Add xidle-dim notifier to dim the screen before xss-lock locks

Fades a black window in over the screen through the compositor, so it works with redshift (no gamma
changes); does nothing without a compositor. README shows it in the xss-lock setup.

.gitignore

@@ -1 +1,4 @@
 CLAUDE.md
+__pycache__/
+.mypy_cache/
+.ruff_cache/

PKGBUILD

@@ -2,26 +2,30 @@
 
 # Maintainer: Daniele Fucini <dfucini [at] gmail [dot] com>
 
-pkgname=xautolock-inhibit
-pkgver=0.1
+pkgname=xidle-inhibit
+pkgver=0.3
 pkgrel=1
-pkgdesc='Honor org.freedesktop.ScreenSaver inhibit requests by disabling xautolock'
+pkgdesc='Honor org.freedesktop.ScreenSaver inhibit requests by blocking xautolock or xss-lock'
 arch=('any')
-url="https://git.shouldnt.work/fuxino/${pkgname}"
+url="https://git.shouldnt.work/fuxino/$pkgname"
 license=('GPL-3.0-or-later')
 depends=('libx11'
          'libxss'
          'python'
-         'python-gobject'
-         'xautolock')
+         'python-gobject')
+optdepends=('xautolock: xautolock backend'
+            'xss-lock: xss-lock backend')
 makedepends=('git')
-source=(git+${url}?signed#tag=${pkgver})
+conflicts=('xautolock-inhibit')
+replaces=('xautolock-inhibit')
+source=("git+$url?signed#tag=$pkgver")
 validpgpkeys=('7E12BC1FF3B6EDB2CD8053EB981A2B2A3BBF5514')
-sha256sums=('SKIP')
+sha256sums=('13390705ad8e0abea5136dbe57f21b7d9509681ee8628109dd0a302497188fbf')
 
 package()
 {
-    cd "${srcdir}/${pkgname}"
-    install -Dm755 "${pkgname}" "${pkgdir}/usr/bin/${pkgname}"
-    install -Dm644 "${pkgname}.service" "${pkgdir}/usr/lib/systemd/user/${pkgname}.service"
+    cd "$srcdir"/"$pkgname"
+    install -Dm755 "$pkgname" "$pkgdir"/usr/bin/"$pkgname"
+    install -Dm644 "$pkgname".service "$pkgdir"/usr/lib/systemd/user/"$pkgname".service
+    install -Dm644 README.md "$pkgdir"/usr/share/doc/"$pkgname"/README.md
 }

