RefRename.java

/*
 * Copyright (C) 2009-2010, Google Inc.
 * Copyright (C) 2009, Robin Rosenberg
 * Copyright (C) 2009, Robin Rosenberg <robin.rosenberg@dewire.com>
 * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
 * 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
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 *   with the distribution.
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 *   names of its contributors may be used to endorse or promote
 *   products derived from this software without specific prior
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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package org.eclipse.jgit.lib;

import java.io.IOException;

import org.eclipse.jgit.lib.RefUpdate.Result;

/**
 * A RefUpdate combination for renaming a reference.
 * <p>
 * If the source reference is currently pointed to by {@code HEAD}, then the
 * HEAD symbolic reference is updated to point to the new destination.
 */
public abstract class RefRename {
    /** Update operation to read and delete the source reference. */
    protected final RefUpdate source;

    /** Update operation to create/overwrite the destination reference. */
    protected final RefUpdate destination;

    private Result result = Result.NOT_ATTEMPTED;

    /**
     * Initialize a new rename operation.
     *
     * @param src
     *            operation to read and delete the source.
     * @param dst
     *            operation to create (or overwrite) the destination.
     */
    protected RefRename(RefUpdate src, RefUpdate dst) {
        source = src;
        destination = dst;

        String cmd = ""; //$NON-NLS-1$
        if (source.getName().startsWith(Constants.R_HEADS)
                && destination.getName().startsWith(Constants.R_HEADS))
            cmd = "Branch: "; //$NON-NLS-1$
        setRefLogMessage(cmd + "renamed " //$NON-NLS-1$
                + Repository.shortenRefName(source.getName()) + " to " //$NON-NLS-1$
                + Repository.shortenRefName(destination.getName()));
    }

    /**
     * Get identity of the user making the change in the reflog.
     *
     * @return identity of the user making the change in the reflog.
     */
    public PersonIdent getRefLogIdent() {
        return destination.getRefLogIdent();
    }

    /**
     * Set the identity of the user appearing in the reflog.
     * <p>
     * The timestamp portion of the identity is ignored. A new identity with the
     * current timestamp will be created automatically when the rename occurs
     * and the log record is written.
     *
     * @param pi
     *            identity of the user. If null the identity will be
     *            automatically determined based on the repository
     *            configuration.
     */
    public void setRefLogIdent(PersonIdent pi) {
        destination.setRefLogIdent(pi);
    }

    /**
     * Get the message to include in the reflog.
     *
     * @return message the caller wants to include in the reflog; null if the
     *         rename should not be logged.
     */
    public String getRefLogMessage() {
        return destination.getRefLogMessage();
    }

    /**
     * Set the message to include in the reflog.
     *
     * @param msg
     *            the message to describe this change.
     */
    public void setRefLogMessage(String msg) {
        if (msg == null)
            disableRefLog();
        else
            destination.setRefLogMessage(msg, false);
    }

    /**
     * Don't record this rename in the ref's associated reflog.
     */
    public void disableRefLog() {
        destination.setRefLogMessage("", false); //$NON-NLS-1$
    }

    /**
     * Get result of rename operation
     *
     * @return result of rename operation
     */
    public Result getResult() {
        return result;
    }

    /**
     * Rename
     *
     * @return the result of the new ref update
     * @throws java.io.IOException
     */
    public Result rename() throws IOException {
        try {
            result = doRename();
            return result;
        } catch (IOException err) {
            result = Result.IO_FAILURE;
            throw err;
        }
    }

    /**
     * Do the actual rename
     *
     * @return the result of the rename operation.
     * @throws java.io.IOException
     */
    protected abstract Result doRename() throws IOException;

    /**
     * Whether the {@code Constants#HEAD} reference needs to be linked to the
     * new destination name.
     *
     * @return true if the {@code Constants#HEAD} reference needs to be linked
     *         to the new destination name.
     * @throws java.io.IOException
     *             the current value of {@code HEAD} cannot be read.
     */
    protected boolean needToUpdateHEAD() throws IOException {
        Ref head = source.getRefDatabase().exactRef(Constants.HEAD);
        if (head != null && head.isSymbolic()) {
            head = head.getTarget();
            return head.getName().equals(source.getName());
        }
        return false;
    }
}