001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.maven.scm.provider.git.jgit.command.diff;
020
021import java.io.ByteArrayOutputStream;
022import java.io.IOException;
023import java.io.OutputStream;
024
025import org.apache.maven.scm.ScmException;
026import org.apache.maven.scm.ScmFileSet;
027import org.apache.maven.scm.ScmVersion;
028import org.apache.maven.scm.command.diff.AbstractDiffCommand;
029import org.apache.maven.scm.command.diff.DiffScmResult;
030import org.apache.maven.scm.provider.ScmProviderRepository;
031import org.apache.maven.scm.provider.git.command.GitCommand;
032import org.apache.maven.scm.provider.git.command.diff.GitDiffConsumer;
033import org.apache.maven.scm.provider.git.jgit.command.JGitUtils;
034import org.eclipse.jgit.api.Git;
035import org.eclipse.jgit.api.errors.GitAPIException;
036import org.eclipse.jgit.lib.ObjectId;
037import org.eclipse.jgit.lib.ObjectReader;
038import org.eclipse.jgit.lib.Repository;
039import org.eclipse.jgit.revwalk.RevWalk;
040import org.eclipse.jgit.treewalk.AbstractTreeIterator;
041import org.eclipse.jgit.treewalk.CanonicalTreeParser;
042
043/**
044 * @author Dominik Bartholdi (imod)
045 * @since 1.9
046 */
047public class JGitDiffCommand extends AbstractDiffCommand implements GitCommand {
048
049    @Override
050    protected DiffScmResult executeDiffCommand(
051            ScmProviderRepository repository, ScmFileSet fileSet, ScmVersion startRevision, ScmVersion endRevision)
052            throws ScmException {
053
054        Git git = null;
055        try {
056            git = JGitUtils.openRepo(fileSet.getBasedir());
057            DiffScmResult diff = callDiff(git, startRevision, endRevision);
058            git.getRepository().close();
059            return diff;
060        } catch (Exception e) {
061            throw new ScmException("JGit diff failure!", e);
062        } finally {
063            JGitUtils.closeRepo(git);
064        }
065    }
066
067    public DiffScmResult callDiff(Git git, ScmVersion startRevision, ScmVersion endRevision)
068            throws IOException, GitAPIException, ScmException {
069
070        AbstractTreeIterator oldTree = null;
071        if (startRevision != null && !startRevision.getName().trim().isEmpty()) {
072            String startRev = startRevision.getName().trim();
073            oldTree = getTreeIterator(git.getRepository(), startRev);
074        }
075
076        AbstractTreeIterator newTree = null;
077        if (endRevision != null && !endRevision.getName().trim().isEmpty()) {
078            String endRev = endRevision.getName().trim();
079            newTree = getTreeIterator(git.getRepository(), endRev);
080        }
081
082        OutputStream out = new ByteArrayOutputStream();
083
084        git.diff()
085                .setOutputStream(out)
086                .setOldTree(oldTree)
087                .setNewTree(newTree)
088                .setCached(false)
089                .call();
090        git.diff()
091                .setOutputStream(out)
092                .setOldTree(oldTree)
093                .setNewTree(newTree)
094                .setCached(true)
095                .call();
096
097        out.flush();
098
099        GitDiffConsumer consumer = new GitDiffConsumer(null);
100        String fullDiff = out.toString();
101        out.close();
102
103        String[] lines = fullDiff.split("\n");
104        for (String aLine : lines) {
105            consumer.consumeLine(aLine);
106        }
107
108        return new DiffScmResult(
109                "JGit diff", consumer.getChangedFiles(), consumer.getDifferences(), consumer.getPatch());
110    }
111
112    private AbstractTreeIterator getTreeIterator(Repository repo, String name) throws IOException {
113        final ObjectId id = repo.resolve(name);
114        if (id == null) {
115            throw new IllegalArgumentException(name);
116        }
117        final CanonicalTreeParser p = new CanonicalTreeParser();
118
119        try (ObjectReader or = repo.newObjectReader();
120                RevWalk revWalk = new RevWalk(repo)) {
121            p.reset(or, revWalk.parseTree(id));
122            return p;
123        }
124    }
125}