README.md

@@ -0,0 +1,147 @@
+# xidle-inhibit
+
+Makes screen locking with `xautolock` or `xss-lock` respect the "don't lock the screen" requests that apps send, on X11 sessions without a desktop environment (for example a plain window manager like xmonad).
+
+Browsers, Steam, gamemode and other apps ask the desktop not to lock or blank the screen while a video or game is running, through the D-Bus service `org.freedesktop.ScreenSaver`. Without a desktop environment nothing provides that service, so the requests are dropped and the screen locks in the middle of a video. xidle-inhibit provides it:
+
+- While at least one request is active, it pauses X screen blanking and DPMS, and with xautolock also runs `xautolock -disable`. xss-lock locks when the X screensaver starts, so pausing it is enough.
+- When the last request is released, it waits a few seconds, then resumes blanking (and runs `xautolock -enable`).
+
+Your locker setup stays as it is; xidle-inhibit only holds it off.
+
+Formerly `xautolock-inhibit`, which supported only xautolock.
+
+## How it works
+
+- Owns `org.freedesktop.ScreenSaver` on the session bus at both `/org/freedesktop/ScreenSaver` and `/ScreenSaver` (apps differ on the path), and implements `Inhibit`, `UnInhibit` and `Lock`.
+- Tracks requests per D-Bus client. If a client disconnects without releasing them (for example a browser crash), its requests are released.
+- Blocks and unblocks only when the number of active requests goes from 0 to 1 or back to 0. Unblocking waits a few seconds (`--release-delay`), because browsers send short bursts of requests when a video starts.
+- Pauses X blanking with `XScreenSaverSuspend`, the same mechanism mpv uses, instead of changing `xset` settings. The X server ends the pause by itself if the daemon exits or crashes.
+- Requests whose reason is on an ignore list (default: `Playing audio`) are accepted and logged, but don't block locking. Firefox-based browsers send one for audio playback, which would otherwise keep the screen unlocked while music plays with nobody at the computer.
+- Keeps the requests it holds in `$XDG_RUNTIME_DIR/xidle-inhibit.json`, so a restarted or crashed daemon takes them over. They are taken over only if the previous daemon stopped at most 30 seconds ago (`--restore-window`) on the same session bus, and only for clients still connected. A request released while no daemon was running can't be seen, so an old file isn't trusted.
+- With xautolock, it re-enables xautolock on exit (including SIGTERM). The systemd unit also runs `xidle-inhibit --cleanup` when it stops, which does the same, as a fallback.
+- `Lock` runs `xautolock -locknow`, or `loginctl lock-session` with xss-lock.
+- If another program (a desktop environment) already owns `org.freedesktop.ScreenSaver`, it exits with status 2 instead of taking over.
+
+## Requirements
+
+- `xautolock` or `xss-lock`, already running in the session
+- `python`, `python-gobject`
+- `libx11`, `libxss`
+- For `xidle-dim`: a compositor, such as picom
+
+## Installation
+
+Build and install the package with the included PKGBUILD, which builds the signed release tag set in `pkgver`:
+
+```
+makepkg -si
+```
+
+Or, with aurutils, build it into a local repository with `aur build` and install it with pacman.
+
+Then start it from your window manager's startup, after the locker. For xmonad with xautolock:
+
+```haskell
+spawnOnce "xautolock -time 10 -locker slock -detectsleep"
+spawnOnce "systemctl --user start xidle-inhibit"
+```
+
+With xss-lock, the lock timeout is the X screensaver timeout (`xset s TIMEOUT CYCLE`). This dims the screen with `xidle-dim` at 9:50 and locks at 10:00:
+
+```haskell
+spawnOnce "xset s 590 10"
+spawnOnce "xss-lock -n xidle-dim -- slock"
+spawnOnce "systemctl --user start xidle-inhibit"
+```
+
+Without dimming, use `xset s 600 0` and `xss-lock -- slock`. Start xss-lock from the window manager, not from a terminal: terminals like kitty run commands outside the login session, and xss-lock then ignores `loginctl lock-session`.
+
+The unit has no `[Install]` section on purpose. Enabling it at login would also start it in a desktop environment, or before X is up; starting it from the window manager limits it to that session. The user service manager needs `DISPLAY` (and `XAUTHORITY`) in its environment, which `/etc/X11/xinit/xinitrc.d/50-systemd-user.sh` sets up for `startx` sessions.
+
+### Upgrading from xautolock-inhibit
+
+The package replaces `xautolock-inhibit`. After upgrading, change the `systemctl --user start` line in your window manager's startup, then switch the running daemon:
+
+```
+systemctl --user stop xautolock-inhibit
+systemctl --user start xidle-inhibit
+```
+
+Requests held by the old daemon are taken over if the new one starts within `--restore-window`.
+
+## Configuration
+
+The backend is set in `~/.config/xidle-inhibit/config` (`$XDG_CONFIG_HOME`):
+
+```
+backend = xss-lock
+```
+
+Values are `xautolock` and `xss-lock`. Without the file, xidle-inhibit uses whichever of the two is installed, and xautolock if both are. Restart the service after changing it.
+
+## Usage
+
+```
+xidle-inhibit [-i REASON] [--count-all] [-d SECONDS] [--restore-window SECONDS] [--cleanup]
+```
+
+- `-i`, `--ignore-reason REASON`: request reason that doesn't block locking. Can be repeated; replaces the default (`Playing audio`).
+- `--count-all`: every request blocks locking; no reasons are ignored.
+- `-d`, `--release-delay SECONDS`: wait this long after the last release before unblocking locking (default 5).
+- `--restore-window SECONDS`: take over requests from a previous daemon that stopped at most this long ago (default 30; 0 disables).
+- `--cleanup`: run `xautolock -enable` if xautolock is the backend, then exit. Used by the unit's `ExecStopPost`.
+
+To change the options used by the service:
+
+```
+systemctl --user edit xidle-inhibit.service
+```
+
+```ini
+[Service]
+ExecStart=
+ExecStart=/usr/bin/xidle-inhibit --count-all
+```
+
+Every request, release and locker command is logged to the journal:
+
+```
+journalctl --user -u xidle-inhibit
+```
+
+### Dimming before the lock
+
+`xidle-dim` is an xss-lock notifier (`-n`). It fades a black window over the screen until xss-lock stops it, on user activity or when the locker starts. It needs a compositor such as picom and does nothing without one. Because it doesn't change gamma, it works alongside redshift.
+
+```
+xidle-dim [--opacity 0-1] [--fade SECONDS]
+```
+
+- `--opacity`: final darkness (default 0.6).
+- `--fade`: fade-in time (default 1.5).
+
+Options go inside the notifier command: `xss-lock -n "xidle-dim --opacity 0.8" -- slock`.
+
+## App notes
+
+- **Sandboxed apps** may be blocked from reaching the service. For a firejail profile that filters D-Bus (`dbus-user filter`, as the Firefox-based profiles do), allow it in the app's `.local` file, e.g. `zen-browser.local`:
+
+  ```
+  dbus-user.talk org.freedesktop.ScreenSaver
+  ```
+
+- **Games**: Steam's overlay and gamemode (`inhibit_screensaver=1`) send requests on their own.
+- **scrcpy** only sends a request when started with `--disable-screensaver`.
+- **mpv** talks to the X server directly and doesn't need this daemon.
+
+## Limitations
+
+- A release sent while the daemon is down is lost: if the daemon is back within `--restore-window`, that request stays active until its app exits. After a longer stop, all held requests are dropped and apps don't send them again.
+- With xss-lock, requests block only the idle timeout: suspending, or `loginctl lock-session` from elsewhere, still locks.
+- `SimulateUserActivity` is accepted but does nothing. Calls are logged once when a client starts sending them and once, with a count, after 5 minutes without any.
+- `GetActive` always returns `false`.
+
+## License
+
+GPL-3.0-or-later. See [LICENSE](LICENSE).

pyproject.toml

@@ -0,0 +1,11 @@
+[tool.ruff]
+line-length = 120
+extend-include = ["xidle-inhibit", "xidle-dim"]
+
+[tool.ruff.lint]
+select = ["E", "F", "W", "I", "B", "UP"]
+
+[tool.mypy]
+# Scripts both map to __main__, so check xidle-dim separately: mypy xidle-dim
+files = ["xidle-inhibit"]
+strict = true

