node: don't malloc in FromConstructorTemplate

* allocate space for argv on the stack
* move the declaration to node_internals.h

src/node.cc

@@ -863,22 +863,14 @@ Local<Value> WinapiErrnoException(int errorno,
 #endif
 
 
-Handle<Value> FromConstructorTemplate(Persistent<FunctionTemplate>& t,
+Handle<Value> FromConstructorTemplate(Persistent<FunctionTemplate> t,
                                       const Arguments& args) {
   HandleScope scope;
-
-  const int argc = args.Length();
-  Local<Value>* argv = new Local<Value>[argc];
-
-  for (int i = 0; i < argc; ++i) {
-    argv[i] = args[i];
-  }
-
-  Local<Object> instance = t->GetFunction()->NewInstance(argc, argv);
-
-  delete[] argv;
-
-  return scope.Close(instance);
+  Local<Value> argv[32];
+  unsigned argc = args.Length();
+  if (argc > ARRAY_SIZE(argv)) argc = ARRAY_SIZE(argv);
+  for (unsigned i = 0; i < argc; ++i) argv[i] = args[i];
+  return scope.Close(t->GetFunction()->NewInstance(argc, argv));
 }
 
 

src/node.h

@@ -150,18 +150,6 @@ NODE_EXTERN ssize_t DecodeWrite(char *buf,
 v8::Local<v8::Object> BuildStatsObject(const uv_statbuf_t* s);
 
 
-/**
- * Call this when your constructor is invoked as a regular function, e.g.
- * Buffer(10) instead of new Buffer(10).
- * @param constructorTemplate Constructor template to instantiate from.
- * @param args The arguments object passed to your constructor.
- * @see v8::Arguments::IsConstructCall
- */
-v8::Handle<v8::Value> FromConstructorTemplate(
-    v8::Persistent<v8::FunctionTemplate>& constructorTemplate,
-    const v8::Arguments& args);
-
-
 static inline v8::Persistent<v8::Function>* cb_persist(
     const v8::Local<v8::Value> &v) {
   v8::Persistent<v8::Function> *fn = new v8::Persistent<v8::Function>();

src/node_internals.h

@@ -97,6 +97,10 @@ inline static v8::Handle<v8::Value> ThrowRangeError(const char* errmsg) {
     abort();                                                                \
   }
 
+v8::Handle<v8::Value> FromConstructorTemplate(
+    v8::Persistent<v8::FunctionTemplate> t,
+    const v8::Arguments& args);
+
 } // namespace node
 
 #endif // SRC_NODE_INTERNALS_H_