Return after throwing an error

When we get into a situation where Nan::ThrowError() needs to be called,
there is no coming back. Albeit, that doesn't stop the execution of the
function it is called from. Moreover, it swallows the error. This commit
fixes this behaviour by making sure the function explicitly returns
after throwing the error.

src/Rsvg.cc

@@ -81,15 +81,15 @@ NAN_METHOD(Rsvg::New) {
             if (error) {
                 Nan::ThrowError(error->message);
                 g_error_free(error);
-                ARGVAR.GetReturnValue().Set(Nan::Undefined());
+                return ARGVAR.GetReturnValue().Set(Nan::Undefined());
             }
         } else {
             handle = rsvg_handle_new();
         }
         // Error handling.
         if (!handle) {
             Nan::ThrowError("Unable to create RsvgHandle instance.");
-            ARGVAR.GetReturnValue().Set(Nan::Undefined());
+            return ARGVAR.GetReturnValue().Set(Nan::Undefined());
         }
         // Create object.
         Rsvg* obj = new Rsvg(handle);
@@ -235,7 +235,7 @@ NAN_METHOD(Rsvg::Dimensions) {
         id = *idArg;
         if (!id) {
             Nan::ThrowError("Invalid argument: id");
-            ARGVAR.GetReturnValue().Set(Nan::Undefined());
+            return ARGVAR.GetReturnValue().Set(Nan::Undefined());
         }
     }
 
@@ -271,7 +271,7 @@ NAN_METHOD(Rsvg::HasElement) {
         id = *idArg;
         if (!id) {
             Nan::ThrowError("Invalid argument: id");
-            ARGVAR.GetReturnValue().Set(Nan::Undefined());
+            return ARGVAR.GetReturnValue().Set(Nan::Undefined());
         }
     }
 
@@ -288,11 +288,11 @@ NAN_METHOD(Rsvg::Render) {
 
     if (width <= 0) {
         Nan::ThrowError("Expected width > 0.");
-        ARGVAR.GetReturnValue().Set(Nan::Undefined());
+        return ARGVAR.GetReturnValue().Set(Nan::Undefined());
     }
     if (height <= 0) {
         Nan::ThrowError("Expected height > 0.");
-        ARGVAR.GetReturnValue().Set(Nan::Undefined());
+        return ARGVAR.GetReturnValue().Set(Nan::Undefined());
     }
 
     String::Utf8Value formatArg(ARGVAR[2]);
@@ -304,20 +304,20 @@ NAN_METHOD(Rsvg::Render) {
         pixelFormat = CAIRO_FORMAT_ARGB32;
     } else if (renderFormat == RENDER_FORMAT_JPEG) {
         Nan::ThrowError("Format not supported: JPEG");
-        ARGVAR.GetReturnValue().Set(Nan::Undefined());
+        return ARGVAR.GetReturnValue().Set(Nan::Undefined());
     } else if (
             renderFormat == RENDER_FORMAT_SVG ||
             renderFormat == RENDER_FORMAT_PDF) {
         pixelFormat = CAIRO_FORMAT_INVALID;
     } else if (renderFormat == RENDER_FORMAT_VIPS) {
         Nan::ThrowError("Format not supported: VIPS");
-        ARGVAR.GetReturnValue().Set(Nan::Undefined());
+        return ARGVAR.GetReturnValue().Set(Nan::Undefined());
     } else {
         renderFormat = RENDER_FORMAT_RAW;
         pixelFormat = CairoFormatFromString(formatString);
         if (pixelFormat == CAIRO_FORMAT_INVALID) {
             Nan::ThrowError("Invalid argument: format");
-            ARGVAR.GetReturnValue().Set(Nan::Undefined());
+            return ARGVAR.GetReturnValue().Set(Nan::Undefined());
         }
     }
 
@@ -327,11 +327,11 @@ NAN_METHOD(Rsvg::Render) {
         id = *idArg;
         if (!id) {
             Nan::ThrowError("Invalid argument: id");
-            ARGVAR.GetReturnValue().Set(Nan::Undefined());
+            return ARGVAR.GetReturnValue().Set(Nan::Undefined());
         }
         if (!rsvg_handle_has_sub(obj->_handle, id)) {
             Nan::ThrowError("SVG element with given id does not exists.");
-            ARGVAR.GetReturnValue().Set(Nan::Undefined());
+            return ARGVAR.GetReturnValue().Set(Nan::Undefined());
         }
     }
 
@@ -340,16 +340,16 @@ NAN_METHOD(Rsvg::Render) {
 
     if (!rsvg_handle_get_position_sub(obj->_handle, &position, id)) {
         Nan::ThrowError("Could not get position of SVG element with given id.");
-        ARGVAR.GetReturnValue().Set(Nan::Undefined());
+        return ARGVAR.GetReturnValue().Set(Nan::Undefined());
     }
 
     if (!rsvg_handle_get_dimensions_sub(obj->_handle, &dimensions, id)) {
         Nan::ThrowError("Could not get dimensions of SVG element or whole image.");
-        ARGVAR.GetReturnValue().Set(Nan::Undefined());
+        return ARGVAR.GetReturnValue().Set(Nan::Undefined());
     }
     if (dimensions.width <= 0 || dimensions.height <= 0) {
         Nan::ThrowError("Got invalid dimensions of SVG element or whole image.");
-        ARGVAR.GetReturnValue().Set(Nan::Undefined());
+        return ARGVAR.GetReturnValue().Set(Nan::Undefined());
     }
 
     std::string data;
@@ -407,7 +407,7 @@ NAN_METHOD(Rsvg::Render) {
         Nan::ThrowError(
                 status ? cairo_status_to_string(status) : "Failed to render image."
                 );
-        ARGVAR.GetReturnValue().Set(Nan::Undefined());
+        return ARGVAR.GetReturnValue().Set(Nan::Undefined());
     }
 
     int stride = -1;
@@ -430,7 +430,7 @@ NAN_METHOD(Rsvg::Render) {
         Nan::ThrowError(
                 "Rendered with invalid stride (byte size of row) for ARGB32 format."
                 );
-        ARGVAR.GetReturnValue().Set(Nan::Undefined());
+        return ARGVAR.GetReturnValue().Set(Nan::Undefined());
     }
 
     Handle<ObjectTemplate> image = ObjectTemplate::New();