first commit based on psycopg2 2.9 version

psycopg/microprotocols.c

@@ -0,0 +1,277 @@
+/* microprotocols.c - minimalist and non-validating protocols implementation
+ *
+ * Copyright (C) 2003-2019 Federico Di Gregorio <fog@debian.org>
+ * Copyright (C) 2020-2021 The Psycopg Team
+ *
+ * This file is part of psycopg.
+ *
+ * psycopg2 is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link this program with the OpenSSL library (or with
+ * modified versions of OpenSSL that use the same license as OpenSSL),
+ * and distribute linked combinations including the two.
+ *
+ * You must obey the GNU Lesser General Public License in all respects for
+ * all of the code used other than OpenSSL.
+ *
+ * psycopg2 is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
+ * License for more details.
+ */
+
+#define PSYCOPG_MODULE
+#include "psycopg/psycopg.h"
+
+#include "psycopg/microprotocols.h"
+#include "psycopg/microprotocols_proto.h"
+#include "psycopg/cursor.h"
+#include "psycopg/connection.h"
+
+
+/** the adapters registry **/
+
+PyObject *psyco_adapters;
+
+/* microprotocols_init - initialize the adapters dictionary */
+
+RAISES_NEG int
+microprotocols_init(PyObject *module)
+{
+    /* create adapters dictionary and put it in module namespace */
+    if (!(psyco_adapters = PyDict_New())) {
+        return -1;
+    }
+
+    Py_INCREF(psyco_adapters);
+    if (0 > PyModule_AddObject(module, "adapters", psyco_adapters)) {
+        Py_DECREF(psyco_adapters);
+        return -1;
+    }
+
+    return 0;
+}
+
+
+/* microprotocols_add - add a reverse type-caster to the dictionary
+ *
+ * Return 0 on success, else -1 and set an exception.
+ */
+RAISES_NEG int
+microprotocols_add(PyTypeObject *type, PyObject *proto, PyObject *cast)
+{
+    PyObject *key = NULL;
+    int rv = -1;
+
+    if (proto == NULL) proto = (PyObject*)&isqlquoteType;
+
+    if (!(key = PyTuple_Pack(2, (PyObject*)type, proto))) { goto exit; }
+    if (0 != PyDict_SetItem(psyco_adapters, key, cast)) { goto exit; }
+
+    rv = 0;
+
+exit:
+    Py_XDECREF(key);
+    return rv;
+}
+
+/* Check if one of `obj` superclasses has an adapter for `proto`.
+ *
+ * If it does, return a *borrowed reference* to the adapter, else to None.
+ */
+BORROWED static PyObject *
+_get_superclass_adapter(PyObject *obj, PyObject *proto)
+{
+    PyTypeObject *type;
+    PyObject *mro, *st;
+    PyObject *key, *adapter;
+    Py_ssize_t i, ii;
+
+    type = Py_TYPE(obj);
+    if (!(type->tp_mro)) {
+        /* has no mro */
+        return Py_None;
+    }
+
+    /* Walk the mro from the most specific subclass. */
+    mro = type->tp_mro;
+    for (i = 1, ii = PyTuple_GET_SIZE(mro); i < ii; ++i) {
+        st = PyTuple_GET_ITEM(mro, i);
+        if (!(key = PyTuple_Pack(2, st, proto))) { return NULL; }
+        adapter = PyDict_GetItem(psyco_adapters, key);
+        Py_DECREF(key);
+
+        if (adapter) {
+            Dprintf(
+                "microprotocols_adapt: using '%s' adapter to adapt '%s'",
+                ((PyTypeObject *)st)->tp_name, type->tp_name);
+
+            /* register this adapter as good for the subclass too,
+             * so that the next time it will be found in the fast path */
+
+            /* