src/java.desktop/share/classes/javax/imageio/stream/FileCacheImageInputStream.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 2000, 2017, 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
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */

 package javax.imageio.stream;

 import java.io.File;
 import java.io.InputStream;
 import java.io.IOException;
 import java.io.RandomAccessFile;
 import java.nio.file.Files;
 import com.sun.imageio.stream.StreamCloser;
 import com.sun.imageio.stream.StreamFinalizer;
 import sun.java2d.Disposer;
 import sun.java2d.DisposerRecord;

 /**
  * An implementation of {@code ImageInputStream} that gets its
  * input from a regular {@code InputStream}.  A file is used to
  * cache previously read data.
  *
  */
 public class FileCacheImageInputStream extends ImageInputStreamImpl {

     private InputStream stream;

     private File cacheFile;

     private RandomAccessFile cache;

     private static final int BUFFER_LENGTH = 1024;

     private byte[] buf = new byte[BUFFER_LENGTH];

     private long length = 0L;

     private boolean foundEOF = false;

     /** The referent to be registered with the Disposer. */
     private final Object disposerReferent;

     /** The DisposerRecord that closes the underlying cache. */
     private final DisposerRecord disposerRecord;

     /** The CloseAction that closes the stream in
      *  the StreamCloser's shutdown hook                     */
     private final StreamCloser.CloseAction closeAction;

     /**
      * Constructs a {@code FileCacheImageInputStream} that will read
      * from a given {@code InputStream}.
      *
      * <p> A temporary file is used as a cache.  If
      * {@code cacheDir} is non-{@code null} and is a
      * directory, the file will be created there.  If it is
      * {@code null}, the system-dependent default temporary-file
      * directory will be used (see the documentation for
      * {@code File.createTempFile} for details).
      *
      * @param stream an {@code InputStream} to read from.
      * @param cacheDir a {@code File} indicating where the
      * cache file should be created, or {@code null} to use the
      * system directory.
      *
      * @exception IllegalArgumentException if {@code stream} is
      * {@code null}.
      * @exception IllegalArgumentException if {@code cacheDir} is
      * non-{@code null} but is not a directory.
      * @throws IOException if a cache file cannot be created.
      */
     public FileCacheImageInputStream(InputStream 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;
         if (cacheDir == null)
             this.cacheFile = Files.createTempFile("imageio", ".tmp").toFile();
         else
             this.cacheFile = Files.createTempFile(cacheDir.toPath(), "imageio", ".tmp")
                                   .toFile();
         this.cache = new RandomAccessFile(cacheFile, "rw");

         this.closeAction = StreamCloser.createCloseAction(this);
         StreamCloser.addToQueue(closeAction);

         disposerRecord = new StreamDisposerRecord(cacheFile, cache);
         if (getClass() == FileCacheImageInputStream.class) {
             disposerReferent = new Object();
             Disposer.addRecord(disposerReferent, disposerRecord);
         } else {
             disposerReferent = new StreamFinalizer(this);
         }
     }

     /**
      * Ensures that at least {@code pos} bytes are cached,
      * or the end of the source is reached.  The return value
      * is equal to the smaller of {@code pos} and the
      * length of the source file.
      *
      * @throws IOException if an I/O error occurs while reading from the
      * source file
      */
     private long readUntil(long pos) throws IOException {
         // We've already got enough data cached
         if (pos < length) {
             return pos;
         }
         // pos >= length but length isn't getting any bigger, so return it
         if (foundEOF) {
             return length;
         }

         long len = pos - length;
         cache.seek(length);
         while (len > 0) {
             // Copy a buffer's worth of data from the source to the cache
             // BUFFER_LENGTH will always fit into an int so this is safe
             int nbytes =
                 stream.read(buf, 0, (int)Math.min(len, (long)BUFFER_LENGTH));
             if (nbytes == -1) {
                 foundEOF = true;
                 return length;
             }

             cache.write(buf, 0, nbytes);
             len -= nbytes;
             length += nbytes;
         }

         return pos;
     }

     public int read() throws IOException {
         checkClosed();
         bitOffset = 0;
         long next = streamPos + 1;
         long pos = readUntil(next);
         if (pos >= next) {
             cache.seek(streamPos++);
             return cache.read();
         } else {
             return -1;
         }
     }

     public int read(byte[] b, int off, int len) throws IOException {
         checkClosed();

         if (b == null) {
             throw new NullPointerException("b == null!");
         }
         // Fix 4430357 - if off + len < 0, overflow occurred
         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;
         }

         long pos = readUntil(streamPos + len);

         // len will always fit into an int so this is safe
         len = (int)Math.min((long)len, pos - streamPos);
         if (len > 0) {
             cache.seek(streamPos);
             cache.readFully(b, off, len);
             streamPos += len;
             return len;
         } else {
             return -1;
         }
     }

     /**
      * Returns {@code true} since this
      * {@code ImageInputStream} caches data in order to allow
      * seeking backwards.
      *
      * @return {@code true}.
      *
      * @see #isCachedMemory
      * @see #isCachedFile
      */
     public boolean isCached() {
         return true;
     }

