From b626718ca18ab5cedc77a0ef331c024a2803bda0 Mon Sep 17 00:00:00 2001
From: EnigmaCurry <ryan@enigmacurry.com>
Date: Sun, 29 Mar 2026 01:51:22 +0000
Subject: [PATCH] Fix file locking on Windows using msvcrt instead of fcntl

---
 src/rigbook/db.py | 43 +++++++++++++++++++++++++++++++++----------
 uv.lock           |  2 +-
 2 files changed, 34 insertions(+), 11 deletions(-)

diff --git a/src/rigbook/db.py b/src/rigbook/db.py
index 95b917f6..3fb9d17a 100644
--- a/src/rigbook/db.py
+++ b/src/rigbook/db.py
@@ -1,5 +1,6 @@
 import logging
 import os
+import sys
 import uuid as _uuid
 from datetime import datetime, timezone
 from pathlib import Path
@@ -15,6 +16,34 @@
 DB_DIR = Path.home() / ".local" / "rigbook"
 
 
+def _lock_exclusive(f) -> None:
+    """Acquire a non-blocking exclusive lock on a file (cross-platform)."""
+    if sys.platform == "win32":
+        import msvcrt
+
+        msvcrt.locking(f.fileno(), msvcrt.LK_NBLCK, 1)
+    else:
+        import fcntl
+
+        fcntl.flock(f, fcntl.LOCK_EX | fcntl.LOCK_NB)
+
+
+def _unlock(f) -> None:
+    """Release a file lock (cross-platform)."""
+    if sys.platform == "win32":
+        import msvcrt
+
+        try:
+            f.seek(0)
+            msvcrt.locking(f.fileno(), msvcrt.LK_UNLCK, 1)
+        except OSError:
+            pass
+    else:
+        import fcntl
+
+        fcntl.flock(f, fcntl.LOCK_UN)
+
+
 class Base(DeclarativeBase):
     pass
 
@@ -178,15 +207,13 @@ def default_db_path(self) -> Path:
 
     def check_lock(self, db_path: Path) -> None:
         """Raise DatabaseLockError if the database is locked by another process."""
-        import fcntl
-
         lock_path = db_path.with_suffix(".lock")
         if not lock_path.exists():
             return
         try:
             with open(lock_path, "r+") as f:
-                fcntl.flock(f, fcntl.LOCK_EX | fcntl.LOCK_NB)
-                fcntl.flock(f, fcntl.LOCK_UN)
+                _lock_exclusive(f)
+                _unlock(f)
         except OSError:
             raise DatabaseLockError(
                 f"Logbook '{db_path.stem}' is already open in another process"
@@ -233,12 +260,10 @@ def _write_lock_content(self) -> None:
 
     def _acquire_lock(self, db_path: Path) -> None:
         """Acquire an exclusive file lock to prevent concurrent access."""
-        import fcntl
-
         lock_path = db_path.with_suffix(".lock")
         self._lock_file = open(lock_path, "w")
         try:
-            fcntl.flock(self._lock_file, fcntl.LOCK_EX | fcntl.LOCK_NB)
+            _lock_exclusive(self._lock_file)
             self._write_lock_content()
         except OSError:
             self._lock_file.close()
@@ -249,11 +274,9 @@ def _acquire_lock(self, db_path: Path) -> None:
 
     def _release_lock(self) -> None:
         """Release the file lock."""
-        import fcntl
-
         if self._lock_file:
             try:
-                fcntl.flock(self._lock_file, fcntl.LOCK_UN)
+                _unlock(self._lock_file)
                 lock_path = Path(self._lock_file.name)
                 self._lock_file.close()
                 lock_path.unlink(missing_ok=True)
diff --git a/uv.lock b/uv.lock
index 5cb1d833..90c764a3 100644
--- a/uv.lock
+++ b/uv.lock
@@ -534,7 +534,7 @@ wheels = [
 
 [[package]]
 name = "rigbook"
-version = "0.1.22"
+version = "0.1.23"
 source = { editable = "." }
 dependencies = [
     { name = "aiosqlite" },