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<Change> 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<Change> workingSet = new LinkedHashSet<Change>(changes);
072
073 for (Iterator<Change> it = workingSet.iterator(); it.hasNext();) {
074 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<Change> it = workingSet.iterator(); it.hasNext();) {
088 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<Change> it = workingSet.iterator(); it.hasNext();) {
119 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<Change> workingSet, ArchiveEntry entry) {
143 String source = entry.getName();
144
145 if (!workingSet.isEmpty()) {
146 for (Change change : workingSet) {
147 final int type = change.type();
148 String target = change.targetFile();
149 if (type == Change.TYPE_DELETE && source.equals(target)) {
150 return true;
151 }
152
153 if (type == Change.TYPE_DELETE_DIR && source.startsWith(target + "/")){
154 return true;
155 }
156 }
157 }
158 return false;
159 }
160
161 /**
162 * Copies the ArchiveEntry to the Output stream
163 *
164 * @param in
165 * the stream to read the data from
166 * @param out
167 * the stream to write the data to
168 * @param entry
169 * the entry to write
170 * @throws IOException
171 * if data cannot be read or written
172 */
173 private void copyStream(InputStream in, ArchiveOutputStream out,
174 ArchiveEntry entry) throws IOException {
175 out.putArchiveEntry(entry);
176 IOUtils.copy(in, out);
177 out.closeArchiveEntry();
178 }
179 }