/* 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 **/

static PyObject *psyco_adapters = NULL;

/* pysqlite_microprotocols_init - initialize the adapters dictionary */

int
pysqlite_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);
}


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

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

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

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

 rc = PyDict_SetItem(psyco_adapters, key, cast);
 Py_DECREF(key);

 return rc;
}

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

PyObject *
pysqlite_microprotocols_adapt(PyObject *obj, PyObject *proto, PyObject *alt)
{
 _Py_IDENTIFIER(__adapt__);
 _Py_IDENTIFIER(__conform__);
 PyObject *adapter, *key, *adapted;

 /* we don't check for exact type conformance as specified in PEP 246
 because the pysqlite_PrepareProtocolType 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_GetItemWithError(psyco_adapters, key);
 Py_DECREF(key);
 if (adapter) {
 Py_INCREF(adapter);
 adapted = PyObject_CallFunctionObjArgs(adapter, obj, NULL);
 Py_DECREF(adapter);
 return adapted;
 }
 if (PyErr_Occurred()) {
 return NULL;
 }

 /* try to have the protocol adapt this object */
 if (_PyObject_LookupAttrId(proto, &PyId___adapt__, &adapter) < 0) {
 return NULL;
 }
 if (adapter) {
 adapted = PyObject_CallFunctionObjArgs(adapter, obj, NULL);
 Py_DECREF(adapter);

 if (adapted == Py_None) {
 Py_DECREF(adapted);
 }
 else if (adapted || !PyErr_ExceptionMatches(PyExc_TypeError)) {
 return adapted;
 }
 else {
 PyErr_Clear();
 }
 }

 /* and finally try to have the object adapt itself */
 if (_PyObject_LookupAttrId(obj, &PyId___conform__, &adapter) < 0) {
 return NULL;
 }
 if (adapter) {
 adapted = PyObject_CallFunctionObjArgs(adapter, proto, NULL);
 Py_DECREF(adapter);

 if (adapted == Py_None) {
 Py_DECREF(adapted);
 }
 else if (adapted || !PyErr_ExceptionMatches(PyExc_TypeError)) {
 return adapted;
 }
 else {
 PyErr_Clear();
 }
 }

 if (alt) {
 Py_INCREF(alt);
 return alt;
 }
 /* else set the right exception and return NULL */
 PyErr_SetString(pysqlite_ProgrammingError, "can't adapt");
 return NULL;
}

/** module-level functions **/

PyObject *
pysqlite_adapt(pysqlite_Cursor *self, PyObject *args)
{
 PyObject *obj, *alt = NULL;
 PyObject *proto = (PyObject*)&pysqlite_PrepareProtocolType;

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