org.eclipse.jgit.dircache.DirCacheEditor Maven / Gradle / Ivy
/*
* Copyright (C) 2008-2009, Google Inc.
* Copyright (C) 2008, Shawn O. Pearce
* 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
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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*/
package org.eclipse.jgit.dircache;
import java.io.IOException;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.Constants;
/**
* Updates a {@link DirCache} by supplying discrete edit commands.
*
* An editor updates a DirCache by taking a list of {@link PathEdit} commands
* and executing them against the entries of the destination cache to produce a
* new cache. This edit style allows applications to insert a few commands and
* then have the editor compute the proper entry indexes necessary to perform an
* efficient in-order update of the index records. This can be easier to use
* than {@link DirCacheBuilder}.
*
*
* @see DirCacheBuilder
*/
public class DirCacheEditor extends BaseDirCacheEditor {
private static final Comparator EDIT_CMP = new Comparator() {
public int compare(final PathEdit o1, final PathEdit o2) {
final byte[] a = o1.path;
final byte[] b = o2.path;
return DirCache.cmp(a, a.length, b, b.length);
}
};
private final List edits;
/**
* Construct a new editor.
*
* @param dc
* the cache this editor will eventually update.
* @param ecnt
* estimated number of entries the editor will have upon
* completion. This sizes the initial entry table.
*/
protected DirCacheEditor(final DirCache dc, final int ecnt) {
super(dc, ecnt);
edits = new ArrayList();
}
/**
* Append one edit command to the list of commands to be applied.
*
* Edit commands may be added in any order chosen by the application. They
* are automatically rearranged by the builder to provide the most efficient
* update possible.
*
* @param edit
* another edit command.
*/
public void add(final PathEdit edit) {
edits.add(edit);
}
@Override
public boolean commit() throws IOException {
if (edits.isEmpty()) {
// No changes? Don't rewrite the index.
//
cache.unlock();
return true;
}
return super.commit();
}
public void finish() {
if (!edits.isEmpty()) {
applyEdits();
replace();
}
}
private void applyEdits() {
Collections.sort(edits, EDIT_CMP);
final int maxIdx = cache.getEntryCount();
int lastIdx = 0;
for (final PathEdit e : edits) {
int eIdx = cache.findEntry(e.path, e.path.length);
final boolean missing = eIdx < 0;
if (eIdx < 0)
eIdx = -(eIdx + 1);
final int cnt = Math.min(eIdx, maxIdx) - lastIdx;
if (cnt > 0)
fastKeep(lastIdx, cnt);
lastIdx = missing ? eIdx : cache.nextEntry(eIdx);
if (e instanceof DeletePath)
continue;
if (e instanceof DeleteTree) {
lastIdx = cache.nextEntry(e.path, e.path.length, eIdx);
continue;
}
if (missing) {
final DirCacheEntry ent = new DirCacheEntry(e.path);
e.apply(ent);
if (ent.getRawMode() == 0)
throw new IllegalArgumentException(MessageFormat.format(JGitText.get().fileModeNotSetForPath
, ent.getPathString()));
fastAdd(ent);
} else {
// Apply to all entries of the current path (different stages)
for (int i = eIdx; i < lastIdx; i++) {
final DirCacheEntry ent = cache.getEntry(i);
e.apply(ent);
fastAdd(ent);
}
}
}
final int cnt = maxIdx - lastIdx;
if (cnt > 0)
fastKeep(lastIdx, cnt);
}
/**
* Any index record update.
*
* Applications should subclass and provide their own implementation for the
* {@link #apply(DirCacheEntry)} method. The editor will invoke apply once
* for each record in the index which matches the path name. If there are
* multiple records (for example in stages 1, 2 and 3), the edit instance
* will be called multiple times, once for each stage.
*/
public abstract static class PathEdit {
final byte[] path;
/**
* Create a new update command by path name.
*
* @param entryPath
* path of the file within the repository.
*/
public PathEdit(final String entryPath) {
path = Constants.encode(entryPath);
}
/**
* Create a new update command for an existing entry instance.
*
* @param ent
* entry instance to match path of. Only the path of this
* entry is actually considered during command evaluation.
*/
public PathEdit(final DirCacheEntry ent) {
path = ent.path;
}
/**
* Apply the update to a single cache entry matching the path.
*
* After apply is invoked the entry is added to the output table, and
* will be included in the new index.
*
* @param ent
* the entry being processed. All fields are zeroed out if
* the path is a new path in the index.
*/
public abstract void apply(DirCacheEntry ent);
}
/**
* Deletes a single file entry from the index.
*
* This deletion command removes only a single file at the given location,
* but removes multiple stages (if present) for that path. To remove a
* complete subtree use {@link DeleteTree} instead.
*
* @see DeleteTree
*/
public static final class DeletePath extends PathEdit {
/**
* Create a new deletion command by path name.
*
* @param entryPath
* path of the file within the repository.
*/
public DeletePath(final String entryPath) {
super(entryPath);
}
/**
* Create a new deletion command for an existing entry instance.
*
* @param ent
* entry instance to remove. Only the path of this entry is
* actually considered during command evaluation.
*/
public DeletePath(final DirCacheEntry ent) {
super(ent);
}
public void apply(final DirCacheEntry ent) {
throw new UnsupportedOperationException(JGitText.get().noApplyInDelete);
}
}
/**
* Recursively deletes all paths under a subtree.
*
* This deletion command is more generic than {@link DeletePath} as it can
* remove all records which appear recursively under the same subtree.
* Multiple stages are removed (if present) for any deleted entry.
*
* This command will not remove a single file entry. To remove a single file
* use {@link DeletePath}.
*
* @see DeletePath
*/
public static final class DeleteTree extends PathEdit {
/**
* Create a new tree deletion command by path name.
*
* @param entryPath
* path of the subtree within the repository. If the path
* does not end with "/" a "/" is implicitly added to ensure
* only the subtree's contents are matched by the command.
* The special case "" (not "/"!) deletes all entries.
*/
public DeleteTree(final String entryPath) {
super(
(entryPath.endsWith("/") || entryPath.length() == 0) ? entryPath
: entryPath + "/");
}
public void apply(final DirCacheEntry ent) {
throw new UnsupportedOperationException(JGitText.get().noApplyInDelete);
}
}
}