J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2000-2007 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package javax.imageio.stream; |
| 27 | |
| 28 | import java.io.File; |
| 29 | import java.io.IOException; |
| 30 | import java.io.OutputStream; |
| 31 | import java.io.RandomAccessFile; |
| 32 | import com.sun.imageio.stream.StreamCloser; |
| 33 | |
| 34 | /** |
| 35 | * An implementation of <code>ImageOutputStream</code> that writes its |
| 36 | * output to a regular <code>OutputStream</code>. A file is used to |
| 37 | * cache data until it is flushed to the output stream. |
| 38 | * |
| 39 | */ |
| 40 | public class FileCacheImageOutputStream extends ImageOutputStreamImpl { |
| 41 | |
| 42 | private OutputStream stream; |
| 43 | |
| 44 | private File cacheFile; |
| 45 | |
| 46 | private RandomAccessFile cache; |
| 47 | |
| 48 | // Pos after last (rightmost) byte written |
| 49 | private long maxStreamPos = 0L; |
| 50 | |
| 51 | /** |
| 52 | * Constructs a <code>FileCacheImageOutputStream</code> that will write |
| 53 | * to a given <code>outputStream</code>. |
| 54 | * |
| 55 | * <p> A temporary file is used as a cache. If |
| 56 | * <code>cacheDir</code>is non-<code>null</code> and is a |
| 57 | * directory, the file will be created there. If it is |
| 58 | * <code>null</code>, the system-dependent default temporary-file |
| 59 | * directory will be used (see the documentation for |
| 60 | * <code>File.createTempFile</code> for details). |
| 61 | * |
| 62 | * @param stream an <code>OutputStream</code> to write to. |
| 63 | * @param cacheDir a <code>File</code> indicating where the |
| 64 | * cache file should be created, or <code>null</code> to use the |
| 65 | * system directory. |
| 66 | * |
| 67 | * @exception IllegalArgumentException if <code>stream</code> |
| 68 | * is <code>null</code>. |
| 69 | * @exception IllegalArgumentException if <code>cacheDir</code> is |
| 70 | * non-<code>null</code> but is not a directory. |
| 71 | * @exception IOException if a cache file cannot be created. |
| 72 | */ |
| 73 | public FileCacheImageOutputStream(OutputStream stream, File cacheDir) |
| 74 | throws IOException { |
| 75 | if (stream == null) { |
| 76 | throw new IllegalArgumentException("stream == null!"); |
| 77 | } |
| 78 | if ((cacheDir != null) && !(cacheDir.isDirectory())) { |
| 79 | throw new IllegalArgumentException("Not a directory!"); |
| 80 | } |
| 81 | this.stream = stream; |
| 82 | this.cacheFile = |
| 83 | File.createTempFile("imageio", ".tmp", cacheDir); |
| 84 | this.cache = new RandomAccessFile(cacheFile, "rw"); |
| 85 | StreamCloser.addToQueue(this); |
| 86 | } |
| 87 | |
| 88 | public int read() throws IOException { |
| 89 | checkClosed(); |
| 90 | bitOffset = 0; |
| 91 | int val = cache.read(); |
| 92 | if (val != -1) { |
| 93 | ++streamPos; |
| 94 | } |
| 95 | return val; |
| 96 | } |
| 97 | |
| 98 | public int read(byte[] b, int off, int len) throws IOException { |
| 99 | checkClosed(); |
| 100 | |
| 101 | if (b == null) { |
| 102 | throw new NullPointerException("b == null!"); |
| 103 | } |
| 104 | if (off < 0 || len < 0 || off + len > b.length || off + len < 0) { |
| 105 | throw new IndexOutOfBoundsException |
| 106 | ("off < 0 || len < 0 || off+len > b.length || off+len < 0!"); |
| 107 | } |
| 108 | |
| 109 | bitOffset = 0; |
| 110 | |
| 111 | if (len == 0) { |
| 112 | return 0; |
| 113 | } |
| 114 | |
| 115 | int nbytes = cache.read(b, off, len); |
| 116 | if (nbytes != -1) { |
| 117 | streamPos += nbytes; |
| 118 | } |
| 119 | return nbytes; |
| 120 | } |
| 121 | |
| 122 | public void write(int b) throws IOException { |
| 123 | flushBits(); // this will call checkClosed() for us |
| 124 | cache.write(b); |
| 125 | ++streamPos; |
| 126 | maxStreamPos = Math.max(maxStreamPos, streamPos); |
| 127 | } |
| 128 | |
| 129 | public void write(byte[] b, int off, int len) throws IOException { |
