IndexDiffFilter.java
/*
* Copyright (C) 2010, Christian Halstrick <christian.halstrick@sap.com> and others
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0 which is available at
* https://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package org.eclipse.jgit.treewalk.filter;
import java.io.IOException;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import org.eclipse.jgit.dircache.DirCacheEntry;
import org.eclipse.jgit.dircache.DirCacheIterator;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.lib.FileMode;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.treewalk.TreeWalk;
import org.eclipse.jgit.treewalk.WorkingTreeIterator;
/**
* A performance optimized variant of
* {@link org.eclipse.jgit.treewalk.filter.TreeFilter#ANY_DIFF} which should be
* used when among the walked trees there is a
* {@link org.eclipse.jgit.dircache.DirCacheIterator} and a
* {@link org.eclipse.jgit.treewalk.WorkingTreeIterator}. Please see the
* documentation of {@link org.eclipse.jgit.treewalk.filter.TreeFilter#ANY_DIFF}
* for a basic description of the semantics.
* <p>
* This filter tries to avoid computing content ids of the files in the
* working-tree. In contrast to
* {@link org.eclipse.jgit.treewalk.filter.TreeFilter#ANY_DIFF} this filter
* takes care to first compare the entry from the
* {@link org.eclipse.jgit.dircache.DirCacheIterator} with the entries from all
* other iterators besides the
* {@link org.eclipse.jgit.treewalk.WorkingTreeIterator}. Since all those
* entries have fast access to content ids that is very fast. If a difference is
* detected in this step this filter decides to include that path before even
* looking at the working-tree entry.
* <p>
* If no difference is found then we have to compare index and working-tree as
* the last step. By making use of
* {@link org.eclipse.jgit.treewalk.WorkingTreeIterator#isModified(org.eclipse.jgit.dircache.DirCacheEntry, boolean, ObjectReader)}
* we can avoid the computation of the content id if the file is not dirty.
* <p>
* Instances of this filter should not be used for multiple
* {@link org.eclipse.jgit.treewalk.TreeWalk}s. Always construct a new instance
* of this filter for each TreeWalk.
*/
public class IndexDiffFilter extends TreeFilter {
private final int dirCache;
private final int workingTree;
private final boolean honorIgnores;
private final Set<String> ignoredPaths = new HashSet<>();
private final LinkedList<String> untrackedParentFolders = new LinkedList<>();
private final LinkedList<String> untrackedFolders = new LinkedList<>();
/**
* Creates a new instance of this filter. Do not use an instance of this
* filter in multiple treewalks.
*
* @param dirCacheIndex
* the index of the
* {@link org.eclipse.jgit.dircache.DirCacheIterator} in the
* associated treewalk
* @param workingTreeIndex
* the index of the
* {@link org.eclipse.jgit.treewalk.WorkingTreeIterator} in the
* associated treewalk
*/
public IndexDiffFilter(int dirCacheIndex, int workingTreeIndex) {
this(dirCacheIndex, workingTreeIndex, true /* honor ignores */);
}
/**
* Creates a new instance of this filter. Do not use an instance of this
* filter in multiple treewalks.
*
* @param dirCacheIndex
* the index of the
* {@link org.eclipse.jgit.dircache.DirCacheIterator} in the
* associated treewalk
* @param workingTreeIndex
* the index of the
* {@link org.eclipse.jgit.treewalk.WorkingTreeIterator} in the
* associated treewalk
* @param honorIgnores
* true if the filter should skip working tree files that are
* declared as ignored by the standard exclude mechanisms.
*/
public IndexDiffFilter(int dirCacheIndex, int workingTreeIndex,
boolean honorIgnores) {
this.dirCache = dirCacheIndex;
this.workingTree = workingTreeIndex;
this.honorIgnores = honorIgnores;
}
/** {@inheritDoc} */
@Override
public boolean include(TreeWalk tw) throws MissingObjectException,
IncorrectObjectTypeException, IOException {
final int cnt = tw.getTreeCount();
final int wm = tw.getRawMode(workingTree);
WorkingTreeIterator wi = workingTree(tw);
String path = tw.getPathString();
DirCacheIterator di = tw.getTree(dirCache, DirCacheIterator.class);
if (di != null) {
DirCacheEntry dce = di.getDirCacheEntry();
if (dce != null) {
if (dce.isAssumeValid())
return false;
// Never filter index entries with a stage different from 0
if (dce.getStage() != 0)
return true;
}
}
if (!tw.isPostOrderTraversal()) {
// detect untracked Folders
// Whenever we enter a folder in the workingtree assume it will
// contain only untracked files and add it to
// untrackedParentFolders. If we later find tracked files we will
// remove it from this list
if (FileMode.TREE.equals(wm)
&& !(honorIgnores && wi.isEntryIgnored())) {
// Clean untrackedParentFolders. This potentially moves entries
// from untrackedParentFolders to untrackedFolders
copyUntrackedFolders(path);
// add the folder we just entered to untrackedParentFolders
untrackedParentFolders.addFirst(path);
}
// detect untracked Folders
// Whenever we see a tracked file we know that all of its parent
// folders do not belong into untrackedParentFolders anymore. Clean
// it.