     /**
      * Returns {@code true} since this
      * {@code ImageInputStream} maintains a file cache.
      *
      * @return {@code true}.
      *
      * @see #isCached
      * @see #isCachedMemory
      */
     public boolean isCachedFile() {
         return true;
     }

     /**
      * Returns {@code false} since this
      * {@code ImageInputStream} does not maintain a main memory
      * cache.
      *
      * @return {@code false}.
      *
      * @see #isCached
      * @see #isCachedFile
      */
     public boolean isCachedMemory() {
         return false;
     }

     /**
      * Closes this {@code FileCacheImageInputStream}, closing
      * and removing the cache file.  The source {@code InputStream}
      * is not closed.
      *
      * @throws IOException if an error occurs.
      */
     public void close() throws IOException {
         super.close();
         disposerRecord.dispose(); // this will close/delete the cache file
         stream = null;
         cache = null;
         cacheFile = null;
         StreamCloser.removeFromQueue(closeAction);
     }

     /**
      * {@inheritDoc}
      *
      * @deprecated The {@code finalize} method has been deprecated.
      *     Subclasses that override {@code finalize} in order to perform cleanup
      *     should be modified to use alternative cleanup mechanisms and
      *     to remove the overriding {@code finalize} method.
      *     When overriding the {@code finalize} method, its implementation must explicitly
      *     ensure that {@code super.finalize()} is invoked as described in {@link Object#finalize}.
      *     See the specification for {@link Object#finalize()} for further
      *     information about migration options.
      */
     @Deprecated(since="9")
     protected void finalize() throws Throwable {
         // Empty finalizer: for performance reasons we instead use the
         // Disposer mechanism for ensuring that the underlying
         // RandomAccessFile is closed/deleted prior to garbage collection
     }

     private static class StreamDisposerRecord implements DisposerRecord {
         private File cacheFile;
         private RandomAccessFile cache;

         public StreamDisposerRecord(File cacheFile, RandomAccessFile cache) {
             this.cacheFile = cacheFile;
             this.cache = cache;
         }

         public synchronized void dispose() {
             if (cache != null) {
                 try {
                     cache.close();
                 } catch (IOException e) {
                 } finally {
                     cache = null;
                 }
             }
             if (cacheFile != null) {
                 cacheFile.delete();
                 cacheFile = null;
             }
             // Note: Explicit removal of the stream from the StreamCloser
             // queue is not mandatory in this case, as it will be removed
             // automatically by GC shortly after this method is called.
         }
     }
 }
	/*
	* Copyright (c) 2000, 2017, 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
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package javax.imageio.stream;

	import java.io.File;
	import java.io.InputStream;
	import java.io.IOException;
	import java.io.RandomAccessFile;
	import java.nio.file.Files;
	import com.sun.imageio.stream.StreamCloser;
	import com.sun.imageio.stream.StreamFinalizer;
	import sun.java2d.Disposer;
	import sun.java2d.DisposerRecord;

	/**
	* An implementation of {@code ImageInputStream} that gets its
	* input from a regular {@code InputStream}. A file is used to
	* cache previously read data.
	*
	*/
	public class FileCacheImageInputStream extends ImageInputStreamImpl {

	private InputStream stream;

	private File cacheFile;

	private RandomAccessFile cache;

	private static final int BUFFER_LENGTH = 1024;

	private byte[] buf = new byte[BUFFER_LENGTH];

	private long length = 0L;

	private boolean foundEOF = false;

	/** The referent to be registered with the Disposer. */
	private final Object disposerReferent;

	/** The DisposerRecord that closes the underlying cache. */
	private final DisposerRecord disposerRecord;

	/** The CloseAction that closes the stream in
	* the StreamCloser's shutdown hook */
	private final StreamCloser.CloseAction closeAction;

	/**
	* Constructs a {@code FileCacheImageInputStream} that will read
	* from a given {@code InputStream}.
	*
	* <p> A temporary file is used as a cache. If
	* {@code cacheDir} is non-{@code null} and is a
	* directory, the file will be created there. If it is
	* {@code null}, the system-dependent default temporary-file
	* directory will be used (see the documentation for
	* {@code File.createTempFile} for details).
	*
	* @param stream an {@code InputStream} to read from.
	* @param cacheDir a {@code File} indicating where the
	* cache file should be created, or {@code null} to use the
	* system directory.
	*
	* @exception IllegalArgumentException if {@code stream} is
	* {@code null}.
	* @exception IllegalArgumentException if {@code cacheDir} is
	* non-{@code null} but is not a directory.
	* @throws IOException if a cache file cannot be created.
	*/
	public FileCacheImageInputStream(InputStream 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;
	if (cacheDir == null)
	this.cacheFile = Files.createTempFile("imageio", ".tmp").toFile();
	else
	this.cacheFile = Files.createTempFile(cacheDir.toPath(), "imageio", ".tmp")
	.toFile();
	this.cache = new RandomAccessFile(cacheFile, "rw");

	this.closeAction = StreamCloser.createCloseAction(this);
	StreamCloser.addToQueue(closeAction);

	disposerRecord = new StreamDisposerRecord(cacheFile, cache);
	if (getClass() == FileCacheImageInputStream.class) {
	disposerReferent = new Object();
	Disposer.addRecord(disposerReferent, disposerRecord);
	} else {
	disposerReferent = new StreamFinalizer(this);
	}
	}

