| // |
| // ======================================================================== |
| // 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.spdy.parser; |
| |
| import java.nio.ByteBuffer; |
| |
| import org.eclipse.jetty.spdy.api.DataInfo; |
| import org.eclipse.jetty.spdy.frames.DataFrame; |
| |
| public abstract class DataFrameParser |
| { |
| private State state = State.STREAM_ID; |
| private int cursor; |
| private int streamId; |
| private byte flags; |
| private int length; |
| |
| /** |
| * <p>Parses the given {@link ByteBuffer} for a data frame.</p> |
| * |
| * @param buffer the {@link ByteBuffer} to parse |
| * @return true if the data frame has been fully parsed, false otherwise |
| */ |
| public boolean parse(ByteBuffer buffer) |
| { |
| while (buffer.hasRemaining()) |
| { |
| switch (state) |
| { |
| case STREAM_ID: |
| { |
| if (buffer.remaining() >= 4) |
| { |
| streamId = buffer.getInt() & 0x7F_FF_FF_FF; |
| state = State.FLAGS; |
| } |
| else |
| { |
| state = State.STREAM_ID_BYTES; |
| cursor = 4; |
| } |
| break; |
| } |
| case STREAM_ID_BYTES: |
| { |
| byte currByte = buffer.get(); |
| --cursor; |
| streamId += (currByte & 0xFF) << 8 * cursor; |
| if (cursor == 0) |
| state = State.FLAGS; |
| break; |
| } |
| case FLAGS: |
| { |
| flags = buffer.get(); |
| cursor = 3; |
| state = State.LENGTH; |
| break; |
| } |
| case LENGTH: |
| { |
| byte currByte = buffer.get(); |
| --cursor; |
| length += (currByte & 0xFF) << 8 * cursor; |
| if (cursor > 0) |
| break; |
| state = State.DATA; |
| // Fall down if length == 0: we can't loop because the buffer |
| // may be empty but we need to invoke the application anyway |
| if (length > 0) |
| break; |
| } |
| case DATA: |
| { |
| // Length can only be at most 3 bytes, which is 16_777_215 i.e. 16 MiB. |
| // However, compliant clients should implement flow control, so it's |
| // unlikely that we will get that 16 MiB chunk. |
| // However, TCP may further split the flow control window, so we may |
| // only have part of the data at this point. |
| |
| int size = Math.min(length, buffer.remaining()); |
| int limit = buffer.limit(); |
| buffer.limit(buffer.position() + size); |
| ByteBuffer bytes = buffer.slice(); |
| buffer.limit(limit); |
| buffer.position(buffer.position() + size); |
| length -= size; |
| if (length == 0) |
| { |
| onDataFrame(bytes); |
| return true; |
| } |
| else |
| { |
| // We got only part of the frame data bytes, |
| // so we generate a synthetic data frame |
| onDataFragment(bytes); |
| } |
| break; |
| } |
| default: |
| { |
| throw new IllegalStateException(); |
| } |
| } |
| } |
| return false; |
| } |
| |
| private void onDataFrame(ByteBuffer bytes) |
| { |
| DataFrame frame = new DataFrame(streamId, flags, bytes.remaining()); |
| onDataFrame(frame, bytes); |
| reset(); |
| } |
| |
| private void onDataFragment(ByteBuffer bytes) |
| { |
| DataFrame frame = new DataFrame(streamId, (byte)(flags & ~DataInfo.FLAG_CLOSE), bytes.remaining()); |
| onDataFrame(frame, bytes); |
| // Do not reset, we're expecting more data |
| } |
| |
| protected abstract void onDataFrame(DataFrame frame, ByteBuffer data); |
| |
| private void reset() |
| { |
| state = State.STREAM_ID; |
| cursor = 0; |
| streamId = 0; |
| flags = 0; |
| length = 0; |
| } |
| |
| private enum State |
| { |
| STREAM_ID, STREAM_ID_BYTES, FLAGS, LENGTH, DATA |
| } |
| } |