1/* cache.h - definitions for the LRU cache
2 *
3 * Copyright (C) 2004-2010 Gerhard Häring <[email protected]>
4 *
5 * This file is part of pysqlite.
6 *
7 * This software is provided 'as-is', without any express or implied
8 * warranty. In no event will the authors be held liable for any damages
9 * arising from the use of this software.
10 *
11 * Permission is granted to anyone to use this software for any purpose,
12 * including commercial applications, and to alter it and redistribute it
13 * freely, subject to the following restrictions:
14 *
15 * 1. The origin of this software must not be misrepresented; you must not
16 * claim that you wrote the original software. If you use this software
17 * in a product, an acknowledgment in the product documentation would be
18 * appreciated but is not required.
19 * 2. Altered source versions must be plainly marked as such, and must not be
20 * misrepresented as being the original software.
21 * 3. This notice may not be removed or altered from any source distribution.
22 */
23
24#ifndef PYSQLITE_CACHE_H
25#define PYSQLITE_CACHE_H
26#include "module.h"
27
28/* The LRU cache is implemented as a combination of a doubly-linked with a
29 * dictionary. The list items are of type 'Node' and the dictionary has the
30 * nodes as values. */
31
32typedef struct _pysqlite_Node
33{
34 PyObject_HEAD
35 PyObject* key;
36 PyObject* data;
37 long count;
38 struct _pysqlite_Node* prev;
39 struct _pysqlite_Node* next;
40} pysqlite_Node;
41
42typedef struct
43{
44 PyObject_HEAD
45 int size;
46
47 /* a dictionary mapping keys to Node entries */
48 PyObject* mapping;
49
50 /* the factory callable */
51 PyObject* factory;
52
53 pysqlite_Node* first;
54 pysqlite_Node* last;
55
56 /* if set, decrement the factory function when the Cache is deallocated.
57 * this is almost always desirable, but not in the pysqlite context */
58 int decref_factory;
59} pysqlite_Cache;
60
61extern PyTypeObject *pysqlite_NodeType;
62extern PyTypeObject *pysqlite_CacheType;
63
64PyObject* pysqlite_cache_get(pysqlite_Cache* self, PyObject* args);
65
66int pysqlite_cache_setup_types(PyObject *module);
67
68#endif
69