xautolock-inhibit

@@ -1,306 +0,0 @@
-#!/usr/bin/env python3
-"""Own org.freedesktop.ScreenSaver and turn inhibit requests into xautolock -disable/-enable.
-
-While an inhibit is active, X screen blanking is also paused (like mpv does).
-"""
-
-import argparse
-import ctypes
-import itertools
-import signal
-import subprocess
-import sys
-
-from gi.repository import Gio, GLib
-
-try:
-    from gi.repository import GLibUnix  # GLib >= 2.80
-    signal_add = GLibUnix.signal_add
-except ImportError:
-    signal_add = GLib.unix_signal_add
-
-BUS_NAME = "org.freedesktop.ScreenSaver"
-OBJECT_PATHS = ("/org/freedesktop/ScreenSaver", "/ScreenSaver")  # Vivaldi uses the first, Zen the second
-EXIT_NAME_TAKEN = 2
-
-INTROSPECTION = """
-<node>
-  <interface name="org.freedesktop.ScreenSaver">
-    <method name="Inhibit">
-      <arg name="application_name" type="s" direction="in"/>
-      <arg name="reason_for_inhibit" type="s" direction="in"/>
-      <arg name="cookie" type="u" direction="out"/>
-    </method>
-    <method name="UnInhibit">
-      <arg name="cookie" type="u" direction="in"/>
-    </method>
-    <method name="SimulateUserActivity"/>
-    <method name="Lock"/>
-    <method name="GetActive">
-      <arg type="b" direction="out"/>
-    </method>
-    <method name="SetActive">
-      <arg type="b" direction="in"/>
-      <arg type="b" direction="out"/>
-    </method>
-    <method name="GetActiveTime">
-      <arg type="u" direction="out"/>
-    </method>
-    <method name="GetSessionIdleTime">
-      <arg type="u" direction="out"/>
-    </method>
-  </interface>
-</node>
-"""
-
-
-def log(msg):
-    print(msg, flush=True)
-
-
-def xautolock(arg):
-    try:
-        subprocess.run(["xautolock", arg], check=True, timeout=10)
-        log(f"xautolock {arg}")
-    except (OSError, subprocess.SubprocessError) as e:
-        log(f"xautolock {arg} failed: {e}")
-
-
-class XBlanking:
-    """Pause X screen blanking with XScreenSaverSuspend (MIT-SCREEN-SAVER extension).
-
-    Unlike `xset s off -dpms` this changes no global setting: the X server ends the
-    pause by itself when this client releases it or its connection closes (exit, crash).
-    """
-
-    def __init__(self):
-        self.dpy = None
-        try:
-            self.x11 = ctypes.CDLL("libX11.so.6")
-            self.xss = ctypes.CDLL("libXss.so.1")
-        except OSError as e:
-            log(f"Cannot load X11 libraries ({e}); X blanking will not be paused")
-            return
-        self.x11.XOpenDisplay.argtypes = [ctypes.c_char_p]
-        self.x11.XOpenDisplay.restype = ctypes.c_void_p
-        self.x11.XFlush.argtypes = [ctypes.c_void_p]
-        self.xss.XScreenSaverQueryExtension.argtypes = [
-            ctypes.c_void_p, ctypes.POINTER(ctypes.c_int), ctypes.POINTER(ctypes.c_int)]
-        self.xss.XScreenSaverSuspend.argtypes = [ctypes.c_void_p, ctypes.c_int]
-
-        dpy = self.x11.XOpenDisplay(None)
-        if not dpy:
-            log("Cannot open the X display; X blanking will not be paused")
-            return
-        event_base, error_base = ctypes.c_int(), ctypes.c_int()
-        if not self.xss.XScreenSaverQueryExtension(dpy, ctypes.byref(event_base), ctypes.byref(error_base)):
-            log("X server lacks the MIT-SCREEN-SAVER extension; X blanking will not be paused")
-            return
-        self.dpy = dpy
-
-    def suspend(self, on):
-        if self.dpy:
-            self.xss.XScreenSaverSuspend(self.dpy, int(on))
-            self.x11.XFlush(self.dpy)
-            log(f"X blanking {'paused' if on else 'resumed'}")
-
-
-class Inhibitor:
-    def __init__(self, ignored_reasons, release_delay, blanking):
-        self.ignored_reasons = ignored_reasons
-        self.blanking = blanking
-        self.release_delay = release_delay
-        self.cookies = {}  # cookie -> (sender, application_name, reason, counts)
-        self.next_cookie = itertools.count(1)
-        self.proc_names = {}  # sender -> "comm[pid]", for logging only
-        self.disabled = False
-        self.release_timer = 0
-        self.conn = None
-
-    # --- lock state -------------------------------------------------------
-
-    def active_count(self):
-        return sum(1 for *_, counts in self.cookies.values() if counts)
-
-    def update(self):
-        """Run xautolock only on 0->1 and 1->0 transitions; delay re-enabling."""
-        active = self.active_count()
-        if active and self.release_timer:
-            GLib.source_remove(self.release_timer)
-            self.release_timer = 0
-        if active and not self.disabled:
-            self.block()
-        elif not active and self.disabled and not self.release_timer:
-            # 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):
-        self.release_timer = 0
-        if not self.active_count() and self.disabled:
-            self.unblock()
-        return GLib.SOURCE_REMOVE
-
-    def block(self):
-        xautolock("-disable")
-        self.blanking.suspend(True)
-        self.disabled = True
-
-    def unblock(self):
-        xautolock("-enable")
-        self.blanking.suspend(False)
-        self.disabled = False
-
-    def shutdown(self):
-        if self.release_timer:
-            GLib.source_remove(self.release_timer)
-            self.release_timer = 0
-        if self.disabled:
-            self.unblock()
-
-    # --- D-Bus ------------------------------------------------------------
-
-    def proc_name(self, sender):
-        if sender not in self.proc_names:
-            try:
