Add type hints and ruff/mypy config

Annotate all functions and check them with mypy --strict (needs
python-pygobject-stubs). pyproject.toml holds only tool config since
the PKGBUILD installs the script directly.

xautolock-inhibit

@@ -17,7 +17,7 @@ from datetime import timedelta
 from gi.repository import Gio, GLib
 
 try:
-    from gi.repository import GLibUnix  # GLib >= 2.80
+    from gi.repository import GLibUnix  # type: ignore[attr-defined]  # GLib >= 2.80, not in pygobject-stubs
     signal_add = GLibUnix.signal_add
 except ImportError:
     signal_add = GLib.unix_signal_add
@@ -27,6 +27,8 @@ OBJECT_PATHS = ("/org/freedesktop/ScreenSaver", "/ScreenSaver")  # Vivaldi uses
 EXIT_NAME_TAKEN = 2
 ACTIVITY_QUIET = 300  # seconds without SimulateUserActivity that end a logged burst
 
+Cookie = tuple[str, str, str, bool]  # sender, application_name, reason, counts
+
 INTROSPECTION = """
 <node>
   <interface name="org.freedesktop.ScreenSaver">
@@ -58,11 +60,11 @@ INTROSPECTION = """
 """
 
 
-def log(msg):
+def log(msg: str) -> None:
     print(msg, flush=True)
 
 
-def xautolock(arg):
+def xautolock(arg: str) -> None:
     try:
         subprocess.run(["xautolock", arg], check=True, timeout=10)
         log(f"xautolock {arg}")
@@ -77,8 +79,8 @@ class XBlanking:
     pause by itself when this client releases it or its connection closes (exit, crash).
     """
 
-    def __init__(self):
-        self.dpy = None
+    def __init__(self) -> None:
+        self.dpy: int | None = None
         try:
             self.x11 = ctypes.CDLL("libX11.so.6")
             self.xss = ctypes.CDLL("libXss.so.1")
@@ -102,7 +104,7 @@ class XBlanking:
             return
         self.dpy = dpy
 
-    def suspend(self, on):
+    def suspend(self, on: bool) -> None:
         if self.dpy:
             self.xss.XScreenSaverSuspend(self.dpy, int(on))
             self.x11.XFlush(self.dpy)
@@ -118,24 +120,24 @@ class ActivityBurst:
 
 
 class Inhibitor:
-    def __init__(self, ignored_reasons, release_delay, blanking):
+    def __init__(self, ignored_reasons: set[str], release_delay: int, blanking: XBlanking) -> None:
         self.ignored_reasons = ignored_reasons
         self.blanking = blanking
         self.release_delay = release_delay
-        self.cookies = {}  # cookie -> (sender, application_name, reason, counts)
+        self.cookies: dict[int, Cookie] = {}
         self.next_cookie = itertools.count(1)
-        self.proc_names = {}  # sender -> "comm[pid]", for logging only
+        self.proc_names: dict[str, str] = {}  # sender -> "comm[pid]", for logging only
         self.activity: dict[str, ActivityBurst] = {}  # sender -> SimulateUserActivity burst
         self.disabled = False
         self.release_timer = 0
-        self.conn = None
+        self.conn: Gio.DBusConnection | None = None
 
     # --- lock state -------------------------------------------------------
 
-    def active_count(self):
+    def active_count(self) -> int:
         return sum(1 for *_, counts in self.cookies.values() if counts)
 
-    def update(self):
+    def update(self) -> None:
         """Run xautolock only on 0->1 and 1->0 transitions; delay re-enabling."""
         active = self.active_count()
         if active and self.release_timer:
@@ -147,18 +149,18 @@ class Inhibitor:
             # Browsers send quick Inhibit/UnInhibit bursts when a video starts.
             self.release_timer = GLib.timeout_add_seconds(self.release_delay, self.on_release_timeout)
 
-    def on_release_timeout(self):
+    def on_release_timeout(self) -> bool:
         self.release_timer = 0
         if not self.active_count() and self.disabled:
             self.unblock()
         return GLib.SOURCE_REMOVE
 
-    def block(self):
+    def block(self) -> None:
         xautolock("-disable")
         self.blanking.suspend(True)
         self.disabled = True
 
