// // ======================================================================== // 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.ErrorCode; import org.eclipse.jetty.http2.frames.PriorityFrame; public class PriorityBodyParser extends BodyParser { private State state = State.PREPARE; private int cursor; private boolean exclusive; private int parentStreamId; public PriorityBodyParser(HeaderParser headerParser, Parser.Listener listener) { super(headerParser, listener); } private void reset() { state = State.PREPARE; cursor = 0; exclusive = false; parentStreamId = 0; } @Override public boolean parse(ByteBuffer buffer) { while (buffer.hasRemaining()) { switch (state) { case PREPARE: { // SPEC: wrong streamId is treated as connection error. if (getStreamId() == 0) return connectionFailure(buffer, ErrorCode.PROTOCOL_ERROR.code, "invalid_priority_frame"); int length = getBodyLength(); if (length != 5) return connectionFailure(buffer, ErrorCode.FRAME_SIZE_ERROR.code, "invalid_priority_frame"); state = State.EXCLUSIVE; break; } case EXCLUSIVE: { // We must only peek the first byte and not advance the buffer // because the 31 least significant bits represent the stream id. int currByte = buffer.get(buffer.position()); exclusive = (currByte & 0x80) == 0x80; state = State.PARENT_STREAM_ID; break; } case PARENT_STREAM_ID: { if (buffer.remaining() >= 4) { parentStreamId = buffer.getInt(); parentStreamId &= 0x7F_FF_FF_FF; state = State.WEIGHT; } else { state = State.PARENT_STREAM_ID_BYTES; cursor = 4; } break; } case PARENT_STREAM_ID_BYTES: { int currByte = buffer.get() & 0xFF; --cursor; parentStreamId += currByte << (8 * cursor); if (cursor == 0) { parentStreamId &= 0x7F_FF_FF_FF; state = State.WEIGHT; } break; } case WEIGHT: { // SPEC: stream cannot depend on itself. if (getStreamId() == parentStreamId) return connectionFailure(buffer, ErrorCode.PROTOCOL_ERROR.code, "invalid_priority_frame"); int weight = (buffer.get() & 0xFF) + 1; return onPriority(parentStreamId, weight, exclusive); } default: { throw new IllegalStateException(); } } } return false; } private boolean onPriority(int parentStreamId, int weight, boolean exclusive) { PriorityFrame frame = new PriorityFrame(getStreamId(), parentStreamId, weight, exclusive); reset(); notifyPriority(frame); return true; } private enum State { PREPARE, EXCLUSIVE, PARENT_STREAM_ID, PARENT_STREAM_ID_BYTES, WEIGHT } }