VPP-534 Remove references to DTOs created in JVpp

JVM objects allocated from a native thread need to be freed,
they are not subject to GC.

Change-Id: If1e140d2ceaec93631735ae7665f45db5aacf7cf
Signed-off-by: Maros Marsalek <mmarsale@cisco.com>

3 files changed, 7 insertions, 0 deletions

diff --git a/vpp-api/java/jvpp-registry/jvpp_registry.c b/vpp-api/java/jvpp-registry/jvpp_registry.c
index af20916e0d9..5d2326a0aa3 100644
--- a/vpp-api/java/jvpp-registry/jvpp_registry.c
+++ b/vpp-api/java/jvpp-registry/jvpp_registry.c
@@ -157,6 +157,7 @@ static void vl_api_control_ping_reply_t_handler(
 
             (*env)->CallVoidMethod(env, rm->registryObject, callbackMethod,
                     dto);
+            (*env)->DeleteLocalRef(env, dto);
         }
     }
 
diff --git a/vpp-api/java/jvpp/gen/jvppgen/jni_gen.py b/vpp-api/java/jvpp/gen/jvppgen/jni_gen.py
index 4b03b31d163..eee8660a2b0 100644
--- a/vpp-api/java/jvpp/gen/jvppgen/jni_gen.py
+++ b/vpp-api/java/jvpp/gen/jvppgen/jni_gen.py
@@ -46,6 +46,7 @@ u8_array_dto_field_setter_template = Template("""
     jbyteArray ${field_reference_name} = (*env)->NewByteArray(env, ${field_length});
     (*env)->SetByteArrayRegion(env, ${field_reference_name}, 0, ${field_length}, (const jbyte*)mp->${c_name});
     (*env)->SetObjectField(env, ${object_name}, ${field_reference_name}FieldId, ${field_reference_name});
+    (*env)->DeleteLocalRef(env, ${field_reference_name});
 """)
 
 u16_array_dto_field_setter_template = Template("""
@@ -59,6 +60,7 @@ u16_array_dto_field_setter_template = Template("""
 
         (*env)->ReleaseShortArrayElements(env,  ${field_reference_name}, ${field_reference_name}ArrayElements, 0);
         (*env)->SetObjectField(env, ${object_name}, ${field_reference_name}FieldId, ${field_reference_name});
+        (*env)->DeleteLocalRef(env, ${field_reference_name});
     }
 """)
 
@@ -73,6 +75,7 @@ u32_array_dto_field_setter_template = Template("""
 
         (*env)->ReleaseIntArrayElements(env,  ${field_reference_name}, ${field_reference_name}ArrayElements, 0);
         (*env)->SetObjectField(env, ${object_name}, ${field_reference_name}FieldId, ${field_reference_name});
+        (*env)->DeleteLocalRef(env, ${field_reference_name});
     }
 """)
 
@@ -89,6 +92,7 @@ u64_array_dto_field_setter_template = Template("""
 
         (*env)->ReleaseLongArrayElements(env,  ${field_reference_name}, ${field_reference_name}ArrayElements, 0);
         (*env)->SetObjectField(env, ${object_name}, ${field_reference_name}FieldId, ${field_reference_name});
+        (*env)->DeleteLocalRef(env, ${field_reference_name});
     }
 """)
 
diff --git a/vpp-api/java/jvpp/gen/jvppgen/jvpp_c_gen.py b/vpp-api/java/jvpp/gen/jvppgen/jvpp_c_gen.py
index 1a35a6c09c0..5fc84c7b050 100644
--- a/vpp-api/java/jvpp/gen/jvppgen/jvpp_c_gen.py
+++ b/vpp-api/java/jvpp/gen/jvppgen/jvpp_c_gen.py
@@ -222,6 +222,8 @@ static void vl_api_${handler_name}_t_handler (vl_api_${handler_name}_t * mp)
     $dto_setters
 
     (*env)->CallVoidMethod(env, plugin_main->callbackObject, callbackMethod, dto);
+    // free DTO as per http://stackoverflow.com/questions/1340938/memory-leak-when-calling-java-code-from-c-using-jni
+    (*env)->DeleteLocalRef(env, dto);
 }""")