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 */
019package org.apache.commons.compress.changes;
020
021import java.io.IOException;
022import java.io.InputStream;
023import java.util.Enumeration;
024import java.util.Iterator;
025import java.util.LinkedHashSet;
026import java.util.Set;
027
028import org.apache.commons.compress.archivers.ArchiveEntry;
029import org.apache.commons.compress.archivers.ArchiveInputStream;
030import org.apache.commons.compress.archivers.ArchiveOutputStream;
031import org.apache.commons.compress.archivers.zip.ZipArchiveEntry;
032import org.apache.commons.compress.archivers.zip.ZipFile;
033import org.apache.commons.compress.utils.IOUtils;
034
035/**
036 * Performs ChangeSet operations on a stream.
037 * This class is thread safe and can be used multiple times.
038 * It operates on a copy of the ChangeSet. If the ChangeSet changes,
039 * a new Performer must be created.
040 *
041 * @ThreadSafe
042 * @Immutable
043 */
044public class ChangeSetPerformer {
045    /**
046     * Used in perform to abstract out getting entries and streams for
047     * those entries.
048     *
049     * <p>Iterator#hasNext is not allowed to throw exceptions that's
050     * why we can't use Iterator&lt;ArchiveEntry&gt; directly -
051     * otherwise we'd need to convert exceptions thrown in
052     * ArchiveInputStream#getNextEntry.</p>
053     */
054    interface ArchiveEntryIterator {
055        InputStream getInputStream() throws IOException;
056        boolean hasNext() throws IOException;
057        ArchiveEntry next();
058    }
059
060    private static class ArchiveInputStreamIterator
061        implements ArchiveEntryIterator {
062        private final ArchiveInputStream in;
063        private ArchiveEntry next;
064        ArchiveInputStreamIterator(final ArchiveInputStream in) {
065            this.in = in;
066        }
067        @Override
068        public InputStream getInputStream() {
069            return in;
070        }
071        @Override
072        public boolean hasNext() throws IOException {
073            return (next = in.getNextEntry()) != null;
074        }
075        @Override
076        public ArchiveEntry next() {
077            return next;
078        }
079    }
080
081    private static class ZipFileIterator
082        implements ArchiveEntryIterator {
083        private final ZipFile in;
084        private final Enumeration<ZipArchiveEntry> nestedEnum;
085        private ZipArchiveEntry current;
086        ZipFileIterator(final ZipFile in) {
087            this.in = in;
088            nestedEnum = in.getEntriesInPhysicalOrder();
089        }
090        @Override
091        public InputStream getInputStream() throws IOException {
092            return in.getInputStream(current);
093        }
094        @Override
095        public boolean hasNext() {
096            return nestedEnum.hasMoreElements();
097        }
098        @Override
099        public ArchiveEntry next() {
100            current = nestedEnum.nextElement();
101            return current;
102        }
103    }
104
105    private final Set<Change> changes;
106
107    /**
108     * Constructs a ChangeSetPerformer with the changes from this ChangeSet
109     * @param changeSet the ChangeSet which operations are used for performing
110     */
111    public ChangeSetPerformer(final ChangeSet changeSet) {
112        changes = changeSet.getChanges();
113    }
114
115    /**
116     * Copies the ArchiveEntry to the Output stream
117     *
118     * @param in
119     *            the stream to read the data from
120     * @param out
121     *            the stream to write the data to
122     * @param entry
123     *            the entry to write
124     * @throws IOException
125     *             if data cannot be read or written
126     */
127    private void copyStream(final InputStream in, final ArchiveOutputStream out,
128            final ArchiveEntry entry) throws IOException {
129        out.putArchiveEntry(entry);
130        IOUtils.copy(in, out);
131        out.closeArchiveEntry();
132    }
133
134    /**
135     * Checks if an ArchiveEntry is deleted later in the ChangeSet. This is
136     * necessary if a file is added with this ChangeSet, but later became
137     * deleted in the same set.
138     *
139     * @param entry
140     *            the entry to check
141     * @return true, if this entry has a deletion change later, false otherwise
142     */
143    private boolean isDeletedLater(final Set<Change> workingSet, final ArchiveEntry entry) {
144        final String source = entry.getName();
145
146        if (!workingSet.isEmpty()) {
147            for (final Change change : workingSet) {
148                final int type = change.type();
149                final 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     * Performs all changes collected in this ChangeSet on the input entries and
164     * streams the result to the output stream.
