1203012 - TranslateToNPCocoaEvent() in nsPluginInstanceOwner.cpp must not work well for NS_MOUSE_SCROLL (eLegacyMouseLineOrPageScroll)

Status: RESOLVED INCOMPLETE

(Core Graveyard :: Plug-ins, defect)

Description

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

When I'm working on bug 895274, I found a mistake in nsPluginInstanceOwner.cpp:

http://mxr.mozilla.org/mozilla-central/source/dom/plugins/base/nsPluginInstanceOwner.cpp?rev=cad395df60d3&mark=1894-1904#1894
> 1894     case NS_MOUSE_SCROLL:
> 1895     {
> 1896       WidgetWheelEvent* wheelEvent = anEvent->AsWheelEvent();
> 1897       if (wheelEvent) {
> 1898         cocoaEvent.data.mouse.deltaX = wheelEvent->lineOrPageDeltaX;
> 1899         cocoaEvent.data.mouse.deltaY = wheelEvent->lineOrPageDeltaY;
> 1900       } else {
> 1901         NS_WARNING("NS_MOUSE_SCROLL is not a WidgetWheelEvent? (could be, haven't checked)");
> 1902       }
> 1903       break;
> 1904     }

NS_MOUSE_SCROLL (being renamed to eLegacyMouseLineOrPixelScroll) is a legacy mouse wheel event which is represented with WidgetMouseScrollEvent. So, this should retrieve AsMouseScrollEvent() or just handle NS_WHEEL_WHEEL. The latter is better, I think.

Note that both lineOrPageDelta[XY] may be 0. In such case, the event shouldn't be needed by the plugin. In such case, we shouldn't sent event to the plugin for reducing IPC cost.

Comment 1

[Benjamin Smedberg]

Resolving old bugs which are likely not relevant any more, since NPAPI plugins are deprecated.