TreeFilter.java
/*
* Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org> 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 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;
/**
* Selects interesting tree entries during walking.
* <p>
* This is an abstract interface. Applications may implement a subclass, or use
* one of the predefined implementations already available within this package.
* <p>
* Unless specifically noted otherwise a TreeFilter implementation is not thread
* safe and may not be shared by different TreeWalk instances at the same time.
* This restriction allows TreeFilter implementations to cache state within
* their instances during {@link #include(TreeWalk)} if it is beneficial to
* their implementation. Deep clones created by {@link #clone()} may be used to
* construct a thread-safe copy of an existing filter.
*
* <p>
* <b>Path filters:</b>
* <ul>
* <li>Matching pathname:
* {@link org.eclipse.jgit.treewalk.filter.PathFilter}</li>
* </ul>
*
* <p>
* <b>Difference filters:</b>
* <ul>
* <li>Only select differences: {@link #ANY_DIFF}.</li>
* </ul>
*
* <p>
* <b>Boolean modifiers:</b>
* <ul>
* <li>AND: {@link org.eclipse.jgit.treewalk.filter.AndTreeFilter}</li>
* <li>OR: {@link org.eclipse.jgit.treewalk.filter.OrTreeFilter}</li>
* <li>NOT: {@link org.eclipse.jgit.treewalk.filter.NotTreeFilter}</li>
* </ul>
*/
public abstract class TreeFilter {
/** Selects all tree entries. */
public static final TreeFilter ALL = new AllFilter();
private static final class AllFilter extends TreeFilter {
@Override
public boolean include(TreeWalk walker) {
return true;
}
@Override
public boolean shouldBeRecursive() {
return false;
}
@Override
public TreeFilter clone() {
return this;
}
@Override
public String toString() {
return "ALL"; //$NON-NLS-1$
}
}
/**
* Selects only tree entries which differ between at least 2 trees.
* <p>
* This filter also prevents a TreeWalk from recursing into a subtree if all
* parent trees have the identical subtree at the same path. This
* dramatically improves walk performance as only the changed subtrees are
* entered into.
* <p>
* If this filter is applied to a walker with only one tree it behaves like
* {@link #ALL}, or as though the walker was matching a virtual empty tree
* against the single tree it was actually given. Applications may wish to
* treat such a difference as "all names added".
* <p>
* When comparing {@link WorkingTreeIterator} and {@link DirCacheIterator}
* applications should use {@link IndexDiffFilter}.
*/
public static final TreeFilter ANY_DIFF = new AnyDiffFilter();
private static final class AnyDiffFilter extends TreeFilter {
private static final int baseTree = 0;
@Override
public boolean include(TreeWalk walker) {
final int n = walker.getTreeCount();
if (n == 1) // Assume they meant difference to empty tree.
return true;
final int m = walker.getRawMode(baseTree);
for (int i = 1; i < n; i++)
if (walker.getRawMode(i) != m || !walker.idEqual(i, baseTree))
return true;
return false;
}
@Override
public boolean shouldBeRecursive() {
return false;
}
@Override
public TreeFilter clone() {
return this;
}
@Override
public String toString() {
return "ANY_DIFF"; //$NON-NLS-1$
}
}
/**
* Create a new filter that does the opposite of this filter.
*
* @return a new filter that includes tree entries this filter rejects.
*/
public TreeFilter negate() {
return NotTreeFilter.create(this);
}
/**
* Determine if the current entry is interesting to report.
* <p>
* This method is consulted for subtree entries even if
* {@link org.eclipse.jgit.treewalk.TreeWalk#isRecursive()} is enabled. The
* consultation allows the filter to bypass subtree recursion on a
* case-by-case basis, even when recursion is enabled at the application
* level.
*
* @param walker
* the walker the filter needs to examine.
* @return true if the current entry should be seen by the application;
* false to hide the entry.
* @throws org.eclipse.jgit.errors.MissingObjectException
* an object the filter needs to consult to determine its answer
* does not exist in the Git repository the walker is operating
* on. Filtering this current walker entry is impossible without
* the object.
* @throws org.eclipse.jgit.errors.IncorrectObjectTypeException
* an object the filter needed to consult was not of the
* expected object type. This usually indicates a corrupt
* repository, as an object link is referencing the wrong type.
* @throws java.io.IOException
* a loose object or pack file could not be read to obtain data
* necessary for the filter to make its decision.
*/
public abstract boolean include(TreeWalk walker)
throws MissingObjectException, IncorrectObjectTypeException,
IOException;
/**
* Determine if the current entry is a parent, a match, or no match.
* <p>
* This method extends the result returned by {@link #include(TreeWalk)}
* with a third option (-1), splitting the value true. This gives the
* application a possibility to distinguish between an exact match and the
* case when a subtree to the current entry might be a match.
*
* @param walker
* the walker the filter needs to examine.
* @return -1 if the current entry is a parent of the filter but no exact
* match has been made; 0 if the current entry should be seen by the
* application; 1 if it should be hidden.
* @throws org.eclipse.jgit.errors.MissingObjectException
* as thrown by {@link #include(TreeWalk)}
* @throws org.eclipse.jgit.errors.IncorrectObjectTypeException
* as thrown by {@link #include(TreeWalk)}
* @throws java.io.IOException
* as thrown by {@link #include(TreeWalk)}
* @since 4.7
*/
public int matchFilter(TreeWalk walker)
throws MissingObjectException, IncorrectObjectTypeException,
IOException
{
return include(walker) ? 0 : 1;
}
/**
* Does this tree filter require a recursive walk to match everything?
* <p>
* If this tree filter is matching on full entry path names and its pattern
* is looking for a '/' then the filter would require a recursive TreeWalk
* to accurately make its decisions. The walker is not required to enable
* recursive behavior for any particular filter, this is only a hint.
*
* @return true if the filter would like to have the walker recurse into
* subtrees to make sure it matches everything correctly; false if
* the filter does not require entering subtrees.
*/
public abstract boolean shouldBeRecursive();
/**
* {@inheritDoc}
*
* Clone this tree filter, including its parameters.
* <p>
* This is a deep clone. If this filter embeds objects or other filters it
* must also clone those, to ensure the instances do not share mutable data.
*/
@Override
public abstract TreeFilter clone();
/** {@inheritDoc} */
@Override
public String toString() {
String n = getClass().getName();
int lastDot = n.lastIndexOf('.');
if (lastDot >= 0) {
n = n.substring(lastDot + 1);
}
return n.replace('$', '.');
}
}