-                pid = self.conn.call_sync(
-                    "org.freedesktop.DBus", "/org/freedesktop/DBus", "org.freedesktop.DBus",
-                    "GetConnectionUnixProcessID", GLib.Variant("(s)", (sender,)),
-                    GLib.VariantType("(u)"), Gio.DBusCallFlags.NONE, 1000, None,
-                ).unpack()[0]
-                with open(f"/proc/{pid}/comm") as f:
-                    self.proc_names[sender] = f"{f.read().strip()}[{pid}]"
-            except (GLib.Error, OSError):
-                self.proc_names[sender] = "?"
-        return f"{sender} {self.proc_names[sender]}"
-
-    def inhibit(self, sender, app, reason):
-        cookie = next(self.next_cookie)
-        counts = reason not in self.ignored_reasons
-        self.cookies[cookie] = (sender, app, reason, counts)
-        note = "" if counts else " (reason ignored, does not block locking)"
-        log(f"Inhibit {cookie}: '{app}' '{reason}' from {self.proc_name(sender)}{note}")
-        self.update()
-        return cookie
-
-    def uninhibit(self, sender, cookie):
-        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")
-            return
-        del self.cookies[cookie]
-        _, app, reason, _ = entry
-        log(f"UnInhibit {cookie}: '{app}' '{reason}'")
-        self.update()
-
-    def release_sender(self, sender):
-        gone = [c for c, (s, *_) in self.cookies.items() if s == sender]
-        for c in gone:
-            _, app, reason, _ = self.cookies.pop(c)
-            log(f"Released {c}: '{app}' '{reason}' ({sender} left the bus)")
-        self.proc_names.pop(sender, None)
-        if gone:
-            self.update()
-
-    def on_method_call(self, conn, sender, path, iface, method, params, invocation):
-        if method == "Inhibit":
-            app, reason = params.unpack()
-            invocation.return_value(GLib.Variant("(u)", (self.inhibit(sender, app, reason),)))
-        elif method == "UnInhibit":
-            self.uninhibit(sender, params.unpack()[0])
-            invocation.return_value(None)
-        elif method == "SimulateUserActivity":
-            log(f"SimulateUserActivity from {self.proc_name(sender)} (not implemented)")
-            invocation.return_value(None)
-        elif method == "Lock":
-            log(f"Lock from {self.proc_name(sender)}")
-            xautolock("-locknow")
-            invocation.return_value(None)
-        elif method in ("GetActive", "SetActive"):
-            invocation.return_value(GLib.Variant("(b)", (False,)))
-        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):
-        name, _old, new = params.unpack()
-        if not new and name.startswith(":"):
-            self.release_sender(name)
-
-    def on_bus_acquired(self, conn, name):
-        self.conn = conn
-        iface = Gio.DBusNodeInfo.new_for_xml(INTROSPECTION).interfaces[0]
-        for path in OBJECT_PATHS:
-            conn.register_object(path, iface, self.on_method_call, None, None)
-        conn.signal_subscribe(
-            "org.freedesktop.DBus", "org.freedesktop.DBus", "NameOwnerChanged",
-            "/org/freedesktop/DBus", None, Gio.DBusSignalFlags.NONE, self.on_name_owner_changed,
-        )
-
-
-def main():
-    parser = argparse.ArgumentParser(description=__doc__)
-    parser.add_argument(
-        "-i", "--ignore-reason", action="append", metavar="REASON",
-        help="inhibit reason that does not block locking (repeatable; default: 'Playing audio')",
-    )
-    parser.add_argument(
-        "--count-all", action="store_true",
-        help="let every inhibit block locking, ignoring no reasons",
-    )
-    parser.add_argument(
-        "-d", "--release-delay", type=int, default=5, metavar="SECONDS",
-        help="wait this long after the last release before re-enabling xautolock (default: 5)",
-    )
-    args = parser.parse_args()
-
-    if args.count_all:
-        ignored = set()
-    else:
-        ignored = set(args.ignore_reason or ["Playing audio"])
-    inhibitor = Inhibitor(ignored, max(args.release_delay, 0), XBlanking())
-    loop = GLib.MainLoop()
-    exit_code = 0
-    acquired = False
-
-    def on_name_acquired(conn, name):
-        nonlocal acquired
-        acquired = True
-        log(f"Owning {name}; ignored reasons: {sorted(ignored) or 'none'}")
-        # Start from a known state, in case a previous instance died while disabled.
-        # Only after owning the name, so a second instance can't undo an active inhibit.
-        xautolock("-enable")
-
-    def on_name_lost(conn, name):
-        nonlocal exit_code
-        if conn is None:
-            log("Could not connect to the session bus")
-            exit_code = 1
-        elif acquired:
-            log(f"Lost {name} (bus connection closed?)")
-            exit_code = 1
-        else:
-            log(f"{name} is owned by another process (a desktop environment?); exiting")
-            exit_code = EXIT_NAME_TAKEN
-        loop.quit()
-
-    def on_signal():
-        log("Signal received, exiting")
-        loop.quit()
-        return GLib.SOURCE_REMOVE
-
-    for sig in (signal.SIGTERM, signal.SIGINT, signal.SIGHUP):
-        signal_add(GLib.PRIORITY_HIGH, sig, on_signal)
-
-    owner_id = Gio.bus_own_name(
-        Gio.BusType.SESSION, BUS_NAME, Gio.BusNameOwnerFlags.DO_NOT_QUEUE,
-        inhibitor.on_bus_acquired, on_name_acquired, on_name_lost,
-    )
-    try:
-        loop.run()
-    finally:
-        inhibitor.shutdown()
-        Gio.bus_unown_name(owner_id)
-    sys.exit(exit_code)
-
-
-if __name__ == "__main__":
-    main()

