Passing an argument from C++ into JavaScript has 'borrow' semantics rather than ownership semantics. That is, to keep a reference beyond the function call, you must call .clone(). This is necessary to avoid special-casing non-overridden virtual functions. (I don't know if this change will stick. It's possible it will have some problems.)

2 files changed, 17 insertions, 1 deletions

diff --git a/src/embind/embind.js b/src/embind/embind.js
index 9f3e6eff..124ea569 100644
--- a/src/embind/embind.js
+++ b/src/embind/embind.js
@@ -590,6 +590,9 @@ function __embind_register_emval(rawType, name) {
         'argPackAdvance': 8,
         'readValueFromPointer': simpleReadValueFromPointer,
         destructorFunction: null, // This type does not need a destructor
+
+        // TODO: do we need a deleteObject here?  write a test where
+        // emval is passed into JS via an interface
     });
 }
 
@@ -1195,6 +1198,12 @@ RegisteredPointer.prototype.destructor = function destructor(ptr) {
 RegisteredPointer.prototype['argPackAdvance'] = 8;
 RegisteredPointer.prototype['readValueFromPointer'] = simpleReadValueFromPointer;
 
+RegisteredPointer.prototype['deleteObject'] = function deleteObject(handle) {
+    if (handle !== null) {
+        handle['delete']();
+    }
+};
+
 RegisteredPointer.prototype['fromWireType'] = function fromWireType(ptr) {
     // ptr is a raw pointer (or a raw smartpointer)
 
diff --git a/src/embind/emval.js b/src/embind/emval.js
index 2b49fc83..1661bc02 100644
--- a/src/embind/emval.js
+++ b/src/embind/emval.js
@@ -265,7 +265,14 @@ function __emval_get_method_caller(argCount, argTypes) {
         "    args += argType" + i + ".argPackAdvance;\n";
     }
     functionBody +=
-        "    var rv = handle[name](" + argsList + ");\n" +
+        "    var rv = handle[name](" + argsList + ");\n";
+    for (var i = 0; i < argCount - 1; ++i) {
+        if (types[i + 1]['deleteObject']) {
+            functionBody +=
+            "    argType" + i + ".deleteObject(arg" + i + ");\n";
+        }
+    }
+    functionBody += 
         "    return retType.toWireType(destructors, rv);\n" +
         "};\n";