| hg-reviewers |
This will allow us to easily replace an lrucachedict with one
with a higher or lower capacity as consumers deem necessary.
IMO it is easier to just create a new cache instance than to
muck with the capacity of an existing cache. Mutating an existing
cache's capacity feels more prone to bugs.
| Automatic diff as part of commit; lint not applicable. |
| Automatic diff as part of commit; unit tests not applicable. |
| def clear(self): | def clear(self): | ||||
| n = self._head | n = self._head | ||||
| while n.key is not _notset: | while n.key is not _notset: | ||||
| n.markempty() | n.markempty() | ||||
| n = n.next | n = n.next | ||||
| self._cache.clear() | self._cache.clear() | ||||
| def copy(self): | def copy(self, capacity=None): | ||||
| result = lrucachedict(self.capacity) | """Create a new cache as a copy of the current one. | ||||
| By default, the new cache has the same capacity as the existing one. | |||||
| But, the cache capacity can be changed as part of performing the | |||||
| copy. | |||||
| Items in the copy have an insertion/access order matching this | |||||
| instance. | |||||
| """ | |||||
| capacity = capacity or self.capacity | |||||
| result = lrucachedict(capacity) | |||||
| # We copy entries by iterating in oldest-to-newest order so the copy | # We copy entries by iterating in oldest-to-newest order so the copy | ||||
| # has the correct ordering. | # has the correct ordering. | ||||
| # Find the first non-empty entry. | # Find the first non-empty entry. | ||||
| n = self._head.prev | n = self._head.prev | ||||
| while n.key is _notset and n is not self._head: | while n.key is _notset and n is not self._head: | ||||
| n = n.prev | n = n.prev | ||||
| # We could potentially skip the first N items when decreasing capacity. | |||||
| # But let's keep it simple unless it is a performance problem. | |||||
| for i in range(len(self._cache)): | for i in range(len(self._cache)): | ||||
| result[n.key] = n.value | result[n.key] = n.value | ||||
| n = n.prev | n = n.prev | ||||
| return result | return result | ||||
| def _movetohead(self, node): | def _movetohead(self, node): | ||||
| """Mark a node as the newest, making it the new head. | """Mark a node as the newest, making it the new head. | ||||
| # Contents and order of original dict should remain unchanged. | # Contents and order of original dict should remain unchanged. | ||||
| dc['b'] = 'vb_new' | dc['b'] = 'vb_new' | ||||
| self.assertEqual(list(iter(d)), ['d', 'c', 'b', 'a']) | self.assertEqual(list(iter(d)), ['d', 'c', 'b', 'a']) | ||||
| for key in ('a', 'b', 'c', 'd'): | for key in ('a', 'b', 'c', 'd'): | ||||
| self.assertEqual(d[key], 'v%s' % key) | self.assertEqual(d[key], 'v%s' % key) | ||||
| def testcopydecreasecapacity(self): | |||||
| d = util.lrucachedict(5) | |||||
| d['a'] = 'va' | |||||
| d['b'] = 'vb' | |||||
| d['c'] = 'vc' | |||||
| d['d'] = 'vd' | |||||
| dc = d.copy(2) | |||||
| for key in ('a', 'b'): | |||||
| self.assertNotIn(key, dc) | |||||
| for key in ('c', 'd'): | |||||
| self.assertIn(key, dc) | |||||
| self.assertEqual(dc[key], 'v%s' % key) | |||||
| dc['e'] = 've' | |||||
| self.assertNotIn('c', dc) | |||||
| for key in ('d', 'e'): | |||||
| self.assertIn(key, dc) | |||||
| self.assertEqual(dc[key], 'v%s' % key) | |||||
| # Original should remain unchanged. | |||||
| for key in ('a', 'b', 'c', 'd'): | |||||
| self.assertIn(key, d) | |||||
| self.assertEqual(d[key], 'v%s' % key) | |||||
| def testcopyincreasecapacity(self): | |||||
| d = util.lrucachedict(5) | |||||
| d['a'] = 'va' | |||||
| d['b'] = 'vb' | |||||
| d['c'] = 'vc' | |||||
| d['d'] = 'vd' | |||||
| dc = d.copy(6) | |||||
| for key in ('a', 'b', 'c', 'd'): | |||||
| self.assertIn(key, dc) | |||||
| self.assertEqual(dc[key], 'v%s' % key) | |||||
| dc['e'] = 've' | |||||
| dc['f'] = 'vf' | |||||
| for key in ('a', 'b', 'c', 'd', 'e', 'f'): | |||||
| self.assertIn(key, dc) | |||||
| self.assertEqual(dc[key], 'v%s' % key) | |||||
| dc['g'] = 'vg' | |||||
| self.assertNotIn('a', dc) | |||||
| for key in ('b', 'c', 'd', 'e', 'f', 'g'): | |||||
| self.assertIn(key, dc) | |||||
| self.assertEqual(dc[key], 'v%s' % key) | |||||
| # Original should remain unchanged. | |||||
| for key in ('a', 'b', 'c', 'd'): | |||||
| self.assertIn(key, d) | |||||
| self.assertEqual(d[key], 'v%s' % key) | |||||
| if __name__ == '__main__': | if __name__ == '__main__': | ||||
| silenttestrunner.main(__name__) | silenttestrunner.main(__name__) | ||||