[meld] Remove tab list from menu, replacing with keybinding actions

[Kai Willadsen <kaiw src gnome org>]

commit df4cf9796a277a2d2924f5ef916590a823f7cef5
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Tue Nov 3 11:11:21 2015 +1000

    Remove tab list from menu, replacing with keybinding actions
    
    This commit creates a new MeldNotebook class for handling some contained
    notebook behaviours and keybindings. Since we're looking to reduce the
    overall UI handled by UIManager, and because it's no longer standard to
    keep a list of open tabs as menu items, we're dropping that bit of the
    UI and accompanying handling. This reimplements only the Alt+number
    keybindings for quick tab switching.

 data/ui/meldapp-ui.xml  |    2 -
 data/ui/meldapp.ui      |    5 +---
 meld/meldwindow.py      |   56 -----------------------------------------------
 meld/ui/gladesupport.py |    1 +
 meld/ui/notebook.py     |   53 ++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 55 insertions(+), 62 deletions(-)
---
diff --git a/data/ui/meldapp-ui.xml b/data/ui/meldapp-ui.xml
index 3cde9bd..330ecb3 100644
--- a/data/ui/meldapp-ui.xml
+++ b/data/ui/meldapp-ui.xml
@@ -57,8 +57,6 @@
       <separator/>
       <menuitem action="MoveTabPrev" />
       <menuitem action="MoveTabNext" />
-      <separator/>
-      <placeholder name="TabPlaceholder" />
     </menu>
   </menubar>
 
diff --git a/data/ui/meldapp.ui b/data/ui/meldapp.ui
index b06c068..4ac2c93 100644
--- a/data/ui/meldapp.ui
+++ b/data/ui/meldapp.ui
@@ -24,17 +24,14 @@
           </packing>
         </child>
         <child>
-          <object class="GtkNotebook" id="notebook">
+          <object class="MeldNotebook" id="notebook">
             <property name="visible">True</property>
             <property name="can_focus">True</property>
             <property name="scrollable">True</property>
             <property name="enable_popup">True</property>
-            <signal name="page-reordered" handler="_update_notebook_menu" swapped="no"/>
             <signal name="page-reordered" handler="after_page_reordered" after="yes" swapped="no"/>
-            <signal name="page-added" handler="_update_notebook_menu" swapped="no"/>
             <signal name="switch-page" handler="on_switch_page" swapped="no"/>
             <signal name="switch-page" handler="after_switch_page" after="yes" swapped="no"/>
-            <signal name="page-removed" handler="_update_notebook_menu" swapped="no"/>
           </object>
           <packing>
             <property name="expand">True</property>
diff --git a/meld/meldwindow.py b/meld/meldwindow.py
index d419692..efbdac3 100644
--- a/meld/meldwindow.py
+++ b/meld/meldwindow.py
@@ -184,9 +184,6 @@ class MeldWindow(gnomeglade.Component):
             self.ui.add_ui_from_file(ui_file)
             self.widget.set_show_menubar(False)
 
-        self.tab_switch_actiongroup = None
-        self.tab_switch_merge_id = None
-
         for menuitem in ("Save", "Undo"):
             self.actiongroup.get_action(menuitem).props.is_important = True
         self.widget.add_accel_group(self.ui.get_accel_group())
@@ -410,10 +407,6 @@ class MeldWindow(gnomeglade.Component):
 
     def after_switch_page(self, notebook, page, which):
         self._update_page_action_sensitivity()
-        actiongroup = self.tab_switch_actiongroup
-        if actiongroup:
-            action_name = "SwitchTab%d" % which
-            actiongroup.get_action(action_name).set_active(True)
 
     def after_page_reordered(self, notebook, page, page_num):
         self._update_page_action_sensitivity()
@@ -431,13 +424,6 @@ class MeldWindow(gnomeglade.Component):
             text = text.encode('utf8')
         self.notebook.child_set_property(page, "menu-label", text)
 
-        actiongroup = self.tab_switch_actiongroup
-        if actiongroup:
-            idx = self.notebook.page_num(page)
-            action_name = "SwitchTab%d" % idx
-            label = text.replace("_", "__")
-            actiongroup.get_action(action_name).set_label(label)
-
     def on_can_undo(self, undosequence, can):
         self.actiongroup.get_action("Undo").set_sensitive(can)
 
