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/*
* 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 com.vaadin.external.apache.commons.fileupload2.util;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* An input stream, which limits its data size. This stream is used, if the
* content length is unknown.
*/
public abstract class LimitedInputStream extends FilterInputStream
implements Closeable {
/**
* The maximum size of an item, in bytes.
*/
private final long sizeMax;
/**
* The current number of bytes.
*/
private long count;
/**
* Whether this stream is already closed.
*/
private boolean closed;
/**
* Creates a new instance.
*
* @param inputStream
* The input stream, which shall be limited.
* @param pSizeMax
* The limit; no more than this number of bytes shall be returned
* by the source stream.
*/
public LimitedInputStream(final InputStream inputStream,
final long pSizeMax) {
super(inputStream);
sizeMax = pSizeMax;
}
/**
* Called to indicate, that the input streams limit has been exceeded.
*
* @param pSizeMax
* The input streams limit, in bytes.
* @param pCount
* The actual number of bytes.
* @throws IOException
* The called method is expected to raise an IOException.
*/
protected abstract void raiseError(long pSizeMax, long pCount)
throws IOException;
/**
* Called to check, whether the input streams limit is reached.
*
* @throws IOException
* The given limit is exceeded.
*/
private void checkLimit() throws IOException {
if (count > sizeMax) {
raiseError(sizeMax, count);
}
}
/**
* Reads the next byte of data from this input stream. The value byte is
* returned as an {@code int} in the range {@code 0} to {@code 255}. If no
* byte is available because the end of the stream has been reached, the
* value {@code -1} is returned. This method blocks until input data is
* available, the end of the stream is detected, or an exception is thrown.
*
* This method simply performs {@code in.read()} and returns the result.
*
* @return the next byte of data, or {@code -1} if the end of the stream is
* reached.
* @throws IOException
* if an I/O error occurs.
* @see java.io.FilterInputStream#in
*/
@Override
public int read() throws IOException {
final int res = super.read();
if (res != -1) {
count++;
checkLimit();
}
return res;
}
/**
* Reads up to {@code len} bytes of data from this input stream into an
* array of bytes. If {@code len} is not zero, the method blocks until some
* input is available; otherwise, no bytes are read and {@code 0} is
* returned.
*
* This method simply performs {@code in.read(b, off, len)} and returns the
* result.
*
* @param b
* the buffer into which the data is read.
* @param off
* The start offset in the destination array {@code b}.
* @param len
* the maximum number of bytes read.
* @return the total number of bytes read into the buffer, or {@code -1} if
* there is no more data because the end of the stream has been
* reached.
* @throws NullPointerException
* If {@code b} is {@code null}.
* @throws IndexOutOfBoundsException
* If {@code off} is negative, {@code len} is negative, or
* {@code len} is greater than {@code b.length - off}
* @throws IOException
* if an I/O error occurs.
* @see java.io.FilterInputStream#in
*/
@Override
public int read(final byte[] b, final int off, final int len)
throws IOException {
final int res = super.read(b, off, len);
if (res > 0) {
count += res;
checkLimit();
}
return res;
}
/**
* Returns, whether this stream is already closed.
*
* @return True, if the stream is closed, otherwise false.
* @throws IOException
* An I/O error occurred.
*/
@Override
public boolean isClosed() throws IOException {
return closed;
}
/**
* Closes this input stream and releases any system resources associated
* with the stream. This method simply performs {@code in.close()}.
*
* @throws IOException
* if an I/O error occurs.
* @see java.io.FilterInputStream#in
*/
@Override
public void close() throws IOException {
closed = true;
super.close();
}
}