[LEAK FIX] Use Nan::ObjectWrap to handle memory management

Nan::ObjectWrap Docs: https://github.com/nodejs/nan/blob/master/doc/object_wrappers.md#api_nan_object_wrap

Prior to this, all wrapper Objects would never be deleted, allowing memory to grow unbounded.

Example:
The following, would leak WrapperObjects, and never

```
while (true) {
  new sass.types.String(‘I LEAK’);
}
```

src/custom_function_bridge.cpp

@@ -4,10 +4,10 @@
 #include "sass_types/factory.h"
 #include "sass_types/value.h"
 
-Sass_Value* CustomFunctionBridge::post_process_return_value(v8::Local<v8::Value> val) const {
-  SassTypes::Value *v_;
-  if ((v_ = SassTypes::Factory::unwrap(val))) {
-    return v_->get_sass_value();
+Sass_Value* CustomFunctionBridge::post_process_return_value(v8::Local<v8::Value> _val) const {
+  SassTypes::Value *value = SassTypes::Factory::unwrap(_val);
+  if (value) {
+    return value->get_sass_value();
   } else {
     return sass_make_error("A SassValue object was expected.");
   }
@@ -17,7 +17,10 @@ std::vector<v8::Local<v8::Value>> CustomFunctionBridge::pre_process_args(std::ve
   std::vector<v8::Local<v8::Value>> argv = std::vector<v8::Local<v8::Value>>();
 
   for (void* value : in) {
-    argv.push_back(SassTypes::Factory::create(static_cast<Sass_Value*>(value))->get_js_object());
+    Sass_Value* x = static_cast<Sass_Value*>(value);
+    SassTypes::Value* y = SassTypes::Factory::create(x);
+
+    argv.push_back(y->get_js_object());
   }
 
   return argv;

src/sass_types/boolean.cpp

@@ -6,7 +6,9 @@ namespace SassTypes
   Nan::Persistent<v8::Function> Boolean::constructor;
   bool Boolean::constructor_locked = false;
 
-  Boolean::Boolean(bool v) : value(v) {}
+  Boolean::Boolean(bool _value) {
+    value = sass_make_boolean(_value);
+  }
 
   Boolean& Boolean::get_singleton(bool v) {
     static Boolean instance_false(false), instance_true(true);
@@ -15,7 +17,7 @@ namespace SassTypes
 
   v8::Local<v8::Function> Boolean::get_constructor() {
     Nan::EscapableHandleScope scope;
-    v8::Local<v8::Function> conslocal; 
+    v8::Local<v8::Function> conslocal;
     if (constructor.IsEmpty()) {
       v8::Local<v8::FunctionTemplate> tpl = Nan::New<v8::FunctionTemplate>(New);
 
@@ -42,16 +44,15 @@ namespace SassTypes
     return scope.Escape(conslocal);
   }
 
-  Sass_Value* Boolean::get_sass_value() {
-    return sass_make_boolean(value);
-  }
-
   v8::Local<v8::Object> Boolean::get_js_object() {
     return Nan::New(this->js_object);
   }
 
-  NAN_METHOD(Boolean::New) {
+  v8::Local<v8::Boolean> Boolean::get_js_boolean() {
+    return sass_boolean_get_value(this->value) ? Nan::True() : Nan::False();
+  }
 
+  NAN_METHOD(Boolean::New) {
     if (info.IsConstructCall()) {
       if (constructor_locked) {
         return Nan::ThrowTypeError("Cannot instantiate SassBoolean");
@@ -67,9 +68,6 @@ namespace SassTypes
   }
 
   NAN_METHOD(Boolean::GetValue) {
-    Boolean *out;
-    if ((out = static_cast<Boolean*>(Factory::unwrap(info.This())))) { 
-      info.GetReturnValue().Set(Nan::New(out->value));
-    }
+    info.GetReturnValue().Set(Boolean::Unwrap<Boolean>(info.This())->get_js_boolean());
   }
 }

src/sass_types/boolean.h

@@ -12,7 +12,6 @@ namespace SassTypes
       static Boolean& get_singleton(bool);
       static v8::Local<v8::Function> get_constructor();
 
