Custom Payload Pool example: avoid copy if owning buffer (#560)

* Custom Payload Pool example: avoid copy if owning buffer

Signed-off-by: Juan Lopez Fernandez <juanlopez@eprosima.com>

* Revert partial change introduced in previous commit c3932ed to force payload owner to 'this' always

Signed-off-by: JesusPoderoso <jesuspoderoso@eprosima.com>

---------

Signed-off-by: Juan Lopez Fernandez <juanlopez@eprosima.com>
Signed-off-by: JesusPoderoso <jesuspoderoso@eprosima.com>
Co-authored-by: JesusPoderoso <jesuspoderoso@eprosima.com>

code/CodeTester.cpp

@@ -934,31 +934,35 @@ void rtps_api_example_create_entities_with_custom_pool()
 
         bool get_payload(
                 SerializedPayload_t& data,
-                IPayloadPool*& /* data_owner */,
-                CacheChange_t& cache_change) override
+                IPayloadPool*& /*data_owner*/,
+                CacheChange_t& cache_change)
         {
             // Reserve new memory for the payload buffer
             octet* payload = new octet[data.length];
 
             // Copy the data
             memcpy(payload, data.data, data.length);
+
+            // Tell the CacheChange who needs to release its payload
+            cache_change.payload_owner(this);
 
             // Assign the payload buffer to the CacheChange and update sizes
             cache_change.serializedPayload.data = payload;
             cache_change.serializedPayload.length = data.length;
             cache_change.serializedPayload.max_size = data.length;
 
-            // Tell the CacheChange who needs to release its payload
-            cache_change.payload_owner(this);
-
             return true;
         }
 
         bool release_payload(
                 CacheChange_t& cache_change) override
         {
             // Ensure precondition
-            assert(this == cache_change.payload_owner());
+            if (this != cache_change.payload_owner())
+            {
+                std::cerr << "Trying to release a payload buffer allocated by a different PayloadPool." << std::endl;
+                return false;
+            }
 
             // Dealloc the buffer of the payload
             delete[] cache_change.serializedPayload.data;