Instead of simply discard the message containing a splitted multivalue property, do not advance the property index and mark discarded properties has appended but not sended.

Compute the exact number of properties that would fit the CBOR buffer and retry send next loop. When no error occurs restore property limit to NO_LIMIT and advance property index.

Author: pennam

src/cbor/CBOREncoder.cpp

@@ -47,6 +47,7 @@ CborError CBOREncoder::encode(PropertyContainer & property_container, uint8_t *
   CborError error = CborNoError;
   int num_encoded_properties = 0;
   int num_checked_properties = 0;
+  static int encoded_properties_message_limit = -1;
 
   if(current_property_index >= property_container.size())
     current_property_index = 0;
@@ -58,7 +59,7 @@ CborError CBOREncoder::encode(PropertyContainer & property_container, uint8_t *
                 property_container.end(),
                 [lightPayload, &arrayEncoder, &error, &num_encoded_properties, &num_checked_properties](Property * p)
                 {
-                  if(error == CborNoError)
+                  if((error == CborNoError) && ((num_encoded_properties < encoded_properties_message_limit) || (encoded_properties_message_limit == -1)))
                   {
                     if (p->shouldBeUpdated() && p->isReadableByCloud())
                     {
@@ -72,14 +73,36 @@ CborError CBOREncoder::encode(PropertyContainer & property_container, uint8_t *
                   }
                 });
 
-  current_property_index += num_checked_properties;
-
-  if ((CborNoError != error) && 
-      (CborErrorOutOfMemory != error))
+  if ((CborNoError != error) && (CborErrorOutOfMemory != error))
+  {
+    /* Trim the number of properties to be included in the next message to avoid multivalue property split */
+    encoded_properties_message_limit = num_encoded_properties;
     return error;
+  }
+
+  /* Restore property message limit to NO_LIMIT */
+  encoded_properties_message_limit = -1;
 
   CHECK_CBOR(cbor_encoder_close_container(&encoder, &arrayEncoder));
 
+  /* The append process has been successful, so we don't need to terty to send this properties set. Cleanup _has_been_appended_but_not_sended flag */
+  iter = property_container.begin();
+  std::advance(iter, current_property_index);
+  int num_appended_properties = 0;
+  std::for_each(iter,
+                property_container.end(),
+                [&num_appended_properties, &num_checked_properties](Property * p)
+                {
+                  if (num_appended_properties < num_checked_properties)
+                  {
+                    p->appendCompleted();
+                    num_appended_properties++;
+                  }
+                });
+
+  /* Advance property index for the nex message */
+  current_property_index += num_checked_properties;
+
   if (num_encoded_properties > 0)
     bytes_encoded = cbor_encoder_get_buffer_size(&encoder, data);
   else

src/property/Property.cpp

@@ -161,6 +161,7 @@ CborError Property::append(CborEncoder *encoder, bool lightPayload) {
   _has_been_updated_once = true;
   _has_been_modified_in_callback = false;
   _update_requested = false;
+  _has_been_appended_but_not_sended = true;
   _last_updated_millis = millis();
   return CborNoError;
 }