signal.hh

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#ifndef LibMultiSense_details_signal_hh
#define LibMultiSense_details_signal_hh

#include "details/utility/Thread.hh"
#include "details/wire/Protocol.h"
#include "details/wire/AckMessage.h"

#include <map>

namespace crl {
namespace multisense {
namespace details {

//
// Here we provide a thread-safe, blocking, signaling
// interface for sensor message RX.

class MessageWatch {
public:

    void signal(wire::IdType id,
                Status       status=Status_Ok) {
        utility::ScopedLock lock(m_lock);

        Map::iterator it = m_map.find(id);

        if (m_map.end() != it)
            it->second->post(status);
    };

    void signal(const wire::Ack& ack) {
        signal(ack.command, ack.status);
    };

private:

    friend class ScopedWatch;

    typedef utility::WaitVar<Status>        Signal;
    typedef std::map<wire::IdType, Signal*> Map;

    void insert(wire::IdType type,
                Signal      *signalP) {
        utility::ScopedLock lock(m_lock);

        Map::const_iterator it = m_map.find(type);

        //
        // Hmm.. this will prohibit multiple threads
        // simultaneously commanding the sensor with this
        // message ID.

        if (m_map.end() != it)
            CRL_EXCEPTION("ack signal already set for id=%d", type);

        m_map[type] = signalP;
    };

    void remove(wire::IdType type) {
        utility::ScopedLock lock(m_lock);

        Map::iterator it = m_map.find(type);

        if (m_map.end() == it)
            CRL_EXCEPTION("ack signal not found for id=%d\n", type);

        m_map.erase(it);
    };

    utility::Mutex m_lock;
    Map            m_map;
};

 //
 // Exception-safe [de]registration of signal handlers

class ScopedWatch {
public:

    ScopedWatch(wire::IdType  t,
                MessageWatch& m) : m_id(t), m_map(m) {
        m_map.insert(m_id, &m_signal);
    };

    ~ScopedWatch() {
        m_map.remove(m_id);
    };

    bool wait(Status&       status,
              const double& timeout) {
        return m_signal.timedWait(status, timeout);
    };

private:

    wire::IdType         m_id;
    MessageWatch&        m_map;
    MessageWatch::Signal m_signal;
};

} // namespace details
} // namespace multisense
} // namespace crl


#endif //  LibMultiSense_details_signal_hh