[modules/caffeine] Re-implement caffeine module

Add caffeine module & add a framework for testing it (no tests yet,
though).

see #23

bumblebee/modules/caffeine.py

@@ -0,0 +1,47 @@
+# pylint: disable=C0111,R0903
+
+"""Enable/disable automatic screen locking.
+"""
+
+import bumblebee.input
+import bumblebee.output
+import bumblebee.engine
+
+class Module(bumblebee.engine.Module):
+    def __init__(self, engine, config):
+        super(Module, self).__init__(engine, config,
+            bumblebee.output.Widget(full_text=self.caffeine)
+        )
+        engine.input.register_callback(self, button=bumblebee.input.LEFT_MOUSE,
+            cmd=self._toggle
+        )
+
+    def caffeine(self):
+        return ""
+
+    def state(self, widget):
+        if self._active():
+            return "activated"
+        return "deactivated"
+
+    def _active(self):
+        for line in bumblebee.util.execute("xset q").split("\n"):
+            if "timeout" in line:
+                timeout = int(line.split(" ")[4])
+                if timeout == 0:
+                    return True
+                return False
+        return False
+
+    def update(self, widgets):
+        pass
+
+    def _toggle(self, widget):
+        if self._active():
+            bumblebee.util.execute("xset s default")
+            bumblebee.util.execute("notify-send \"Out of coffee\"")
+        else:
+            bumblebee.util.execute("xset s off")
+            bumblebee.util.execute("notify-send \"Consuming caffeine\"")
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4