Adding a function to register a callback function for retrieving a global timestamp

src/ArduinoCloudProperty.cpp

@@ -39,6 +39,7 @@ ArduinoCloudProperty::ArduinoCloudProperty()
       _min_delta_property(0.0f),
       _min_time_between_updates_millis(0),
       _permission(Permission::Read),
+      _get_time_func{nullptr},
       _update_callback_func(nullptr),
       _sync_callback_func(nullptr),
       _has_been_updated_once(false),
@@ -56,9 +57,10 @@ ArduinoCloudProperty::ArduinoCloudProperty()
 /******************************************************************************
    PUBLIC MEMBER FUNCTIONS
  ******************************************************************************/
-void ArduinoCloudProperty::init(String const name, Permission const permission) {
+void ArduinoCloudProperty::init(String const name, Permission const permission, GetTimeCallbackFunc func) {
   _name = name;
   _permission = permission;
+  _get_time_func = func;
 }
 
 ArduinoCloudProperty & ArduinoCloudProperty::onUpdate(UpdateCallbackFunc func) {
@@ -259,7 +261,11 @@ String ArduinoCloudProperty::getAttributeName(String propertyName, char separato
 
 void ArduinoCloudProperty::updateLocalTimestamp() {
   if (isReadableByCloud()) {
-    _last_local_change_timestamp = getTimestamp();
+    if (_get_time_func) {
+      _last_local_change_timestamp = _get_time_func();
+    } else {
+      _last_local_change_timestamp = getTimestamp();
+    }
   }
 }
 

src/ArduinoCloudProperty.h

@@ -122,6 +122,7 @@ enum class UpdatePolicy {
 };
 
 typedef void(*UpdateCallbackFunc)(void);
+typedef unsigned long(*GetTimeCallbackFunc)();
 
 /******************************************************************************
    CLASS DECLARATION
@@ -131,7 +132,7 @@ class ArduinoCloudProperty {
     typedef void(*SyncCallbackFunc)(ArduinoCloudProperty &property);
   public:
     ArduinoCloudProperty();
-    void init(String const name, Permission const permission);
+    void init(String const name, Permission const permission, GetTimeCallbackFunc func);
 
     /* Composable configuration of the ArduinoCloudProperty class */
     ArduinoCloudProperty & onUpdate(UpdateCallbackFunc func);
@@ -192,6 +193,7 @@ class ArduinoCloudProperty {
 
   private:
     Permission         _permission;
+    GetTimeCallbackFunc _get_time_func;
     UpdateCallbackFunc _update_callback_func;
     void (*_sync_callback_func)(ArduinoCloudProperty &property);
 

src/ArduinoCloudThing.cpp

@@ -44,6 +44,7 @@ void PrintFreeRam(void) {
  ******************************************************************************/
 
 ArduinoCloudThing::ArduinoCloudThing() :
+  _get_time_func{nullptr},
   _numPrimitivesProperties(0),
   _numProperties(0),
   _isSyncMessage(false),
@@ -59,6 +60,10 @@ ArduinoCloudThing::ArduinoCloudThing() :
 void ArduinoCloudThing::begin() {
 }
 
+void ArduinoCloudThing::registerGetTimeCallbackFunc(GetTimeCallbackFunc func) {
+  _get_time_func = func;
+}
+
 int ArduinoCloudThing::encode(uint8_t * data, size_t const size, bool lightPayload) {
 
   // check if backing storage and cloud has diverged
@@ -87,7 +92,7 @@ int ArduinoCloudThing::encode(uint8_t * data, size_t const size, bool lightPaylo
 }
 
 ArduinoCloudProperty& ArduinoCloudThing::addPropertyReal(ArduinoCloudProperty & property, String const & name, Permission const permission, int propertyIdentifier) {
-  property.init(name, permission);
+  property.init(name, permission, _get_time_func);
   if (isPropertyInContainer(name)) {
     return (*getProperty(name));
   } else {

src/ArduinoCloudThing.h

@@ -77,6 +77,7 @@ class ArduinoCloudThing {
     ArduinoCloudThing();
 
     void begin();
+    void registerGetTimeCallbackFunc(GetTimeCallbackFunc func);
     //if propertyIdentifier is different from -1, an integer identifier is associated to the added property to be use instead of the property name when the parameter lightPayload is true in the encode method
     ArduinoCloudProperty   & addPropertyReal(ArduinoCloudProperty   & property, String const & name, Permission const permission, int propertyIdentifier = -1);
 
@@ -93,6 +94,7 @@ class ArduinoCloudThing {
     String getPropertyNameByIdentifier(int propertyIdentifier);
 
   private:
+    GetTimeCallbackFunc                  _get_time_func;
     LinkedList<ArduinoCloudProperty *>   _property_list;
     /* Keep track of the number of primitive properties in the Thing. If 0 it allows the early exit in updateTimestampOnLocallyChangedProperties() */
     int                                  _numPrimitivesProperties;