1 /* microprotocols.c - minimalist and non-validating protocols implementation
2 *
3 * Copyright (C) 2003-2004 Federico Di Gregorio <fog@debian.org>
4 *
5 * This file is part of psycopg and was adapted for pysqlite. Federico Di
6 * Gregorio gave the permission to use it within pysqlite under the following
7 * license:
8 *
9 * This software is provided 'as-is', without any express or implied
10 * warranty. In no event will the authors be held liable for any damages
11 * arising from the use of this software.
12 *
13 * Permission is granted to anyone to use this software for any purpose,
14 * including commercial applications, and to alter it and redistribute it
15 * freely, subject to the following restrictions:
16 *
17 * 1. The origin of this software must not be misrepresented; you must not
18 * claim that you wrote the original software. If you use this software
19 * in a product, an acknowledgment in the product documentation would be
20 * appreciated but is not required.
21 * 2. Altered source versions must be plainly marked as such, and must not be
22 * misrepresented as being the original software.
23 * 3. This notice may not be removed or altered from any source distribution.
24 */
25
26 #include <Python.h>
27 #include <structmember.h>
28
29 #include "cursor.h"
30 #include "microprotocols.h"
31 #include "prepare_protocol.h"
32
33
34 /** the adapters registry **/
35
36 PyObject *psyco_adapters;
37
38 /* pysqlite_microprotocols_init - initialize the adapters dictionary */
39
40 int
pysqlite_microprotocols_init(PyObject * dict)41 pysqlite_microprotocols_init(PyObject *dict)
42 {
43 /* create adapters dictionary and put it in module namespace */
44 if ((psyco_adapters = PyDict_New()) == NULL) {
45 return -1;
46 }
47
48 return PyDict_SetItemString(dict, "adapters", psyco_adapters);
49 }
50
51
52 /* pysqlite_microprotocols_add - add a reverse type-caster to the dictionary */
53
54 int
pysqlite_microprotocols_add(PyTypeObject * type,PyObject * proto,PyObject * cast)55 pysqlite_microprotocols_add(PyTypeObject *type, PyObject *proto, PyObject *cast)
56 {
57 PyObject* key;
58 int rc;
59
60 if (proto == NULL) proto = (PyObject*)&pysqlite_PrepareProtocolType;
61
62 key = Py_BuildValue("(OO)", (PyObject*)type, proto);
63 if (!key) {
64 return -1;
65 }
66
67 rc = PyDict_SetItem(psyco_adapters, key, cast);
68 Py_DECREF(key);
69
70 return rc;
71 }
72
73 /* pysqlite_microprotocols_adapt - adapt an object to the built-in protocol */
74
75 PyObject *
pysqlite_microprotocols_adapt(PyObject * obj,PyObject * proto,PyObject * alt)76 pysqlite_microprotocols_adapt(PyObject *obj, PyObject *proto, PyObject *alt)
77 {
78 PyObject *adapter, *key;
79
80 /* we don't check for exact type conformance as specified in PEP 246
81 because the pysqlite_PrepareProtocolType type is abstract and there is no
82 way to get a quotable object to be its instance */
83
84 /* look for an adapter in the registry */
85 key = Py_BuildValue("(OO)", (PyObject*)obj->ob_type, proto);
86 if (!key) {
87 return NULL;
88 }
89 adapter = PyDict_GetItem(psyco_adapters, key);
90 Py_DECREF(key);
91 if (adapter) {
92 PyObject *adapted = PyObject_CallFunctionObjArgs(adapter, obj, NULL);
93 return adapted;
94 }
95
96 /* try to have the protocol adapt this object*/
97 if (PyObject_HasAttrString(proto, "__adapt__")) {
98 PyObject *adapted = PyObject_CallMethod(proto, "__adapt__", "O", obj);
99 if (adapted) {
100 if (adapted != Py_None) {
101 return adapted;
102 } else {
103 Py_DECREF(adapted);
104 }
105 }
106
107 if (PyErr_Occurred() && !PyErr_ExceptionMatches(PyExc_TypeError))
108 return NULL;
109 }
110
111 /* and finally try to have the object adapt itself */
112 if (PyObject_HasAttrString(obj, "__conform__")) {
113 PyObject *adapted = PyObject_CallMethod(obj, "__conform__","O", proto);
114 if (adapted) {
115 if (adapted != Py_None) {
116 return adapted;
117 } else {
118 Py_DECREF(adapted);
119 }
120 }
121
122 if (PyErr_Occurred() && !PyErr_ExceptionMatches(PyExc_TypeError)) {
123 return NULL;
124 }
125 }
126
127 /* else set the right exception and return NULL */
128 PyErr_SetString(pysqlite_ProgrammingError, "can't adapt");
129 return NULL;
130 }
131
132 /** module-level functions **/
133
134 PyObject *
pysqlite_adapt(pysqlite_Cursor * self,PyObject * args)135 pysqlite_adapt(pysqlite_Cursor *self, PyObject *args)
136 {
137 PyObject *obj, *alt = NULL;
138 PyObject *proto = (PyObject*)&pysqlite_PrepareProtocolType;
139
140 if (!PyArg_ParseTuple(args, "O|OO", &obj, &proto, &alt)) return NULL;
141 return pysqlite_microprotocols_adapt(obj, proto, alt);
142 }
143