| 130 | flushBits(); // this will call checkClosed() for us |
| 131 | cache.write(b, off, len); |
| 132 | streamPos += len; |
| 133 | maxStreamPos = Math.max(maxStreamPos, streamPos); |
| 134 | } |
| 135 | |
| 136 | public long length() { |
| 137 | try { |
| 138 | checkClosed(); |
| 139 | return cache.length(); |
| 140 | } catch (IOException e) { |
| 141 | return -1L; |
| 142 | } |
| 143 | } |
| 144 | |
| 145 | /** |
| 146 | * Sets the current stream position and resets the bit offset to |
| 147 | * 0. It is legal to seek past the end of the file; an |
| 148 | * <code>EOFException</code> will be thrown only if a read is |
| 149 | * performed. The file length will not be increased until a write |
| 150 | * is performed. |
| 151 | * |
| 152 | * @exception IndexOutOfBoundsException if <code>pos</code> is smaller |
| 153 | * than the flushed position. |
| 154 | * @exception IOException if any other I/O error occurs. |
| 155 | */ |
| 156 | public void seek(long pos) throws IOException { |
| 157 | checkClosed(); |
| 158 | |
| 159 | if (pos < flushedPos) { |
| 160 | throw new IndexOutOfBoundsException(); |
| 161 | } |
| 162 | |
| 163 | cache.seek(pos); |
| 164 | this.streamPos = cache.getFilePointer(); |
| 165 | maxStreamPos = Math.max(maxStreamPos, streamPos); |
| 166 | this.bitOffset = 0; |
| 167 | } |
| 168 | |
| 169 | /** |
| 170 | * Returns <code>true</code> since this |
| 171 | * <code>ImageOutputStream</code> caches data in order to allow |
| 172 | * seeking backwards. |
| 173 | * |
| 174 | * @return <code>true</code>. |
| 175 | * |
| 176 | * @see #isCachedMemory |
| 177 | * @see #isCachedFile |
| 178 | */ |
| 179 | public boolean isCached() { |
| 180 | return true; |
| 181 | } |
| 182 | |
| 183 | /** |
| 184 | * Returns <code>true</code> since this |
| 185 | * <code>ImageOutputStream</code> maintains a file cache. |
| 186 | * |
| 187 | * @return <code>true</code>. |
| 188 | * |
| 189 | * @see #isCached |
| 190 | * @see #isCachedMemory |
| 191 | */ |
| 192 | public boolean isCachedFile() { |
| 193 | return true; |
| 194 | } |
| 195 | |
| 196 | /** |
| 197 | * Returns <code>false</code> since this |
| 198 | * <code>ImageOutputStream</code> does not maintain a main memory |
| 199 | * cache. |
| 200 | * |
| 201 | * @return <code>false</code>. |
| 202 | * |
| 203 | * @see #isCached |
| 204 | * @see #isCachedFile |
| 205 | */ |
| 206 | public boolean isCachedMemory() { |
| 207 | return false; |
| 208 | } |
| 209 | |
| 210 | /** |
| 211 | * Closes this <code>FileCacheImageOututStream</code>. All |
| 212 | * pending data is flushed to the output, and the cache file |
| 213 | * is closed and removed. The destination <code>OutputStream</code> |
| 214 | * is not closed. |
| 215 | * |
| 216 | * @exception IOException if an error occurs. |
| 217 | */ |
| 218 | public void close() throws IOException { |
| 219 | maxStreamPos = cache.length(); |
| 220 | |
| 221 | seek(maxStreamPos); |
| 222 | flushBefore(maxStreamPos); |
| 223 | super.close(); |
| 224 | cache.close(); |
| 225 | cache = null; |
| 226 | cacheFile.delete(); |
| 227 | cacheFile = null; |
| 228 | stream.flush(); |
| 229 | stream = null; |
| 230 | StreamCloser.removeFromQueue(this); |
| 231 | } |
| 232 | |
| 233 | public void flushBefore(long pos) throws IOException { |
| 234 | long oFlushedPos = flushedPos; |
| 235 | super.flushBefore(pos); // this will call checkClosed() for us |
| 236 | |
| 237 | long flushBytes = flushedPos - oFlushedPos; |
| 238 | if (flushBytes > 0) { |
| 239 | int bufLen = 512; |
| 240 | byte[] buf = new byte[bufLen]; |
| 241 | cache.seek(oFlushedPos); |
| 242 | while (flushBytes > 0) { |
| 243 | int len = (int)Math.min(flushBytes, bufLen); |
| 244 | cache.readFully(buf, 0, len); |
| 245 | stream.write(buf, 0, len); |
| 246 | flushBytes -= len; |
| 247 | } |
| 248 | stream.flush(); |
| 249 | } |
| 250 | } |
| 251 | } |