Merge "Initialize DnsTlsDispatcher instance only when needed" am: ac949907

    mFactory.reset(new DnsTlsSocketFactory());

}

DnsTlsDispatcher& DnsTlsDispatcher::getInstance() {

    static DnsTlsDispatcher instance;

    return instance;

}

std::list<DnsTlsServer> DnsTlsDispatcher::getOrderedServerList(

        const std::list<DnsTlsServer> &tlsServers, unsigned mark) const {

    // Our preferred DnsTlsServer order is:

// Queries made here are dispatched to an existing or newly constructed DnsTlsTransport.

class DnsTlsDispatcher {

  public:

    // Default constructor.

    DnsTlsDispatcher();

    // Constructor with dependency injection for testing.

    explicit DnsTlsDispatcher(std::unique_ptr<IDnsTlsSocketFactory> factory)

        : mFactory(std::move(factory)) {}

    static DnsTlsDispatcher& getInstance();

    // Enqueues |query| for resolution via the given |tlsServers| on the

    // network indicated by |mark|; writes the response into |ans|, and stores

    // the count of bytes written in |resplen|. Returns a success or error code.

                                    int* _Nonnull resplen, bool* _Nonnull connectTriggered);

  private:

    DnsTlsDispatcher();

    // This lock is static so that it can be used to annotate the Transport struct.

    // DnsTlsDispatcher is a singleton in practice, so making this static does not change

    // the locking behavior.

using android::netdutils::Slice;

using android::netdutils::Stopwatch;

static DnsTlsDispatcher sDnsTlsDispatcher;

static int send_vc(res_state statp, res_params* params, const uint8_t* buf, int buflen,

                   uint8_t* ans, int anssiz, int* terrno, size_t ns, time_t* at, int* rcode,

                   int* delay);

    LOG(INFO) << __func__ << ": performing query over TLS";

    const auto response = sDnsTlsDispatcher.query(privateDnsStatus.validatedServers(), statp, query,

                                                  answer, &resplen);

    const auto response = DnsTlsDispatcher::getInstance().query(privateDnsStatus.validatedServers(),

                                                                statp, query, answer, &resplen);

    LOG(INFO) << __func__ << ": TLS query result: " << static_cast<int>(response);