checkNewStreamAllowed() — netty Function Reference

Source Code

codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2Connection.java lines 910–945

        private void checkNewStreamAllowed(int streamId, State state) throws Http2Exception {
            assert state != IDLE;
            if (lastStreamKnownByPeer >= 0 && streamId > lastStreamKnownByPeer) {
                throw streamError(streamId, REFUSED_STREAM,
                        "Cannot create stream %d greater than Last-Stream-ID %d from GOAWAY.",
                        streamId, lastStreamKnownByPeer);
            }
            if (!isValidStreamId(streamId)) {
                if (streamId < 0) {
                    throw new Http2NoMoreStreamIdsException();
                }
                throw connectionError(PROTOCOL_ERROR, "Request stream %d is not correct for %s connection", streamId,
                        server ? "server" : "client");
            }
            // This check must be after all id validated checks, but before the max streams check because it may be
            // recoverable to some degree for handling frames which can be sent on closed streams.
            if (streamId < nextStreamIdToCreate) {
                throw closedStreamError(PROTOCOL_ERROR, "Request stream %d is behind the next expected stream %d",
                        streamId, nextStreamIdToCreate);
            }
            if (nextStreamIdToCreate <= 0) {
                // We exhausted the stream id space that we can use. Let's signal this back but also signal that
                // we still may want to process active streams.
                throw new Http2Exception(REFUSED_STREAM, "Stream IDs are exhausted for this endpoint.",
                        Http2Exception.ShutdownHint.GRACEFUL_SHUTDOWN);
            }
            boolean isReserved = state == RESERVED_LOCAL || state == RESERVED_REMOTE;
            if (!isReserved && !canOpenStream() || isReserved && numStreams >= maxStreams) {
                throw streamError(streamId, REFUSED_STREAM, "Maximum active streams violated for this endpoint: " +
                        (isReserved ? maxStreams : maxActiveStreams));
            }
            if (isClosed()) {
                throw connectionError(INTERNAL_ERROR, "Attempted to create stream id %d after connection was closed",
                                      streamId);
            }
        }