/**
* Recursively compute the difference between snapshots under a given directory/file.
*
* @param node The directory/file under which the diff is computed.
* @param parentPath Relative path (corresponding to the snapshot root) of the node's parent.
* @param diffReport data structure used to store the diff.
*/
private void computeDiffRecursively(
INode node, List<byte[]> parentPath, SnapshotDiffInfo diffReport) {
ChildrenDiff diff = new ChildrenDiff();
byte[][] relativePath = parentPath.toArray(new byte[parentPath.size()][]);
if (node.isDirectory()) {
INodeDirectory dir = node.asDirectory();
if (dir instanceof INodeDirectoryWithSnapshot) {
INodeDirectoryWithSnapshot sdir = (INodeDirectoryWithSnapshot) dir;
boolean change = sdir.computeDiffBetweenSnapshots(diffReport.from, diffReport.to, diff);
if (change) {
diffReport.addDirDiff(sdir, relativePath, diff);
}
}
ReadOnlyList<INode> children =
dir.getChildrenList(diffReport.isFromEarlier() ? diffReport.to : diffReport.from);
for (INode child : children) {
final byte[] name = child.getLocalNameBytes();
if (diff.searchIndex(ListType.CREATED, name) < 0
&& diff.searchIndex(ListType.DELETED, name) < 0) {
parentPath.add(name);
computeDiffRecursively(child, parentPath, diffReport);
parentPath.remove(parentPath.size() - 1);
}
}
} else if (node.isFile() && node.asFile() instanceof FileWithSnapshot) {
FileWithSnapshot file = (FileWithSnapshot) node.asFile();
Snapshot earlierSnapshot = diffReport.isFromEarlier() ? diffReport.from : diffReport.to;
Snapshot laterSnapshot = diffReport.isFromEarlier() ? diffReport.to : diffReport.from;
boolean change = file.getDiffs().changedBetweenSnapshots(earlierSnapshot, laterSnapshot);
if (change) {
diffReport.addFileDiff(file.asINodeFile(), relativePath);
}
}
}
/**
* Compute the difference between two snapshots (or a snapshot and the current directory) of the
* directory.
*
* @param from The name of the start point of the comparison. Null indicating the current tree.
* @param to The name of the end point. Null indicating the current tree.
* @return The difference between the start/end points.
* @throws SnapshotException If there is no snapshot matching the starting point, or if
* endSnapshotName is not null but cannot be identified as a previous snapshot.
*/
SnapshotDiffInfo computeDiff(final String from, final String to) throws SnapshotException {
Snapshot fromSnapshot = getSnapshotByName(from);
Snapshot toSnapshot = getSnapshotByName(to);
// if the start point is equal to the end point, return null
if (from.equals(to)) {
return null;
}
SnapshotDiffInfo diffs = new SnapshotDiffInfo(this, fromSnapshot, toSnapshot);
computeDiffRecursively(this, new ArrayList<byte[]>(), diffs);
return diffs;
}