Function ParseH2Settings

src/brpc/policy/http2_rpc_protocol.cpp:163–211

Parse from n bytes from the iterator. Returns true on success.

// Parse from n bytes from the iterator.
// Returns true on success.
bool ParseH2Settings(H2Settings* out, butil::IOBufBytesIterator& it, size_t n) {
    const uint32_t npairs = n / 6;
    if (npairs * 6 != n) {
        LOG(ERROR) << "Invalid payload_size=" << n;
        return false;
    }
    for (uint32_t i = 0; i < npairs; ++i) {
        uint16_t id = LoadUint16(it);
        uint32_t value = LoadUint32(it);
        switch (static_cast<H2SettingsIdentifier>(id)) {
        case H2_SETTINGS_HEADER_TABLE_SIZE:
            out->header_table_size = value;
            break;
        case H2_SETTINGS_ENABLE_PUSH:
            if (value > 1) {
                LOG(ERROR) << "Invalid value=" << value << " for ENABLE_PUSH";
                return false;
            }
            out->enable_push = value;
            break;
        case H2_SETTINGS_MAX_CONCURRENT_STREAMS:
            out->max_concurrent_streams = value;
            break;
        case H2_SETTINGS_STREAM_WINDOW_SIZE:
            if (value > H2Settings::MAX_WINDOW_SIZE) {
                LOG(ERROR) << "Invalid stream_window_size=" << value;
                return false;
            }
            out->stream_window_size = value;
            break;
        case H2_SETTINGS_MAX_FRAME_SIZE:
            if (value > H2Settings::MAX_OF_MAX_FRAME_SIZE ||
                value < H2Settings::DEFAULT_MAX_FRAME_SIZE) {
                LOG(ERROR) << "Invalid max_frame_size=" << value;
                return false;
            }
            out->max_frame_size = value;
            break;
        case H2_SETTINGS_MAX_HEADER_LIST_SIZE:
            out->max_header_list_size = value;
            break;
        default:
            // An endpoint that receives a SETTINGS frame with any unknown or
            // unsupported identifier MUST ignore that setting (section 6.5.2)
            break;
        }
    }
    return true;
}

// Maximum value that may be returned by SerializeH2Settings
static const size_t H2_SETTINGS_MAX_BYTE_SIZE = 36;