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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         _Py_IDENTIFIER(__adapt__);
99         PyObject *adapted = _PyObject_CallMethodId(proto, &PyId___adapt__, "O", obj);
100 
101         if (adapted) {
102             if (adapted != Py_None) {
103                 return adapted;
104             } else {
105                 Py_DECREF(adapted);
106             }
107         }
108 
109         if (PyErr_Occurred() && !PyErr_ExceptionMatches(PyExc_TypeError))
110             return NULL;
111     }
112 
113     /* and finally try to have the object adapt itself */
114     if (PyObject_HasAttrString(obj, "__conform__")) {
115         _Py_IDENTIFIER(__conform__);
116         PyObject *adapted = _PyObject_CallMethodId(obj, &PyId___conform__,"O", proto);
117 
118         if (adapted) {
119             if (adapted != Py_None) {
120                 return adapted;
121             } else {
122                 Py_DECREF(adapted);
123             }
124         }
125 
126         if (PyErr_Occurred() && !PyErr_ExceptionMatches(PyExc_TypeError)) {
127             return NULL;
128         }
129     }
130 
131     /* else set the right exception and return NULL */
132     PyErr_SetString(pysqlite_ProgrammingError, "can't adapt");
133     return NULL;
134 }
135 
136 /** module-level functions **/
137 
138 PyObject *
pysqlite_adapt(pysqlite_Cursor * self,PyObject * args)139 pysqlite_adapt(pysqlite_Cursor *self, PyObject *args)
140 {
141     PyObject *obj, *alt = NULL;
142     PyObject *proto = (PyObject*)&pysqlite_PrepareProtocolType;
143 
144     if (!PyArg_ParseTuple(args, "O|OO", &obj, &proto, &alt)) return NULL;
145     return pysqlite_microprotocols_adapt(obj, proto, alt);
146 }
147