@@ -563,48 +549,6 @@ class MeldWindow(gnomeglade.Component):
         child = self.notebook.get_nth_page(page_num)
         self.notebook.reorder_child(child, page_num + 1)
 
-    def _update_notebook_menu(self, *args):
-        if self.tab_switch_merge_id:
-            self.ui.remove_ui(self.tab_switch_merge_id)
-            self.ui.remove_action_group(self.tab_switch_actiongroup)
-            self.ui.ensure_update()
-            self.tab_switch_merge_id = None
-            self.tab_switch_actiongroup = None
-
-        if not self.notebook.get_n_pages():
-            return
-
-        self.tab_switch_merge_id = self.ui.new_merge_id()
-        self.tab_switch_actiongroup = Gtk.ActionGroup(name="TabSwitchActions")
-        self.ui.insert_action_group(self.tab_switch_actiongroup)
-        group = None
-        current_page = self.notebook.get_current_page()
-        for i in range(self.notebook.get_n_pages()):
-            page = self.notebook.get_nth_page(i)
-            label = self.notebook.get_menu_label_text(page) or ""
-            label = label.replace("_", "__")
-            name = "SwitchTab%d" % i
-            tooltip = _("Switch to this tab")
-            action = Gtk.RadioAction(
-                name=name, label=label, tooltip=tooltip,
-                stock_id=None, value=i)
-            action.join_group(group)
-            group = action
-            action.set_active(current_page == i)
-
-            def current_tab_changed_cb(action, current):
-                if action == current:
-                    self.notebook.set_current_page(action.get_current_value())
-            action.connect("changed", current_tab_changed_cb)
-            if i < 10:
-                accel = "<Alt>%d" % ((i + 1) % 10)
-            else:
-                accel = None
-            self.tab_switch_actiongroup.add_action_with_accel(action, accel)
-            self.ui.add_ui(self.tab_switch_merge_id,
-                           "/Menubar/TabMenu/TabPlaceholder",
-                           name, name, Gtk.UIManagerItemType.MENUITEM, False)
-
     def page_removed(self, page, status):
         if hasattr(page, 'scheduler'):
             self.scheduler.remove_scheduler(page.scheduler)
diff --git a/meld/ui/gladesupport.py b/meld/ui/gladesupport.py
index 4ea0442..fe100b0 100644
--- a/meld/ui/gladesupport.py
+++ b/meld/ui/gladesupport.py
@@ -7,4 +7,5 @@ from meld import sourceview
 from meld.ui import emblemcellrenderer
 from meld.ui import historyentry
 from meld.ui import msgarea
+from meld.ui import notebook
 from meld.ui import statusbar
diff --git a/meld/ui/notebook.py b/meld/ui/notebook.py
new file mode 100644
index 0000000..8f70caf
--- /dev/null
+++ b/meld/ui/notebook.py
@@ -0,0 +1,53 @@
+# Copyright (C) 2015 Kai Willadsen <kai willadsen gmail com>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or (at
+# your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from gi.repository import Gdk
+from gi.repository import GObject
+from gi.repository import Gtk
+
+
+class MeldNotebook(Gtk.Notebook):
+
+    __gtype_name__ = "MeldNotebook"
+
+    __gsignals__ = {
+        'tab-switch': (GObject.SignalFlags.ACTION, None, (int,)),
+    }
+
+    css = """
+        @binding-set TabSwitchBindings {}
+        MeldNotebook { gtk-key-bindings: TabSwitchBindings; }
+    """
+
+    def __init__(self, *args, **kwargs):
+        Gtk.Notebook.__init__(self, *args, **kwargs)
+
+        provider = Gtk.CssProvider()
+        provider.load_from_data(self.css)
+        Gtk.StyleContext.add_provider_for_screen(
+            Gdk.Screen.get_default(), provider,
+            Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION)
+
+        # Awful hacks because we can't create GtkBindingArg from Python, or
+        # create a BindingSet from Python, or get a set by class from Python.
+        bindings = Gtk.BindingSet.find('TabSwitchBindings')
+        for i in range(10):
+            key = (i + 1) % 10
+            Gtk.BindingEntry().add_signal_from_string(
+                bindings, 'bind "<Alt>%d" { "tab-switch" (%d) };' % (key, i))
+        self.connect('tab-switch', self.do_tab_switch)
+
+    def do_tab_switch(self, notebook, page_num):
+        notebook.set_current_page(page_num)