[meld] Add some sensitivity handling to VC comparisons

[Kai Willadsen <kaiw src gnome org>]

commit b8c9dad0d16ac6562990056f7160ae3a0d769f94
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sun Dec 9 06:31:54 2012 +1000

    Add some sensitivity handling to VC comparisons
    
    We can only sensibly perform VC operations when we actually have
    selected files or folders. In order to avoid an error popup, we now
    set such actions as insensitive if we have no selection.

 meld/vcview.py |   18 ++++++++++++++----
 1 files changed, 14 insertions(+), 4 deletions(-)
---
diff --git a/meld/vcview.py b/meld/vcview.py
index a221ff8..7c26f5e 100644
--- a/meld/vcview.py
+++ b/meld/vcview.py
@@ -190,7 +190,9 @@ class VcView(melddoc.MeldDoc, gnomeglade.Component):
         self.model = VcTreeStore()
         self.widget.connect("style-set", self.model.on_style_set)
         self.treeview.set_model(self.model)
-        self.treeview.get_selection().set_mode(gtk.SELECTION_MULTIPLE)
+        selection = self.treeview.get_selection()
+        selection.set_mode(gtk.SELECTION_MULTIPLE)
+        selection.connect("changed", self.on_treeview_selection_changed)
         self.treeview.set_headers_visible(1)
         self.treeview.set_search_equal_func(self.treeview_search_cb)
         self.current_path, self.prev_path, self.next_path = None, None, None
@@ -250,6 +252,7 @@ class VcView(melddoc.MeldDoc, gnomeglade.Component):
         if not self.prefs.vc_console_visible:
             self.on_console_view_toggle(self.console_hide_box)
         self.vc = None
+        self.valid_vc_actions = tuple()
         # VC ComboBox
         self.combobox_vcs = gtk.ComboBox()
         self.combobox_vcs.lock = True
@@ -270,13 +273,16 @@ class VcView(melddoc.MeldDoc, gnomeglade.Component):
     def update_actions_sensitivity(self):
         """Disable actions that use not implemented VC plugin methods
         """
+        valid_vc_actions = ["VcDeleteLocally"]
         for action_name, (meth_name, args) in self.action_vc_cmds_map.items():
             action = self.actiongroup.get_action(action_name)
             try:
                 getattr(self.vc, meth_name)(*args)
                 action.props.sensitive = True
+                valid_vc_actions.append(action_name)
             except NotImplementedError:
                 action.props.sensitive = False
+        self.valid_vc_actions = tuple(valid_vc_actions)
 
     def choose_vc(self, vcs):
         """Display VC plugin(s) that can handle the location"""
@@ -502,6 +508,12 @@ class VcView(melddoc.MeldDoc, gnomeglade.Component):
         self.prefs.vc_status_filters = active_filters
         self.refresh()
 
+    def on_treeview_selection_changed(self, selection):
+        model, rows = selection.get_selected_rows()
+        have_selection = bool(rows)
+        for action in self.valid_vc_actions:
+            self.actiongroup.get_action(action).set_sensitive(have_selection)
+
     def _get_selected_files(self):
         sel = []
         def gather(model, path, it):
@@ -547,13 +559,11 @@ class VcView(melddoc.MeldDoc, gnomeglade.Component):
         """Run 'command' on 'files'.
         """
         self.scheduler.add_task(self._command_iter(command, files, refresh))
-        
+
     def _command_on_selected(self, command, refresh=1):
         files = self._get_selected_files()
         if len(files):
             self._command(command, files, refresh)
-        else:
-            misc.run_dialog( _("Select some files first."), parent=self, messagetype=gtk.MESSAGE_INFO)
 
     def on_button_update_clicked(self, obj):
         self._command_on_selected( self.vc.update_command() )