1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.fileupload.util; 18 19 import java.io.FilterInputStream; 20 import java.io.IOException; 21 import java.io.InputStream; 22 23 /** 24 * An input stream, which limits its data size. This stream is 25 * used, if the content length is unknown. 26 */ 27 public abstract class LimitedInputStream extends FilterInputStream implements Closeable { 28 29 /** 30 * The maximum size of an item, in bytes. 31 */ 32 private final long sizeMax; 33 34 /** 35 * The current number of bytes. 36 */ 37 private long count; 38 39 /** 40 * Whether this stream is already closed. 41 */ 42 private boolean closed; 43 44 /** 45 * Creates a new instance. 46 * 47 * @param inputStream The input stream, which shall be limited. 48 * @param pSizeMax The limit; no more than this number of bytes 49 * shall be returned by the source stream. 50 */ 51 public LimitedInputStream(InputStream inputStream, long pSizeMax) { 52 super(inputStream); 53 sizeMax = pSizeMax; 54 } 55 56 /** 57 * Called to indicate, that the input streams limit has 58 * been exceeded. 59 * 60 * @param pSizeMax The input streams limit, in bytes. 61 * @param pCount The actual number of bytes. 62 * @throws IOException The called method is expected 63 * to raise an IOException. 64 */ 65 protected abstract void raiseError(long pSizeMax, long pCount) 66 throws IOException; 67 68 /** 69 * Called to check, whether the input streams 70 * limit is reached. 71 * 72 * @throws IOException The given limit is exceeded. 73 */ 74 private void checkLimit() throws IOException { 75 if (count > sizeMax) { 76 raiseError(sizeMax, count); 77 } 78 } 79 80 /** 81 * Reads the next byte of data from this input stream. The value 82 * byte is returned as an <code>int</code> in the range 83 * <code>0</code> to <code>255</code>. If no byte is available 84 * because the end of the stream has been reached, the value 85 * <code>-1</code> is returned. This method blocks until input data 86 * is available, the end of the stream is detected, or an exception 87 * is thrown. 88 * <p> 89 * This method 90 * simply performs <code>in.read()</code> and returns the result. 91 * 92 * @return the next byte of data, or <code>-1</code> if the end of the 93 * stream is reached. 94 * @throws IOException if an I/O error occurs. 95 * @see java.io.FilterInputStream#in 96 */ 97 @Override 98 public int read() throws IOException { 99 int res = super.read(); 100 if (res != -1) { 101 count++; 102 checkLimit(); 103 } 104 return res; 105 } 106 107 /** 108 * Reads up to <code>len</code> bytes of data from this input stream 109 * into an array of bytes. If <code>len</code> is not zero, the method 110 * blocks until some input is available; otherwise, no 111 * bytes are read and <code>0</code> is returned. 112 * <p> 113 * This method simply performs <code>in.read(b, off, len)</code> 114 * and returns the result. 115 * 116 * @param b the buffer into which the data is read. 117 * @param off The start offset in the destination array 118 * <code>b</code>. 119 * @param len the maximum number of bytes read. 120 * @return the total number of bytes read into the buffer, or 121 * <code>-1</code> if there is no more data because the end of 122 * the stream has been reached. 123 * @throws NullPointerException If <code>b</code> is <code>null</code>. 124 * @throws IndexOutOfBoundsException If <code>off</code> is negative, 125 * <code>len</code> is negative, or <code>len</code> is greater than 126 * <code>b.length - off</code> 127 * @throws IOException if an I/O error occurs. 128 * @see java.io.FilterInputStream#in 129 */ 130 @Override 131 public int read(byte[] b, int off, int len) throws IOException { 132 int res = super.read(b, off, len); 133 if (res > 0) { 134 count += res; 135 checkLimit(); 136 } 137 return res; 138 } 139 140 /** 141 * Returns, whether this stream is already closed. 142 * 143 * @return True, if the stream is closed, otherwise false. 144 * @throws IOException An I/O error occurred. 145 */ 146 public boolean isClosed() throws IOException { 147 return closed; 148 } 149 150 /** 151 * Closes this input stream and releases any system resources 152 * associated with the stream. 153 * This 154 * method simply performs <code>in.close()</code>. 155 * 156 * @throws IOException if an I/O error occurs. 157 * @see java.io.FilterInputStream#in 158 */ 159 @Override 160 public void close() throws IOException { 161 closed = true; 162 super.close(); 163 } 164 165 }