xautolock-inhibit.service

@@ -1,10 +0,0 @@
-[Unit]
-Description=Turn org.freedesktop.ScreenSaver inhibit requests into xautolock control
-
-[Service]
-Type=dbus
-BusName=org.freedesktop.ScreenSaver
-ExecStart=/usr/bin/xautolock-inhibit
-ExecStopPost=-/usr/bin/xautolock -enable
-Restart=on-failure
-RestartPreventExitStatus=2

xidle-dim

@@ -0,0 +1,119 @@
+#!/usr/bin/env python3
+"""Dim the screen until killed, as an xss-lock notifier: xss-lock -n xidle-dim -- slock.
+
+Maps a black window over the whole screen and fades in its opacity through the compositor; gamma is left alone,
+so it doesn't clash with redshift. Without a compositor it does nothing, as the window would be solid black.
+"""
+
+import argparse
+import ctypes
+import signal
+import sys
+import time
+from types import FrameType
+
+CW_BACK_PIXEL = 1 << 1
+CW_OVERRIDE_REDIRECT = 1 << 9
+INPUT_OUTPUT = 1
+XA_CARDINAL = 6
+PROP_MODE_REPLACE = 0
+OPACITY_MAX = 0xFFFFFFFF
+
+
+class XSetWindowAttributes(ctypes.Structure):
+    _fields_ = [
+        ("background_pixmap", ctypes.c_ulong),
+        ("background_pixel", ctypes.c_ulong),
+        ("border_pixmap", ctypes.c_ulong),
+        ("border_pixel", ctypes.c_ulong),
+        ("bit_gravity", ctypes.c_int),
+        ("win_gravity", ctypes.c_int),
+        ("backing_store", ctypes.c_int),
+        ("backing_planes", ctypes.c_ulong),
+        ("backing_pixel", ctypes.c_ulong),
+        ("save_under", ctypes.c_int),
+        ("event_mask", ctypes.c_long),
+        ("do_not_propagate_mask", ctypes.c_long),
+        ("override_redirect", ctypes.c_int),
+        ("colormap", ctypes.c_ulong),
+        ("cursor", ctypes.c_ulong),
+    ]
+
+
+def load_x11() -> ctypes.CDLL:
+    x11 = ctypes.CDLL("libX11.so.6")
+    p, ul, i = ctypes.c_void_p, ctypes.c_ulong, ctypes.c_int
+    x11.XOpenDisplay.argtypes = [ctypes.c_char_p]
+    x11.XOpenDisplay.restype = p
+    for name in ("XDefaultScreen",):
+        getattr(x11, name).argtypes = [p]
+    for name in ("XRootWindow", "XBlackPixel"):
+        getattr(x11, name).argtypes = [p, i]
+        getattr(x11, name).restype = ul
+    for name in ("XDisplayWidth", "XDisplayHeight"):
+        getattr(x11, name).argtypes = [p, i]
+    x11.XInternAtom.argtypes = [p, ctypes.c_char_p, i]
+    x11.XInternAtom.restype = ul
+    x11.XGetSelectionOwner.argtypes = [p, ul]
+    x11.XGetSelectionOwner.restype = ul
+    x11.XCreateWindow.argtypes = [p, ul, i, i, ctypes.c_uint, ctypes.c_uint, ctypes.c_uint, i, ctypes.c_uint, p, ul,
+                                  ctypes.POINTER(XSetWindowAttributes)]
+    x11.XCreateWindow.restype = ul
+    x11.XChangeProperty.argtypes = [p, ul, ul, ul, i, i, p, i]
+    x11.XMapRaised.argtypes = [p, ul]
+    x11.XFlush.argtypes = [p]
+    return x11
+
+
+def parse_args() -> argparse.Namespace:
+    parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
+    parser.add_argument("--opacity", type=float, default=0.6, help="final darkness, 0 to 1 (default: %(default)s)")
+    parser.add_argument("--fade", type=float, default=1.5, help="fade-in time in seconds (default: %(default)s)")
+    args = parser.parse_args()
+    if not 0 <= args.opacity <= 1 or args.fade < 0:
+        parser.error("--opacity must be between 0 and 1 and --fade not negative")
+    return args
+
+
+def exit_on_signal(_signum: int, _frame: FrameType | None) -> None:
+    sys.exit(0)  # the X server removes the window when the connection closes
+
+
+def main() -> None:
+    args = parse_args()
+    # xss-lock sends SIGHUP on user activity and SIGTERM when the locker starts.
+    for sig in (signal.SIGHUP, signal.SIGTERM, signal.SIGINT):
+        signal.signal(sig, exit_on_signal)
+
+    x11 = load_x11()
+    dpy = x11.XOpenDisplay(None)
+    if not dpy:
+        sys.exit("xidle-dim: cannot open display")
+    screen = x11.XDefaultScreen(dpy)
+    if not x11.XGetSelectionOwner(dpy, x11.XInternAtom(dpy, f"_NET_WM_CM_S{screen}".encode(), False)):
+        print("xidle-dim: no compositor running, not dimming", file=sys.stderr)
+        signal.pause()  # stay alive like a notifier should, until xss-lock kills us
+
+    attrs = XSetWindowAttributes(background_pixel=x11.XBlackPixel(dpy, screen), override_redirect=True)
+    win = x11.XCreateWindow(dpy, x11.XRootWindow(dpy, screen), 0, 0, x11.XDisplayWidth(dpy, screen),
+                            x11.XDisplayHeight(dpy, screen), 0, 0, INPUT_OUTPUT, None,
+                            CW_BACK_PIXEL | CW_OVERRIDE_REDIRECT, ctypes.byref(attrs))
+    opacity_atom = x11.XInternAtom(dpy, b"_NET_WM_WINDOW_OPACITY", False)
+
+    def set_opacity(level: float) -> None:
+        value = ctypes.c_ulong(int(level * OPACITY_MAX))  # format 32 properties are passed as longs
+        x11.XChangeProperty(dpy, win, opacity_atom, XA_CARDINAL, 32, PROP_MODE_REPLACE, ctypes.byref(value), 1)
+        x11.XFlush(dpy)
+
+    set_opacity(0)
+    x11.XMapRaised(dpy, win)
+    steps = max(1, int(args.fade * 30))
+    for n in range(1, steps + 1):
+        set_opacity(args.opacity * n / steps)
+        time.sleep(args.fade / steps)
+    while True:
+        signal.pause()
+
+
+if __name__ == "__main__":
+    main()

