    001    /*
    002     * Licensed to the Apache Software Foundation (ASF) under one
    003     * or more contributor license agreements.  See the NOTICE file
    004     * distributed with this work for additional information
    005     * regarding copyright ownership.  The ASF licenses this file
    006     * to you under the Apache License, Version 2.0 (the
    007     * "License"); you may not use this file except in compliance
    008     * with the License.  You may obtain a copy of the License at
    009     *
    010     * http://www.apache.org/licenses/LICENSE-2.0
    011     *
    012     * Unless required by applicable law or agreed to in writing,
    013     * software distributed under the License is distributed on an
    014     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015     * KIND, either express or implied.  See the License for the
    016     * specific language governing permissions and limitations
    017     * under the License.
    018     */
    019    package org.apache.commons.compress.changes;
    020
    021    import java.io.IOException;
    022    import java.io.InputStream;
    023    import java.util.Iterator;
    024    import java.util.LinkedHashSet;
    025    import java.util.Set;
    026
    027    import org.apache.commons.compress.archivers.ArchiveEntry;
    028    import org.apache.commons.compress.archivers.ArchiveInputStream;
    029    import org.apache.commons.compress.archivers.ArchiveOutputStream;
    030    import org.apache.commons.compress.utils.IOUtils;
    031
    032    /**
    033     * Performs ChangeSet operations on a stream.
    034     * This class is thread safe and can be used multiple times.
    035     * It operates on a copy of the ChangeSet. If the ChangeSet changes,
    036     * a new Performer must be created.
    037     *
    038     * @ThreadSafe
    039     * @Immutable
    040     */
    041    public class ChangeSetPerformer {
    042        private final Set changes;
    043
    044        /**
    045         * Constructs a ChangeSetPerformer with the changes from this ChangeSet
    046         * @param changeSet the ChangeSet which operations are used for performing
    047         */
    048        public ChangeSetPerformer(final ChangeSet changeSet) {
    049            changes = changeSet.getChanges();
    050        }
    051
    052        /**
    053         * Performs all changes collected in this ChangeSet on the input stream and
    054         * streams the result to the output stream. Perform may be called more than once.
    055         *
    056         * This method finishes the stream, no other entries should be added
    057         * after that.
    058         *
    059         * @param in
    060         *            the InputStream to perform the changes on
    061         * @param out
    062         *            the resulting OutputStream with all modifications
    063         * @throws IOException
    064         *             if an read/write error occurs
    065         * @return the results of this operation
    066         */
    067        public ChangeSetResults perform(ArchiveInputStream in, ArchiveOutputStream out)
    068                throws IOException {
    069            ChangeSetResults results = new ChangeSetResults();
    070
    071            Set workingSet = new LinkedHashSet(changes);
    072
    073            for (Iterator it = workingSet.iterator(); it.hasNext();) {
    074                Change change = (Change) it.next();
    075
    076                if (change.type() == Change.TYPE_ADD && change.isReplaceMode()) {
    077                    copyStream(change.getInput(), out, change.getEntry());
    078                    it.remove();
    079                    results.addedFromChangeSet(change.getEntry().getName());
    080                }
    081            }
    082
    083            ArchiveEntry entry = null;
    084            while ((entry = in.getNextEntry()) != null) {
    085                boolean copy = true;
    086
    087                for (Iterator it = workingSet.iterator(); it.hasNext();) {
    088                    Change change = (Change) it.next();
    089
    090                    final int type = change.type();
    091                    final String name = entry.getName();
    092                    if (type == Change.TYPE_DELETE && name != null) {
    093                        if (name.equals(change.targetFile())) {
    094                            copy = false;
    095                            it.remove();
    096                            results.deleted(name);
    097                            break;
    098                        }
    099                    } else if (type == Change.TYPE_DELETE_DIR && name != null) {
    100                        // don't combine ifs to make future extensions more easy
    101                        if (name.startsWith(change.targetFile() + "/")) { // NOPMD
    102                            copy = false;
    103                            results.deleted(name);
    104                            break;
    105                        }
    106                    }
    107                }
    108
    109                if (copy
    110                    && !isDeletedLater(workingSet, entry)
    111                    && !results.hasBeenAdded(entry.getName())) {
    112                    copyStream(in, out, entry);
    113                    results.addedFromStream(entry.getName());
    114                }
    115            }
    116
    117            // Adds files which hasn't been added from the original and do not have replace mode on
    118            for (Iterator it = workingSet.iterator(); it.hasNext();) {
    119                Change change = (Change) it.next();
    120
    121                if (change.type() == Change.TYPE_ADD &&
    122                    !change.isReplaceMode() &&
    123                    !results.hasBeenAdded(change.getEntry().getName())) {
    124                    copyStream(change.getInput(), out, change.getEntry());
    125                    it.remove();
    126                    results.addedFromChangeSet(change.getEntry().getName());
    127                }
    128            }
    129            out.finish();
    130            return results;
    131        }
    132
    133        /**
    134         * Checks if an ArchiveEntry is deleted later in the ChangeSet. This is
    135         * necessary if an file is added with this ChangeSet, but later became
    136         * deleted in the same set.
    137         *
    138         * @param entry
    139         *            the entry to check
    140         * @return true, if this entry has an deletion change later, false otherwise
    141         */
    142        private boolean isDeletedLater(Set workingSet, ArchiveEntry entry) {
    143            String source = entry.getName();
    144
    145            if (!workingSet.isEmpty()) {
    146                for (Iterator it = workingSet.iterator(); it.hasNext();) {
    147                    Change change = (Change) it.next();
    148                    final int type = change.type();
    149                    String target = change.targetFile();
    150                    if (type == Change.TYPE_DELETE && source.equals(target)) {
    151                        return true;
    152                    }
    153
    154                    if (type == Change.TYPE_DELETE_DIR && source.startsWith(target + "/")){
    155                        return true;
    156                    }
    157                }
    158            }
    159            return false;
    160        }
    161
    162        /**
    163         * Copies the ArchiveEntry to the Output stream
    164         *
    165         * @param in
    166         *            the stream to read the data from
    167         * @param out
    168         *            the stream to write the data to
    169         * @param entry
    170         *            the entry to write
    171         * @throws IOException
    172         *             if data cannot be read or written
    173         */
    174        private void copyStream(InputStream in, ArchiveOutputStream out,
    175                ArchiveEntry entry) throws IOException {
    176            out.putArchiveEntry(entry);
    177            IOUtils.copy(in, out);
    178            out.closeArchiveEntry();
    179        }
    180    }