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
36PyObject *psyco_adapters;
37
38/* pysqlite_microprotocols_init - initialize the adapters dictionary */
39
40int
41pysqlite_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
54int
55pysqlite_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
75PyObject *
76pysqlite_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
138PyObject *
139pysqlite_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