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

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// Copyright (C) 2012 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 static com.google.gerrit.server.change.PatchSetInserter.ValidatePolicy;

import com.google.common.collect.Lists;
import com.google.gerrit.reviewdb.client.Change;
import com.google.gerrit.reviewdb.client.PatchSet;
import com.google.gerrit.reviewdb.client.PatchSetApproval;
import com.google.gerrit.server.IdentifiedUser;
import com.google.gerrit.server.changedetail.PathConflictException;
import com.google.gerrit.server.changedetail.RebaseChange;
import com.google.gerrit.server.project.InvalidChangeOperationException;
import com.google.gerrit.server.project.NoSuchChangeException;
import com.google.gwtorm.server.OrmException;

import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.PersonIdent;

import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class RebaseIfNecessary extends SubmitStrategy {

    private final RebaseChange rebaseChange;
    private final Map<Change.Id, CodeReviewCommit> newCommits;
    private final PersonIdent committerIdent;

    RebaseIfNecessary(final SubmitStrategy.Arguments args, final RebaseChange rebaseChange,
            PersonIdent committerIdent) {
        super(args);
        this.rebaseChange = rebaseChange;
        this.newCommits = new HashMap<Change.Id, CodeReviewCommit>();
        this.committerIdent = committerIdent;
    }

    @Override
    protected CodeReviewCommit _run(final CodeReviewCommit mergeTip, final List<CodeReviewCommit> toMerge)
            throws MergeException {
        CodeReviewCommit newMergeTip = mergeTip;
        sort(toMerge);

        while (!toMerge.isEmpty()) {
            final CodeReviewCommit n = toMerge.remove(0);

            if (newMergeTip == null) {
                // The branch is unborn. Take a fast-forward resolution to
                // create the branch.
                //
                newMergeTip = n;
                n.statusCode = CommitMergeStatus.CLEAN_MERGE;

            } else if (n.getParentCount() == 0) {
                // Refuse to merge a root commit into an existing branch,
                // we cannot obtain a delta for the rebase to apply.
                //
                n.statusCode = CommitMergeStatus.CANNOT_REBASE_ROOT;

            } else if (n.getParentCount() == 1) {
                if (args.mergeUtil.canFastForward(args.mergeSorter, newMergeTip, args.rw, n)) {
                    newMergeTip = n;
                    n.statusCode = CommitMergeStatus.CLEAN_MERGE;

                } else {
                    try {
                        final IdentifiedUser uploader = args.identifiedUserFactory
                                .create(args.mergeUtil.getSubmitter(n.patchsetId).getAccountId());
                        final PatchSet newPatchSet = rebaseChange.rebase(args.repo, args.rw, args.inserter,
                                n.patchsetId, n.change, uploader, newMergeTip, args.mergeUtil, committerIdent,
                                false, false, ValidatePolicy.NONE);
                        List<PatchSetApproval> approvals = Lists.newArrayList();
                        for (PatchSetApproval a : args.mergeUtil.getApprovalsForCommit(n)) {
                            approvals.add(new PatchSetApproval(newPatchSet.getId(), a));
                        }
                        args.db.patchSetApprovals().insert(approvals);
                        newMergeTip = (CodeReviewCommit) args.rw
                                .parseCommit(ObjectId.fromString(newPatchSet.getRevision().get()));
                        newMergeTip.copyFrom(n);
                        newMergeTip.patchsetId = newPatchSet.getId();
                        newMergeTip.change = args.db.changes().get(newPatchSet.getId().getParentKey());
                        newMergeTip.statusCode = CommitMergeStatus.CLEAN_REBASE;
                        newCommits.put(newPatchSet.getId().getParentKey(), newMergeTip);
                        setRefLogIdent(args.mergeUtil.getSubmitter(n.patchsetId));
                    } catch (PathConflictException e) {
                        n.statusCode = CommitMergeStatus.PATH_CONFLICT;
                    } catch (NoSuchChangeException e) {
                        throw new MergeException("Cannot rebase " + n.name(), e);
                    } catch (OrmException e) {
                        throw new MergeException("Cannot rebase " + n.name(), e);
                    } catch (IOException e) {
                        throw new MergeException("Cannot rebase " + n.name(), e);
                    } catch (InvalidChangeOperationException e) {
                        throw new MergeException("Cannot rebase " + n.name(), e);
                    }
                }

            } else if (n.getParentCount() > 1) {
                // There are multiple parents, so this is a merge commit. We
                // don't want to rebase the merge as clients can't easily
                // rebase their history with that merge present and replaced
                // by an equivalent merge with a different first parent. So
                // instead behave as though MERGE_IF_NECESSARY was configured.
                //
                try {
                    if (args.rw.isMergedInto(newMergeTip, n)) {
                        newMergeTip = n;
                    } else {
                        newMergeTip = args.mergeUtil.mergeOneCommit(args.myIdent, args.repo, args.rw, args.inserter,
                                args.canMergeFlag, args.destBranch, newMergeTip, n);
                    }
                    final PatchSetApproval submitApproval = args.mergeUtil.markCleanMerges(args.rw,
                            args.canMergeFlag, newMergeTip, args.alreadyAccepted);
                    setRefLogIdent(submitApproval);
                } catch (IOException e) {
                    throw new MergeException("Cannot merge " + n.name(), e);
                }
            }

            args.alreadyAccepted.add(newMergeTip);
        }

        return newMergeTip;
    }

    private void sort(final List<CodeReviewCommit> toSort) throws MergeException {
        try {
            final List<CodeReviewCommit> sorted = new RebaseSorter(args.rw, args.alreadyAccepted, args.canMergeFlag)
                    .sort(toSort);
            toSort.clear();
            toSort.addAll(sorted);
        } catch (IOException e) {
            throw new MergeException("Commit sorting failed", e);
        }
    }

    @Override
    public Map<Change.Id, CodeReviewCommit> getNewCommits() {
        return newCommits;
    }

    @Override
    public boolean dryRun(final CodeReviewCommit mergeTip, final CodeReviewCommit toMerge) throws MergeException {
        return !args.mergeUtil.hasMissingDependencies(args.mergeSorter, toMerge)
                && args.mergeUtil.canCherryPick(args.mergeSorter, args.repo, mergeTip, args.rw, toMerge);
    }
}