Virtual libraries as tabs above book list

Add an option to display virtual libraries as tabs above the book list.
Convenient to quickly switch between virtual libraries. To enable, click
the Virtual library button and select 'Show virtual libraries as tabs'.
You can re-arrange the tabs by drag and drop and close tabs you do not
want. Right click on the tabs to restore closed tabs.

src/calibre/db/backend.py

@@ -423,6 +423,7 @@ class DB(object):
         ]
         defs['virtual_libraries'] = {}
         defs['virtual_lib_on_startup'] = defs['cs_virtual_lib_on_startup'] = ''
+        defs['virt_libs_hidden'] = defs['virt_libs_order'] = ()
 
         # Migrate the bool tristate tweak
         defs['bools_are_tristate'] = \

src/calibre/gui2/__init__.py

@@ -118,6 +118,7 @@ defs['cover_grid_color'] = (80, 80, 80)
 defs['cover_grid_cache_size'] = 100
 defs['cover_grid_disk_cache_size'] = 2500
 defs['cover_grid_show_title'] = False
+defs['show_vl_tabs'] = False
 del defs
 # }}}
 

src/calibre/gui2/init.py

@@ -8,9 +8,10 @@ __docformat__ = 'restructuredtext en'
 import functools
 
 from PyQt4.Qt import (Qt, QApplication, QStackedWidget, QMenu, QTimer,
-        QSize, QSizePolicy, QStatusBar, QLabel, QFont, QAction)
+        QSize, QSizePolicy, QStatusBar, QLabel, QFont, QAction, QTabBar)
 
 from calibre.utils.config import prefs, tweaks
+from calibre.utils.icu import sort_key
 from calibre.constants import (isosx, __appname__, preferred_encoding,
     get_version)
 from calibre.gui2 import config, is_widescreen, gprefs
@@ -278,9 +279,99 @@ class GridViewButton(LayoutButton):  # {{{
 
 # }}}
 
+class VLTabs(QTabBar):  # {{{
+
+    def __init__(self, parent):
+        QTabBar.__init__(self, parent)
+        self.setDocumentMode(True)
+        self.setDrawBase(False)
+        self.setMovable(True)
+        self.setTabsClosable(True)
+        self.gui = parent
+        self.currentChanged.connect(self.tab_changed)
+        self.tabMoved.connect(self.tab_moved, type=Qt.QueuedConnection)
+        self.tabCloseRequested.connect(self.tab_close)
+        self.setStyleSheet('QTabBar::tab:selected { font-weight: bold } QTabBar::tab { text-align: center }')
+        self.setVisible(gprefs['show_vl_tabs'])
+
+    def enable_bar(self):
+        gprefs['show_vl_tabs'] = True
+        self.setVisible(True)
+
+    def disable_bar(self):
+        gprefs['show_vl_tabs'] = False
+        self.setVisible(False)
+
+    def tab_changed(self, idx):
+        vl = unicode(self.tabData(idx).toString()).strip() or None
+        self.gui.apply_virtual_library(vl)
+
+    def tab_moved(self, from_, to):
+        self.current_db.prefs['virt_libs_order'] = [unicode(self.tabData(i).toString()) for i in range(self.count())]
+
+    def tab_close(self, index):
+        vl = unicode(self.tabData(index).toString())
+        if vl:  # Dont allow closing the All Books tab
+            self.current_db.prefs['virt_libs_hidden'] = list(
+                self.current_db.prefs['virt_libs_hidden']) + [vl]
+            self.removeTab(index)
+
+    @property
+    def current_db(self):
+        return self.gui.current_db
+
+    def rebuild(self):
+        self.currentChanged.disconnect(self.tab_changed)
+        db = self.current_db
+        virt_libs = frozenset(db.prefs.get('virtual_libraries', {}))
+        hidden = frozenset(db.prefs['virt_libs_hidden'])
+        if hidden - virt_libs:
+            db.prefs['virt_libs_hidden'] = list(hidden.intersection(virt_libs))
+        order = db.prefs['virt_libs_order']
+        while self.count():
+            self.removeTab(0)
+        current_lib = db.data.get_base_restriction_name()
+        current_idx = all_idx = None
+        virt_libs = (set(virt_libs) - hidden) | {''}
+        order = {x:i for i, x in enumerate(order)}
+        for i, vl in enumerate(sorted(virt_libs, key=lambda x:(order.get(x, 0), sort_key(x)))):
+            self.addTab(vl or _('All books'))
+            self.setTabData(i, vl)
+            if vl == current_lib:
+                current_idx = i
+            if not vl:
+                all_idx = i
+        self.setCurrentIndex(all_idx if current_idx is None else current_idx)
+        self.currentChanged.connect(self.tab_changed)
+        self.tabButton(all_idx, self.RightSide).setVisible(False)
+
+    def contextMenuEvent(self, ev):
+        m = QMenu(self)
+        m.addAction(_('Sort alphabetically'), self.sort_alphabetically)
+        hidden = self.current_db.prefs['virt_libs_hidden']
+        if hidden:
+            s = m._s = m.addMenu(_('Restore hidden tabs'))
+            for x in hidden:
+                s.addAction(x, partial(self.restore, x))
+        m.addAction(_('Hide virtual library tabs'), self.disable_bar)
+        m.exec_(ev.globalPos())
+
+    def sort_alphabetically(self):
+        self.current_db.prefs['virt_libs_order'] = ()
+        self.rebuild()
+
+    def restore(self, x):
+        h = self.current_db.prefs['virt_libs_hidden']
+        self.current_db.prefs['virt_libs_hidden'] = list(set(h) - {x})
+        self.rebuild()
+
+# }}}
+
 class LayoutMixin(object):  # {{{
 
