Switch jgit library to the EDL (3-clause BSD)

[egit/zawir.git] / org.spearce.jgit / src / org / spearce / jgit / lib / TreeEntry.java

/*
 * Copyright (C) 2008, Robin Rosenberg <robin.rosenberg@dewire.com>
 * Copyright (C) 2007, Shawn O. Pearce <spearce@spearce.org>
 *
 * 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 Git Development Community 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.spearce.jgit.lib;

import java.io.IOException;
import java.io.UnsupportedEncodingException;

import org.spearce.jgit.lib.GitIndex.Entry;

/**
 * This class represents an entry in a tree, like a blob or another tree.
 */
public abstract class TreeEntry implements Comparable {
        /**
         * a flag for {@link TreeEntry#accept(TreeVisitor, int)} to visit only modified entries
         */
        public static final int MODIFIED_ONLY = 1 << 0;

        /**
         * a flag for {@link TreeEntry#accept(TreeVisitor, int)} to visit only loaded entries
         */
        public static final int LOADED_ONLY = 1 << 1;

        /**
         * a flag for {@link TreeEntry#accept(TreeVisitor, int)} obsolete?
         */
        public static final int CONCURRENT_MODIFICATION = 1 << 2;

        private byte[] nameUTF8;

        private Tree parent;

        private ObjectId id;

        /**
         * Construct a named tree entry.
         *
         * @param myParent
         * @param myId
         * @param myNameUTF8
         */
        protected TreeEntry(final Tree myParent, final ObjectId myId,
                        final byte[] myNameUTF8) {
                nameUTF8 = myNameUTF8;
                parent = myParent;
                id = myId;
        }

        /**
         * @return parent of this tree.
         */
        public Tree getParent() {
                return parent;
        }

        /**
         * Delete this entry.
         */
        public void delete() {
                getParent().removeEntry(this);
                detachParent();
        }

        /**
         * Detach this entry from it's parent.
         */
        public void detachParent() {
                parent = null;
        }

        void attachParent(final Tree p) {
                parent = p;
        }

        /**
         * @return the repository owning this entry.
         */
        public Repository getRepository() {
                return getParent().getRepository();
        }

        /**
         * @return the raw byte name of this entry.
         */
        public byte[] getNameUTF8() {
                return nameUTF8;
        }

        /**
         * @return the name of this entry.
         */
        public String getName() {
                try {
                        return nameUTF8 != null ? new String(nameUTF8,
                                        Constants.CHARACTER_ENCODING) : null;
                } catch (UnsupportedEncodingException uee) {
                        throw new RuntimeException("JVM doesn't support "
                                        + Constants.CHARACTER_ENCODING, uee);
                }
        }

        /**
         * Rename this entry.
         *
         * @param n The new name
         * @throws IOException
         */
        public void rename(final String n) throws IOException {
                rename(n.getBytes(Constants.CHARACTER_ENCODING));
        }

        /**
         * Rename this entry.
         *
         * @param n The new name
         * @throws IOException
         */
        public void rename(final byte[] n) throws IOException {
                final Tree t = getParent();
                if (t != null) {
                        delete();
                }
                nameUTF8 = n;
                if (t != null) {
                        t.addEntry(this);
                }
        }

        /**
         * @return true if this entry is new or modified since being loaded.
         */
        public boolean isModified() {
                return getId() == null;
        }

        /**
         * Mark this entry as modified.
         */
        public void setModified() {
                setId(null);
        }

        /**
         * @return SHA-1 of this tree entry (null for new unhashed entries)
         */
        public ObjectId getId() {
                return id;
        }

        /**
         * Set (update) the SHA-1 of this entry. Invalidates the id's of all
         * entries above this entry as they will have to be recomputed.
         *
         * @param n SHA-1 for this entry.
         */
        public void setId(final ObjectId n) {
                // If we have a parent and our id is being cleared or changed then force
                // the parent's id to become unset as it depends on our id.
                //
                final Tree p = getParent();
                if (p != null && id != n) {
                        if ((id == null && n != null) || (id != null && n == null)
                                        || !id.equals(n)) {
                                p.setId(null);
                        }
                }

                id = n;
        }

        /**
         * @return repository relative name of this entry
         */
        public String getFullName() {
                final StringBuffer r = new StringBuffer();
                appendFullName(r);
                return r.toString();
        }

        /**
         * @return repository relative name of the entry
         * FIXME better encoding
         */
        public byte[] getFullNameUTF8() {
                return getFullName().getBytes();
        }

        public int compareTo(final Object o) {
                if (this == o)
                        return 0;
                if (o instanceof TreeEntry)
                        return Tree.compareNames(nameUTF8, ((TreeEntry) o).nameUTF8, lastChar(this), lastChar((TreeEntry)o));
                return -1;
        }

        /**
         * Helper for accessing tree/blob methods.
         *
         * @param treeEntry
         * @return '/' for Tree entries and NUL for non-treeish objects.
         */
        final public static int lastChar(TreeEntry treeEntry) {
                if (treeEntry instanceof FileTreeEntry)
                        return '\0';
                else
                        return '/';
        }

        /**
         * Helper for accessing tree/blob/index methods.
         *
         * @param i
         * @return '/' for Tre entries and NUL for non-treeish objects
         */
        final public static int lastChar(Entry i) {
                // FIXME, gitlink etc. Currently Trees cannot appear in the
                // index so '\0' is always returned, except maybe for submodules
                // which we do not support yet.
                return FileMode.TREE.equals(i.getModeBits()) ? '/' : '\0';
        }

        /**
         * See @{link {@link #accept(TreeVisitor, int)}.
         *
         * @param tv
         * @throws IOException
         */
        public void accept(final TreeVisitor tv) throws IOException {
                accept(tv, 0);
        }

        /**
         * Visit the members of this TreeEntry.
         *
         * @param tv
         *            A visitor object doing the work
         * @param flags
         *            Specification for what members to visit. See
         *            {@link #MODIFIED_ONLY}, {@link #LOADED_ONLY},
         *            {@link #CONCURRENT_MODIFICATION}.
         * @throws IOException
         */
        public abstract void accept(TreeVisitor tv, int flags) throws IOException;

        /**
         * @return mode (type of object)
         */
        public abstract FileMode getMode();

        private void appendFullName(final StringBuffer r) {
                final TreeEntry p = getParent();
                final String n = getName();
                if (p != null) {
                        p.appendFullName(r);
                        if (r.length() > 0) {
                                r.append('/');
                        }
                }
                if (n != null) {
                        r.append(n);
                }
        }
}