...

cxx/mcc_mount_telemetry.h

@@ -12,7 +12,7 @@
 
 namespace mcc
 {
-enum class MccMountTelemetryErrorCode : int { ERROR_OK, ERROR_HARDWARE };
+enum class MccMountTelemetryErrorCode : int { ERROR_OK, ERROR_HARDWARE, ERROR_DATA_TIMEOUT };
 
 /*  error category definition  */
 
@@ -31,6 +31,8 @@ struct MccMountTelemetryCategory : public std::error_category {
                 return "OK";
             case MccMountTelemetryErrorCode::ERROR_HARDWARE:
                 return "hardware request failed";
+            case MccMountTelemetryErrorCode::ERROR_DATA_TIMEOUT:
+                return "an timeout occured while waiting for new data";
             default:
                 return "UNKNOWN";
         }
@@ -138,11 +140,6 @@ public:
 
     typedef std::error_code error_t;
 
-    typedef std::function<void(mount_telemetry_data_t)> update_callback_func_t;
-    typedef std::list<update_callback_func_t> update_callback_container_t;
-
-    typedef std::list<std::shared_ptr<std::packaged_task<update_callback_func_t>>> cc_t;
-
     MccMountTelemetry(astrom_engine_t& astrom_engine, pec_t& pec, hardware_t& hardware)
         : base_t(astrom_engine, pec), _hardware(hardware)
     {
@@ -265,49 +262,37 @@ public:
 
         _data = std::move(current_data);
 
-        std::lock_guard cl_lock{_callbackMutex};
-
-        // callbacks will be invoked with its own copy of telemetry data!
-        for (auto& func : _callbackFuncs) {
-            std::thread t([this, &func] {
-                auto d = _data;
-                func(std::move(d));
-            });
-            t.detach();
-        }
+        // notify all threads for new telemetry data
+        _updateCondVar.notify_all();
 
         return MccMountTelemetryErrorCode::ERROR_OK;
     }
 
 
-    update_callback_container_t::iterator addCallbackFunc(update_callback_func_t func)
-    {
-        std::lock_guard lock{_callbackMutex};
-
-        return _callbackFuncs.emplace_back(std::move(func));
-    }
-
-    void delCallbackFunc(update_callback_container_t::iterator iter)
-    {
-        std::lock_guard lock{_callbackMutex};
-
-        if (_callbackFuncs.size()) {
-            _callbackFuncs.erase(iter);
-        }
-    }
-
-    void clearCallbackFuncs()
-    {
-        std::lock_guard lock{_callbackMutex};
-
-        _callbackFuncs.clear();
-    }
-
     error_t data(mount_telemetry_data_t& data)
     {
         std::lock_guard lock{_updateMutex};
 
-        data = std::move(_data);
+        data = _data;
+
+        return MccMountTelemetryErrorCode::ERROR_OK;
+    }
+
+    // wait until data is updated or given timeout occurs
+    template <traits::mcc_time_duration_c DT>
+    error_t waitForUpdatedData(mount_telemetry_data_t& data, const DT& timeout)
+    {
+        auto timeout_tp = std::chrono::steady_clock::now() + timeout;
+
+        std::unique_lock lk(_updateMutex);
+
+        auto res = _updateCondVar.wait_until(
+            lk, timeout_tp, [last_time_point = _data.time_point, this]() { return last_time_point < _data.timepoint; });
+        if (res == std::cv_status::timeout) {
+            return MccMountTelemetryErrorCode::ERROR_DATA_TIMEOUT;
+        }
+
+        data = _data;
 
         return MccMountTelemetryErrorCode::ERROR_OK;
     }
@@ -315,10 +300,9 @@ public:
 protected:
     mount_telemetry_data_t _data{};
     hardware_t& _hardware;
-    update_callback_container_t _callbackFuncs{};
 
     std::mutex _updateMutex;
-    std::mutex _callbackMutex;
+    std::condition_variable _updateCondVar;
 };