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/*
* Copyright (C) 2007 The Guava Authors
* Copyright (C) 2014, Sasa Zivkov <sasa.zivkov@sap.com>, SAP AG
* and other copyright owners as documented in the project's IP log.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Distribution License v1.0 which
* accompanies this distribution, is reproduced below, and is
* available at http://www.eclipse.org/org/documents/edl-v10.php
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* - Neither the name of the Eclipse Foundation, Inc. nor the
* names of its contributors may be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.eclipse.jgit.util.io;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import org.eclipse.jgit.internal.JGitText;
/**
* Wraps a {@link java.io.InputStream}, limiting the number of bytes which can
* be read.
*
* This class was copied and modifed from the Google Guava 16.0. Differently
* from the original Guava code, when a caller tries to read from this stream
* past the given limit and the wrapped stream hasn't yet reached its EOF this
* class will call the limitExceeded method instead of returning EOF.
*
* @since 3.3
*/
public abstract class LimitedInputStream extends FilterInputStream {
private long left;
/** Max number of bytes to be read from the wrapped stream */
protected final long limit;
private long mark = -1;
/**
* Create a new LimitedInputStream
*
* @param in an InputStream
* @param limit max number of bytes to read from the InputStream
*/
protected LimitedInputStream(InputStream in, long limit) {
super(in);
left = limit;
this.limit = limit;
}
/** {@inheritDoc} */
@Override
public int available() throws IOException {
return (int) Math.min(in.available(), left);
}
// it's okay to mark even if mark isn't supported, as reset won't work
/** {@inheritDoc} */
@Override
public synchronized void mark(int readLimit) {
in.mark(readLimit);
mark = left;
}
/** {@inheritDoc} */
@Override
public int read() throws IOException {
if (left == 0) {
if (in.available() == 0)
return -1;
else
limitExceeded();
}
int result = in.read();
if (result != -1)
--left;
return result;
}
/** {@inheritDoc} */
@Override
public int read(byte[] b, int off, int len) throws IOException {
if (left == 0) {
if (in.available() == 0)
return -1;
else
limitExceeded();
}
len = (int) Math.min(len, left);
int result = in.read(b, off, len);
if (result != -1)
left -= result;
return result;
}
/** {@inheritDoc} */
@Override
public synchronized void reset() throws IOException {
if (!in.markSupported())
throw new IOException(JGitText.get().unsupportedMark);
if (mark == -1)
throw new IOException(JGitText.get().unsetMark);
in.reset();
left = mark;
}
/** {@inheritDoc} */
@Override
public long skip(long n) throws IOException {
n = Math.min(n, left);
long skipped = in.skip(n);
left -= skipped;
return skipped;
}
/**
* Called when trying to read past the given {@link #limit} and the wrapped
* InputStream {@link #in} hasn't yet reached its EOF
*
* @throws java.io.IOException
* subclasses can throw an {@link java.io.IOException} when the
* limit is exceeded. The throws java.io.IOException will be
* forwarded back to the caller of the read method which read
* the stream past the limit.
*/
protected abstract void limitExceeded() throws IOException;
}
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