[mousetrap/gnome3-wip: 113/240] Introduced History class to manage length of histories.

[Heidi Ellis <heidiellis src gnome org>]

commit 716cdeff2fc2cea76d6c181e4451311686522b58
Author: Stoney Jackson <dr stoney gmail com>
Date:   Sun Jun 22 00:46:57 2014 -0400

    Introduced History class to manage length of histories.

 src/mousetrap/plugins/eyes.py |   28 +++++++++++++++++++---------
 1 files changed, 19 insertions(+), 9 deletions(-)
---
diff --git a/src/mousetrap/plugins/eyes.py b/src/mousetrap/plugins/eyes.py
index ce25b51..0aa8aa2 100644
--- a/src/mousetrap/plugins/eyes.py
+++ b/src/mousetrap/plugins/eyes.py
@@ -9,15 +9,15 @@ LOGGER = log.get_logger(__name__)
 class EyesPlugin(interface.Plugin):
     def __init__(self):
         self._left_locator = LeftEyeLocator()
-        self._eye_detection_history = []
-        self._pointer_history = []
+        self._eye_detection_history = History(max_length=15)
+        self._pointer_history = History(max_length=5)
         self._is_closed = False
 
     def run(self, app):
         self._eye_detection_history.append(self._left_locator.locate(app.image))
 
         if self._stationary(app) and self._detect_closed():
-            self._eye_detection_history = []
+            self._eye_detection_history.clear()
             app.pointer.click()
 
     def _stationary(self, app):
@@ -25,9 +25,6 @@ class EyesPlugin(interface.Plugin):
 
         last_point = app.pointer.get_position()
 
-        while len(self._pointer_history) > 5:
-            del self._pointer_history[0]
-
         for point in self._pointer_history:
             if point != last_point:
                 return False
@@ -35,9 +32,6 @@ class EyesPlugin(interface.Plugin):
         return True
 
     def _detect_closed(self):
-        while len(self._eye_detection_history) > 15:
-            del self._eye_detection_history[0]
-
         misses = self._eye_detection_history.count(False)
 
         return misses > 12
@@ -65,3 +59,19 @@ class LeftEyeLocator(object):
             return True
         except FeatureNotFoundException:
             return False
+
+
+class History(list):
+    def __init__(self, max_length):
+        super(History, self).__init__()
+        self._max_length = max_length
+
+    def append(self, value):
+        super(History, self).append(value)
+        while len(self) > self._max_length:
+            del self[0]
+
+    def clear(self):
+        del self[:]
+
+