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- /*
- * Copyright (C) 2009, 2013 Google Inc.
- * 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.IOException;
- import java.io.InputStream;
- import java.util.Iterator;
- import java.util.LinkedList;
-
- /**
- * An InputStream which reads from one or more InputStreams.
- * <p>
- * This stream may enter into an EOF state, returning -1 from any of the read
- * methods, and then later successfully read additional bytes if a new
- * InputStream is added after reaching EOF.
- * <p>
- * Currently this stream does not support the mark/reset APIs. If mark and later
- * reset functionality is needed the caller should wrap this stream with a
- * {@link java.io.BufferedInputStream}.
- * */
- public class UnionInputStream extends InputStream {
- private static final InputStream EOF = new InputStream() {
- @Override
- public int read() throws IOException {
- return -1;
- }
- };
-
- private final LinkedList<InputStream> streams = new LinkedList<InputStream>();
-
- /** Create an empty InputStream that is currently at EOF state. */
- public UnionInputStream() {
- // Do nothing.
- }
-
- /**
- * Create an InputStream that is a union of the individual streams.
- * <p>
- * As each stream reaches EOF, it will be automatically closed before bytes
- * from the next stream are read.
- *
- * @param inputStreams
- * streams to be pushed onto this stream.
- */
- public UnionInputStream(InputStream... inputStreams) {
- for (InputStream i : inputStreams)
- add(i);
- }
-
- private InputStream head() {
- return streams.isEmpty() ? EOF : streams.getFirst();
- }
-
- private void pop() throws IOException {
- if (!streams.isEmpty())
- streams.removeFirst().close();
- }
-
- /**
- * Add the given InputStream onto the end of the stream queue.
- * <p>
- * When the stream reaches EOF it will be automatically closed.
- *
- * @param in
- * the stream to add; must not be null.
- */
- public void add(final InputStream in) {
- streams.add(in);
- }
-
- /**
- * Returns true if there are no more InputStreams in the stream queue.
- * <p>
- * If this method returns {@code true} then all read methods will signal EOF
- * by returning -1, until another InputStream has been pushed into the queue
- * with {@link #add(InputStream)}.
- *
- * @return true if there are no more streams to read from.
- */
- public boolean isEmpty() {
- return streams.isEmpty();
- }
-
- @Override
- public int read() throws IOException {
- for (;;) {
- final InputStream in = head();
- final int r = in.read();
- if (0 <= r)
- return r;
- else if (in == EOF)
- return -1;
- else
- pop();
- }
- }
-
- @Override
- public int read(byte[] b, int off, int len) throws IOException {
- if (len == 0)
- return 0;
- for (;;) {
- final InputStream in = head();
- final int n = in.read(b, off, len);
- if (0 < n)
- return n;
- else if (in == EOF)
- return -1;
- else
- pop();
- }
- }
-
- @Override
- public int available() throws IOException {
- return head().available();
- }
-
- @Override
- public long skip(final long count) throws IOException {
- long skipped = 0;
- long cnt = count;
- while (0 < cnt) {
- final InputStream in = head();
- final long n = in.skip(cnt);
- if (0 < n) {
- skipped += n;
- cnt -= n;
-
- } else if (in == EOF) {
- return skipped;
-
- } else {
- // Is this stream at EOF? We can't tell from skip alone.
- // Read one byte to test for EOF, discard it if we aren't
- // yet at EOF.
- //
- final int r = in.read();
- if (r < 0) {
- pop();
- if (0 < skipped)
- break;
- } else {
- skipped += 1;
- cnt -= 1;
- }
- }
- }
- return skipped;
- }
-
- @Override
- public void close() throws IOException {
- IOException err = null;
-
- for (Iterator<InputStream> i = streams.iterator(); i.hasNext();) {
- try {
- i.next().close();
- } catch (IOException closeError) {
- err = closeError;
- }
- i.remove();
- }
-
- if (err != null)
- throw err;
- }
- }
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