keycodes_from_xmodmap returns one-to-one mapping instead of one-to-many

[nkruglikov]

Background

I want to define a key mapping to control Spotify via DBus. For that, I want to link XF86AudioPlay key (Fn+F9 on my keyboard) with a spawn("dbus-send ..."). However, it didn't work: the key press did nothing.

The issue

Digging into the code, I discovered the following.

• parse_keybindings_with_xmodmap works by getting a mapping from String to u8 from keycodes_from_xmodmap and using that to convert key names like XF86AudioPlay to key codes like 172.
• keycodes_from_xmodmap executes xmodmap -pke. This command dumps keycode mappings in lines of the following format:

  ...
  keycode  52 = z Z Cyrillic_ya Cyrillic_YA
  ...
  

  The above line would be turned into the following pairs:

  ...
  (z, 52)
  (Z, 52)
  (Cyrillic_ya, 52)
  (Cyrillic_YA, 52)
  ...
  

  Then this pairs are collected into a HashMap.
• On my system, xmodmap -pke | grep -i xf86audioplay outputs the following:

  keycode 172 = XF86AudioPlay XF86AudioPause XF86AudioPlay XF86AudioPause
  keycode 208 = XF86AudioPlay NoSymbol XF86AudioPlay
  keycode 215 = XF86AudioPlay NoSymbol XF86AudioPlay
  

  This means that keycodes_from_xmodmap would first turn it into the following pairs:

  (XF86AudioPlay, 172)
  ...
  (XF86AudioPlay, 208)
  ...
  (XF86AudioPlay, 215)
  ...
  

  and then, during collect, just into a mapping

  XF86AudioPlay => 215
  

• With xev utility, I confirmed that pressing "Play" button of my keyboard emits keycode 172. Thus, it doesn't get captured by Penrose.

Possible fix

Possible fix would modify the logic of keycodes_from_xmodmap so that it returns Result<HashMap<String, Vec<u8>>> instead of Result<HashMap<String, u8>> and then adapting parse_bindings_with_xmodmap / parse_binding functions. I am not sure how popular is this problem, though, and whether changing the signature of keycodes_from_xmodmap worth it. In any case, I am open to implementing it.

System details

I run Penrose on Arch Linux with startx.

setxkbmap -print -verbose 10 returns this:

Setting verbose level to 10
locale is C
Trying to load rules file ./rules/evdev...
Trying to load rules file /usr/share/X11/xkb/rules/evdev...
Success.
Applied rules from evdev:
rules:      evdev
model:      pc105
layout:     us,ru
options:    grp:caps_toggle
Trying to build keymap using the following components:
keycodes:   evdev+aliases(qwerty)
types:      complete
compat:     complete
symbols:    pc+us+ru:2+inet(evdev)+group(caps_toggle)
geometry:   pc(pc105)
xkb_keymap {
	xkb_keycodes  { include "evdev+aliases(qwerty)"	};
	xkb_types     { include "complete"	};
	xkb_compat    { include "complete"	};
	xkb_symbols   { include "pc+us+ru:2+inet(evdev)+group(caps_toggle)"	};
	xkb_geometry  { include "pc(pc105)"	};
};

It is a fairly standard configuration with English / Russian layout switch on CapsLock.

My keyboard is Logitech G Pro:

Picture of the keyboard