Create SizedDict

src/open_irceline/utils.py

@@ -0,0 +1,22 @@
+from collections import OrderedDict
+
+
+class SizedDict(OrderedDict):
+    """Dictionary with a maximum size.  When more items are added, the least recently accessed element is evicted"""
+
+    def __init__(self, size: int):
+        super().__init__()
+        self._size = size
+
+    def __setitem__(self, key, value):
+        super().__setitem__(key, value)
+        self.move_to_end(key)
+        if len(self) > self._size:
+            self.popitem(False)
+
+    def __getitem__(self, key):
+        super().__getitem__(key)
+        self.move_to_end(key)
+
+    def update(self, __m, **kwargs):
+        raise NotImplementedError()

tests/test_sized_dict.py

@@ -0,0 +1,30 @@
+from src.open_irceline.utils import SizedDict
+
+
+def test_size_dict():
+    s_dict = SizedDict(5)
+    assert len(s_dict) == 0
+
+    s_dict['a'] = 1
+    s_dict['b'] = 2
+    s_dict['c'] = 3
+    s_dict['d'] = 4
+    s_dict['e'] = 5
+    assert len(s_dict) == 5
+
+    s_dict['f'] = 6
+    assert 'a' not in s_dict
+    assert 'f' in s_dict
+    assert len(s_dict) == 5
+
+    s_dict['b'] = 42
+    s_dict['g'] = 7
+    assert 'f' in s_dict
+    assert 'g' in s_dict
+    assert 'b' in s_dict
+    assert 'c' not in s_dict
+    assert len(s_dict) == 5
+
+    del s_dict['b']
+    assert len(s_dict) == 4
+    assert 'b' not in s_dict