com.fireflysource.net.http.common.v2.decoder.PushPromiseBodyParser Maven / Gradle / Ivy

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package com.fireflysource.net.http.common.v2.decoder;

import com.fireflysource.net.http.common.model.MetaData;
import com.fireflysource.net.http.common.v2.frame.ErrorCode;
import com.fireflysource.net.http.common.v2.frame.Flags;
import com.fireflysource.net.http.common.v2.frame.PushPromiseFrame;

import java.nio.ByteBuffer;

public class PushPromiseBodyParser extends BodyParser {
    private final HeaderBlockParser headerBlockParser;
    private State state = State.PREPARE;
    private int cursor;
    private int length;
    private int paddingLength;
    private int streamId;

    public PushPromiseBodyParser(HeaderParser headerParser, Parser.Listener listener, HeaderBlockParser headerBlockParser) {
        super(headerParser, listener);
        this.headerBlockParser = headerBlockParser;
    }

    private void reset() {
        state = State.PREPARE;
        cursor = 0;
        length = 0;
        paddingLength = 0;
        streamId = 0;
    }

    @Override
    public boolean parse(ByteBuffer buffer) {
        boolean loop = false;
        while (buffer.hasRemaining() || loop) {
            switch (state) {
                case PREPARE: {
                    // SPEC: wrong streamId is treated as connection error.
                    if (getStreamId() == 0)
                        return connectionFailure(buffer, ErrorCode.PROTOCOL_ERROR.code, "invalid_push_promise_frame");

                    // For now we don't support PUSH_PROMISE frames that don't have END_HEADERS.
                    if (!hasFlag(Flags.END_HEADERS))
                        return connectionFailure(buffer, ErrorCode.INTERNAL_ERROR.code, "unsupported_push_promise_frame");

                    length = getBodyLength();

                    if (isPadding()) {
                        state = State.PADDING_LENGTH;
                    } else {
                        state = State.STREAM_ID;
                    }
                    break;
                }
                case PADDING_LENGTH: {
                    paddingLength = buffer.get() & 0xFF;
                    --length;
                    length -= paddingLength;
                    state = State.STREAM_ID;
                    if (length < 4)
                        return connectionFailure(buffer, ErrorCode.FRAME_SIZE_ERROR.code, "invalid_push_promise_frame");
                    break;
                }
                case STREAM_ID: {
                    if (buffer.remaining() >= 4) {
                        streamId = buffer.getInt();
                        streamId &= 0x7F_FF_FF_FF;
                        length -= 4;
                        state = State.HEADERS;
                        loop = length == 0;
                    } else {
                        state = State.STREAM_ID_BYTES;
                        cursor = 4;
                    }
                    break;
                }
                case STREAM_ID_BYTES: {
                    int currByte = buffer.get() & 0xFF;
                    --cursor;
                    streamId += currByte << (8 * cursor);
                    --length;
                    if (cursor > 0 && length <= 0)
                        return connectionFailure(buffer, ErrorCode.FRAME_SIZE_ERROR.code, "invalid_push_promise_frame");
                    if (cursor == 0) {
                        streamId &= 0x7F_FF_FF_FF;
                        state = State.HEADERS;
                        loop = length == 0;
                    }
                    break;
                }
                case HEADERS: {
                    MetaData metaData = headerBlockParser.parse(buffer, length);
                    if (metaData == HeaderBlockParser.SESSION_FAILURE)
                        return false;
                    if (metaData != null) {
                        state = State.PADDING;
                        loop = paddingLength == 0;
                        if (metaData != HeaderBlockParser.STREAM_FAILURE)
                            onPushPromise(streamId, metaData);
                    }
                    break;
                }
                case PADDING: {
                    int size = Math.min(buffer.remaining(), paddingLength);
                    buffer.position(buffer.position() + size);
                    paddingLength -= size;
                    if (paddingLength == 0) {
                        reset();
                        return true;
                    }
                    break;
                }
                default: {
                    throw new IllegalStateException();
                }
            }
        }
        return false;
    }

    private void onPushPromise(int streamId, MetaData metaData) {
        PushPromiseFrame frame = new PushPromiseFrame(getStreamId(), streamId, metaData);
        frame.setEndHeaders(hasFlag(Flags.END_HEADERS));
        notifyPushPromise(frame);
    }

    private enum State {
        PREPARE, PADDING_LENGTH, STREAM_ID, STREAM_ID_BYTES, HEADERS, PADDING
    }
}