/*
* Copyright (C) 2010, Christian Halstrick <christian.halstrick@sap.com>
* and other copyright owners as documented in the project's IP log.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Distribution License v1.0 which
* accompanies this distribution, is reproduced below, and is
* available at http://www.eclipse.org/org/documents/edl-v10.php
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* - Neither the name of the Eclipse Foundation, Inc. nor the
* names of its contributors may be used to endorse or promote
* products derived from this software without specific prior
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*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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package org.eclipse.jgit.treewalk.filter;
import java.io.IOException;
import org.eclipse.jgit.dircache.DirCacheIterator;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.treewalk.TreeWalk;
import org.eclipse.jgit.treewalk.WorkingTreeIterator;
/**
* A performance optimized variant of {@link TreeFilter#ANY_DIFF} which should
* be used when among the walked trees there is a {@link DirCacheIterator} and a
* {@link WorkingTreeIterator}. Please see the documentation of
* {@link 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 TreeFilter#ANY_DIFF} this filter takes
* care to first compare the entry from the {@link DirCacheIterator} with the
* entries from all other iterators besides the {@link 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 WorkingTreeIterator#isModified(org.eclipse.jgit.dircache.DirCacheEntry, boolean)}
* 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 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;
/**
* 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 DirCacheIterator} in the associated
* treewalk
* @param workingTreeIndex
* the index of the {@link 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 DirCacheIterator} in the associated
* treewalk
* @param workingTreeIndex
* the index of the {@link 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;
}
@Override
public boolean include(TreeWalk tw) throws MissingObjectException,
IncorrectObjectTypeException, IOException {
// If the working tree file doesn't exist, it does exist for at least
// one other so include this difference.
final int wm = tw.getRawMode(workingTree);
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 cnt = tw.getTreeCount();
final int dm = tw.getRawMode(dirCache);
if (dm == 0) {
if (honorIgnores && workingTree(tw).isEntryIgnored()) {
int i = 0;
for (; i < cnt; i++) {
if (i == dirCache || i == workingTree)
continue;
if (tw.getRawMode(i) != 0)
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 ? false : true;
} else {
// 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.
WorkingTreeIterator wi = workingTree(tw);
DirCacheIterator di = tw.getTree(dirCache, DirCacheIterator.class);
return wi.isModified(di.getDirCacheEntry(), true);
}
private WorkingTreeIterator workingTree(TreeWalk tw) {
return tw.getTree(workingTree, WorkingTreeIterator.class);
}
@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;
}
@Override
public TreeFilter clone() {
return this;
}
@Override
public String toString() {
return "INDEX_DIFF_FILTER";
}
}