feat: support registering media play/pause/stop/next/prev keys

[amrbashir]

closes #70

[amrbashir]

@pewsheen could you research the macOS part? here is a few things I found:

• https://stackoverflow.com/questions/114541/how-do-i-access-listen-for-the-multimedia-keys-play-pause-in-mac-os-x
• https://chromium.googlesource.com/experimental/chromium/src/+/refs/wip/bajones/webvr/chrome/browser/extensions/global_shortcut_listener_mac.mm

[pewsheen]

I pushed a WIP commit to another branch: 0f51409

There are some limitations on macOS:

• It requires adding a MachPort source into CFRunLoop (to listening OS events), this will trigger OS to request Accessibility permission
• It can only detect which media key is pressed. If you press Cmd+MediaPlay, we only know the MediaPlay button is pressed.
• Need to store EventTap and EventTapSource somewhere (Global?) to release it when we want to stop watching the media key
• We need to find a way to check the media key is registered and its hotkey ID inside the callback closure (maybe Global variable again?) so that we can emit the event to the hotkey event channel. Or we can just hardcode the ID and emit it every time, letting the user decide whether to handle it or not.

[amrbashir]

There are some limitations on macOS:

• It requires adding a MachPort source into CFRunLoop (to listening OS events), this will trigger OS to request Accessibility permission

Does this need changes in plist file or it automatically requests it at runtime?

• It can only detect which media key is pressed. If you press Cmd+MediaPlay, we only know the MediaPlay button is pressed.

Can't we check the NSEvent for modifiers?

• Need to store EventTap and EventTapSource somewhere (Global?) to release it when we want to stop watching the media key

can we have multiple EventTap? if so, then store it on GlobalHotkeyManager and release it on drop

• We need to find a way to check the media key is registered and its hotkey ID inside the callback closure (maybe Global variable again?) so that we can emit the event to the hotkey event channel. Or we can just hardcode the ID and emit it every time, letting the user decide whether to handle it or not.

CGEventTapCreate allows passing a pointer to a data, so you can create an Arc<Mutex> stored on GlobalHotKeyManager, that tracks if any media key is registered, then we clone it and convert it to a raw pointer and send it to the callback, that way you can check if it was registered

[pewsheen]

Does this need changes in plist file or it automatically requests it at runtime?

It'll pop up automatically. Currently, it will only ask when registering media keys

I'm storing the event tap and media hotkey information in the GlobalHotKeyManager now. It will require the register and unregister to use &mut self