summaryrefslogtreecommitdiffstats
path: root/Modules/_sqlite/microprotocols.c
blob: 5040acdc0decc383e711b5513fa13e31b3dd1c44 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
/* microprotocols.c - minimalist and non-validating protocols implementation
 *
 * Copyright (C) 2003-2004 Federico Di Gregorio <fog@debian.org>
 *
 * This file is part of psycopg and was adapted for pysqlite. Federico Di
 * Gregorio gave the permission to use it within pysqlite under the following
 * license:
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
 *    appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */

#include <Python.h>
#include <structmember.h>

#include "cursor.h"
#include "microprotocols.h"
#include "prepare_protocol.h"


/** the adapters registry **/

PyObject *psyco_adapters;

/* microprotocols_init - initialize the adapters dictionary */

int
microprotocols_init(PyObject *dict)
{
    /* create adapters dictionary and put it in module namespace */
    if ((psyco_adapters = PyDict_New()) == NULL) {
        return -1;
    }

    return PyDict_SetItemString(dict, "adapters", psyco_adapters);
}


/* microprotocols_add - add a reverse type-caster to the dictionary */

int
microprotocols_add(PyTypeObject *type, PyObject *proto, PyObject *cast)
{
    PyObject* key;

    if (proto == NULL) proto = (PyObject*)&SQLitePrepareProtocolType;

    /*
    Dprintf("microprotocols_add: cast %p for (%s, ?)",
            cast, type->tp_name);
    */


    key = Py_BuildValue("(OO)", (PyObject*)type, proto);
    if (!key) {
        return -1;
    }

    if (PyDict_SetItem(psyco_adapters, key, cast) != 0) {
        Py_DECREF(key);
        return -1;
    }

    Py_DECREF(key);

    return 0;
}

/* microprotocols_adapt - adapt an object to the built-in protocol */

PyObject *
microprotocols_adapt(PyObject *obj, PyObject *proto, PyObject *alt)
{
    PyObject *adapter, *key;

    /* we don't check for exact type conformance as specified in PEP 246
       because the SQLitePrepareProtocolType type is abstract and there is no
       way to get a quotable object to be its instance */

    /* look for an adapter in the registry */
    key = Py_BuildValue("(OO)", (PyObject*)obj->ob_type, proto);
    if (!key) {
        return NULL;
    }
    adapter = PyDict_GetItem(psyco_adapters, key);
    Py_DECREF(key);
    if (adapter) {
        PyObject *adapted = PyObject_CallFunctionObjArgs(adapter, obj, NULL);
        return adapted;
    }

    /* try to have the protocol adapt this object*/
    if (PyObject_HasAttrString(proto, "__adapt__")) {
        PyObject *adapted = PyObject_CallMethod(proto, "__adapt__", "O", obj);
        if (adapted) {
            if (adapted != Py_None) {
                return adapted;
            } else {
                Py_DECREF(adapted);
            }
        }

        if (PyErr_Occurred() && !PyErr_ExceptionMatches(PyExc_TypeError))
            return NULL;
    }

    /* and finally try to have the object adapt itself */
    if (PyObject_HasAttrString(obj, "__conform__")) {
        PyObject *adapted = PyObject_CallMethod(obj, "__conform__","O", proto);
        if (adapted) {
            if (adapted != Py_None) {
                return adapted;
            } else {
                Py_DECREF(adapted);
            }
        }

        if (PyErr_Occurred() && !PyErr_ExceptionMatches(PyExc_TypeError)) {
            return NULL;
        }
    }

    /* else set the right exception and return NULL */
    PyErr_SetString(ProgrammingError, "can't adapt");
    return NULL;
}

/** module-level functions **/

PyObject *
psyco_microprotocols_adapt(Cursor *self, PyObject *args)
{
    PyObject *obj, *alt = NULL;
    PyObject *proto = (PyObject*)&SQLitePrepareProtocolType;

    if (!PyArg_ParseTuple(args, "O|OO", &obj, &proto, &alt)) return NULL;
    return microprotocols_adapt(obj, proto, alt);
}