-      Sass_Value* get_sass_value();
       v8::Local<v8::Object> get_js_object();
 
       static NAN_METHOD(New);
@@ -21,11 +20,11 @@ namespace SassTypes
     private:
       Boolean(bool);
 
-      bool value;
       Nan::Persistent<v8::Object> js_object;
 
       static Nan::Persistent<v8::Function> constructor;
       static bool constructor_locked;
+      v8::Local<v8::Boolean> get_js_boolean();
   };
 }
 

src/sass_types/color.cpp

@@ -62,19 +62,19 @@ namespace SassTypes
   }
 
   NAN_METHOD(Color::GetR) {
-    info.GetReturnValue().Set(sass_color_get_r(unwrap(info.This())->value));
+    info.GetReturnValue().Set(sass_color_get_r(Color::Unwrap<Color>(info.This())->value));
   }
 
   NAN_METHOD(Color::GetG) {
-    info.GetReturnValue().Set(sass_color_get_g(unwrap(info.This())->value));
+    info.GetReturnValue().Set(sass_color_get_g(Color::Unwrap<Color>(info.This())->value));
   }
 
   NAN_METHOD(Color::GetB) {
-    info.GetReturnValue().Set(sass_color_get_b(unwrap(info.This())->value));
+    info.GetReturnValue().Set(sass_color_get_b(Color::Unwrap<Color>(info.This())->value));
   }
 
   NAN_METHOD(Color::GetA) {
-    info.GetReturnValue().Set(sass_color_get_a(unwrap(info.This())->value));
+    info.GetReturnValue().Set(sass_color_get_a(Color::Unwrap<Color>(info.This())->value));
   }
 
   NAN_METHOD(Color::SetR) {
@@ -86,7 +86,7 @@ namespace SassTypes
       return Nan::ThrowTypeError("Supplied value should be a number");
     }
 
-    sass_color_set_r(unwrap(info.This())->value, Nan::To<double>(info[0]).FromJust());
+    sass_color_set_r(Color::Unwrap<Color>(info.This())->value, Nan::To<double>(info[0]).FromJust());
   }
 
   NAN_METHOD(Color::SetG) {
@@ -98,7 +98,7 @@ namespace SassTypes
       return Nan::ThrowTypeError("Supplied value should be a number");
     }
 
-    sass_color_set_g(unwrap(info.This())->value, Nan::To<double>(info[0]).FromJust());
+    sass_color_set_g(Color::Unwrap<Color>(info.This())->value, Nan::To<double>(info[0]).FromJust());
   }
 
   NAN_METHOD(Color::SetB) {
@@ -110,7 +110,7 @@ namespace SassTypes
       return Nan::ThrowTypeError("Supplied value should be a number");
     }
 
-    sass_color_set_b(unwrap(info.This())->value, Nan::To<double>(info[0]).FromJust());
+    sass_color_set_b(Color::Unwrap<Color>(info.This())->value, Nan::To<double>(info[0]).FromJust());
   }
 
   NAN_METHOD(Color::SetA) {
@@ -122,6 +122,6 @@ namespace SassTypes
       return Nan::ThrowTypeError("Supplied value should be a number");
     }
 
-    sass_color_set_a(unwrap(info.This())->value, Nan::To<double>(info[0]).FromJust());
+    sass_color_set_a(Color::Unwrap<Color>(info.This())->value, Nan::To<double>(info[0]).FromJust());
   }
 }

src/sass_types/factory.cpp

@@ -61,11 +61,12 @@ namespace SassTypes
   }
 
   Value* Factory::unwrap(v8::Local<v8::Value> obj) {
-    // Todo: non-SassValue objects could easily fall under that condition, need to be more specific.
-    if (!obj->IsObject() || obj.As<v8::Object>()->InternalFieldCount() != 1) {
+      if (obj->IsObject()) {
+          v8::Local<v8::Object> v8_obj = obj.As<v8::Object>();
+          if (v8_obj->InternalFieldCount() == 1) {
+              return SassTypes::Value::Unwrap<Value>(v8_obj);
+          }
+      }
       return NULL;
-    }
-
-    return static_cast<Value*>(Nan::GetInternalFieldPointer(obj.As<v8::Object>(), 0));
   }
 }

src/sass_types/list.cpp

@@ -47,7 +47,7 @@ namespace SassTypes
       return Nan::ThrowTypeError("Supplied index should be an integer");
     }
 