-    def unblock(self):
+    def unblock(self) -> None:
         xautolock("-enable")
         self.blanking.suspend(False)
         self.disabled = False
@@ -174,8 +176,9 @@ class Inhibitor:
 
     # --- D-Bus ------------------------------------------------------------
 
-    def proc_name(self, sender):
+    def proc_name(self, sender: str) -> str:
         if sender not in self.proc_names:
+            assert self.conn is not None  # set in on_bus_acquired, before any method call
             try:
                 pid = self.conn.call_sync(
                     "org.freedesktop.DBus", "/org/freedesktop/DBus", "org.freedesktop.DBus",
@@ -188,7 +191,7 @@ class Inhibitor:
                 self.proc_names[sender] = "?"
         return f"{sender} {self.proc_names[sender]}"
 
-    def inhibit(self, sender, app, reason):
+    def inhibit(self, sender: str, app: str, reason: str) -> int:
         cookie = next(self.next_cookie)
         counts = reason not in self.ignored_reasons
         self.cookies[cookie] = (sender, app, reason, counts)
@@ -197,7 +200,7 @@ class Inhibitor:
         self.update()
         return cookie
 
-    def uninhibit(self, sender, cookie):
+    def uninhibit(self, sender: str, cookie: int) -> None:
         entry = self.cookies.get(cookie)
         if entry is None or entry[0] != sender:
             log(f"UnInhibit {cookie} from {self.proc_name(sender)}: unknown cookie, ignored")
@@ -246,7 +249,10 @@ class Inhibitor:
         if gone:
             self.update()
 
-    def on_method_call(self, conn, sender, path, iface, method, params, invocation):
+    def on_method_call(
+        self, conn: Gio.DBusConnection, sender: str, path: str, iface: str, method: str,
+        params: GLib.Variant, invocation: Gio.DBusMethodInvocation,
+    ) -> None:
         if method == "Inhibit":
             app, reason = params.unpack()
             invocation.return_value(GLib.Variant("(u)", (self.inhibit(sender, app, reason),)))
@@ -265,12 +271,15 @@ class Inhibitor:
         elif method in ("GetActiveTime", "GetSessionIdleTime"):
             invocation.return_value(GLib.Variant("(u)", (0,)))
 
-    def on_name_owner_changed(self, conn, sender, path, iface, signal_name, params):
+    def on_name_owner_changed(
+        self, conn: Gio.DBusConnection, sender: str, path: str, iface: str, signal_name: str,
+        params: GLib.Variant,
+    ) -> None:
         name, _old, new = params.unpack()
         if not new and name.startswith(":"):
             self.release_sender(name)
 
-    def on_bus_acquired(self, conn, name):
+    def on_bus_acquired(self, conn: Gio.DBusConnection, name: str) -> None:
         self.conn = conn
         iface = Gio.DBusNodeInfo.new_for_xml(INTROSPECTION).interfaces[0]
         for path in OBJECT_PATHS:
@@ -281,7 +290,7 @@ class Inhibitor:
         )
 
 
-def main():
+def main() -> None:
     parser = argparse.ArgumentParser(description=__doc__)
     parser.add_argument(
         "-i", "--ignore-reason", action="append", metavar="REASON",
@@ -297,6 +306,7 @@ def main():
     )
     args = parser.parse_args()
 
+    ignored: set[str]
     if args.count_all:
         ignored = set()
     else:
@@ -306,7 +316,7 @@ def main():
     exit_code = 0
     acquired = False
 
-    def on_name_acquired(conn, name):
+    def on_name_acquired(conn: Gio.DBusConnection, name: str) -> None:
         nonlocal acquired
         acquired = True
         log(f"Owning {name}; ignored reasons: {sorted(ignored) or 'none'}")
@@ -314,7 +324,7 @@ def main():
         # Only after owning the name, so a second instance can't undo an active inhibit.
         xautolock("-enable")
 
-    def on_name_lost(conn, name):
+    def on_name_lost(conn: Gio.DBusConnection | None, name: str) -> None:
         nonlocal exit_code
         if conn is None:
             log("Could not connect to the session bus")
@@ -327,7 +337,7 @@ def main():
             exit_code = EXIT_NAME_TAKEN
         loop.quit()
 
-    def on_signal():
+    def on_signal() -> bool:
         log("Signal received, exiting")
         loop.quit()
         return GLib.SOURCE_REMOVE