Hooking windows messages

[omrilitov]

As discussed here #3217
Hooked into the windows messages and emits them through the window instance with the event 'message'

[anaisbetts]

Hooking every window message seems like it'll cause performance and reentrancy problems, maybe allow people to register for specific ones?

[zcbenz]

The API proposal in #1121 looks like a good start.

[omrilitov]

Well, because it's the window's wndproc it already receives all the messages.
The difference registering for a specific message would make is that it won't emit to the javascript callback which most of the time won't do anything anyway.
The question for me is if emitting to the javascript is a big performance hit.
If not the registration can also be done in pure javascript

[zcbenz]

Yeah emitting an event in JavaScript is quite expensive, it involves obtaining the lock, creating several JavaScript objects, and calling into JavaScript context, though all the details have been hidden in the Emit method, it is enough to have negative affect on performance.

[omrilitov]

The API is now similar to global shortcut, you hook with a specific message

[zcbenz]

Awesome, thanks!