-    Sass_Value* list = unwrap(info.This())->value;
+    Sass_Value* list = List::Unwrap<List>(info.This())->value;
     size_t index = Nan::To<uint32_t>(info[0]).FromJust();
 
 
@@ -73,14 +73,14 @@ namespace SassTypes
 
     Value* sass_value = Factory::unwrap(info[1]);
     if (sass_value) {
-      sass_list_set_value(unwrap(info.This())->value, Nan::To<uint32_t>(info[0]).FromJust(), sass_value->get_sass_value());
+      sass_list_set_value(List::Unwrap<List>(info.This())->value, Nan::To<uint32_t>(info[0]).FromJust(), sass_value->get_sass_value());
     } else {
       Nan::ThrowTypeError("A SassValue is expected as the list item");
     }
   }
 
   NAN_METHOD(List::GetSeparator) {
-    info.GetReturnValue().Set(sass_list_get_separator(unwrap(info.This())->value) == SASS_COMMA);
+    info.GetReturnValue().Set(sass_list_get_separator(List::Unwrap<List>(info.This())->value) == SASS_COMMA);
   }
 
   NAN_METHOD(List::SetSeparator) {
@@ -92,10 +92,10 @@ namespace SassTypes
       return Nan::ThrowTypeError("Supplied value should be a boolean");
     }
 
-    sass_list_set_separator(unwrap(info.This())->value, Nan::To<bool>(info[0]).FromJust() ? SASS_COMMA : SASS_SPACE);
+    sass_list_set_separator(List::Unwrap<List>(info.This())->value, Nan::To<bool>(info[0]).FromJust() ? SASS_COMMA : SASS_SPACE);
   }
 
   NAN_METHOD(List::GetLength) {
-    info.GetReturnValue().Set(Nan::New<v8::Number>(sass_list_get_length(unwrap(info.This())->value)));
+    info.GetReturnValue().Set(Nan::New<v8::Number>(sass_list_get_length(List::Unwrap<List>(info.This())->value)));
   }
 }

src/sass_types/map.cpp

@@ -37,7 +37,7 @@ namespace SassTypes
       return Nan::ThrowTypeError("Supplied index should be an integer");
     }
 
-    Sass_Value* map = unwrap(info.This())->value;
+    Sass_Value* map = Map::Unwrap<Map>(info.This())->value;
     size_t index = Nan::To<uint32_t>(info[0]).FromJust();
 
 
@@ -63,14 +63,13 @@ namespace SassTypes
 
     Value* sass_value = Factory::unwrap(info[1]);
     if (sass_value) {
-      sass_map_set_value(unwrap(info.This())->value, Nan::To<uint32_t>(info[0]).FromJust(), sass_value->get_sass_value());
+      sass_map_set_value(Map::Unwrap<Map>(info.This())->value, Nan::To<uint32_t>(info[0]).FromJust(), sass_value->get_sass_value());
     } else {
       Nan::ThrowTypeError("A SassValue is expected as a map value");
     }
   }
 
   NAN_METHOD(Map::GetKey) {
-
     if (info.Length() != 1) {
       return Nan::ThrowTypeError("Expected just one argument");
     }
@@ -79,15 +78,17 @@ namespace SassTypes
       return Nan::ThrowTypeError("Supplied index should be an integer");
     }
 
