org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheEditor.java - jgit - Git at Google

 /*
  * Copyright (C) 2008-2009, Google Inc.
  * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
  * 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
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 package org.eclipse.jgit.dircache;

 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;

 import org.eclipse.jgit.lib.Constants;

 /**
  * Updates a {@link DirCache} by supplying discrete edit commands.
  * <p>
  * 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}.
  * <p>
  *
  * @see DirCacheBuilder
  */
 public class DirCacheEditor extends BaseDirCacheEditor {
 	private static final Comparator<PathEdit> EDIT_CMP = new Comparator<PathEdit>() {
 		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<PathEdit> 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<PathEdit>();
 	}

 	/**
 	 * Append one edit command to the list of commands to be applied.
 	 * <p>
 	 * 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;
 			}

 			final DirCacheEntry ent;
 			if (missing) {
 				ent = new DirCacheEntry(e.path);
 				e.apply(ent);
 				if (ent.getRawMode() == 0)
 					throw new IllegalArgumentException("FileMode not set"
 							+ " for path " + ent.getPathString());
 			} else {
 				ent = cache.getEntry(eIdx);
 				e.apply(ent);
 			}
 			fastAdd(ent);
 		}

 		final int cnt = maxIdx - lastIdx;
 		if (cnt > 0)
 			fastKeep(lastIdx, cnt);
 	}

 	/**
 	 * Any index record update.
 	 * <p>
 	 * 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.
 		 * <p>
 		 * 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.
 	 * <p>
 	 * 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("No apply in delete");
 		}
 	}

 	/**
 	 * Recursively deletes all paths under a subtree.
 	 * <p>
 	 * 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.
 	 * <p>
 	 * 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.
 		 */
 		public DeleteTree(final String entryPath) {
 			super(entryPath.endsWith("/") ? entryPath : entryPath + "/");
 		}

 		public void apply(final DirCacheEntry ent) {
 			throw new UnsupportedOperationException("No apply in delete");
 		}
 	}
 }
	/*
	* Copyright (C) 2008-2009, Google Inc.
	* Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
	* 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
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
	* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
	* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
	* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
	* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	package org.eclipse.jgit.dircache;

	import java.io.IOException;
	import java.util.ArrayList;
	import java.util.Collections;
	import java.util.Comparator;
	import java.util.List;

	import org.eclipse.jgit.lib.Constants;

	/**
	* Updates a {@link DirCache} by supplying discrete edit commands.
	* <p>
	* 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}.
	* <p>
	*
	* @see DirCacheBuilder
	*/
	public class DirCacheEditor extends BaseDirCacheEditor {
	private static final Comparator<PathEdit> EDIT_CMP = new Comparator<PathEdit>() {
	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<PathEdit> 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<PathEdit>();
	}

	/**
	* Append one edit command to the list of commands to be applied.
	* <p>
	* 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;
	}

	final DirCacheEntry ent;
	if (missing) {
	ent = new DirCacheEntry(e.path);
	e.apply(ent);
	if (ent.getRawMode() == 0)
	throw new IllegalArgumentException("FileMode not set"
	+ " for path " + ent.getPathString());
	} else {
	ent = cache.getEntry(eIdx);
	e.apply(ent);
	}
	fastAdd(ent);
	}

	final int cnt = maxIdx - lastIdx;
	if (cnt > 0)
	fastKeep(lastIdx, cnt);
	}

	/**
	* Any index record update.
	* <p>
	* 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.
	* <p>
	* 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.
	* <p>
	* 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("No apply in delete");
	}
	}

	/**
	* Recursively deletes all paths under a subtree.
	* <p>
	* 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.
	* <p>
	* 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.
	*/
	public DeleteTree(final String entryPath) {
	super(entryPath.endsWith("/") ? entryPath : entryPath + "/");
	}

	public void apply(final DirCacheEntry ent) {
	throw new UnsupportedOperationException("No apply in delete");
	}
	}
	}