com.firefly.codec.http2.decode.PriorityBodyParser Maven / Gradle / Ivy
package com.firefly.codec.http2.decode;
import java.nio.ByteBuffer;
import com.firefly.codec.http2.frame.ErrorCode;
import com.firefly.codec.http2.frame.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
}
}