Initial commit: Korin Timer

src/titletimer/input_devices.py

@@ -0,0 +1,62 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+from evdev import InputDevice, ecodes, list_devices
+
+
+def is_mouse(dev: InputDevice) -> bool:
+    keys = dev.capabilities().get(ecodes.EV_KEY, [])
+    rels = dev.capabilities().get(ecodes.EV_REL, [])
+    return ecodes.BTN_LEFT in keys and ecodes.REL_X in rels and ecodes.REL_Y in rels
+
+
+def is_keyboard(dev: InputDevice) -> bool:
+    caps = dev.capabilities().get(ecodes.EV_KEY, [])
+    # Gaming mice (e.g. Logitech G502) commonly also advertise KEY_A/
+    # KEY_SPACE (programmable buttons / media-key emulation) and would
+    # otherwise get opened redundantly as both "keyboard" and "mouse" by
+    # separate listeners, which was observed to make one of the duplicate
+    # opens randomly drop ("Input device disconnected").
+    return ecodes.KEY_A in caps and ecodes.KEY_SPACE in caps and not is_mouse(dev)
+
+
+def inaccessible_keyboard_names() -> list[str]:
+    """Best-effort list of device names the kernel flags as keyboards (a
+    "kbd" handler in /proc/bus/input/devices) but that this process can't
+    actually open.
+
+    evdev.list_devices() silently drops any /dev/input/eventN this process
+    fails an os.access(R_OK | W_OK) check on - no exception, no gap in the
+    returned list, so a real keyboard blocked by permissions just vanishes
+    without a trace and whatever else happens to qualify as "keyboard-like"
+    (e.g. a gaming mouse's macro-key HID sub-interface) silently becomes
+    the only thing listened on. Observed on a Bazzite/GNOME machine: the
+    physical keyboard's device node wasn't covered by the desktop
+    session's usual per-session uaccess ACL (likely stripped by a
+    Steam-Input udev rule for recognized gaming-keyboard hardware IDs),
+    leaving it gated by the static 'input' group alone - which only takes
+    effect for the process's *next* login session, not a new terminal in
+    an already-running one. /proc/bus/input/devices is a plain readable
+    text file regardless of any of that, so it's used here purely to
+    produce an actionable diagnostic, never to open anything.
+    """
+    try:
+        text = Path("/proc/bus/input/devices").read_text()
+    except OSError:
+        return []
+
+    accessible = {Path(p).name for p in list_devices()}
+    missing: list[str] = []
+    name: str | None = None
+    for line in text.splitlines():
+        if line.startswith("N: Name="):
+            name = line.split("=", 1)[1].strip('"')
+        elif line.startswith("H: Handlers="):
+            handlers = line.split("=", 1)[1].split()
+            if "kbd" not in handlers:
+                continue
+            event_handlers = [h for h in handlers if h.startswith("event")]
+            if event_handlers and event_handlers[0] not in accessible:
+                missing.append(name or event_handlers[0])
+    return missing