org.apache.commons.compress.changes.ChangeSetPerformer Maven / Gradle / Ivy
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Apache Commons Compress software defines an API for working with
compression and archive formats. These include: bzip2, gzip, pack200,
lzma, xz, Snappy, traditional Unix Compress, DEFLATE, DEFLATE64, LZ4,
Brotli, Zstandard and ar, cpio, jar, tar, zip, dump, 7z, arj.
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.commons.compress.changes;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.Set;
import org.apache.commons.compress.archivers.ArchiveEntry;
import org.apache.commons.compress.archivers.ArchiveInputStream;
import org.apache.commons.compress.archivers.ArchiveOutputStream;
import org.apache.commons.compress.archivers.zip.ZipArchiveEntry;
import org.apache.commons.compress.archivers.zip.ZipFile;
import org.apache.commons.compress.utils.IOUtils;
/**
* Performs ChangeSet operations on a stream.
* This class is thread safe and can be used multiple times.
* It operates on a copy of the ChangeSet. If the ChangeSet changes,
* a new Performer must be created.
*
* @ThreadSafe
* @Immutable
*/
public class ChangeSetPerformer {
/**
* Used in perform to abstract out getting entries and streams for
* those entries.
*
* Iterator#hasNext is not allowed to throw exceptions that's
* why we can't use Iterator<ArchiveEntry> directly -
* otherwise we'd need to convert exceptions thrown in
* ArchiveInputStream#getNextEntry.
*/
interface ArchiveEntryIterator {
InputStream getInputStream() throws IOException;
boolean hasNext() throws IOException;
ArchiveEntry next();
}
private static class ArchiveInputStreamIterator
implements ArchiveEntryIterator {
private final ArchiveInputStream in;
private ArchiveEntry next;
ArchiveInputStreamIterator(final ArchiveInputStream in) {
this.in = in;
}
@Override
public InputStream getInputStream() {
return in;
}
@Override
public boolean hasNext() throws IOException {
return (next = in.getNextEntry()) != null;
}
@Override
public ArchiveEntry next() {
return next;
}
}
private static class ZipFileIterator
implements ArchiveEntryIterator {
private final ZipFile in;
private final Enumeration nestedEnum;
private ZipArchiveEntry current;
ZipFileIterator(final ZipFile in) {
this.in = in;
nestedEnum = in.getEntriesInPhysicalOrder();
}
@Override
public InputStream getInputStream() throws IOException {
return in.getInputStream(current);
}
@Override
public boolean hasNext() {
return nestedEnum.hasMoreElements();
}
@Override
public ArchiveEntry next() {
current = nestedEnum.nextElement();
return current;
}
}
private final Set changes;
/**
* Constructs a ChangeSetPerformer with the changes from this ChangeSet
* @param changeSet the ChangeSet which operations are used for performing
*/
public ChangeSetPerformer(final ChangeSet changeSet) {
changes = changeSet.getChanges();
}
/**
* Copies the ArchiveEntry to the Output stream
*
* @param in
* the stream to read the data from
* @param out
* the stream to write the data to
* @param entry
* the entry to write
* @throws IOException
* if data cannot be read or written
*/
private void copyStream(final InputStream in, final ArchiveOutputStream out,
final ArchiveEntry entry) throws IOException {
out.putArchiveEntry(entry);
IOUtils.copy(in, out);
out.closeArchiveEntry();
}
/**
* Checks if an ArchiveEntry is deleted later in the ChangeSet. This is
* necessary if an file is added with this ChangeSet, but later became
* deleted in the same set.
*
* @param entry
* the entry to check
* @return true, if this entry has an deletion change later, false otherwise
*/
private boolean isDeletedLater(final Set workingSet, final ArchiveEntry entry) {
final String source = entry.getName();
if (!workingSet.isEmpty()) {
for (final Change change : workingSet) {
final int type = change.type();
final String target = change.targetFile();
if (type == Change.TYPE_DELETE && source.equals(target)) {
return true;
}
if (type == Change.TYPE_DELETE_DIR && source.startsWith(target + "/")){
return true;
}
}
}
return false;
}
/**
* Performs all changes collected in this ChangeSet on the input entries and
* streams the result to the output stream.
*
* This method finishes the stream, no other entries should be added
* after that.
*
* @param entryIterator
* the entries to perform the changes on
* @param out
* the resulting OutputStream with all modifications
* @throws IOException
* if an read/write error occurs
* @return the results of this operation
*/
private ChangeSetResults perform(final ArchiveEntryIterator entryIterator,
final ArchiveOutputStream out)
throws IOException {
final ChangeSetResults results = new ChangeSetResults();
final Set workingSet = new LinkedHashSet<>(changes);
for (final Iterator it = workingSet.iterator(); it.hasNext();) {
final Change change = it.next();
if (change.type() == Change.TYPE_ADD && change.isReplaceMode()) {
copyStream(change.getInput(), out, change.getEntry());
it.remove();
results.addedFromChangeSet(change.getEntry().getName());
}
}
while (entryIterator.hasNext()) {
final ArchiveEntry entry = entryIterator.next();
boolean copy = true;
for (final Iterator it = workingSet.iterator(); it.hasNext();) {
final Change change = it.next();
final int type = change.type();
final String name = entry.getName();
if (type == Change.TYPE_DELETE && name != null) {
if (name.equals(change.targetFile())) {
copy = false;
it.remove();
results.deleted(name);
break;
}
} else if (type == Change.TYPE_DELETE_DIR && name != null) {
// don't combine ifs to make future extensions more easy
if (name.startsWith(change.targetFile() + "/")) { // NOPMD NOSONAR
copy = false;
results.deleted(name);
break;
}
}
}
if (copy
&& !isDeletedLater(workingSet, entry)
&& !results.hasBeenAdded(entry.getName())) {
copyStream(entryIterator.getInputStream(), out, entry);
results.addedFromStream(entry.getName());
}
}
// Adds files which hasn't been added from the original and do not have replace mode on
for (final Iterator it = workingSet.iterator(); it.hasNext();) {
final Change change = it.next();
if (change.type() == Change.TYPE_ADD &&
!change.isReplaceMode() &&
!results.hasBeenAdded(change.getEntry().getName())) {
copyStream(change.getInput(), out, change.getEntry());
it.remove();
results.addedFromChangeSet(change.getEntry().getName());
}
}
out.finish();
return results;
}
/**
* Performs all changes collected in this ChangeSet on the input stream and
* streams the result to the output stream. Perform may be called more than once.
*
* This method finishes the stream, no other entries should be added
* after that.
*
* @param in
* the InputStream to perform the changes on
* @param out
* the resulting OutputStream with all modifications
* @throws IOException
* if an read/write error occurs
* @return the results of this operation
*/
public ChangeSetResults perform(final ArchiveInputStream in, final ArchiveOutputStream out)
throws IOException {
return perform(new ArchiveInputStreamIterator(in), out);
}
/**
* Performs all changes collected in this ChangeSet on the ZipFile and
* streams the result to the output stream. Perform may be called more than once.
*
* This method finishes the stream, no other entries should be added
* after that.
*
* @param in
* the ZipFile to perform the changes on
* @param out
* the resulting OutputStream with all modifications
* @throws IOException
* if an read/write error occurs
* @return the results of this operation
* @since 1.5
*/
public ChangeSetResults perform(final ZipFile in, final ArchiveOutputStream out)
throws IOException {
return perform(new ZipFileIterator(in), out);
}
}