xidle-inhibit

@@ -0,0 +1,551 @@
+#!/usr/bin/env python3
+"""Own org.freedesktop.ScreenSaver and block screen locking by xautolock or xss-lock while inhibits are held.
+
+While an inhibit is active, X screen blanking is paused (like mpv does), which also keeps xss-lock from
+locking; with xautolock, it is also switched off with xautolock -disable.
+"""
+
+import argparse
+import ctypes
+import json
+import os
+import shutil
+import signal
+import subprocess
+import sys
+import time
+from dataclasses import dataclass
+from datetime import timedelta
+from typing import Any
+
+from gi.repository import Gio, GLib
+
+try:
+    from gi.repository import GLibUnix  # GLib >= 2.80
+    signal_add = GLibUnix.signal_add
+except ImportError:
+    signal_add = GLib.unix_signal_add
+
+BUS_NAME = "org.freedesktop.ScreenSaver"
+OBJECT_PATHS = ("/org/freedesktop/ScreenSaver", "/ScreenSaver")  # Vivaldi uses the first, Zen the second
+EXIT_NAME_TAKEN = 2
+ACTIVITY_QUIET = 300  # seconds without SimulateUserActivity that end a logged burst
+STATE_FILE = "xidle-inhibit.json"  # in $XDG_RUNTIME_DIR
+OLD_STATE_FILE = "xautolock-inhibit.json"  # before the rename (0.2); read once when upgrading
+STATE_HEARTBEAT = 10  # seconds between state file touches while inhibits are held
+CONFIG_FILE = "xidle-inhibit/config"  # in $XDG_CONFIG_HOME
+BACKENDS = ("xautolock", "xss-lock")
+
+Cookie = tuple[str, str, str, bool]  # sender, application_name, reason, counts
+
+INTROSPECTION = """
+<node>
+  <interface name="org.freedesktop.ScreenSaver">
+    <method name="Inhibit">
+      <arg name="application_name" type="s" direction="in"/>
+      <arg name="reason_for_inhibit" type="s" direction="in"/>
+      <arg name="cookie" type="u" direction="out"/>
+    </method>
+    <method name="UnInhibit">
+      <arg name="cookie" type="u" direction="in"/>
+    </method>
+    <method name="SimulateUserActivity"/>
+    <method name="Lock"/>
+    <method name="GetActive">
+      <arg type="b" direction="out"/>
+    </method>
+    <method name="SetActive">
+      <arg type="b" direction="in"/>
+      <arg type="b" direction="out"/>
+    </method>
+    <method name="GetActiveTime">
+      <arg type="u" direction="out"/>
+    </method>
+    <method name="GetSessionIdleTime">
+      <arg type="u" direction="out"/>
+    </method>
+  </interface>
+</node>
+"""
+
+
+def log(msg: str) -> None:
+    print(msg, flush=True)
+
+
+def run(*cmd: str) -> None:
+    try:
+        subprocess.run(cmd, check=True, timeout=10)
+        log(" ".join(cmd))
+    except (OSError, subprocess.SubprocessError) as e:
+        log(f"{' '.join(cmd)} failed: {e}")
+
+
+def xautolock(arg: str) -> None:
+    run("xautolock", arg)
+
+
+def read_backend() -> str:
+    """Return the backend set in the config file, else the installed locker (xautolock if both are)."""
+    config_home = os.environ.get("XDG_CONFIG_HOME") or os.path.expanduser("~/.config")
+    path = os.path.join(config_home, CONFIG_FILE)
+    try:
+        with open(path) as f:
+            for line in f:
+                key, sep, value = line.partition("=")
+                if not sep or key.strip() != "backend":
+                    continue
+                value = value.strip().strip("\"'")
+                if value in BACKENDS:
+                    return value
+                log(f"{path}: unknown backend '{value}' (expected {' or '.join(BACKENDS)}); detecting")
+    except FileNotFoundError:
+        pass
+    except OSError as e:
+        log(f"Cannot read {path}: {e}; detecting the backend")
+    if not shutil.which("xautolock") and shutil.which("xss-lock"):
+        return "xss-lock"
+    return "xautolock"
+
+
+class XBlanking:
+    """Pause X screen blanking with XScreenSaverSuspend (MIT-SCREEN-SAVER extension).
+
+    Unlike `xset s off -dpms` this changes no global setting: the X server ends the
+    pause by itself when this client releases it or its connection closes (exit, crash).
+    """
+
+    def __init__(self) -> None:
+        self.dpy: int | None = None
+        try:
+            self.x11 = ctypes.CDLL("libX11.so.6")
+            self.xss = ctypes.CDLL("libXss.so.1")
+        except OSError as e:
+            log(f"Cannot load X11 libraries ({e}); X blanking will not be paused")
+            return
+        self.x11.XOpenDisplay.argtypes = [ctypes.c_char_p]
+        self.x11.XOpenDisplay.restype = ctypes.c_void_p
+        self.x11.XFlush.argtypes = [ctypes.c_void_p]
+        self.xss.XScreenSaverQueryExtension.argtypes = [
+            ctypes.c_void_p, ctypes.POINTER(ctypes.c_int), ctypes.POINTER(ctypes.c_int)]
+        self.xss.XScreenSaverSuspend.argtypes = [ctypes.c_void_p, ctypes.c_int]
+
+        dpy = self.x11.XOpenDisplay(None)
+        if not dpy:
+            log("Cannot open the X display; X blanking will not be paused")
+            return
+        event_base, error_base = ctypes.c_int(), ctypes.c_int()
+        if not self.xss.XScreenSaverQueryExtension(dpy, ctypes.byref(event_base), ctypes.byref(error_base)):
+            log("X server lacks the MIT-SCREEN-SAVER extension; X blanking will not be paused")
+            return
+        self.dpy = dpy
+
+    def suspend(self, on: bool) -> None:
+        if self.dpy:
+            self.xss.XScreenSaverSuspend(self.dpy, int(on))
+            self.x11.XFlush(self.dpy)
+            log(f"X blanking {'paused' if on else 'resumed'}")
+
+
+@dataclass
+class ActivityBurst:
+    first: float
+    last: float
+    calls: int = 0
+    timer: int = 0
+
+
+class Inhibitor:
+    def __init__(
+        self, backend: str, ignored_reasons: set[str], release_delay: int, blanking: XBlanking,
+        state_path: str | None, restore_window: int,
+    ) -> None:
+        self.xautolock = backend == "xautolock"  # else xss-lock: pausing X blanking is enough
+        self.ignored_reasons = ignored_reasons
+        self.blanking = blanking
+        self.release_delay = release_delay
+        self.state_path = state_path
+        self.restore_window = restore_window
+        self.state_ready = False  # set once this instance owns the name and may write the state file
+        self.heartbeat_timer = 0
+        self.cookies: dict[int, Cookie] = {}
+        self.last_cookie = 0
+        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: Gio.DBusConnection | None = None
+
+    # --- lock state -------------------------------------------------------
+
+    def active_count(self) -> int:
+        return sum(1 for *_, counts in self.cookies.values() if counts)
+
+    def update(self) -> None:
+        """Block or unblock only on 0->1 and 1->0 transitions; delay unblocking."""
+        active = self.active_count()
+        if active and self.release_timer:
+            GLib.source_remove(self.release_timer)
+            self.release_timer = 0
+        if active and not self.disabled:
+            self.block()
+        elif not active and self.disabled and not self.release_timer:
+            # 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) -> bool:
+        self.release_timer = 0
