lint: de-duplicate boxed value copying logic

Author: peat-psuwit

src/boxed.cc

@@ -179,17 +179,9 @@ static void BoxedConstructor(const Nan::FunctionCallbackInfo<Value> &info) {
         boxed = External::Cast(*info[0])->Value();
 
         if (mustCopy) {
-            if (gtype != G_TYPE_NONE) {
-                boxed = g_boxed_copy (gtype, boxed);
-            }
-            else if ((size = Boxed::GetSize(gi_info)) != 0) {
-                void *boxedCopy = malloc(size);
-                memcpy(boxedCopy, boxed, size);
-                boxed = boxedCopy;
-            }
-            else {
+            boxed = CopyBoxed(gi_info, boxed, &size);
+            if (!boxed)
                 ERROR("Could not copy boxed object.");
-            }
         }
         else {
             owns_memory = false;
@@ -445,4 +437,24 @@ void* PointerFromWrapper(Local<Value> value) {
     return boxed;
 }
 
+void* CopyBoxed(GIBaseInfo *gi_info, void *boxed, size_t *size_out)
+{
+    GType gtype = g_registered_type_info_get_g_type (gi_info);
+    size_t size;
+
+    if (gtype != G_TYPE_NONE) {
+        return g_boxed_copy (gtype, boxed);
+    } else if ((size = Boxed::GetSize(gi_info)) != 0) {
+        void *boxedCopy = malloc(size);
+        memcpy(boxedCopy, boxed, size);
+        if (size_out)
+            *size_out = size;
+        return boxedCopy;
+    } else {
+        WARN("Cannot copy a boxed object of type '%s'.",
+                g_base_info_get_name(gi_info));
+        return NULL;
+    }
+}
+
 };

src/boxed.h

@@ -32,5 +32,6 @@ Local<Function>         MakeBoxedClass   (GIBaseInfo *info);
 Local<FunctionTemplate> GetBoxedTemplate (GIBaseInfo *info, GType gtype);
 Local<Value>            WrapperFromBoxed (GIBaseInfo *info, void *data, bool mustCopy = false);
 void *                  PointerFromWrapper (Local<Value>);
+void *                  CopyBoxed (GIBaseInfo *gi_info, void *boxed, size_t *size_out = nullptr);
 
 };

src/value.cc

@@ -644,20 +644,9 @@ bool V8ToGIArgument(GIBaseInfo *gi_info, GIArgument *arg, Local<Value> value, GI
     case GI_INFO_TYPE_UNION:
         arg->v_pointer = PointerFromWrapper(value);
         if (transfer == GI_TRANSFER_EVERYTHING) {
-            GType gtype = g_registered_type_info_get_g_type (gi_info);
-            size_t size;
-
-            if (gtype != G_TYPE_NONE) {
-                arg->v_pointer = g_boxed_copy (gtype, arg->v_pointer);
-            } else if ((size = Boxed::GetSize(gi_info)) != 0) {
-                void *boxedCopy = malloc(size);
-                memcpy(boxedCopy, arg->v_pointer, size);
-                arg->v_pointer = boxedCopy;
-            } else {
-                // XXX what else can we do? Should we just abort?
-                WARN("Cannot copy a boxed object of type '%s'; memory corruption might occur.",
-                        g_base_info_get_name(gi_info));
-            }
+            arg->v_pointer = CopyBoxed(gi_info, arg->v_pointer);
+            if (!arg->v_pointer)
+                return false;
         }
         break;