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 static PyObject *psyco_adapters = NULL;
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 _Py_IDENTIFIER(__adapt__);
79 _Py_IDENTIFIER(__conform__);
80 PyObject *adapter, *key, *adapted;
81
82 /* we don't check for exact type conformance as specified in PEP 246
83 because the pysqlite_PrepareProtocolType type is abstract and there is no
84 way to get a quotable object to be its instance */
85
86 /* look for an adapter in the registry */
87 key = Py_BuildValue("(OO)", (PyObject*)obj->ob_type, proto);
88 if (!key) {
89 return NULL;
90 }
91 adapter = PyDict_GetItemWithError(psyco_adapters, key);
92 Py_DECREF(key);
93 if (adapter) {
94 Py_INCREF(adapter);
95 adapted = PyObject_CallFunctionObjArgs(adapter, obj, NULL);
96 Py_DECREF(adapter);
97 return adapted;
98 }
99 if (PyErr_Occurred()) {
100 return NULL;
101 }
102
103 /* try to have the protocol adapt this object */
104 if (_PyObject_LookupAttrId(proto, &PyId___adapt__, &adapter) < 0) {
105 return NULL;
106 }
107 if (adapter) {
108 adapted = PyObject_CallFunctionObjArgs(adapter, obj, NULL);
109 Py_DECREF(adapter);
110
111 if (adapted == Py_None) {
112 Py_DECREF(adapted);
113 }
114 else if (adapted || !PyErr_ExceptionMatches(PyExc_TypeError)) {
115 return adapted;
116 }
117 else {
118 PyErr_Clear();
119 }
120 }
121
122 /* and finally try to have the object adapt itself */
123 if (_PyObject_LookupAttrId(obj, &PyId___conform__, &adapter) < 0) {
124 return NULL;
125 }
126 if (adapter) {
127 adapted = PyObject_CallFunctionObjArgs(adapter, proto, NULL);
128 Py_DECREF(adapter);
129
130 if (adapted == Py_None) {
131 Py_DECREF(adapted);
132 }
133 else if (adapted || !PyErr_ExceptionMatches(PyExc_TypeError)) {
134 return adapted;
135 }
136 else {
137 PyErr_Clear();
138 }
139 }
140
141 if (alt) {
142 Py_INCREF(alt);
143 return alt;
144 }
145 /* else set the right exception and return NULL */
146 PyErr_SetString(pysqlite_ProgrammingError, "can't adapt");
147 return NULL;
148 }
149
150 /** module-level functions **/
151
152 PyObject *
pysqlite_adapt(pysqlite_Cursor * self,PyObject * args)153 pysqlite_adapt(pysqlite_Cursor *self, PyObject *args)
154 {
155 PyObject *obj, *alt = NULL;
156 PyObject *proto = (PyObject*)&pysqlite_PrepareProtocolType;
157
158 if (!PyArg_ParseTuple(args, "O|OO", &obj, &proto, &alt)) return NULL;
159 return pysqlite_microprotocols_adapt(obj, proto, alt);
160 }
161