// Copyright 2010 Google Inc. All Rights Reserved.
//
// Licensed 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.google.enterprise.connector.util;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* This Filter protects against the poorly behaved Apache Commons IO
* {@code AutoCloseInputStream}, which can close a stream out from underneath
* us. When that happens, reads while at EOF throw {@code IOException} rather
* than returning -1. This filter avoids calling {@code read()} on the
* source stream once it is known to be at End-Of-File.
*
* @since 2.8
*/
public class EofFilterInputStream extends FilterInputStream {
private boolean atEOF;
public EofFilterInputStream(InputStream in) {
super(in);
atEOF = false;
}
@Override
public int read() throws IOException {
if (atEOF) {
return -1;
}
int rtn = super.read();
if (rtn == -1) {
atEOF = true;
}
return rtn;
}
@Override
public int read(byte[] b) throws IOException {
return read(b, 0, b.length);
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
if (atEOF) {
return -1;
}
int rtn = super.read(b, off, len);
if (rtn == -1) {
atEOF = true;
}
return rtn;
}
@Override
public void reset() throws IOException {
super.reset();
// Doesn't protect against someone setting the mark while at EOF,
// but good enough for our purposes.
atEOF = false;
}
@Override
public void close() throws IOException {
// Once we are explicitly closed, we no longer need to protect
// against unwarranted IOExceptions.
atEOF = false;
super.close();
}
}