/*
* 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 java.util.zip;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Enumeration;
import java.util.LinkedHashMap;
import java.util.Iterator;
/**
* This class provides random read access to a <i>ZIP-archive</i> file.
* <p>
* While {@code ZipInputStream} provides stream based read access to a
* <i>ZIP-archive</i>, this class implements more efficient (file based) access
* and makes use of the <i>central directory</i> within a <i>ZIP-archive</i>.
* <p>
* Use {@code ZipOutputStream} if you want to create an archive.
* <p>
* A temporary ZIP file can be marked for automatic deletion upon closing it.
*
* @see ZipEntry
* @see ZipOutputStream
*/
public class ZipFile implements ZipConstants {
/**
* Open ZIP file for read.
*/
public static final int OPEN_READ = 1;
/**
* Delete ZIP file when closed.
*/
public static final int OPEN_DELETE = 4;
private final String fileName;
private File fileToDeleteOnClose;
private RandomAccessFile mRaf;
private final ZipEntry.LittleEndianReader ler = new ZipEntry.LittleEndianReader();
private final LinkedHashMap<String, ZipEntry> mEntries
= new LinkedHashMap<String, ZipEntry>();
/**
* Constructs a new {@code ZipFile} with the specified file.
*
* @param file
* the file to read from.
* @throws ZipException
* if a ZIP error occurs.
* @throws IOException
* if an {@code IOException} occurs.
*/
public ZipFile(File file) throws ZipException, IOException {
this(file, OPEN_READ);
}
/**
* Opens a file as <i>ZIP-archive</i>. "mode" must be {@code OPEN_READ} or
* {@code OPEN_DELETE} . The latter sets the "delete on exit" flag through a
* file.
*
* @param file
* the ZIP file to read.
* @param mode
* the mode of the file open operation.
* @throws IOException
* if an {@code IOException} occurs.
*/
public ZipFile(File file, int mode) throws IOException {
fileName = file.getPath();
if (mode != OPEN_READ && mode != (OPEN_READ | OPEN_DELETE)) {
throw new IllegalArgumentException();
}
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkRead(fileName);
}
if ((mode & OPEN_DELETE) != 0) {
if (security != null) {
security.checkDelete(fileName);
}
fileToDeleteOnClose = file; // file.deleteOnExit();
} else {
fileToDeleteOnClose = null;
}
mRaf = new RandomAccessFile(fileName, "r");
readCentralDir();
}
/**
* Opens a ZIP archived file.
*
* @param name
* the name of the ZIP file.
* @throws IOException
* if an IOException occurs.
*/
public ZipFile(String name) throws IOException {
this(new File(name), OPEN_READ);
}
@Override
protected void finalize() throws IOException {
close();
}
/**
* Closes this ZIP file. This method is idempotent.
*
* @throws IOException
* if an IOException occurs.
*/
public void close() throws IOException {
RandomAccessFile raf = mRaf;
if (raf != null) { // Only close initialized instances
synchronized(raf) {
mRaf = null;
raf.close();
}
if (fileToDeleteOnClose != null) {
AccessController.doPrivileged(new PrivilegedAction<Object>() {
public Object run() {
new File(fileName).delete();
return null;
}
});
// fileToDeleteOnClose.delete();
fileToDeleteOnClose = null;
}
}
}
private void checkNotClosed() {
if (mRaf == null) {
throw new IllegalStateException("Zip File closed.");
}
}
/**
* Returns an enumeration of the entries. The entries are listed in the
* order in which they appear in the ZIP archive.
*
* @return the enumeration of the entries.
* @throws IllegalStateException if this ZIP file has been closed.
*/
public Enumeration<? extends ZipEntry> entries() {
checkNotClosed();
final Iterator<ZipEntry> iterator = mEntries.values().iterator();
return new Enumeration<ZipEntry>() {
public boolean hasMoreElements() {
checkNotClosed();
return iterator.hasNext();
}
public ZipEntry nextElement() {
checkNotClosed();
return iterator.next();
}
};
}
/**
* Gets the ZIP entry with the specified name from this {@code ZipFile}.
*
* @param entryName
* the name of the entry in the ZIP file.
* @return a {@code ZipEntry} or {@code null} if the entry name does not
* exist in the ZIP file.
* @throws IllegalStateException if this ZIP file has been closed.
*/
public ZipEntry getEntry(String entryName) {
checkNotClosed();
if (entryName == null) {
throw new NullPointerException();
}
ZipEntry ze = mEntries.get(entryName);
if (ze == null) {
ze = mEntries.get(entryName + "/");
}
return ze;
}
/**
* Returns an input stream on the data of the specified {@code ZipEntry}.
*
* @param entry
* the ZipEntry.
* @return an input stream of the data contained in the {@code ZipEntry}.
* @throws IOException
* if an {@code IOException} occurs.
* @throws IllegalStateException if this ZIP file has been closed.
*/
public InputStream getInputStream(ZipEntry entry) throws IOException {
/*
* Make sure this ZipEntry is in this Zip file. We run it through
* the name lookup.
*/
entry = getEntry(entry.getName());
if (entry == null) {
return null;
}
/*
* Create a ZipInputStream at the right part of the file.
*/
RandomAccessFile raf = mRaf;
synchronized (raf) {
// We don't know the entry data's start position. All we have is the
// position of the entry's local header. At position 28 we find the
// length of the extra data. In some cases this length differs from
// the one coming in the central header.
