feat: dzgui 7 alpha

dzgui/init/flock.py

@@ -0,0 +1,25 @@
+import fcntl
+import os
+import sys
+
+from pathlib import Path
+from typing import TextIO
+
+from dzgui.views.dialogs.early_alert import EarlyAlertDialog
+from dzgui.util.strings import cannot_acquire_lock
+
+
+def lock_release(lock: TextIO) -> None:
+    fcntl.flock(lock, fcntl.LOCK_UN)
+    os.close(lock.fileno())
+
+
+def lock_acquire() -> TextIO:
+    lockfile = Path("/tmp/dzgui.flock")
+    lock = open(lockfile, "w")
+    try:
+        fcntl.flock(lock, fcntl.LOCK_EX | fcntl.LOCK_NB)
+    except OSError:
+        EarlyAlertDialog(cannot_acquire_lock)
+        sys.exit(1)
+    return lock