Initial SyncVito release with installer updater

src/syncvito/file_locks.py

@@ -0,0 +1,114 @@
+"""Ermittlung von Prozessen, die Dateien unter Windows sperren."""
+
+from __future__ import annotations
+
+import ctypes
+import os
+from ctypes import wintypes
+from dataclasses import dataclass
+from pathlib import Path
+
+__all__ = ["LockingProcess", "find_locking_processes", "is_file_locked"]
+
+
+@dataclass(frozen=True, slots=True)
+class LockingProcess:
+    """Ein vom Windows Restart Manager gemeldeter Prozess."""
+
+    pid: int
+    name: str
+
+
+def is_file_locked(path: Path) -> bool:
+    """Prüft eine vorhandene Datei durch exklusives Öffnen ohne Schreibzugriff."""
+    if not path.exists() or os.name != "nt":
+        return False
+    handle = ctypes.windll.kernel32.CreateFileW(
+        str(path),
+        0x80000000,
+        0,
+        None,
+        3,
+        0x80,
+        None,
+    )
+    invalid_handle = ctypes.c_void_p(-1).value
+    if handle == invalid_handle:
+        return ctypes.get_last_error() in {5, 32, 33}
+    ctypes.windll.kernel32.CloseHandle(handle)
+    return False
+
+
+def find_locking_processes(path: Path) -> list[LockingProcess]:
+    """Liefert sperrende Prozesse über die Windows-Restart-Manager-API."""
+    if os.name != "nt" or not path.exists():
+        return []
+    try:
+        return _restart_manager_processes(path)
+    except (OSError, AttributeError, ctypes.ArgumentError):
+        return []
+
+
+def _restart_manager_processes(path: Path) -> list[LockingProcess]:
+    rstrtmgr = ctypes.WinDLL("Rstrtmgr")
+    session_handle = wintypes.DWORD()
+    session_key = ctypes.create_unicode_buffer(33)
+    if rstrtmgr.RmStartSession(ctypes.byref(session_handle), 0, session_key) != 0:
+        return []
+    try:
+        resources = (wintypes.LPCWSTR * 1)(str(path))
+        if rstrtmgr.RmRegisterResources(session_handle, 1, resources, 0, None, 0, None) != 0:
+            return []
+        needed = wintypes.UINT(0)
+        count = wintypes.UINT(0)
+        reboot_reasons = wintypes.DWORD(0)
+        result = rstrtmgr.RmGetList(
+            session_handle,
+            ctypes.byref(needed),
+            ctypes.byref(count),
+            None,
+            ctypes.byref(reboot_reasons),
+        )
+        if result not in {0, 234} or needed.value == 0:
+            return []
+        process_info_type = _rm_process_info_type()
+        process_array = (process_info_type * needed.value)()
+        count.value = needed.value
+        result = rstrtmgr.RmGetList(
+            session_handle,
+            ctypes.byref(needed),
+            ctypes.byref(count),
+            process_array,
+            ctypes.byref(reboot_reasons),
+        )
+        if result != 0:
+            return []
+        return [
+            LockingProcess(
+                pid=int(item.Process.dwProcessId), name=item.strAppName or f"Prozess {item.Process.dwProcessId}"
+            )
+            for item in process_array[: count.value]
+        ]
+    finally:
+        rstrtmgr.RmEndSession(session_handle)
+
+
+def _rm_process_info_type() -> type[ctypes.Structure]:
+    class FileTime(ctypes.Structure):
+        _fields_ = [("dwLowDateTime", wintypes.DWORD), ("dwHighDateTime", wintypes.DWORD)]
+
+    class UniqueProcess(ctypes.Structure):
+        _fields_ = [("dwProcessId", wintypes.DWORD), ("ProcessStartTime", FileTime)]
+
+    class ProcessInfo(ctypes.Structure):
+        _fields_ = [
+            ("Process", UniqueProcess),
+            ("strAppName", wintypes.WCHAR * 256),
+            ("strServiceShortName", wintypes.WCHAR * 64),
+            ("ApplicationType", wintypes.UINT),
+            ("AppStatus", wintypes.ULONG),
+            ("TSSessionId", wintypes.DWORD),
+            ("bRestartable", wintypes.BOOL),
+        ]
+
+    return ProcessInfo