Windows: Run library restore ina separate process as on some windows machines, running it in the main process causes something in the system to lock the db file.

src/calibre/gui2/dialogs/restore_library.py

@@ -17,7 +17,7 @@ class DBRestore(QDialog):
 
     update_signal = pyqtSignal(object, object)
 
-    def __init__(self, parent, library_path):
+    def __init__(self, parent, library_path, wait_time=2):
         QDialog.__init__(self, parent)
         self.l = QVBoxLayout()
         self.setLayout(self.l)
@@ -46,7 +46,7 @@ class DBRestore(QDialog):
         self.restorer.daemon = True
 
         # Give the metadata backup thread time to stop
-        QTimer.singleShot(2000, self.start)
+        QTimer.singleShot(wait_time * 1000, self.start)
 
     def start(self):
         self.restorer.start()
@@ -117,14 +117,14 @@ def restore_database(db, parent=None):
         _show_success_msg(r, parent=parent)
     return True
 
-def repair_library_at(library_path, parent=None):
-    d = DBRestore(parent, library_path)
+def repair_library_at(library_path, parent=None, wait_time=2):
+    d = DBRestore(parent, library_path, wait_time=wait_time)
     d.exec_()
     if d.rejected:
         return False
     r = d.restorer
     if r.tb is not None:
-        error_dialog(parent, _('Failed'),
+        error_dialog(parent, _('Failed to repair library'),
         _('Restoring database failed, click Show details to see details'),
         det_msg=r.tb, show=True)
         return False

src/calibre/gui2/main.py

@@ -151,6 +151,29 @@ def repair_library(library_path):
     from calibre.gui2.dialogs.restore_library import repair_library_at
     return repair_library_at(library_path)
 
+def windows_repair(library_path=None):
+    from binascii import hexlify, unhexlify
+    import cPickle, subprocess
+    if library_path:
+        library_path = hexlify(cPickle.dumps(library_path, -1))
+        winutil.prepare_for_restart()
+        os.environ['CALIBRE_REPAIR_CORRUPTED_DB'] = library_path
+        subprocess.Popen([sys.executable])
+    else:
+        try:
+            app = Application([])
+            from calibre.gui2.dialogs.restore_library import repair_library_at
+            library_path = cPickle.loads(unhexlify(os.environ.pop('CALIBRE_REPAIR_CORRUPTED_DB')))
+            done = repair_library_at(library_path, wait_time=4)
+        except Exception:
+            done = False
+            error_dialog(None, _('Failed to repair library'), _(
+                'Could not repair library. Click "Show details" for more information.'), det_msg=traceback.format_exc(), show=True)
+        if done:
+            subprocess.Popen([sys.executable])
+        app.quit()
+
+
 class EventAccumulator(object):
 
     def __init__(self):
@@ -266,6 +289,13 @@ class GuiRunner(QObject):
                         det_msg=traceback.format_exc()
                         )
             if repair:
+                if iswindows:
+                    # On some windows systems the existing db file gets locked
+                    # by something when running restore from the main process.
+                    # So run the restore in a separate process.
+                    windows_repair(self.library_path)
+                    self.app.quit()
+                    return
                 if repair_library(self.library_path):
                     db = LibraryDatabase(self.library_path)
         except:
@@ -455,6 +485,9 @@ def create_listener():
     return Listener(address=gui_socket_address())
 
 def main(args=sys.argv):
+    if iswindows and 'CALIBRE_REPAIR_CORRUPTED_DB' in os.environ:
+        windows_repair()
+        return 0
     gui_debug = None
     if args[0] == '__CALIBRE_GUI_DEBUG__':
         gui_debug = args[1]