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- /*
- * Copyright (C) 2008-2009, Google Inc.
- * 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.merge;
-
- import java.io.IOException;
- import java.text.MessageFormat;
-
- import org.eclipse.jgit.JGitText;
- import org.eclipse.jgit.errors.IncorrectObjectTypeException;
- import org.eclipse.jgit.lib.AnyObjectId;
- import org.eclipse.jgit.lib.Constants;
- import org.eclipse.jgit.lib.ObjectId;
- import org.eclipse.jgit.lib.ObjectInserter;
- import org.eclipse.jgit.lib.Repository;
- import org.eclipse.jgit.lib.ObjectReader;
- import org.eclipse.jgit.revwalk.RevCommit;
- import org.eclipse.jgit.revwalk.RevObject;
- import org.eclipse.jgit.revwalk.RevTree;
- import org.eclipse.jgit.revwalk.RevWalk;
- import org.eclipse.jgit.revwalk.filter.RevFilter;
- import org.eclipse.jgit.treewalk.AbstractTreeIterator;
- import org.eclipse.jgit.treewalk.CanonicalTreeParser;
- import org.eclipse.jgit.treewalk.EmptyTreeIterator;
-
- /**
- * Instance of a specific {@link MergeStrategy} for a single {@link Repository}.
- */
- public abstract class Merger {
- /** The repository this merger operates on. */
- protected final Repository db;
-
- /** Reader to support {@link #walk} and other object loading. */
- protected final ObjectReader reader;
-
- /** A RevWalk for computing merge bases, or listing incoming commits. */
- protected final RevWalk walk;
-
- private ObjectInserter inserter;
-
- /** The original objects supplied in the merge; this can be any tree-ish. */
- protected RevObject[] sourceObjects;
-
- /** If {@link #sourceObjects}[i] is a commit, this is the commit. */
- protected RevCommit[] sourceCommits;
-
- /** The trees matching every entry in {@link #sourceObjects}. */
- protected RevTree[] sourceTrees;
-
- /**
- * Create a new merge instance for a repository.
- *
- * @param local
- * the repository this merger will read and write data on.
- */
- protected Merger(final Repository local) {
- db = local;
- reader = db.newObjectReader();
- walk = new RevWalk(reader);
- }
-
- /**
- * @return the repository this merger operates on.
- */
- public Repository getRepository() {
- return db;
- }
-
- /**
- * @return an object writer to create objects in {@link #getRepository()}.
- */
- public ObjectInserter getObjectInserter() {
- if (inserter == null)
- inserter = getRepository().newObjectInserter();
- return inserter;
- }
-
- /**
- * Merge together two or more tree-ish objects.
- * <p>
- * Any tree-ish may be supplied as inputs. Commits and/or tags pointing at
- * trees or commits may be passed as input objects.
- *
- * @param tips
- * source trees to be combined together. The merge base is not
- * included in this set.
- * @return true if the merge was completed without conflicts; false if the
- * merge strategy cannot handle this merge or there were conflicts
- * preventing it from automatically resolving all paths.
- * @throws IncorrectObjectTypeException
- * one of the input objects is not a commit, but the strategy
- * requires it to be a commit.
- * @throws IOException
- * one or more sources could not be read, or outputs could not
- * be written to the Repository.
- */
- public boolean merge(final AnyObjectId[] tips) throws IOException {
- sourceObjects = new RevObject[tips.length];
- for (int i = 0; i < tips.length; i++)
- sourceObjects[i] = walk.parseAny(tips[i]);
-
- sourceCommits = new RevCommit[sourceObjects.length];
- for (int i = 0; i < sourceObjects.length; i++) {
- try {
- sourceCommits[i] = walk.parseCommit(sourceObjects[i]);
- } catch (IncorrectObjectTypeException err) {
- sourceCommits[i] = null;
- }
- }
-
- sourceTrees = new RevTree[sourceObjects.length];
- for (int i = 0; i < sourceObjects.length; i++)
- sourceTrees[i] = walk.parseTree(sourceObjects[i]);
-
- try {
- return mergeImpl();
- } finally {
- if (inserter != null)
- inserter.release();
- reader.release();
- }
- }
-
- /**
- * Create an iterator to walk the merge base of two commits.
- *
- * @param aIdx
- * index of the first commit in {@link #sourceObjects}.
- * @param bIdx
- * index of the second commit in {@link #sourceObjects}.
- * @return the new iterator
- * @throws IncorrectObjectTypeException
- * one of the input objects is not a commit.
- * @throws IOException
- * objects are missing or multiple merge bases were found.
- */
- protected AbstractTreeIterator mergeBase(final int aIdx, final int bIdx)
- throws IOException {
- RevCommit base = getBaseCommit(aIdx, bIdx);
- return (base == null) ? new EmptyTreeIterator() : openTree(base.getTree());
- }
-
- /**
- * Return the merge base of two commits.
- *
- * @param aIdx
- * index of the first commit in {@link #sourceObjects}.
- * @param bIdx
- * index of the second commit in {@link #sourceObjects}.
- * @return the merge base of two commits
- * @throws IncorrectObjectTypeException
- * one of the input objects is not a commit.
- * @throws IOException
- * objects are missing or multiple merge bases were found.
- */
- public RevCommit getBaseCommit(final int aIdx, final int bIdx)
- throws IncorrectObjectTypeException,
- IOException {
- if (sourceCommits[aIdx] == null)
- throw new IncorrectObjectTypeException(sourceObjects[aIdx],
- Constants.TYPE_COMMIT);
- if (sourceCommits[bIdx] == null)
- throw new IncorrectObjectTypeException(sourceObjects[bIdx],
- Constants.TYPE_COMMIT);
- walk.reset();
- walk.setRevFilter(RevFilter.MERGE_BASE);
- walk.markStart(sourceCommits[aIdx]);
- walk.markStart(sourceCommits[bIdx]);
- final RevCommit base = walk.next();
- if (base == null)
- return null;
- final RevCommit base2 = walk.next();
- if (base2 != null) {
- throw new IOException(MessageFormat.format(JGitText.get().multipleMergeBasesFor
- , sourceCommits[aIdx].name(), sourceCommits[bIdx].name()
- , base.name(), base2.name()));
- }
- return base;
- }
-
- /**
- * Open an iterator over a tree.
- *
- * @param treeId
- * the tree to scan; must be a tree (not a treeish).
- * @return an iterator for the tree.
- * @throws IncorrectObjectTypeException
- * the input object is not a tree.
- * @throws IOException
- * the tree object is not found or cannot be read.
- */
- protected AbstractTreeIterator openTree(final AnyObjectId treeId)
- throws IncorrectObjectTypeException, IOException {
- return new CanonicalTreeParser(null, reader, treeId);
- }
-
- /**
- * Execute the merge.
- * <p>
- * This method is called from {@link #merge(AnyObjectId[])} after the
- * {@link #sourceObjects}, {@link #sourceCommits} and {@link #sourceTrees}
- * have been populated.
- *
- * @return true if the merge was completed without conflicts; false if the
- * merge strategy cannot handle this merge or there were conflicts
- * preventing it from automatically resolving all paths.
- * @throws IncorrectObjectTypeException
- * one of the input objects is not a commit, but the strategy
- * requires it to be a commit.
- * @throws IOException
- * one or more sources could not be read, or outputs could not
- * be written to the Repository.
- */
- protected abstract boolean mergeImpl() throws IOException;
-
- /**
- * @return resulting tree, if {@link #merge(AnyObjectId[])} returned true.
- */
- public abstract ObjectId getResultTreeId();
- }
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