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- /*
- * Copyright (C) 2013, CloudBees, 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.api;
-
- import org.eclipse.jgit.api.errors.GitAPIException;
- import org.eclipse.jgit.api.errors.JGitInternalException;
- import org.eclipse.jgit.api.errors.RefNotFoundException;
- import org.eclipse.jgit.errors.IncorrectObjectTypeException;
- import org.eclipse.jgit.errors.MissingObjectException;
- import org.eclipse.jgit.internal.JGitText;
- import org.eclipse.jgit.lib.Constants;
- import org.eclipse.jgit.lib.ObjectId;
- import org.eclipse.jgit.lib.Ref;
- import org.eclipse.jgit.lib.Repository;
- import org.eclipse.jgit.revwalk.*;
-
- import java.io.IOException;
- import java.text.MessageFormat;
- import java.util.ArrayList;
- import java.util.Collections;
- import java.util.Comparator;
- import java.util.HashMap;
- import java.util.List;
- import java.util.Map;
-
- import static org.eclipse.jgit.lib.Constants.R_TAGS;
-
- /**
- * Given a commit, show the most recent tag that is reachable from a commit.
- *
- * @since 3.2
- */
- public class DescribeCommand extends GitCommand<String> {
- private final RevWalk w;
-
- /**
- * Commit to describe.
- */
- private RevCommit target;
-
- /**
- * How many tags we'll consider as candidates.
- * This can only go up to the number of flags JGit can support in a walk,
- * which is 24.
- */
- private int maxCandidates = 10;
-
- /**
- *
- * @param repo
- */
- protected DescribeCommand(Repository repo) {
- super(repo);
- w = new RevWalk(repo);
- w.setRetainBody(false);
- }
-
- /**
- * Sets the commit to be described.
- *
- * @param target
- * A non-null object ID to be described.
- * @return {@code this}
- * @throws MissingObjectException
- * the supplied commit does not exist.
- * @throws IncorrectObjectTypeException
- * the supplied id is not a commit or an annotated tag.
- * @throws IOException
- * a pack file or loose object could not be read.
- */
- public DescribeCommand setTarget(ObjectId target) throws IOException {
- this.target = w.parseCommit(target);
- return this;
- }
-
- /**
- * Sets the commit to be described.
- *
- * @param rev
- * Commit ID, tag, branch, ref, etc.
- * See {@link Repository#resolve(String)} for allowed syntax.
- * @return {@code this}
- * @throws IncorrectObjectTypeException
- * the supplied id is not a commit or an annotated tag.
- * @throws RefNotFoundException
- * the given rev didn't resolve to any object.
- * @throws IOException
- * a pack file or loose object could not be read.
- */
- public DescribeCommand setTarget(String rev) throws IOException,
- RefNotFoundException {
- ObjectId id = repo.resolve(rev);
- if (id == null)
- throw new RefNotFoundException(MessageFormat.format(JGitText.get().refNotResolved, rev));
- return setTarget(id);
- }
-
- /**
- * Describes the specified commit. Target defaults to HEAD if no commit was
- * set explicitly.
- *
- * @return if there's a tag that points to the commit being described, this
- * tag name is returned. Otherwise additional suffix is added to the
- * nearest tag, just like git-describe(1).
- * <p>
- * If none of the ancestors of the commit being described has any
- * tags at all, then this method returns null, indicating that
- * there's no way to describe this tag.
- */
- @Override
- public String call() throws GitAPIException {
- try {
- checkCallable();
-
- if (target == null)
- setTarget(Constants.HEAD);
-
- Map<ObjectId, Ref> tags = new HashMap<ObjectId, Ref>();
-
- for (Ref r : repo.getRefDatabase().getRefs(R_TAGS).values()) {
- ObjectId key = repo.peel(r).getPeeledObjectId();
- if (key == null)
- key = r.getObjectId();
- tags.put(key, r);
- }
-
- // combined flags of all the candidate instances
- final RevFlagSet allFlags = new RevFlagSet();
-
- /**
- * Tracks the depth of each tag as we find them.
- */
- class Candidate {
- final Ref tag;
- final RevFlag flag;
-
- /**
- * This field counts number of commits that are reachable from
- * the tip but not reachable from the tag.
- */
- int depth;
-
- Candidate(RevCommit commit, Ref tag) {
- this.tag = tag;
- this.flag = w.newFlag(tag.getName());
- // we'll mark all the nodes reachable from this tag accordingly
- allFlags.add(flag);
- w.carry(flag);
- commit.add(flag);
- // As of this writing, JGit carries a flag from a child to its parents
- // right before RevWalk.next() returns, so all the flags that are added
- // must be manually carried to its parents. If that gets fixed,
- // this will be unnecessary.
- commit.carry(flag);
- }
-
- /**
- * Does this tag contain the given commit?
- */
- boolean reaches(RevCommit c) {
- return c.has(flag);
- }
-
- String describe(ObjectId tip) throws IOException {
- return String.format("%s-%d-g%s", tag.getName().substring(R_TAGS.length()), //$NON-NLS-1$
- Integer.valueOf(depth), w.getObjectReader().abbreviate(tip).name());
- }
- }
- List<Candidate> candidates = new ArrayList<Candidate>(); // all the candidates we find
-
- // is the target already pointing to a tag? if so, we are done!
- Ref lucky = tags.get(target);
- if (lucky != null)
- return lucky.getName().substring(R_TAGS.length());
-
- w.markStart(target);
-
- int seen = 0; // commit seen thus far
- RevCommit c;
- while ((c = w.next()) != null) {
- if (!c.hasAny(allFlags)) {
- // if a tag already dominates this commit,
- // then there's no point in picking a tag on this commit
- // since the one that dominates it is always more preferable
- Ref t = tags.get(c);
- if (t != null) {
- Candidate cd = new Candidate(c, t);
- candidates.add(cd);
- cd.depth = seen;
- }
- }
-
- // if the newly discovered commit isn't reachable from a tag that we've seen
- // it counts toward the total depth.
- for (Candidate cd : candidates) {
- if (!cd.reaches(c))
- cd.depth++;
- }
-
- // if we have search going for enough tags, we will start
- // closing down. JGit can only give us a finite number of bits,
- // so we can't track all tags even if we wanted to.
- if (candidates.size() >= maxCandidates)
- break;
-
- // TODO: if all the commits in the queue of RevWalk has allFlags
- // there's no point in continuing search as we'll not discover any more
- // tags. But RevWalk doesn't expose this.
- seen++;
- }
-
- // at this point we aren't adding any more tags to our search,
- // but we still need to count all the depths correctly.
- while ((c = w.next()) != null) {
- if (c.hasAll(allFlags)) {
- // no point in visiting further from here, so cut the search here
- for (RevCommit p : c.getParents())
- p.add(RevFlag.SEEN);
- } else {
- for (Candidate cd : candidates) {
- if (!cd.reaches(c))
- cd.depth++;
- }
- }
- }
-
- // if all the nodes are dominated by all the tags, the walk stops
- if (candidates.isEmpty())
- return null;
-
- Candidate best = Collections.min(candidates, new Comparator<Candidate>() {
- public int compare(Candidate o1, Candidate o2) {
- return o1.depth - o2.depth;
- }
- });
-
- return best.describe(target);
- } catch (IOException e) {
- throw new JGitInternalException(e.getMessage(), e);
- } finally {
- setCallable(false);
- w.release();
- }
- }
- }
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