Windows support in SaraSuite

Programs/ServiceRun.py

@@ -0,0 +1,40 @@
+"""Runs a SaraSuite program as a background service on Windows, the stand-in
+for a systemd --user service. Started windowless with pythonw.exe, both at
+login (by the program's shortcut in the Startup folder) and when SaraSuite
+or the program's own GUI (e.g. SaraSort for SaraSortd) starts it:
+
+    pythonw.exe ServiceRun.py <Name> <Script>       (in the service's working folder)
+
+It records its PID in %LOCALAPPDATA%\\SaraSuite\\Services\\<Name>.pid, so
+anything can tell whether the service runs, and stop it (taskkill), without
+a Windows service and without admin rights. Installed next to each program
+that has a Windows service (Programs/<Name>/Manifest.toml, [[Services]]).
+"""
+
+import os
+import runpy
+import sys
+from pathlib import Path
+
+
+def Main() -> None:
+    Name, Script = sys.argv[1], Path(sys.argv[2])
+    LocalAppData = Path(os.environ.get("LOCALAPPDATA") or Path.home() / "AppData" / "Local")
+    PidFile = LocalAppData / "SaraSuite" / "Services" / f"{Name}.pid"
+    PidFile.parent.mkdir(parents=True, exist_ok=True)
+    PidFile.write_text(str(os.getpid()))
+    try:
+        sys.argv = [str(Script)]
+        sys.path.insert(0, str(Script.parent))
+        runpy.run_path(str(Script), run_name="__main__")
+    finally:
+        # Only remove it if it's still ours (a newer start may have replaced it).
+        try:
+            if PidFile.read_text().strip() == str(os.getpid()):
+                PidFile.unlink()
+        except OSError:
+            pass
+
+
+if __name__ == "__main__":
+    Main()