| /* |
| * Copyright (C) 2008-2010, Google Inc. and others |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Distribution License v. 1.0 which is available at |
| * https://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| |
| package org.eclipse.jgit.transport; |
| |
| import java.io.IOException; |
| import java.io.OutputStream; |
| import java.text.MessageFormat; |
| |
| import org.eclipse.jgit.internal.JGitText; |
| |
| /** |
| * Multiplexes data and progress messages. |
| * <p> |
| * This stream is buffered at packet sizes, so the caller doesn't need to wrap |
| * it in yet another buffered stream. |
| * |
| * @since 2.0 |
| */ |
| public class SideBandOutputStream extends OutputStream { |
| /** Channel used for pack data. */ |
| public static final int CH_DATA = SideBandInputStream.CH_DATA; |
| |
| /** Channel used for progress messages. */ |
| public static final int CH_PROGRESS = SideBandInputStream.CH_PROGRESS; |
| |
| /** Channel used for error messages. */ |
| public static final int CH_ERROR = SideBandInputStream.CH_ERROR; |
| |
| /** Default buffer size for a small amount of data. */ |
| public static final int SMALL_BUF = 1000; |
| |
| /** Maximum buffer size for a single packet of sideband data. */ |
| public static final int MAX_BUF = 65520; |
| |
| static final int HDR_SIZE = 5; |
| |
| private final OutputStream out; |
| |
| private final byte[] buffer; |
| |
| /** |
| * Number of bytes in {@link #buffer} that are valid data. |
| * <p> |
| * Initialized to {@link #HDR_SIZE} if there is no application data in the |
| * buffer, as the packet header always appears at the start of the buffer. |
| */ |
| private int cnt; |
| |
| /** |
| * Create a new stream to write side band packets. |
| * |
| * @param chan |
| * channel number to prefix all packets with, so the remote side |
| * can demultiplex the stream and get back the original data. |
| * Must be in the range [1, 255]. |
| * @param sz |
| * maximum size of a data packet within the stream. The remote |
| * side needs to agree to the packet size to prevent buffer |
| * overflows. Must be in the range [HDR_SIZE + 1, MAX_BUF). |
| * @param os |
| * stream that the packets are written onto. This stream should |
| * be attached to a SideBandInputStream on the remote side. |
| */ |
| public SideBandOutputStream(int chan, int sz, OutputStream os) { |
| if (chan <= 0 || chan > 255) |
| throw new IllegalArgumentException(MessageFormat.format( |
| JGitText.get().channelMustBeInRange1_255, |
| Integer.valueOf(chan))); |
| if (sz <= HDR_SIZE) |
| throw new IllegalArgumentException(MessageFormat.format( |
| JGitText.get().packetSizeMustBeAtLeast, |
| Integer.valueOf(sz), Integer.valueOf(HDR_SIZE))); |
| else if (MAX_BUF < sz) |
| throw new IllegalArgumentException(MessageFormat.format( |
| JGitText.get().packetSizeMustBeAtMost, Integer.valueOf(sz), |
| Integer.valueOf(MAX_BUF))); |
| |
| out = os; |
| buffer = new byte[sz]; |
| buffer[4] = (byte) chan; |
| cnt = HDR_SIZE; |
| } |
| |
| void flushBuffer() throws IOException { |
| if (HDR_SIZE < cnt) |
| writeBuffer(); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public void flush() throws IOException { |
| flushBuffer(); |
| out.flush(); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public void write(byte[] b, int off, int len) throws IOException { |
| while (0 < len) { |
| int capacity = buffer.length - cnt; |
| if (cnt == HDR_SIZE && capacity < len) { |
| // Our block to write is bigger than the packet size, |
| // stream it out as-is to avoid unnecessary copies. |
| PacketLineOut.formatLength(buffer, buffer.length); |
| out.write(buffer, 0, HDR_SIZE); |
| out.write(b, off, capacity); |
| off += capacity; |
| len -= capacity; |
| |
| } else { |
| if (capacity == 0) |
| writeBuffer(); |
| |
| int n = Math.min(len, capacity); |
| System.arraycopy(b, off, buffer, cnt, n); |
| cnt += n; |
| off += n; |
| len -= n; |
| } |
| } |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public void write(int b) throws IOException { |
| if (cnt == buffer.length) |
| writeBuffer(); |
| buffer[cnt++] = (byte) b; |
| } |
| |
| private void writeBuffer() throws IOException { |
| PacketLineOut.formatLength(buffer, cnt); |
| out.write(buffer, 0, cnt); |
| cnt = HDR_SIZE; |
| } |
| } |