1 /* cache.h - definitions for the LRU cache

     2  *

     3  * Copyright (C) 2004-2007 Gerhard Häring <gh@ghaering.de>

     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 "Python.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 

    32 typedef 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 

    42 typedef 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 

    61 extern PyTypeObject pysqlite_NodeType;

    62 extern PyTypeObject pysqlite_CacheType;

    63 

    64 int pysqlite_node_init(pysqlite_Node* self, PyObject* args, PyObject* kwargs);

    65 void pysqlite_node_dealloc(pysqlite_Node* self);

    66 

    67 int pysqlite_cache_init(pysqlite_Cache* self, PyObject* args, PyObject* kwargs);

    68 void pysqlite_cache_dealloc(pysqlite_Cache* self);

    69 PyObject* pysqlite_cache_get(pysqlite_Cache* self, PyObject* args);

    70 

    71 int pysqlite_cache_setup_types(void);

    72 

    73 #endif