com.firefly.codec.http2.decode.WindowUpdateBodyParser 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.WindowUpdateFrame;
public class WindowUpdateBodyParser extends BodyParser {
private State state = State.PREPARE;
private int cursor;
private int windowDelta;
public WindowUpdateBodyParser(HeaderParser headerParser, Parser.Listener listener) {
super(headerParser, listener);
}
private void reset() {
state = State.PREPARE;
cursor = 0;
windowDelta = 0;
}
@Override
public boolean parse(ByteBuffer buffer) {
while (buffer.hasRemaining()) {
switch (state) {
case PREPARE: {
int length = getBodyLength();
if (length != 4)
return connectionFailure(buffer, ErrorCode.FRAME_SIZE_ERROR.code, "invalid_window_update_frame");
state = State.WINDOW_DELTA;
break;
}
case WINDOW_DELTA: {
if (buffer.remaining() >= 4) {
windowDelta = buffer.getInt() & 0x7F_FF_FF_FF;
return onWindowUpdate(windowDelta);
} else {
state = State.WINDOW_DELTA_BYTES;
cursor = 4;
}
break;
}
case WINDOW_DELTA_BYTES: {
byte currByte = buffer.get();
--cursor;
windowDelta += (currByte & 0xFF) << 8 * cursor;
if (cursor == 0) {
windowDelta &= 0x7F_FF_FF_FF;
return onWindowUpdate(windowDelta);
}
break;
}
default: {
throw new IllegalStateException();
}
}
}
return false;
}
private boolean onWindowUpdate(int windowDelta) {
WindowUpdateFrame frame = new WindowUpdateFrame(getStreamId(), windowDelta);
reset();
notifyWindowUpdate(frame);
return true;
}
private enum State {
PREPARE, WINDOW_DELTA, WINDOW_DELTA_BYTES
}
}