MergeMessageFormatter.java

/*
 * Copyright (C) 2010-2012, Robin Stocker <robin@nibor.org> and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0 which is available at
 * https://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */
package org.eclipse.jgit.merge;

import java.util.ArrayList;
import java.util.List;

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.util.ChangeIdUtil;
import org.eclipse.jgit.util.StringUtils;

/**
 * Formatter for constructing the commit message for a merge commit.
 * <p>
 * The format should be the same as C Git does it, for compatibility.
 */
public class MergeMessageFormatter {
    /**
     * Construct the merge commit message.
     *
     * @param refsToMerge
     *            the refs which will be merged
     * @param target
     *            the branch ref which will be merged into
     * @return merge commit message
     */
    public String format(List<Ref> refsToMerge, Ref target) {
        StringBuilder sb = new StringBuilder();
        sb.append("Merge "); //$NON-NLS-1$

        List<String> branches = new ArrayList<>();
        List<String> remoteBranches = new ArrayList<>();
        List<String> tags = new ArrayList<>();
        List<String> commits = new ArrayList<>();
        List<String> others = new ArrayList<>();
        for (Ref ref : refsToMerge) {
            if (ref.getName().startsWith(Constants.R_HEADS)) {
                branches.add("'" + Repository.shortenRefName(ref.getName()) //$NON-NLS-1$
                        + "'"); //$NON-NLS-1$
            } else if (ref.getName().startsWith(Constants.R_REMOTES)) {
                remoteBranches.add("'" //$NON-NLS-1$
                        + Repository.shortenRefName(ref.getName()) + "'"); //$NON-NLS-1$
            } else if (ref.getName().startsWith(Constants.R_TAGS)) {
                tags.add("'" + Repository.shortenRefName(ref.getName()) + "'"); //$NON-NLS-1$ //$NON-NLS-2$
            } else {
                ObjectId objectId = ref.getObjectId();
                if (objectId != null && ref.getName().equals(objectId.getName())) {
                    commits.add("'" + ref.getName() + "'"); //$NON-NLS-1$ //$NON-NLS-2$
                } else {
                    others.add(ref.getName());
                }
            }
        }

        List<String> listings = new ArrayList<>();

        if (!branches.isEmpty())
            listings.add(joinNames(branches, "branch", "branches")); //$NON-NLS-1$//$NON-NLS-2$

        if (!remoteBranches.isEmpty())
            listings.add(joinNames(remoteBranches, "remote-tracking branch", //$NON-NLS-1$
                    "remote-tracking branches")); //$NON-NLS-1$

        if (!tags.isEmpty())
            listings.add(joinNames(tags, "tag", "tags")); //$NON-NLS-1$ //$NON-NLS-2$

        if (!commits.isEmpty())
            listings.add(joinNames(commits, "commit", "commits")); //$NON-NLS-1$ //$NON-NLS-2$

        if (!others.isEmpty())
            listings.add(StringUtils.join(others, ", ", " and ")); //$NON-NLS-1$ //$NON-NLS-2$

        sb.append(StringUtils.join(listings, ", ")); //$NON-NLS-1$

        String targetName = target.getLeaf().getName();
        if (!targetName.equals(Constants.R_HEADS + Constants.MASTER)) {
            String targetShortName = Repository.shortenRefName(targetName);
            sb.append(" into " + targetShortName); //$NON-NLS-1$
        }

        return sb.toString();
    }

    /**
     * Add section with conflicting paths to merge message.
     *
     * @param message
     *            the original merge message
     * @param conflictingPaths
     *            the paths with conflicts
     * @return merge message with conflicting paths added
     */
    public String formatWithConflicts(String message,
            List<String> conflictingPaths) {
        StringBuilder sb = new StringBuilder();
        String[] lines = message.split("\n"); //$NON-NLS-1$
        int firstFooterLine = ChangeIdUtil.indexOfFirstFooterLine(lines);
        for (int i = 0; i < firstFooterLine; i++)
            sb.append(lines[i]).append('\n');
        if (firstFooterLine == lines.length && message.length() != 0)
            sb.append('\n');
        addConflictsMessage(conflictingPaths, sb);
        if (firstFooterLine < lines.length)
            sb.append('\n');
        for (int i = firstFooterLine; i < lines.length; i++)
            sb.append(lines[i]).append('\n');
        return sb.toString();
    }

    private static void addConflictsMessage(List<String> conflictingPaths,
            StringBuilder sb) {
        sb.append("Conflicts:\n"); //$NON-NLS-1$
        for (String conflictingPath : conflictingPaths) {
            sb.append('\t').append(conflictingPath).append('\n');
        }
    }

    private static String joinNames(List<String> names, String singular,
            String plural) {
        if (names.size() == 1) {
            return singular + " " + names.get(0); //$NON-NLS-1$
        }
        return plural + " " + StringUtils.join(names, ", ", " and "); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
    }
}