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
28 #include "cursor.h"
29 #include "microprotocols.h"
30 #include "prepare_protocol.h"
31
32 /** the adapters registry **/
33
34 static PyObject *psyco_adapters = NULL;
35
36 /* pysqlite_microprotocols_init - initialize the adapters dictionary */
37
38 int
pysqlite_microprotocols_init(PyObject * module)39 pysqlite_microprotocols_init(PyObject *module)
40 {
41 /* create adapters dictionary and put it in module namespace */
42 if ((psyco_adapters = PyDict_New()) == NULL) {
43 return -1;
44 }
45
46 int res = PyModule_AddObjectRef(module, "adapters", psyco_adapters);
47 Py_DECREF(psyco_adapters);
48
49 return res;
50 }
51
52
53 /* pysqlite_microprotocols_add - add a reverse type-caster to the dictionary */
54
55 int
pysqlite_microprotocols_add(PyTypeObject * type,PyObject * proto,PyObject * cast)56 pysqlite_microprotocols_add(PyTypeObject *type, PyObject *proto, PyObject *cast)
57 {
58 PyObject* key;
59 int rc;
60
61 if (proto == NULL) proto = (PyObject*)pysqlite_PrepareProtocolType;
62
63 key = Py_BuildValue("(OO)", (PyObject*)type, proto);
64 if (!key) {
65 return -1;
66 }
67
68 rc = PyDict_SetItem(psyco_adapters, key, cast);
69 Py_DECREF(key);
70
71 return rc;
72 }
73
74 /* pysqlite_microprotocols_adapt - adapt an object to the built-in protocol */
75
76 PyObject *
pysqlite_microprotocols_adapt(PyObject * obj,PyObject * proto,PyObject * alt)77 pysqlite_microprotocols_adapt(PyObject *obj, PyObject *proto, PyObject *alt)
78 {
79 _Py_IDENTIFIER(__adapt__);
80 _Py_IDENTIFIER(__conform__);
81 PyObject *adapter, *key, *adapted;
82
83 /* we don't check for exact type conformance as specified in PEP 246
84 because the pysqlite_PrepareProtocolType type is abstract and there is no
85 way to get a quotable object to be its instance */
86
87 /* look for an adapter in the registry */
88 key = Py_BuildValue("(OO)", (PyObject*)Py_TYPE(obj), proto);
89 if (!key) {
90 return NULL;
91 }
92 adapter = PyDict_GetItemWithError(psyco_adapters, key);
93 Py_DECREF(key);
94 if (adapter) {
95 Py_INCREF(adapter);
96 adapted = PyObject_CallOneArg(adapter, obj);
97 Py_DECREF(adapter);
98 return adapted;
99 }
100 if (PyErr_Occurred()) {
101 return NULL;
102 }
103
104 /* try to have the protocol adapt this object */
105 if (_PyObject_LookupAttrId(proto, &PyId___adapt__, &adapter) < 0) {
106 return NULL;
107 }
108 if (adapter) {
109 adapted = PyObject_CallOneArg(adapter, obj);
110 Py_DECREF(adapter);
111
112 if (adapted == Py_None) {
113 Py_DECREF(adapted);
114 }
115 else if (adapted || !PyErr_ExceptionMatches(PyExc_TypeError)) {
116 return adapted;
117 }
118 else {
119 PyErr_Clear();
120 }
121 }
122
123 /* and finally try to have the object adapt itself */
124 if (_PyObject_LookupAttrId(obj, &PyId___conform__, &adapter) < 0) {
125 return NULL;
126 }
127 if (adapter) {
128 adapted = PyObject_CallOneArg(adapter, proto);
129 Py_DECREF(adapter);
130
131 if (adapted == Py_None) {
132 Py_DECREF(adapted);
133 }
134 else if (adapted || !PyErr_ExceptionMatches(PyExc_TypeError)) {
135 return adapted;
136 }
137 else {
138 PyErr_Clear();
139 }
140 }
141
142 if (alt) {
143 return Py_NewRef(alt);
144 }
145 /* else set the right exception and return NULL */
146 PyErr_SetString(pysqlite_ProgrammingError, "can't adapt");
147 return NULL;
148 }
149