|
10542.5.1
by Abel Deuring
let the checkwatches script log SQL statements |
1 |
# Copyright 2010 Canonical Ltd. This software is licensed under the
|
2 |
# GNU Affero General Public License version 3 (see the file LICENSE).
|
|
3 |
||
4 |
__metaclass__ = type |
|
5 |
__all__ = [ |
|
6 |
'LimitedList', |
|
7 |
]
|
|
8 |
||
9 |
class LimitedList(list): |
|
|
10542.5.4
by Abel Deuring
implemented reviewer's comments |
10 |
"""A mutable sequence that takes a limited number of elements."""
|
|
10542.5.1
by Abel Deuring
let the checkwatches script log SQL statements |
11 |
|
12 |
def __new__(cls, max_length, value=None): |
|
13 |
return super(LimitedList, cls).__new__(cls) |
|
14 |
||
15 |
def __init__(self, max_length, value=None): |
|
16 |
if value is None: |
|
17 |
value = [] |
|
18 |
elif len(value) > max_length: |
|
19 |
value = value[-max_length:] |
|
20 |
super(LimitedList, self).__init__(value) |
|
21 |
self.max_length = max_length |
|
22 |
||
23 |
def __repr__(self): |
|
24 |
return ( |
|
25 |
'<LimitedList(%s, %s)>' |
|
26 |
% (self.max_length, super(LimitedList, self).__repr__())) |
|
27 |
||
28 |
def _ensureLength(self): |
|
29 |
"""Ensure that the maximum length is not exceeded."""
|
|
30 |
elements_to_drop = self.__len__() - self.max_length |
|
31 |
if elements_to_drop > 0: |
|
32 |
self.__delslice__(0, elements_to_drop) |
|
33 |
||
34 |
def __add__(self, other): |
|
35 |
return LimitedList( |
|
36 |
self.max_length, super(LimitedList, self).__add__(other)) |
|
37 |
||
38 |
def __radd__(self, other): |
|
39 |
return LimitedList(self.max_length, other.__add__(self)) |
|
40 |
||
41 |
def __iadd__(self, other): |
|
42 |
result = super(LimitedList, self).__iadd__(other) |
|
43 |
self._ensureLength() |
|
44 |
return result |
|
45 |
||
46 |
def __mul__(self, other): |
|
47 |
return LimitedList( |
|
48 |
self.max_length, super(LimitedList, self).__mul__(other)) |
|
49 |
||
50 |
def __rmul__(self, other): |
|
51 |
return self.__mul__(other) |
|
52 |
||
53 |
def __imul__(self, other): |
|
54 |
result = super(LimitedList, self).__imul__(other) |
|
55 |
self._ensureLength() |
|
56 |
return result |
|
57 |
||
58 |
def __setslice__(self, i, j, sequence): |
|
59 |
result = super(LimitedList, self).__setslice__(i, j, sequence) |
|
60 |
self._ensureLength() |
|
61 |
return result |
|
62 |
||
63 |
def append(self, value): |
|
64 |
result = super(LimitedList, self).append(value) |
|
65 |
self._ensureLength() |
|
66 |
return result |
|
67 |
||
68 |
def extend(self, value): |
|
69 |
result = super(LimitedList, self).extend(value) |
|
70 |
self._ensureLength() |
|
71 |
return result |
|
72 |
||
73 |
def insert(self, position, value): |
|
74 |
result = super(LimitedList, self).insert(position, value) |
|
75 |
self._ensureLength() |
|
76 |
return result |