add "info windows" and "delete window"

This adds the "info windows" and "delete window" commands.

"info windows" unfortunately overlaps with the TUI's "info win".
So maybe we should rename this one.

This also adds a new "toplevel" component that knows how to track
windows.

gui/__init__.py

@@ -16,3 +16,7 @@
 import os.path
 
 self_dir = os.path.abspath(os.path.dirname(__file__))
+
+# Import anything that defines a command or parameter.
+import gui.commands
+import gui.toplevel

gui/commands.py

@@ -28,6 +28,7 @@ class GuiSourceCommand(gdb.Command):
                                                gdb.COMMAND_SUPPORT)
 
     def invoke(self, arg, from_tty):
+        self.dont_repeat()
         gui.startup.start_gtk()
         gui.startup.send_to_gtk(gui.source.SourceWindow)
 

gui/source.py

@@ -17,8 +17,10 @@
 
 import gdb
 from gui.invoker import Invoker
+from gui.toplevel import Toplevel
 import gui.startup
 import os.path
+import gui.toplevel
 
 from gi.repository import Gtk, GtkSource, GObject
 
@@ -140,8 +142,10 @@ class LRUHandler:
 
 lru_handler = LRUHandler()
 
-class SourceWindow:
+class SourceWindow(Toplevel):
     def __init__(self):
+        super(SourceWindow, self).__init__()
+
         self.frame = None
 
         self.do_step = Invoker("step")

gui/toplevel.py

@@ -0,0 +1,93 @@
+# Copyright (C) 2013 Tom Tromey <tom@tromey.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/>.
+
+# Toplevel handling.
+
+import gdb
+import gui.startup
+import threading
+
+class _ToplevelState(object):
+    def __init__(self):
+        # This lock must be held when using the other globals here.
+        self.toplevel_lock = threading.Lock()
+        self.next_toplevel = 1
+        self.toplevels = {}
+
+    def add(self, obj):
+        with self.toplevel_lock:
+            obj.number = self.next_toplevel
+            self.next_toplevel = self.next_toplevel + 1
+            self.toplevels[obj.number] = obj
+
+    def remove(self, obj):
+        with self.toplevel_lock:
+            del self.toplevels[obj.number]
+
+    def get(self, winno):
+        window = None
+        with self.toplevel_lock:
+            if winno in self.toplevels:
+                window = self.toplevels[winno]
+        return window
+
+    def display(self):
+        with self.toplevel_lock:
+            if len(self.toplevels) == 0:
+                print "No windows"
+                return
+
+            print ' Num    Name'
+            for winno in range(1, self.next_toplevel):
+                if winno in self.toplevels:
+                    window = self.toplevels[winno]
+                    print ' %3d    %s' % (window.number,
+                                          window.window.get_title())
+
+_toplevel_state = _ToplevelState()
+
+class Toplevel(object):
+    def __init__(self):
+        _toplevel_state.add(self)
+        # The subclass must set this.
+        self.window = None
+
+    def destroy(self):
+        _toplevel_state.remove(self)
+        gui.startup.send_to_gtk(self.window.destroy)
+
+class InfoWindowsCommand(gdb.Command):
+    def __init__(self):
+        super(InfoWindowsCommand, self).__init__('info windows',
+                                                 gdb.COMMAND_SUPPORT)
+
+    def invoke(self, arg, from_tty):
+        self.dont_repeat()
+        _toplevel_state.display()
+
+class DeleteWindowsCommand(gdb.Command):
+    def __init__(self):
+        super(DeleteWindowsCommand, self).__init__('delete window',
+                                                   gdb.COMMAND_SUPPORT)
+
+    def invoke(self, arg, from_tty):
+        self.dont_repeat()
+        winno = int(arg)
+        window = _toplevel_state.get(winno)
+        if window is not None:
+            window.destroy()
+
+InfoWindowsCommand()
+DeleteWindowsCommand()