add frame support

if you have a gdb that can wrap commands (not yet upstream)
then up/down/frame commands will update the source window
when a selected-frame event is available, we can change
the code to use that instead

gui/commands.py

@@ -19,6 +19,7 @@ import gui.source
 import gui.logwindow
 import gui.toplevel
 import gui.dprintf
+import gui.events
 import re
 
 class GuiCommand(gdb.Command):
@@ -153,3 +154,42 @@ GuiOutputCommand()
 GuiPrintfCommand()
 InfoWindowsCommand()
 DeleteWindowsCommand()
+
+_can_override = False
+
+# A temporary test to see if you have a gdb that supports this.
+class TestCommand(gdb.Command):
+    """A temporary test command created for the GUI.
+    This does nothing, the GUI startup code uses it to see if
+    your copy of gdb has some command-overriding support."""
+
+    def __init__(self, set_it):
+        super(TestCommand, self).__init__('maint gui-test', gdb.COMMAND_DATA)
+        self.set_it = set_it
+
+    def invoke(self, arg, from_tty):
+        if self.set_it:
+            global _can_override
+            _can_override = True
+        else:
+            try:
+                super(TestCommand, self).invoke(arg, from_tty)
+            except:
+                pass
+
+TestCommand(True)
+TestCommand(False).invoke('', 0)
+
+if _can_override:
+    class Overrider(gdb.Command):
+        def __init__(self, name, event):
+            super(Overrider, self).__init__(name, gdb.COMMAND_DATA)
+            self.event = event
+
+        def invoke(self, arg, from_tty):
+            super(Overrider, self).invoke(arg, from_tty)
+            self.event.post()
+
+        Overrider('up', gui.events.frame_changed)
+        Overrider('down', gui.events.frame_changed)
+        Overrider('frame', gui.events.frame_changed)

gui/events.py

@@ -0,0 +1,32 @@
+# Copyright (C) 2013 Tom Tromey <tom@trolley.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 3 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/>.
+
+import gdb
+
+class _Event(object):
+    def __init__(self):
+        self.funcs = []
+
+    def connect(self, callback):
+        self.funcs.append(callback)
+
+    def disconnect(self, callback):
+        self.funcs.remove(callback)
+
+    def post(self):
+        for fun in self.funcs:
+            fun()
+
+frame_changed = _Event()

gui/source.py

@@ -20,6 +20,7 @@ from gui.invoker import Invoker
 from gui.toplevel import Toplevel
 import gui.startup
 import gui.toplevel
+import gui.events
 
 from gi.repository import Gtk, GtkSource, GObject, Gdk
 
@@ -83,7 +84,7 @@ class LRUHandler:
     # These functions must run in the gdb thread.
     #
 
-    def on_event(self, event):
+    def on_event(self, *args):
         (frame, filename, lineno) = get_current_location()
         if filename is not None:
             gui.startup.send_to_gtk(lambda: self.show_source(frame,
@@ -95,9 +96,11 @@ class LRUHandler:
         # ... and thread-changed
         # really just pre-prompt would be good enough
         gdb.events.stop.connect(self.on_event)
+        gui.events.frame_changed.connect(self.on_event)
 
     def _disconnect_events(self):
         gdb.events.stop.disconnect(self.on_event)
+        gui.event.frame_changed.disconnect(self.on_event)
 
     #
     # These functions must run in the Gtk thread.