+        if not self.active_count() and self.disabled:
+            self.unblock()
+        return GLib.SOURCE_REMOVE
+
+    def block(self) -> None:
+        if self.xautolock:
+            xautolock("-disable")
+        self.blanking.suspend(True)
+        self.disabled = True
+
+    def unblock(self) -> None:
+        if self.xautolock:
+            xautolock("-enable")
+        self.blanking.suspend(False)
+        self.disabled = False
+
+    def shutdown(self) -> None:
+        for sender in list(self.activity):
+            self.end_activity(sender)
+        if self.release_timer:
+            GLib.source_remove(self.release_timer)
+            self.release_timer = 0
+        self.save(stopped=True)
+        if self.disabled:
+            self.unblock()
+
+    # --- state file -------------------------------------------------------
+
+    def start(self) -> None:
+        """Take over inhibits saved by a previous instance, then set the locker to match."""
+        self.restore()
+        self.state_ready = True
+        self.save()
+        if self.state_path:
+            old = os.path.join(os.path.dirname(self.state_path), OLD_STATE_FILE)
+            try:
+                os.remove(old)
+            except FileNotFoundError:
+                pass
+            except OSError as e:
+                log(f"Cannot remove old state file {old}: {e}")
+        if self.active_count():
+            self.block()
+        elif self.xautolock:
+            # Start from a known state, in case a previous instance died while disabled.
+            xautolock("-enable")
+
+    def restore(self) -> None:
+        if not self.state_path:
+            log("XDG_RUNTIME_DIR is not set; inhibits will not survive a restart")
+            return
+        assert self.conn is not None
+        path = self.state_path
+        old = os.path.join(os.path.dirname(path), OLD_STATE_FILE)
+        if not os.path.exists(path) and os.path.exists(old):
+            path = old
+        try:
+            with open(path) as f:
+                state = json.load(f)
+            age = time.time() - (state["stopped_at"] or os.stat(path).st_mtime)
+            bus_id = state["bus_id"]
+            last_cookie = int(state["last_cookie"])
+            saved = [(int(c), s, a, r) for c, s, a, r in state["cookies"]]
+        except FileNotFoundError:
+            return
+        except (OSError, ValueError, KeyError, TypeError) as e:
+            log(f"Ignoring unreadable state file {path}: {e}")
+            return
+        if path == old:
+            log(f"Reading inhibits from {old} (xautolock-inhibit)")
+        if bus_id != self.conn.get_guid():
+            # Unique names like :1.42 are reused by a new bus, so they would mean other clients.
+            if saved:
+                log(f"Not restoring {len(saved)} inhibit(s): saved on another session bus")
+            return
+        # Keep numbering after old cookies, so a late UnInhibit can't hit a new one.
+        self.last_cookie = last_cookie
+        if not saved:
+            return
+        if age > self.restore_window:
+            # An UnInhibit sent while no instance ran is lost; don't trust an old file.
+            log(f"Not restoring {len(saved)} inhibit(s): saved {age:.0f}s ago, "
+                f"over the {self.restore_window}s window")
+            return
+        for cookie, sender, app, reason in saved:
+            if not self.has_owner(sender):
+                log(f"Not restoring {cookie}: '{app}' '{reason}' ({sender} left the bus)")
+                continue
+            counts = reason not in self.ignored_reasons
+            self.cookies[cookie] = (sender, app, reason, counts)
+            note = "" if counts else " (reason ignored, does not block locking)"
+            log(f"Restored {cookie}: '{app}' '{reason}' from {self.proc_name(sender)}{note}")
+
+    def save(self, stopped: bool = False) -> None:
+        """Write the held inhibits atomically; while any are held, touch the file regularly.
+
+        The touches keep the mtime recent, so after a crash the next instance can tell how
+        long ago it happened. A clean stop records the time in `stopped_at` instead.
+        """
+        if not self.state_ready or not self.state_path:
+            return
+        assert self.conn is not None
+        state = {
+            "bus_id": self.conn.get_guid(),
+            "last_cookie": self.last_cookie,
+            "stopped_at": time.time() if stopped else None,
+            "cookies": [[c, s, a, r] for c, (s, a, r, _) in self.cookies.items()],
+        }
+        tmp = f"{self.state_path}.tmp"
+        try:
+            with open(tmp, "w") as f:
+                json.dump(state, f)
+            os.replace(tmp, self.state_path)
+        except OSError as e:
+            log(f"Cannot write state file {self.state_path}: {e}")
+        if self.cookies and not stopped:
+            if not self.heartbeat_timer:
+                self.heartbeat_timer = GLib.timeout_add_seconds(STATE_HEARTBEAT, self.on_heartbeat)
+        elif self.heartbeat_timer:
+            GLib.source_remove(self.heartbeat_timer)
+            self.heartbeat_timer = 0
+
+    def on_heartbeat(self) -> bool:
+        assert self.state_path is not None
+        try:
+            os.utime(self.state_path)
+        except OSError as e:
+            log(f"Cannot touch state file {self.state_path}: {e}")
+        return GLib.SOURCE_CONTINUE
+
+    # --- D-Bus ------------------------------------------------------------
+
+    def bus_call(self, method: str, name: str, reply_type: str) -> Any:
+        """Call an org.freedesktop.DBus method that takes a bus name; return its single result."""
+        assert self.conn is not None  # set in on_bus_acquired, before any method call
+        return self.conn.call_sync(
+            "org.freedesktop.DBus", "/org/freedesktop/DBus", "org.freedesktop.DBus",
+            method, GLib.Variant("(s)", (name,)),
+            GLib.VariantType(reply_type), Gio.DBusCallFlags.NONE, 1000, None,
+        ).unpack()[0]
+
+    def has_owner(self, name: str) -> bool:
+        try:
+            return bool(self.bus_call("NameHasOwner", name, "(b)"))
+        except GLib.Error:
+            return False
+
+    def proc_name(self, sender: str) -> str:
+        if sender not in self.proc_names:
+            try:
+                pid = self.bus_call("GetConnectionUnixProcessID", sender, "(u)")
+                with open(f"/proc/{pid}/comm") as f:
+                    self.proc_names[sender] = f"{f.read().strip()}[{pid}]"
+            except (GLib.Error, OSError):
+                self.proc_names[sender] = "?"
+        return f"{sender} {self.proc_names[sender]}"
+
+    def inhibit(self, sender: str, app: str, reason: str) -> int:
+        self.last_cookie += 1
+        cookie = self.last_cookie
+        counts = reason not in self.ignored_reasons
+        self.cookies[cookie] = (sender, app, reason, counts)
+        note = "" if counts else " (reason ignored, does not block locking)"
