| // |
| // ======================================================================== |
| // Copyright (c) 1995-2017 Mort Bay Consulting Pty. Ltd. |
| // ------------------------------------------------------------------------ |
| // All rights reserved. This program and the accompanying materials |
| // are made available under the terms of the Eclipse Public License v1.0 |
| // and Apache License v2.0 which accompanies this distribution. |
| // |
| // The Eclipse Public License is available at |
| // http://www.eclipse.org/legal/epl-v10.html |
| // |
| // The Apache License v2.0 is available at |
| // http://www.opensource.org/licenses/apache2.0.php |
| // |
| // You may elect to redistribute this code under either of these licenses. |
| // ======================================================================== |
| // |
| |
| package org.eclipse.jetty.http2.parser; |
| |
| import java.nio.ByteBuffer; |
| |
| import org.eclipse.jetty.http2.frames.Frame; |
| |
| /** |
| * <p>The parser for the frame header of HTTP/2 frames.</p> |
| * |
| * @see Parser |
| */ |
| public class HeaderParser |
| { |
| private State state = State.LENGTH; |
| private int cursor; |
| |
| private int length; |
| private int type; |
| private int flags; |
| private int streamId; |
| |
| protected void reset() |
| { |
| state = State.LENGTH; |
| cursor = 0; |
| |
| length = 0; |
| type = 0; |
| flags = 0; |
| streamId = 0; |
| } |
| |
| /** |
| * <p>Parses the header bytes in the given {@code buffer}; only the header |
| * bytes are consumed, therefore when this method returns, the buffer may |
| * contain unconsumed bytes.</p> |
| * |
| * @param buffer the buffer to parse |
| * @return true if the whole header bytes were parsed, false if not enough |
| * header bytes were present in the buffer |
| */ |
| public boolean parse(ByteBuffer buffer) |
| { |
| while (buffer.hasRemaining()) |
| { |
| switch (state) |
| { |
| case LENGTH: |
| { |
| int octet = buffer.get() & 0xFF; |
| length = (length << 8) + octet; |
| if (++cursor == 3) |
| { |
| length &= Frame.MAX_MAX_LENGTH; |
| state = State.TYPE; |
| } |
| break; |
| } |
| case TYPE: |
| { |
| type = buffer.get() & 0xFF; |
| state = State.FLAGS; |
| break; |
| } |
| case FLAGS: |
| { |
| flags = buffer.get() & 0xFF; |
| state = State.STREAM_ID; |
| break; |
| } |
| case STREAM_ID: |
| { |
| if (buffer.remaining() >= 4) |
| { |
| streamId = buffer.getInt(); |
| // Most significant bit MUST be ignored as per specification. |
| streamId &= 0x7F_FF_FF_FF; |
| return true; |
| } |
| else |
| { |
| state = State.STREAM_ID_BYTES; |
| cursor = 4; |
| } |
| break; |
| } |
| case STREAM_ID_BYTES: |
| { |
| int currByte = buffer.get() & 0xFF; |
| --cursor; |
| streamId += currByte << (8 * cursor); |
| if (cursor == 0) |
| { |
| // Most significant bit MUST be ignored as per specification. |
| streamId &= 0x7F_FF_FF_FF; |
| return true; |
| } |
| break; |
| } |
| default: |
| { |
| throw new IllegalStateException(); |
| } |
| } |
| } |
| return false; |
| } |
| |
| public int getLength() |
| { |
| return length; |
| } |
| |
| public int getFrameType() |
| { |
| return type; |
| } |
| |
| public boolean hasFlag(int bit) |
| { |
| return (flags & bit) == bit; |
| } |
| |
| public int getStreamId() |
| { |
| return streamId; |
| } |
| |
| private enum State |
| { |
| LENGTH, TYPE, FLAGS, STREAM_ID, STREAM_ID_BYTES |
| } |
| } |