Allow even quicker switching of libraries, via drop down menu on the Choose Library button

src/calibre/gui2/actions/choose_library.py

@@ -5,8 +5,64 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
+import os
+from functools import partial
+
+from PyQt4.Qt import QMenu
+
+from calibre import isbytestring
+from calibre.constants import filesystem_encoding
+from calibre.utils.config import prefs
+from calibre.gui2 import gprefs
 from calibre.gui2.actions import InterfaceAction
 
+class LibraryUsageStats(object):
+
+    def __init__(self):
+        self.stats = {}
+        self.read_stats()
+
+    def read_stats(self):
+        stats = gprefs.get('library_usage_stats', {})
+        self.stats = stats
+
+    def write_stats(self):
+        locs = list(self.stats.keys())
+        locs.sort(cmp=lambda x, y: cmp(self.stats[x], self.stats[y]),
+                reverse=True)
+        for key in locs[15:]:
+            self.stats.pop(key)
+        gprefs.set('library_usage_stats', self.stats)
+
+    def canonicalize_path(self, lpath):
+        if isbytestring(lpath):
+            lpath = lpath.decode(filesystem_encoding)
+        lpath = lpath.replace(os.sep, '/')
+        return lpath
+
+    def library_used(self, db):
+        lpath = self.canonicalize_path(db.library_path)
+        if lpath not in self.stats:
+            self.stats[lpath] = 0
+        self.stats[lpath] += 1
+        self.write_stats()
+
+    def locations(self, db):
+        lpath = self.canonicalize_path(db.library_path)
+        locs = list(self.stats.keys())
+        if lpath in locs:
+            locs.remove(lpath)
+        locs.sort(cmp=lambda x, y: cmp(self.stats[x], self.stats[y]),
+                reverse=True)
+        for loc in locs:
+            yield self.pretty(loc), loc
+
+    def pretty(self, loc):
+        if loc.endswith('/'):
+            loc = loc[:-1]
+        return loc.split('/')[-1]
+
+
 class ChooseLibraryAction(InterfaceAction):
 
     name = 'Choose Library'
@@ -17,10 +73,62 @@ class ChooseLibraryAction(InterfaceAction):
         self.count_changed(0)
         self.qaction.triggered.connect(self.choose_library)
 
+        self.stats = LibraryUsageStats()
+        self.create_action(spec=(_('Switch to library...'), 'lt.png', None,
+            None), attr='action_choose')
+        self.action_choose.triggered.connect(self.choose_library)
+        self.choose_menu = QMenu(self.gui)
+        self.choose_menu.addAction(self.action_choose)
+        self.qaction.setMenu(self.choose_menu)
+
+        self.quick_menu = QMenu(_('Quick switch'))
+        self.quick_menu_action = self.choose_menu.addMenu(self.quick_menu)
+        self.qs_separator = self.choose_menu.addSeparator()
+        self.switch_actions = []
+        for i in range(5):
+            ac = self.create_action(spec=('', None, None, None),
+                    attr='switch_action%d'%i)
+            self.switch_actions.append(ac)
+            ac.setVisible(False)
+            ac.triggered.connect(partial(self.qs_requested, i))
+            self.choose_menu.addAction(ac)
+
+    def library_used(self, db):
+        self.stats.library_used(db)
+        self.build_menus()
+
+    def build_menus(self):
+        db = self.gui.library_view.model().db
+        locations = list(self.stats.locations(db))
+        for ac in self.switch_actions:
+            ac.setVisible(False)
+        self.quick_menu.clear()
+        self.qs_locations = [i[1] for i in locations]
+        for name, loc in locations:
+            self.quick_menu.addAction(name, partial(self.switch_requested,
+                loc))
+
+        for i, x in enumerate(locations[:len(self.switch_actions)]):
+            name, loc = x
+            ac = self.switch_actions[i]
+            ac.setText(name)
+            ac.setVisible(True)
+
+        self.quick_menu_action.setVisible(bool(locations))
+
+
     def location_selected(self, loc):
         enabled = loc == 'library'
         self.qaction.setEnabled(enabled)
 
+    def switch_requested(self, location):
+        loc = location.replace('/', os.sep)
+        prefs['library_path'] = loc
+        self.gui.library_moved(loc)
+
+    def qs_requested(self, idx, *args):
+        self.switch_requested(self.qs_locations[idx])
+
     def count_changed(self, new_count):
         text = self.action_spec[0]%new_count
         a = self.qaction

src/calibre/gui2/ui.py

@@ -251,6 +251,7 @@ class Main(MainWindow, MainWindowMixin, DeviceMixin, # {{{
         self.donate_button.start_animation()
 
         self.iactions['Fetch News'].connect_scheduler()
+        self.iactions['Choose Library'].library_used(self.library_view.model().db)
 
     def start_content_server(self):
         from calibre.library.server.main import start_threaded_server
@@ -368,6 +369,7 @@ class Main(MainWindow, MainWindowMixin, DeviceMixin, # {{{
         self.library_view.model().count_changed()
         self.iactions['Fetch News'].database_changed(db)
         prefs['library_path'] = self.library_path
+        self.iactions['Choose Library'].library_used(self.library_view.model().db)
 
 
     def location_selected(self, location):