for (int i = 0; i < cnt; i++) {
int rmode = tw.getRawMode(i);
if (i != workingTree && rmode != FileMode.TYPE_MISSING
&& FileMode.TREE.equals(rmode)) {
untrackedParentFolders.clear();
break;
}
}
}
// If the working tree file doesn't exist, it does exist for at least
// one other so include this difference.
if (wm == 0)
return true;
// If the path does not appear in the DirCache and its ignored
// we can avoid returning a result here, but only if its not in any
// other tree.
final int dm = tw.getRawMode(dirCache);
if (dm == FileMode.TYPE_MISSING) {
if (honorIgnores && wi.isEntryIgnored()) {
ignoredPaths.add(wi.getEntryPathString());
int i = 0;
for (; i < cnt; i++) {
if (i == dirCache || i == workingTree)
continue;
if (tw.getRawMode(i) != FileMode.TYPE_MISSING)
break;
}
// If i is cnt then the path does not appear in any other tree,
// and this working tree entry can be safely ignored.
return i != cnt;
}
// In working tree and not ignored, and not in DirCache.
return true;
}
// Always include subtrees as WorkingTreeIterator cannot provide
// efficient elimination of unmodified subtrees.
if (tw.isSubtree())
return true;
// Try the inexpensive comparisons between index and all real trees
// first. Only if we don't find a diff here we have to bother with
// the working tree
for (int i = 0; i < cnt; i++) {
if (i == dirCache || i == workingTree)
continue;
if (tw.getRawMode(i) != dm || !tw.idEqual(i, dirCache))
return true;
}
// Only one chance left to detect a diff: between index and working
// tree. Make use of the WorkingTreeIterator#isModified() method to
// avoid computing SHA1 on filesystem content if not really needed.
return wi.isModified(di == null ? null : di.getDirCacheEntry(), true,
tw.getObjectReader());
}
/**
* Copy all entries which are still in untrackedParentFolders and which
* belong to a path this treewalk has left into untrackedFolders. It is sure
* that we will not find any tracked files underneath these paths. Therefore
* these paths definitely belong to untracked folders.
*
* @param currentPath
* the current path of the treewalk
*/
private void copyUntrackedFolders(String currentPath) {
String pathToBeSaved = null;
while (!untrackedParentFolders.isEmpty() && !currentPath
.startsWith(untrackedParentFolders.getFirst() + '/')) {
pathToBeSaved = untrackedParentFolders.removeFirst();
}
if (pathToBeSaved != null) {
while (!untrackedFolders.isEmpty() && untrackedFolders.getLast()
.startsWith(pathToBeSaved + '/')) {
untrackedFolders.removeLast();
}
untrackedFolders.addLast(pathToBeSaved);
}
}
private WorkingTreeIterator workingTree(TreeWalk tw) {
return tw.getTree(workingTree, WorkingTreeIterator.class);
}
/** {@inheritDoc} */
@Override
public boolean shouldBeRecursive() {
// We cannot compare subtrees in the working tree, so encourage
// use of recursive walks where the subtrees are always dived into.
return true;
}
/** {@inheritDoc} */
@Override
public TreeFilter clone() {
return this;
}
/** {@inheritDoc} */
@Override
public String toString() {
return "INDEX_DIFF_FILTER"; //$NON-NLS-1$
}
/**
* The method returns the list of ignored files and folders. Only the root
* folder of an ignored folder hierarchy is reported. If a/b/c is listed in
* the .gitignore then you should not expect a/b/c/d/e/f to be reported
* here. Only a/b/c will be reported. Furthermore only ignored files /
* folders are returned that are NOT in the index.
*
* @return ignored paths
*/
public Set<String> getIgnoredPaths() {
return ignoredPaths;
}
/**
* <p>Getter for the field <code>untrackedFolders</code>.</p>
*
* @return all paths of folders which contain only untracked files/folders.
* If on the associated treewalk postorder traversal was turned on
* (see {@link org.eclipse.jgit.treewalk.TreeWalk#setPostOrderTraversal(boolean)}) then an
* empty list will be returned.
*/
public List<String> getUntrackedFolders() {
LinkedList<String> ret = new LinkedList<>(untrackedFolders);
if (!untrackedParentFolders.isEmpty()) {
String toBeAdded = untrackedParentFolders.getLast();
while (!ret.isEmpty() && ret.getLast().startsWith(toBeAdded))
ret.removeLast();
ret.addLast(toBeAdded);
}
return ret;
}
}