com.google.gerrit.server.git.MergeSuperSet.java Source code

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// Copyright (C) 2015 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package com.google.gerrit.server.git;

import com.google.common.base.Strings;
import com.google.common.collect.Multimap;
import com.google.gerrit.common.data.SubmitTypeRecord;
import com.google.gerrit.extensions.client.SubmitType;
import com.google.gerrit.reviewdb.client.Branch;
import com.google.gerrit.reviewdb.client.Change;
import com.google.gerrit.reviewdb.client.PatchSet;
import com.google.gerrit.reviewdb.client.Project;
import com.google.gerrit.reviewdb.server.ReviewDb;
import com.google.gerrit.server.change.Submit;
import com.google.gerrit.server.config.GerritServerConfig;
import com.google.gerrit.server.project.SubmitRuleEvaluator;
import com.google.gerrit.server.query.change.ChangeData;
import com.google.gerrit.server.query.change.InternalChangeQuery;
import com.google.gwtorm.server.OrmException;
import com.google.inject.Inject;
import com.google.inject.Provider;
import com.google.inject.Singleton;

import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.lib.Config;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevSort;
import org.eclipse.jgit.revwalk.RevWalk;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

/**
 * Calculates the minimal superset of changes required to be merged.
 * <p>
 * This includes all parents between a change and the tip of its target
 * branch for the merging/rebasing submit strategies. For the cherry-pick
 * strategy no additional changes are included.
 * <p>
 * If change.submitWholeTopic is enabled, also all changes of the topic
 * and their parents are included.
 */
@Singleton
public class MergeSuperSet {
    private static final Logger log = LoggerFactory.getLogger(MergeOp.class);

    private final ChangeData.Factory changeDataFactory;
    private final Provider<InternalChangeQuery> queryProvider;
    private final GitRepositoryManager repoManager;
    private final Config cfg;

    @Inject
    MergeSuperSet(@GerritServerConfig Config cfg, ChangeData.Factory changeDataFactory,
            Provider<InternalChangeQuery> queryProvider, GitRepositoryManager repoManager) {
        this.cfg = cfg;
        this.changeDataFactory = changeDataFactory;
        this.queryProvider = queryProvider;
        this.repoManager = repoManager;
    }

    public ChangeSet completeChangeSet(ReviewDb db, Change change)
            throws MissingObjectException, IncorrectObjectTypeException, IOException, OrmException {
        ChangeData cd = changeDataFactory.create(db, change.getId());
        if (Submit.wholeTopicEnabled(cfg)) {
            return completeChangeSetIncludingTopics(db, new ChangeSet(cd));
        } else {
            return completeChangeSetWithoutTopic(db, new ChangeSet(cd));
        }
    }

    private ChangeSet completeChangeSetWithoutTopic(ReviewDb db, ChangeSet changes)
            throws MissingObjectException, IncorrectObjectTypeException, IOException, OrmException {
        List<ChangeData> ret = new ArrayList<>();

        Multimap<Project.NameKey, Change.Id> pc = changes.changesByProject();
        for (Project.NameKey project : pc.keySet()) {
            try (Repository repo = repoManager.openRepository(project);
                    RevWalk rw = CodeReviewCommit.newRevWalk(repo)) {
                for (Change.Id cId : pc.get(project)) {
                    ChangeData cd = changeDataFactory.create(db, cId);

                    SubmitTypeRecord r = new SubmitRuleEvaluator(cd).getSubmitType();
                    if (r.status != SubmitTypeRecord.Status.OK) {
                        logErrorAndThrow("Failed to get submit type for " + cd.getId());
                    }
                    if (r.type == SubmitType.CHERRY_PICK) {
                        ret.add(cd);
                        continue;
                    }

                    // Get the underlying git commit object
                    PatchSet ps = cd.currentPatchSet();
                    String objIdStr = ps.getRevision().get();
                    RevCommit commit = rw.parseCommit(ObjectId.fromString(objIdStr));

                    // Collect unmerged ancestors
                    Branch.NameKey destBranch = cd.change().getDest();
                    repo.getRefDatabase().refresh();
                    Ref ref = repo.getRefDatabase().getRef(destBranch.get());

                    rw.reset();
                    rw.sort(RevSort.TOPO);
                    rw.markStart(commit);
                    if (ref != null) {
                        RevCommit head = rw.parseCommit(ref.getObjectId());
                        rw.markUninteresting(head);
                    }

                    List<String> hashes = new ArrayList<>();
                    for (RevCommit c : rw) {
                        hashes.add(c.name());
                    }

                    if (!hashes.isEmpty()) {
                        // Merged changes are ok to exclude
                        Iterable<ChangeData> destChanges = queryProvider.get()
                                .byCommitsOnBranchNotMerged(cd.change().getDest(), hashes);
                        for (ChangeData chd : destChanges) {
                            ret.add(chd);
                        }
                    }
                }
            }
        }

        return new ChangeSet(ret);
    }

    private ChangeSet completeChangeSetIncludingTopics(ReviewDb db, ChangeSet changes)
            throws MissingObjectException, IncorrectObjectTypeException, IOException, OrmException {
        Set<String> topicsTraversed = new HashSet<>();
        boolean done = false;
        ChangeSet newCs = completeChangeSetWithoutTopic(db, changes);
        while (!done) {
            List<ChangeData> chgs = new ArrayList<>();
            done = true;
            for (ChangeData cd : newCs.changes()) {
                chgs.add(cd);
                String topic = cd.change().getTopic();
                if (!Strings.isNullOrEmpty(topic) && !topicsTraversed.contains(topic)) {
                    chgs.addAll(queryProvider.get().byTopicOpen(topic));
                    done = false;
                    topicsTraversed.add(topic);
                }
            }
            changes = new ChangeSet(chgs);
            newCs = completeChangeSetWithoutTopic(db, changes);
        }
        return newCs;
    }

    private void logError(String msg) {
        if (log.isErrorEnabled()) {
            log.error(msg);
        }
    }

    private void logErrorAndThrow(String msg) throws OrmException {
        logError(msg);
        throw new OrmException(msg);
    }
}