1) changes to ondevice scan to use Kovid's iterator

2) correction to path construction in USMBS

src/calibre/devices/usbms/driver.py

@@ -190,8 +190,8 @@ class USBMS(CLI, Device):
                 print 'in add_books_to_metadata. Prefix is None!', path, self._main_prefix
                 continue
             lpath = path.partition(prefix)[2]
-            if lpath.startswith(os.sep):
-                lpath = lpath[len(os.sep):]
+            if lpath.startswith('/') or lpath.startswith('\\'):
+                lpath = lpath[1:]
             book = self.book_class(prefix, lpath, other=info)
             if book.size is None:
                 book.size = os.stat(self.normalize_path(path)).st_size

src/calibre/gui2/device.py

@@ -1091,16 +1091,8 @@ class DeviceGUI(object):
             self.db_book_title_cache = {}
             self.db_book_uuid_cache = set()
             db = self.library_view.model().db
-            # The following is a terrible hack, made necessary because the db
-            # result_cache will always use the results filtered by the current
-            # search. We need all the db entries here. Choice was to either
-            # cache the search results so we can use the entire db, to duplicate
-            # large parts of the get_metadata code, or to use db_ids and pay the
-            # large performance penalty of zillions of SQL queries. Choice:
-            # save/restore the search state.
-            state = db.get_state_before_scan()
-            for idx in range(db.count()):
-                mi = db.get_metadata(idx, index_is_id=False)
+            for id in db.data.iterallids():
+                mi = db.get_metadata(id, index_is_id=True)
                 title = re.sub('(?u)\W|[_]', '', mi.title.lower())
                 if title not in self.db_book_title_cache:
                     self.db_book_title_cache[title] = {'authors':{}, 'db_ids':{}}
@@ -1109,7 +1101,6 @@ class DeviceGUI(object):
                 self.db_book_title_cache[title]['authors'][authors] = mi
                 self.db_book_title_cache[title]['db_ids'][mi.application_id] = mi
                 self.db_book_uuid_cache.add(mi.uuid)
-            db.restore_state_after_scan(state)
 
         # Now iterate through all the books on the device, setting the
         # in_library field Fastest and most accurate key is the uuid. Second is

src/calibre/library/caches.py

@@ -563,14 +563,6 @@ class ResultCache(SearchQueryParser):
             if item is not None:
                 item[ondevice_col] = db.book_on_device_string(item[0])
 
-    def get_state_before_scan(self):
-        retval = self._map_filtered
-        self._map_filtered = self._map
-        return retval
-
-    def restore_state_after_scan(self, map_filtered):
-        self._map_filtered = map_filtered
-
     def refresh(self, db, field=None, ascending=True):
         temp = db.conn.get('SELECT * FROM meta2')
         self._data = list(itertools.repeat(None, temp[-1][0]+2)) if temp else []

src/calibre/library/database2.py

@@ -245,8 +245,6 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
         self.has_id  = self.data.has_id
         self.count   = self.data.count
 
-        self.get_state_before_scan    = self.data.get_state_before_scan
-        self.restore_state_after_scan = self.data.restore_state_after_scan
         self.refresh_ondevice = functools.partial(self.data.refresh_ondevice, self)
 
         self.refresh()