RAFStream rafstrm = new RAFStream(raf,
entry.mLocalHeaderRelOffset + 28);
int localExtraLenOrWhatever = ler.readShortLE(rafstrm);
// Skip the name and this "extra" data or whatever it is:
rafstrm.skip(entry.nameLen + localExtraLenOrWhatever);
rafstrm.mLength = rafstrm.mOffset + entry.compressedSize;
if (entry.compressionMethod == ZipEntry.DEFLATED) {
int bufSize = Math.max(1024, (int)Math.min(entry.getSize(), 65535L));
return new ZipInflaterInputStream(rafstrm, new Inflater(true), bufSize, entry);
} else {
return rafstrm;
}
}
}
/**
* Gets the file name of this {@code ZipFile}.
*
* @return the file name of this {@code ZipFile}.
*/
public String getName() {
return fileName;
}
/**
* Returns the number of {@code ZipEntries} in this {@code ZipFile}.
*
* @return the number of entries in this file.
* @throws IllegalStateException if this ZIP file has been closed.
*/
public int size() {
checkNotClosed();
return mEntries.size();
}
/**
* Find the central directory and read the contents.
*
* <p>The central directory can be followed by a variable-length comment
* field, so we have to scan through it backwards. The comment is at
* most 64K, plus we have 18 bytes for the end-of-central-dir stuff
* itself, plus apparently sometimes people throw random junk on the end
* just for the fun of it.
*
* <p>This is all a little wobbly. If the wrong value ends up in the EOCD
* area, we're hosed. This appears to be the way that everybody handles
* it though, so we're in good company if this fails.
*/
private void readCentralDir() throws IOException {
/*
* Scan back, looking for the End Of Central Directory field. If
* the archive doesn't have a comment, we'll hit it on the first
* try.
*
* No need to synchronize mRaf here -- we only do this when we
* first open the Zip file.
*/
long scanOffset = mRaf.length() - ENDHDR;
if (scanOffset < 0) {
throw new ZipException("too short to be Zip");
}
long stopOffset = scanOffset - 65536;
if (stopOffset < 0) {
stopOffset = 0;
}
while (true) {
mRaf.seek(scanOffset);
if (ZipEntry.readIntLE(mRaf) == 101010256L) {
break;
}
scanOffset--;
if (scanOffset < stopOffset) {
throw new ZipException("EOCD not found; not a Zip archive?");
}
}
/*
* Found it, read the EOCD.
*
* For performance we want to use buffered I/O when reading the
* file. We wrap a buffered stream around the random-access file
* object. If we just read from the RandomAccessFile we'll be
* doing a read() system call every time.
*/
RAFStream rafs = new RAFStream(mRaf, mRaf.getFilePointer());
BufferedInputStream bin = new BufferedInputStream(rafs, ENDHDR);
int diskNumber = ler.readShortLE(bin);
int diskWithCentralDir = ler.readShortLE(bin);
int numEntries = ler.readShortLE(bin);
int totalNumEntries = ler.readShortLE(bin);
/*centralDirSize =*/ ler.readIntLE(bin);
long centralDirOffset = ler.readIntLE(bin);
/*commentLen =*/ ler.readShortLE(bin);
if (numEntries != totalNumEntries ||
diskNumber != 0 ||
diskWithCentralDir != 0) {
throw new ZipException("spanned archives not supported");
}
/*
* Seek to the first CDE and read all entries.
*/
rafs = new RAFStream(mRaf, centralDirOffset);
bin = new BufferedInputStream(rafs, 4096);
for (int i = 0; i < numEntries; i++) {
ZipEntry newEntry = new ZipEntry(ler, bin);
mEntries.put(newEntry.getName(), newEntry);
}
}
/**
* Wrap a stream around a RandomAccessFile. The RandomAccessFile is shared
* among all streams returned by getInputStream(), so we have to synchronize
* access to it. (We can optimize this by adding buffering here to reduce
* collisions.)
*
* <p>We could support mark/reset, but we don't currently need them.
*/
static class RAFStream extends InputStream {
RandomAccessFile mSharedRaf;
long mOffset;
long mLength;
public RAFStream(RandomAccessFile raf, long pos) throws IOException {
mSharedRaf = raf;
mOffset = pos;
mLength = raf.length();
}
@Override
public int available() throws IOException {
return (mOffset < mLength ? 1 : 0);
}
@Override
public int read() throws IOException {
byte[] singleByteBuf = new byte[1];
if (read(singleByteBuf, 0, 1) == 1) {
return singleByteBuf[0] & 0XFF;
} else {
return -1;
}
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
synchronized (mSharedRaf) {
mSharedRaf.seek(mOffset);
if (len > mLength - mOffset) {
len = (int) (mLength - mOffset);
}
int count = mSharedRaf.read(b, off, len);
if (count > 0) {
mOffset += count;
return count;
} else {
return -1;
}
}
}
@Override
public long skip(long n) throws IOException {
if (n > mLength - mOffset) {
n = mLength - mOffset;
}
mOffset += n;
return n;
}
}
static class ZipInflaterInputStream extends InflaterInputStream {
ZipEntry entry;
long bytesRead = 0;
public ZipInflaterInputStream(InputStream is, Inflater inf, int bsize, ZipEntry entry) {
super(is, inf, bsize);
this.entry = entry;
}
@Override
public int read(byte[] buffer, int off, int nbytes) throws IOException {
int i = super.read(buffer, off, nbytes);
if (i != -1) {
bytesRead += i;
}
return i;
}
@Override
public int available() throws IOException {
return super.available() == 0 ? 0 : (int) (entry.getSize() - bytesRead);
}
}
}