Summary:
Fixes T10229. Broadly:
- When the user hovers over a line number or inline comment, we update the yellow reticle to highlight the relevant lines. Specifically, this is in response to a `mouseover` event.
- On touch devices, touches fire `mouseover` and if you mutate the DOM inside the event, the device aborts the touch.
To remedy this:
- Distingiush between mouse-originated and touch-originated cursor events.
- We do this, roughly, by setting a flag when we see "touchstart", and clearing it when we see the second copy of any unique cursor event.
- This method is complex, but should be robust to any implementation differences between devices (for example, it will work no matter which order the events are fired in).
- This method should also produce the correct results on weird devices that have both mouse-devices and touch-devices available for cursor input.
- When we see a touch-originated `mouseover` or `mouseout`, don't mutate the DOM.
- Put an extra DOM mutation into the `click` event to improve highlighting behavior on touch devices.
Test Plan:
- In iOS Simulator (4s, iOS 9.2), clicked various inline actions ("Reply", "Hide", "Done", "Cancel", line numbers, etc). Got responses after a single touch.
- Verified hover + click behavior on a desktop.
- Logged and examined a bunch of events as a general sanity check.
Reviewers: chad
Reviewed By: chad
Subscribers: aljungberg
Maniphest Tasks: T10229
Differential Revision: https://secure.phabricator.com/D15136
bf43d4cf2a