Python-2.7.3/Modules/_sqlite/microprotocols.c

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