-    Sass_Value* map = unwrap(info.This())->value;
+    Sass_Value* map = Map::Unwrap<Map>(info.This())->value;
     size_t index = Nan::To<uint32_t>(info[0]).FromJust();
 
 
     if (index >= sass_map_get_length(map)) {
       return Nan::ThrowRangeError(Nan::New("Out of bound index").ToLocalChecked());
     }
 
-    info.GetReturnValue().Set(Factory::create(sass_map_get_key(map, Nan::To<uint32_t>(info[0]).FromJust()))->get_js_object());
+    SassTypes::Value* obj = Factory::create(sass_map_get_key(map, Nan::To<uint32_t>(info[0]).FromJust()));
+    v8::Local<v8::Object> js_obj = obj->get_js_object();
+    info.GetReturnValue().Set(js_obj);
   }
 
   NAN_METHOD(Map::SetKey) {
@@ -105,13 +106,13 @@ namespace SassTypes
 
     Value* sass_value = Factory::unwrap(info[1]);
     if (sass_value) {
-      sass_map_set_key(unwrap(info.This())->value, Nan::To<uint32_t>(info[0]).FromJust(), sass_value->get_sass_value());
+      sass_map_set_key(Map::Unwrap<Map>(info.This())->value, Nan::To<uint32_t>(info[0]).FromJust(), sass_value->get_sass_value());
     } else {
       Nan::ThrowTypeError("A SassValue is expected as a map key");
     }
   }
 
   NAN_METHOD(Map::GetLength) {
-    info.GetReturnValue().Set(Nan::New<v8::Number>(sass_map_get_length(unwrap(info.This())->value)));
+    info.GetReturnValue().Set(Nan::New<v8::Number>(sass_map_get_length(Map::Unwrap<Map>(info.This())->value)));
   }
 }

src/sass_types/null.cpp

@@ -6,7 +6,9 @@ namespace SassTypes
   Nan::Persistent<v8::Function> Null::constructor;
   bool Null::constructor_locked = false;
 
-  Null::Null() {}
+  Null::Null() {
+      value = sass_make_null();
+  }
 
   Null& Null::get_singleton() {
     static Null singleton_instance;
@@ -37,10 +39,6 @@ namespace SassTypes
     return scope.Escape(conslocal);
   }
 
-  Sass_Value* Null::get_sass_value() {
-    return sass_make_null();
-  }
-
   v8::Local<v8::Object> Null::get_js_object() {
     return Nan::New(this->js_object);
   }

src/sass_types/number.cpp

@@ -41,11 +41,11 @@ namespace SassTypes
   }
 
   NAN_METHOD(Number::GetValue) {
-    info.GetReturnValue().Set(Nan::New<v8::Number>(sass_number_get_value(unwrap(info.This())->value)));
+    info.GetReturnValue().Set(Nan::New<v8::Number>(sass_number_get_value(Number::Unwrap<Number>(info.This())->value)));
   }
 
   NAN_METHOD(Number::GetUnit) {
-    info.GetReturnValue().Set(Nan::New<v8::String>(sass_number_get_unit(unwrap(info.This())->value)).ToLocalChecked());
+    info.GetReturnValue().Set(Nan::New<v8::String>(sass_number_get_unit(Number::Unwrap<Number>(info.This())->value)).ToLocalChecked());
   }
 
   NAN_METHOD(Number::SetValue) {
@@ -58,7 +58,7 @@ namespace SassTypes
       return Nan::ThrowTypeError("Supplied value should be a number");
     }
 
-    sass_number_set_value(unwrap(info.This())->value, Nan::To<double>(info[0]).FromJust());
+    sass_number_set_value(Number::Unwrap<Number>(info.This())->value, Nan::To<double>(info[0]).FromJust());
   }
 
   NAN_METHOD(Number::SetUnit) {
@@ -70,6 +70,6 @@ namespace SassTypes
       return Nan::ThrowTypeError("Supplied value should be a string");
     }
 
-    sass_number_set_unit(unwrap(info.This())->value, create_string(info[0]));
+    sass_number_set_unit(Number::Unwrap<Number>(info.This())->value, create_string(info[0]));
   }
 }