	/**
	* Ensures that at least {@code pos} bytes are cached,
	* or the end of the source is reached. The return value
	* is equal to the smaller of {@code pos} and the
	* length of the source file.
	*
	* @throws IOException if an I/O error occurs while reading from the
	* source file
	*/
	private long readUntil(long pos) throws IOException {
	// We've already got enough data cached
	if (pos < length) {
	return pos;
	}
	// pos >= length but length isn't getting any bigger, so return it
	if (foundEOF) {
	return length;
	}

	long len = pos - length;
	cache.seek(length);
	while (len > 0) {
	// Copy a buffer's worth of data from the source to the cache
	// BUFFER_LENGTH will always fit into an int so this is safe
	int nbytes =
	stream.read(buf, 0, (int)Math.min(len, (long)BUFFER_LENGTH));
	if (nbytes == -1) {
	foundEOF = true;
	return length;
	}

	cache.write(buf, 0, nbytes);
	len -= nbytes;
	length += nbytes;
	}

	return pos;
	}

	public int read() throws IOException {
	checkClosed();
	bitOffset = 0;
	long next = streamPos + 1;
	long pos = readUntil(next);
	if (pos >= next) {
	cache.seek(streamPos++);
	return cache.read();
	} else {
	return -1;
	}
	}

	public int read(byte[] b, int off, int len) throws IOException {
	checkClosed();

	if (b == null) {
	throw new NullPointerException("b == null!");
	}
	// Fix 4430357 - if off + len < 0, overflow occurred
	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;
	}

	long pos = readUntil(streamPos + len);

	// len will always fit into an int so this is safe
	len = (int)Math.min((long)len, pos - streamPos);
	if (len > 0) {
	cache.seek(streamPos);
	cache.readFully(b, off, len);
	streamPos += len;
	return len;
	} else {
	return -1;
	}
	}

	/**
	* Returns {@code true} since this
	* {@code ImageInputStream} caches data in order to allow
	* seeking backwards.
	*
	* @return {@code true}.
	*
	* @see #isCachedMemory
	* @see #isCachedFile
	*/
	public boolean isCached() {
	return true;
	}

	/**
	* Returns {@code true} since this
	* {@code ImageInputStream} maintains a file cache.
	*
	* @return {@code true}.
	*
	* @see #isCached
	* @see #isCachedMemory
	*/
	public boolean isCachedFile() {
	return true;
	}

	/**
	* Returns {@code false} since this
	* {@code ImageInputStream} does not maintain a main memory
	* cache.
	*
	* @return {@code false}.
	*
	* @see #isCached
	* @see #isCachedFile
	*/
	public boolean isCachedMemory() {
	return false;
	}

	/**
	* Closes this {@code FileCacheImageInputStream}, closing
	* and removing the cache file. The source {@code InputStream}
	* is not closed.
	*
	* @throws IOException if an error occurs.
	*/
	public void close() throws IOException {
	super.close();
	disposerRecord.dispose(); // this will close/delete the cache file
	stream = null;
	cache = null;
	cacheFile = null;
	StreamCloser.removeFromQueue(closeAction);
	}

	/**
	* {@inheritDoc}
	*
	* @deprecated The {@code finalize} method has been deprecated.
	* Subclasses that override {@code finalize} in order to perform cleanup
	* should be modified to use alternative cleanup mechanisms and
	* to remove the overriding {@code finalize} method.
	* When overriding the {@code finalize} method, its implementation must explicitly
	* ensure that {@code super.finalize()} is invoked as described in {@link Object#finalize}.
	* See the specification for {@link Object#finalize()} for further
	* information about migration options.
	*/
	@Deprecated(since="9")
	protected void finalize() throws Throwable {
	// Empty finalizer: for performance reasons we instead use the
	// Disposer mechanism for ensuring that the underlying
	// RandomAccessFile is closed/deleted prior to garbage collection
	}

	private static class StreamDisposerRecord implements DisposerRecord {
	private File cacheFile;
	private RandomAccessFile cache;

	public StreamDisposerRecord(File cacheFile, RandomAccessFile cache) {
	this.cacheFile = cacheFile;
	this.cache = cache;
	}

	public synchronized void dispose() {
	if (cache != null) {
	try {
	cache.close();
	} catch (IOException e) {
	} finally {
	cache = null;
	}
	}
	if (cacheFile != null) {
	cacheFile.delete();
	cacheFile = null;
	}
	// Note: Explicit removal of the stream from the StreamCloser
	// queue is not mandatory in this case, as it will be removed
	// automatically by GC shortly after this method is called.
	}
	}
	}