[core] Each module can now access theme data

Add a method "theme()" to the generic module to have access to the theme
information.

Specifically, "theme().get(widget, attribute, default_value)" can be
used to retrieve theming for a widget with an arbitrary attribute.

This is in response to #412 - thanks to @bbernhard for the suggestion!

bumblebee/engine.py

@@ -41,6 +41,7 @@ class Module(object):
         self.error = None
         self._next = int(time.time())
         self._default_interval = 0
+        self._engine = engine
 
         self._configFile = None
         for cfg in [os.path.expanduser("~/.bumblebee-status.conf"), os.path.expanduser("~/.config/bumblebee-status.conf")]:
@@ -56,6 +57,9 @@ class Module(object):
         if widgets:
             self._widgets = widgets if isinstance(widgets, list) else [widgets]
 
+    def theme(self):
+        return self._engine.theme()
+
     def widgets(self, widgets=None):
         """Return the widgets to draw for this module"""
         if widgets:
@@ -160,6 +164,9 @@ class Engine(object):
 
         self.input.start()
 
+    def theme(self):
+        return self._theme
+
     def _toggle_minimize(self, event):
         for module in self._modules:
             widget = module.widget_by_id(event["instance"])

bumblebee/theme.py

@@ -105,6 +105,9 @@ class Theme(object):
         if icon is None:
             return self._get(widget, "prefix", None)
 
+    def get(self, widget, attribute, default_value=""):
+        return self._get(widget, attribute, default_value)
+
     def padding(self, widget):
         """Return padding for widget"""
         return self._get(widget, "padding", "")