+        log(f"Inhibit {cookie}: '{app}' '{reason}' from {self.proc_name(sender)}{note}")
+        self.save()
+        self.update()
+        return 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")
+            return
+        del self.cookies[cookie]
+        _, app, reason, _ = entry
+        log(f"UnInhibit {cookie}: '{app}' '{reason}'")
+        self.save()
+        self.update()
+
+    def simulate_activity(self, sender: str) -> None:
+        """Log a sender's calls once per burst: Steam sends thousands per hour."""
+        now = time.monotonic()
+        burst = self.activity.get(sender)
+        if burst is None:
+            log(f"SimulateUserActivity from {self.proc_name(sender)} (not implemented)")
+            burst = self.activity[sender] = ActivityBurst(first=now, last=now)
+        else:
+            GLib.source_remove(burst.timer)
+        burst.calls += 1
+        burst.last = now
+        burst.timer = GLib.timeout_add_seconds(ACTIVITY_QUIET, self.on_activity_quiet, sender)
+
+    def on_activity_quiet(self, sender: str) -> bool:
+        self.activity[sender].timer = 0
+        self.end_activity(sender)
+        return GLib.SOURCE_REMOVE
+
+    def end_activity(self, sender: str) -> None:
+        burst = self.activity.pop(sender, None)
+        if burst is None:
+            return
+        if burst.timer:
+            GLib.source_remove(burst.timer)
+        if burst.calls == 1:
+            return
+        span = timedelta(seconds=round(burst.last - burst.first))
+        log(f"SimulateUserActivity from {self.proc_name(sender)}: {burst.calls} calls over {span}")
+
+    def release_sender(self, sender: str) -> None:
+        gone = [c for c, (s, *_) in self.cookies.items() if s == sender]
+        for c in gone:
+            _, app, reason, _ = self.cookies.pop(c)
+            log(f"Released {c}: '{app}' '{reason}' ({sender} left the bus)")
+        self.end_activity(sender)
+        self.proc_names.pop(sender, None)
+        if gone:
+            self.save()
+            self.update()
+
+    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),)))
+        elif method == "UnInhibit":
+            self.uninhibit(sender, params.unpack()[0])
+            invocation.return_value(None)
+        elif method == "SimulateUserActivity":
+            self.simulate_activity(sender)
+            invocation.return_value(None)
+        elif method == "Lock":
+            log(f"Lock from {self.proc_name(sender)}")
+            if self.xautolock:
+                xautolock("-locknow")
+            else:
+                run("loginctl", "lock-session")
+            invocation.return_value(None)
+        elif method in ("GetActive", "SetActive"):
+            invocation.return_value(GLib.Variant("(b)", (False,)))
+        elif method in ("GetActiveTime", "GetSessionIdleTime"):
+            invocation.return_value(GLib.Variant("(u)", (0,)))
+
+    def on_name_owner_changed(
+        self, conn: Gio.DBusConnection, sender: str | None, 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: Gio.DBusConnection, name: str) -> None:
+        self.conn = conn
+        iface = Gio.DBusNodeInfo.new_for_xml(INTROSPECTION).interfaces[0]
+        for path in OBJECT_PATHS:
+            conn.register_object(path, iface, self.on_method_call, None, None)
+        conn.signal_subscribe(
+            "org.freedesktop.DBus", "org.freedesktop.DBus", "NameOwnerChanged",
+            "/org/freedesktop/DBus", None, Gio.DBusSignalFlags.NONE, self.on_name_owner_changed,
+        )
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument(
+        "-i", "--ignore-reason", action="append", metavar="REASON",
+        help="inhibit reason that does not block locking (repeatable; default: 'Playing audio')",
+    )
+    parser.add_argument(
+        "--count-all", action="store_true",
+        help="let every inhibit block locking, ignoring no reasons",
+    )
+    parser.add_argument(
+        "-d", "--release-delay", type=int, default=5, metavar="SECONDS",
+        help="wait this long after the last release before unblocking locking (default: 5)",
+    )
+    parser.add_argument(
+        "--restore-window", type=int, default=30, metavar="SECONDS",
+        help="take over inhibits from a previous instance that stopped at most this long ago "
+             "(default: 30; 0 disables)",
+    )
+    parser.add_argument(
+        "--cleanup", action="store_true",
+        help="re-enable xautolock if it is the backend, then exit (for the unit's ExecStopPost)",
+    )
+    args = parser.parse_args()
+
+    backend = read_backend()
+    if args.cleanup:
+        if backend == "xautolock":
+            xautolock("-enable")
+        return
+
+    ignored: set[str]
+    if args.count_all:
+        ignored = set()
+    else:
+        ignored = set(args.ignore_reason or ["Playing audio"])
+    runtime_dir = os.environ.get("XDG_RUNTIME_DIR")
+    state_path = os.path.join(runtime_dir, STATE_FILE) if runtime_dir else None
+    blanking = XBlanking()
+    if backend == "xss-lock" and not blanking.dpy:
+        log("Warning: with xss-lock, inhibits block locking only through X blanking, which is unavailable")
+    inhibitor = Inhibitor(
+        backend, ignored, max(args.release_delay, 0), blanking, state_path, max(args.restore_window, 0),
+    )
+    loop = GLib.MainLoop()
+    exit_code = 0
+    acquired = False
+
+    def on_name_acquired(conn: Gio.DBusConnection, name: str) -> None:
+        nonlocal acquired
+        acquired = True
+        log(f"Owning {name}; backend: {backend}; ignored reasons: {sorted(ignored) or 'none'}")
+        # Only after owning the name, so a second instance can't undo an active inhibit
+        # or overwrite the state file.
+        inhibitor.start()
+
+    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")
+            exit_code = 1
+        elif acquired:
+            log(f"Lost {name} (bus connection closed?)")
+            exit_code = 1
+        else:
+            log(f"{name} is owned by another process (a desktop environment?); exiting")
+            exit_code = EXIT_NAME_TAKEN
+        loop.quit()
+
+    def on_signal() -> bool:
+        log("Signal received, exiting")
+        loop.quit()
+        return GLib.SOURCE_REMOVE
+
+    for sig in (signal.SIGTERM, signal.SIGINT, signal.SIGHUP):
+        signal_add(GLib.PRIORITY_HIGH, sig, on_signal)
+
+    owner_id = Gio.bus_own_name(
+        Gio.BusType.SESSION, BUS_NAME, Gio.BusNameOwnerFlags.DO_NOT_QUEUE,
+        inhibitor.on_bus_acquired, on_name_acquired, on_name_lost,
+    )
+    try:
+        loop.run()
+    finally:
+        inhibitor.shutdown()
+        Gio.bus_unown_name(owner_id)
+    sys.exit(exit_code)
+
+
+if __name__ == "__main__":
+    main()

xidle-inhibit.service

@@ -0,0 +1,10 @@
+[Unit]
+Description=Block screen locking (xautolock or xss-lock) on org.freedesktop.ScreenSaver inhibit requests
+
+[Service]
+Type=dbus
+BusName=org.freedesktop.ScreenSaver
+ExecStart=/usr/bin/xidle-inhibit
+ExecStopPost=-/usr/bin/xidle-inhibit --cleanup
+Restart=on-failure
+RestartPreventExitStatus=2