/*
* Copyright (c) 2000, 2007, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package javax.imageio.stream;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import com.sun.imageio.stream.StreamCloser;
/**
* An implementation of <code>ImageOutputStream</code> that writes its
* output to a regular <code>OutputStream</code>. A file is used to
* cache data until it is flushed to the output stream.
*
*/
public class FileCacheImageOutputStream extends ImageOutputStreamImpl {
private OutputStream stream;
private File cacheFile;
private RandomAccessFile cache;
// Pos after last (rightmost) byte written
private long maxStreamPos = 0L;
/** The CloseAction that closes the stream in
* the StreamCloser's shutdown hook */
private final StreamCloser.CloseAction closeAction;
/**
* Constructs a <code>FileCacheImageOutputStream</code> that will write
* to a given <code>outputStream</code>.
*
* <p> A temporary file is used as a cache. If
* <code>cacheDir</code>is non-<code>null</code> and is a
* directory, the file will be created there. If it is
* <code>null</code>, the system-dependent default temporary-file
* directory will be used (see the documentation for
* <code>File.createTempFile</code> for details).
*
* @param stream an <code>OutputStream</code> to write to.
* @param cacheDir a <code>File</code> indicating where the
* cache file should be created, or <code>null</code> to use the
* system directory.
*
* @exception IllegalArgumentException if <code>stream</code>
* is <code>null</code>.
* @exception IllegalArgumentException if <code>cacheDir</code> is
* non-<code>null</code> but is not a directory.
* @exception IOException if a cache file cannot be created.
*/
public FileCacheImageOutputStream(OutputStream stream, File cacheDir)
throws IOException {
if (stream == null) {
throw new IllegalArgumentException("stream == null!");
}
if ((cacheDir != null) && !(cacheDir.isDirectory())) {
throw new IllegalArgumentException("Not a directory!");
}
this.stream = stream;
this.cacheFile =
File.createTempFile("imageio", ".tmp", cacheDir);
this.cache = new RandomAccessFile(cacheFile, "rw");
this.closeAction = StreamCloser.createCloseAction(this);
StreamCloser.addToQueue(closeAction);
}
public int read() throws IOException {
checkClosed();
bitOffset = 0;
int val = cache.read();
if (val != -1) {
++streamPos;
}
return val;
}
public int read(byte[] b, int off, int len) throws IOException {
checkClosed();
if (b == null) {
throw new NullPointerException("b == null!");
}
if (off < 0 || len < 0 || off + len > b.length || off + len < 0) {
throw new IndexOutOfBoundsException
("off < 0 || len < 0 || off+len > b.length || off+len < 0!");
}
bitOffset = 0;
if (len == 0) {
return 0;
}
int nbytes = cache.read(b, off, len);
if (nbytes != -1) {
streamPos += nbytes;
}
return nbytes;
}
public void write(int b) throws IOException {
flushBits(); // this will call checkClosed() for us
cache.write(b);
++streamPos;
maxStreamPos = Math.max(maxStreamPos, streamPos);
}
public void write(byte[] b, int off, int len) throws IOException {
flushBits(); // this will call checkClosed() for us
cache.write(b, off, len);
streamPos += len;
maxStreamPos = Math.max(maxStreamPos, streamPos);
}
public long length() {
try {
checkClosed();
return cache.length();
} catch (IOException e) {
return -1L;
}
}
/**
* Sets the current stream position and resets the bit offset to
* 0. It is legal to seek past the end of the file; an
* <code>EOFException</code> will be thrown only if a read is
* performed. The file length will not be increased until a write
* is performed.
*
* @exception IndexOutOfBoundsException if <code>pos</code> is smaller
* than the flushed position.
* @exception IOException if any other I/O error occurs.
*/
public void seek(long pos) throws IOException {
checkClosed();
if (pos < flushedPos) {
throw new IndexOutOfBoundsException();
}
cache.seek(pos);
this.streamPos = cache.getFilePointer();
maxStreamPos = Math.max(maxStreamPos, streamPos);
this.bitOffset = 0;
}
/**
* Returns <code>true</code> since this
* <code>ImageOutputStream</code> caches data in order to allow
* seeking backwards.
*
* @return <code>true</code>.
*
* @see #isCachedMemory
* @see #isCachedFile
*/
public boolean isCached() {
return true;
}
/**
* Returns <code>true</code> since this
* <code>ImageOutputStream</code> maintains a file cache.
*
* @return <code>true</code>.
*
* @see #isCached
* @see #isCachedMemory
*/
public boolean isCachedFile() {
return true;
}
/**
* Returns <code>false</code> since this
* <code>ImageOutputStream</code> does not maintain a main memory
* cache.
*
* @return <code>false</code>.
*
* @see #isCached
* @see #isCachedFile
*/
public boolean isCachedMemory() {
return false;
}
/**
* Closes this <code>FileCacheImageOututStream</code>. All
* pending data is flushed to the output, and the cache file
* is closed and removed. The destination <code>OutputStream</code>
* is not closed.
*
* @exception IOException if an error occurs.
*/
public void close() throws IOException {
maxStreamPos = cache.length();
seek(maxStreamPos);
flushBefore(maxStreamPos);
super.close();
cache.close();
cache = null;
cacheFile.delete();
cacheFile = null;
stream.flush();
stream = null;
StreamCloser.removeFromQueue(closeAction);
}
public void flushBefore(long pos) throws IOException {
long oFlushedPos = flushedPos;
super.flushBefore(pos); // this will call checkClosed() for us
long flushBytes = flushedPos - oFlushedPos;
if (flushBytes > 0) {
int bufLen = 512;
byte[] buf = new byte[bufLen];
cache.seek(oFlushedPos);
while (flushBytes > 0) {
int len = (int)Math.min(flushBytes, bufLen);
cache.readFully(buf, 0, len);
stream.write(buf, 0, len);
flushBytes -= len;
}
stream.flush();
}
}
}