add exampleTask

lib/api/GwApi.h

@@ -4,6 +4,7 @@
 #include "N2kMessages.h"
 #include "NMEA0183Messages.h"
 #include "GWConfig.h"
+#include "GwBoatData.h"
 //API to be used for additional tasks
 class GwApi{
     public:
@@ -13,5 +14,6 @@ class GwApi{
         virtual int getSourceId()=0;
         virtual GwConfigHandler *getConfig()=0;
         virtual GwLog *getLogger()=0;
+        virtual GwBoatData *getBoatData()=0;
 };
 #endif

lib/exampletask/GwExampleTask.cpp

@@ -0,0 +1,82 @@
+
+#include "GwApi.h"
+
+#define INVALID_COORD -99999
+class GetBoatDataRequest: public GwMessage{
+    private:
+        GwApi *api;
+    public:
+        double latitude;
+        double longitude;
+        GetBoatDataRequest(GwApi *api):GwMessage(F("boat data")){
+            this->api=api;
+        }
+        virtual ~GetBoatDataRequest(){}
+    protected:
+        /**
+         * this methos will be executed within the main thread
+         * be sure not to make any time consuming or blocking operation
+         */    
+        virtual void processImpl(){
+            //api->getLogger()->logDebug(GwLog::DEBUG,"boatData request from example task");
+            /*access the values from boatData (see GwBoatData.h)
+              by using getDataWithDefault it will return the given default value
+              if there is no valid data available
+              so be sure to use a value that never will be a valid one
+              alternatively you can check using the isValid() method at each boatData item
+              */
+            latitude=api->getBoatData()->Latitude->getDataWithDefault(INVALID_COORD);
+            longitude=api->getBoatData()->Longitude->getDataWithDefault(INVALID_COORD);
+        };
+};
+void exampleTask(void *param){
+    GwApi *api=(GwApi*)param;
+    GwLog *logger=api->getLogger();
+    //------
+    //initialization goes here
+    //------
+    bool hasPosition=false;
+    while(true){
+        delay(1000);
+        /*
+        * getting values from the internal data store (boatData) requires some special handling
+        * our tasks runs (potentially) at some time on a different core then the main code
+        * and as the boatData has no synchronization (for performance reasons)
+        * we must ensure to access it only from the main thread.
+        * The pattern is to create a request object (a class that inherits from GwMessage -
+        * GetBoatDataRequest above)
+        * and to access the boatData in the processImpl method of this object.
+        * Once the object is created we enqueue it into a request queue and wait for
+        * the main thread to call the processImpl method (sendAndWait).
+        * Afterwards we can use the data we have stored in the request.
+        * As this request object can be accessed from different threads we must be careful
+        * about it's lifetime.
+        * The pattern below handles this correctly. We do not call delete on this object but
+        * instead call the "unref" Method when we don't need it any more.
+        */
+        GetBoatDataRequest *r=new GetBoatDataRequest(api);
+        if (api->getQueue()->sendAndWait(r,10000) != GwRequestQueue::MSG_OK){
+            r->unref(); //delete the request
+            api->getLogger()->logDebug(GwLog::ERROR,"request not handled");
+            continue;
+        }
+        if (r->latitude == INVALID_COORD || r->longitude == INVALID_COORD){
+            if (hasPosition){
+                logger->logDebug(GwLog::ERROR,"position lost...");
+                hasPosition=false;
+            }
+        }
+        else{
+            //do something with the data we have from boatData
+            if (! hasPosition){
+                logger->logDebug(GwLog::LOG,"postion now available lat=%f, lon=%f",
+                    r->latitude,r->longitude);
+                    hasPosition=true;
+            }
+
+        }
+        r->unref(); //delete the request
+    }
+    vTaskDelete(NULL);
+    
+}

lib/exampletask/GwExampleTask.h

@@ -0,0 +1,5 @@
+#ifndef _GWEXAMPLETASK_H
+#define _GWEXAMPLETASK_H
+//task function
+void exampleTask(void *param);
+#endif

src/main.cpp

@@ -61,6 +61,7 @@ const unsigned long HEAP_REPORT_TIME=2000; //set to 0 to disable heap reporting
 #include "GwLeds.h"
 #include "GwCounter.h"
 #include "GwXDRMappings.h"
+#include "GwExampleTask.h"
 
 
 //NMEA message channels
@@ -235,6 +236,9 @@ public:
   virtual GwLog* getLogger(){
     return &logger;
   }
+  virtual GwBoatData *getBoatData(){
+    return &boatData;
+  }
 };
 
 bool delayedRestart(){
@@ -660,6 +664,7 @@ void setup() {
   startAddOnTask(handleButtons,100);
   setLedMode(LED_GREEN);
   startAddOnTask(handleLeds,101);
+  startAddOnTask(exampleTask,102);
   logger.logDebug(GwLog::LOG,"setup done");
 }  
 //*****************************************************************************