot/s1/bar), the number of INodes is
/// (number_of_path_components - 1).
/// An UnresolvedPathException is always thrown when an intermediate path
/// component refers to a symbolic link. If the final path component refers
/// to a symbolic link then an UnresolvedPathException is only thrown if
/// resolveLink is true.
/// <p>
/// Example: <br />
/// Given the path /c1/c2/c3 where only /c1/c2 exists, resulting in the
/// following path components: ["","c1","c2","c3"]
/// <p>
/// <code>getExistingPathINodes(["","c1","c2"])</code> should fill
/// the array with [rootINode,c1,c2], <br />
/// <code>getExistingPathINodes(["","c1","c2","c3"])</code> should
/// fill the array with [rootINode,c1,c2,null]
/// </remarks>
/// <param name="startingDir">the starting directory</param>
/// <param name="components">array of path component name</param>
/// <param name="resolveLink">
/// indicates whether UnresolvedLinkException should
/// be thrown when the path refers to a symbolic link.
/// </param>
/// <returns>the specified number of existing INodes in the path</returns>
/// <exception cref="Org.Apache.Hadoop.FS.UnresolvedLinkException"/>
internal static Org.Apache.Hadoop.Hdfs.Server.Namenode.INodesInPath Resolve(INodeDirectory
startingDir, byte[][] components, bool resolveLink)
{
Preconditions.CheckArgument(startingDir.CompareTo(components[0]) == 0);
INode curNode = startingDir;
int count = 0;
int inodeNum = 0;
INode[] inodes = new INode[components.Length];
bool isSnapshot = false;
int snapshotId = Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot.CurrentStateId;
while (count < components.Length && curNode != null)
{
bool lastComp = (count == components.Length - 1);
inodes[inodeNum++] = curNode;
bool isRef = curNode.IsReference();
bool isDir = curNode.IsDirectory();
INodeDirectory dir = isDir ? curNode.AsDirectory() : null;
if (!isRef && isDir && dir.IsWithSnapshot())
{
//if the path is a non-snapshot path, update the latest snapshot.
if (!isSnapshot && ShouldUpdateLatestId(dir.GetDirectoryWithSnapshotFeature().GetLastSnapshotId
(), snapshotId))
{
snapshotId = dir.GetDirectoryWithSnapshotFeature().GetLastSnapshotId();
}
}
else
{
if (isRef && isDir && !lastComp)
{
// If the curNode is a reference node, need to check its dstSnapshot:
// 1. if the existing snapshot is no later than the dstSnapshot (which
// is the latest snapshot in dst before the rename), the changes
// should be recorded in previous snapshots (belonging to src).
// 2. however, if the ref node is already the last component, we still
// need to know the latest snapshot among the ref node's ancestors,
// in case of processing a deletion operation. Thus we do not overwrite
// the latest snapshot if lastComp is true. In case of the operation is
// a modification operation, we do a similar check in corresponding
// recordModification method.
if (!isSnapshot)
{
int dstSnapshotId = curNode.AsReference().GetDstSnapshotId();
if (snapshotId == Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot.CurrentStateId ||
(dstSnapshotId != Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot.CurrentStateId &&
dstSnapshotId >= snapshotId))
{
// no snapshot in dst tree of rename
// the above scenario
int lastSnapshot = Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot.CurrentStateId;
DirectoryWithSnapshotFeature sf;
if (curNode.IsDirectory() && (sf = curNode.AsDirectory().GetDirectoryWithSnapshotFeature
()) != null)
{
lastSnapshot = sf.GetLastSnapshotId();
}
snapshotId = lastSnapshot;
}
}
}
}
if (curNode.IsSymlink() && (!lastComp || resolveLink))
{
string path = ConstructPath(components, 0, components.Length);
string preceding = ConstructPath(components, 0, count);
string remainder = ConstructPath(components, count + 1, components.Length);
string link = DFSUtil.Bytes2String(components[count]);
string target = curNode.AsSymlink().GetSymlinkString();
if (Log.IsDebugEnabled())
{
Log.Debug("UnresolvedPathException " + " path: " + path + " preceding: " + preceding
+ " count: " + count + " link: " + link + " target: " + target + " remainder: "
+ remainder);
}
throw new UnresolvedPathException(path, preceding, remainder, target);
}
if (lastComp || !isDir)
{
break;
}
byte[] childName = components[count + 1];
// check if the next byte[] in components is for ".snapshot"
if (IsDotSnapshotDir(childName) && dir.IsSnapshottable())
{
// skip the ".snapshot" in components
count++;
isSnapshot = true;
// check if ".snapshot" is the last element of components
if (count == components.Length - 1)
{
break;
}
// Resolve snapshot root
Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot s = dir.GetSnapshot(components
[count + 1]);
if (s == null)
{
curNode = null;
}
else
{
// snapshot not found
curNode = s.GetRoot();
snapshotId = s.GetId();
}
}
else
{
// normal case, and also for resolving file/dir under snapshot root
curNode = dir.GetChild(childName, isSnapshot ? snapshotId : Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot
.CurrentStateId);
}
count++;
}
if (isSnapshot && !IsDotSnapshotDir(components[components.Length - 1]))
{
// for snapshot path shrink the inode array. however, for path ending with
// .snapshot, still keep last the null inode in the array
INode[] newNodes = new INode[components.Length - 1];
System.Array.Copy(inodes, 0, newNodes, 0, newNodes.Length);
inodes = newNodes;
}
return(new Org.Apache.Hadoop.Hdfs.Server.Namenode.INodesInPath(inodes, components
, isSnapshot, snapshotId));
}