165     *
166     * This method finishes the stream, no other entries should be added
167     * after that.
168     *
169     * @param entryIterator
170     *            the entries to perform the changes on
171     * @param out
172     *            the resulting OutputStream with all modifications
173     * @throws IOException
174     *             if a read/write error occurs
175     * @return the results of this operation
176     */
177    private ChangeSetResults perform(final ArchiveEntryIterator entryIterator,
178                                     final ArchiveOutputStream out)
179            throws IOException {
180        final ChangeSetResults results = new ChangeSetResults();
181
182        final Set<Change> workingSet = new LinkedHashSet<>(changes);
183
184        for (final Iterator<Change> it = workingSet.iterator(); it.hasNext();) {
185            final Change change = it.next();
186
187            if (change.type() == Change.TYPE_ADD && change.isReplaceMode()) {
188                copyStream(change.getInput(), out, change.getEntry());
189                it.remove();
190                results.addedFromChangeSet(change.getEntry().getName());
191            }
192        }
193
194        while (entryIterator.hasNext()) {
195            final ArchiveEntry entry = entryIterator.next();
196            boolean copy = true;
197
198            for (final Iterator<Change> it = workingSet.iterator(); it.hasNext();) {
199                final Change change = it.next();
200
201                final int type = change.type();
202                final String name = entry.getName();
203                if (type == Change.TYPE_DELETE && name != null) {
204                    if (name.equals(change.targetFile())) {
205                        copy = false;
206                        it.remove();
207                        results.deleted(name);
208                        break;
209                    }
210                } else if (type == Change.TYPE_DELETE_DIR && name != null) {
211                    // don't combine ifs to make future extensions more easy
212                    if (name.startsWith(change.targetFile() + "/")) { // NOPMD NOSONAR
213                        copy = false;
214                        results.deleted(name);
215                        break;
216                    }
217                }
218            }
219
220            if (copy
221                && !isDeletedLater(workingSet, entry)
222                && !results.hasBeenAdded(entry.getName())) {
223                copyStream(entryIterator.getInputStream(), out, entry);
224                results.addedFromStream(entry.getName());
225            }
226        }
227
228        // Adds files which hasn't been added from the original and do not have replace mode on
229        for (final Iterator<Change> it = workingSet.iterator(); it.hasNext();) {
230            final Change change = it.next();
231
232            if (change.type() == Change.TYPE_ADD &&
233                !change.isReplaceMode() &&
234                !results.hasBeenAdded(change.getEntry().getName())) {
235                copyStream(change.getInput(), out, change.getEntry());
236                it.remove();
237                results.addedFromChangeSet(change.getEntry().getName());
238            }
239        }
240        out.finish();
241        return results;
242    }
243
244    /**
245     * Performs all changes collected in this ChangeSet on the input stream and
246     * streams the result to the output stream. Perform may be called more than once.
247     *
248     * This method finishes the stream, no other entries should be added
249     * after that.
250     *
251     * @param in
252     *            the InputStream to perform the changes on
253     * @param out
254     *            the resulting OutputStream with all modifications
255     * @throws IOException
256     *             if a read/write error occurs
257     * @return the results of this operation
258     */
259    public ChangeSetResults perform(final ArchiveInputStream in, final ArchiveOutputStream out)
260            throws IOException {
261        return perform(new ArchiveInputStreamIterator(in), out);
262    }
263
264    /**
265     * Performs all changes collected in this ChangeSet on the ZipFile and
266     * streams the result to the output stream. Perform may be called more than once.
267     *
268     * This method finishes the stream, no other entries should be added
269     * after that.
270     *
271     * @param in
272     *            the ZipFile to perform the changes on
273     * @param out
274     *            the resulting OutputStream with all modifications
275     * @throws IOException
276     *             if a read/write error occurs
277     * @return the results of this operation
278     * @since 1.5
279     */
280    public ChangeSetResults perform(final ZipFile in, final ArchiveOutputStream out)
281            throws IOException {
282        return perform(new ZipFileIterator(in), out);
283    }
284}