     def __init__(self):
+        self.vl_tabs = VLTabs(self)
+        self.centralwidget.layout().addWidget(self.vl_tabs)
 
         if config['gui_layout'] == 'narrow':  # narrow {{{
             self.book_details = BookDetails(False, self)

src/calibre/gui2/search_restriction_mixin.py

@@ -12,7 +12,7 @@ from PyQt4.Qt import (
     Qt, QMenu, QPoint, QIcon, QDialog, QGridLayout, QLabel, QLineEdit, QComboBox,
     QDialogButtonBox, QSize, QVBoxLayout, QListWidget, QStringList, QRadioButton)
 
-from calibre.gui2 import error_dialog, question_dialog
+from calibre.gui2 import error_dialog, question_dialog, gprefs
 from calibre.gui2.dialogs.confirm_delete import confirm
 from calibre.gui2.widgets import ComboBoxWithHelp
 from calibre.utils.config_base import tweaks
@@ -334,6 +334,7 @@ class SearchRestrictionMixin(object):
         virt_libs = db.prefs.get('virtual_libraries', {})
         virt_libs[name] = search
         db.prefs.set('virtual_libraries', virt_libs)
+        self.rebuild_vl_tabs()
 
     def do_create_edit(self, name=None):
         db = self.library_view.model().db
@@ -361,6 +362,11 @@ class SearchRestrictionMixin(object):
         self.build_virtual_library_list(a, self.remove_vl_triggered)
         m.addMenu(a)
 
+        if gprefs['show_vl_tabs']:
+            m.addAction(_('Hide virtual library tabs'), self.vl_tabs.disable_bar)
+        else:
+            m.addAction(_('Show virtual libraries as tabs'), self.vl_tabs.enable_bar)
+
         m.addSeparator()
 
         db = self.library_view.model().db
@@ -402,6 +408,9 @@ class SearchRestrictionMixin(object):
         p = QPoint(0, self.virtual_library.height())
         self.virtual_library_menu.popup(self.virtual_library.mapToGlobal(p))
 
+    def rebuild_vl_tabs(self):
+        self.vl_tabs.rebuild()
+
     def apply_virtual_library(self, library=None):
         db = self.library_view.model().db
         virt_libs = db.prefs.get('virtual_libraries', {})
@@ -471,6 +480,7 @@ class SearchRestrictionMixin(object):
         db.prefs.set('virtual_libraries', virt_libs)
         if reapply and db.data.get_base_restriction_name() == name:
             self.apply_virtual_library('')
+        self.rebuild_vl_tabs()
 
     def _trim_restriction_name(self, name):
         return name[0:MAX_VIRTUAL_LIBRARY_NAME_LENGTH].strip()
@@ -591,11 +601,13 @@ class SearchRestrictionMixin(object):
                     'QLabel { border-radius: 6px; background-color: %s }' %
                     tweaks['highlight_virtual_library'])
             self.clear_vl.setVisible(True)
+            self.search_count.setVisible(not gprefs['show_vl_tabs'])
         else:  # No restriction or not library view
             t = ''
             self.search_count.setStyleSheet(
                     'QLabel { background-color: transparent; }')
             self.clear_vl.setVisible(False)
+            self.search_count.setVisible(False)
         self.search_count.setText(t)
 
 if __name__ == '__main__':

src/calibre/gui2/ui.py

@@ -341,6 +341,7 @@ class Main(MainWindow, MainWindowMixin, DeviceMixin, EmailMixin,  # {{{
         ######################### Search Restriction ##########################
         if db.prefs['virtual_lib_on_startup']:
             self.apply_virtual_library(db.prefs['virtual_lib_on_startup'])
+        self.rebuild_vl_tabs()
 
         ########################### Cover Flow ################################
 
@@ -627,6 +628,7 @@ class Main(MainWindow, MainWindowMixin, DeviceMixin, EmailMixin,  # {{{
         self.saved_searches_changed(recount=False)  # reload the search restrictions combo box
         if db.prefs['virtual_lib_on_startup']:
             self.apply_virtual_library(db.prefs['virtual_lib_on_startup'])
+        self.rebuild_vl_tabs()
         for action in self.iactions.values():
             action.library_changed(db)
         if olddb is not None:

src/calibre/library/database2.py

@@ -235,6 +235,7 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
         ]
         defs['virtual_libraries'] = {}
         defs['virtual_lib_on_startup'] = defs['cs_virtual_lib_on_startup'] = ''
+        defs['virt_libs_hidden'] = defs['virt_libs_order'] = ()
 
         # Migrate the bool tristate tweak
         defs['bools_are_tristate'] = \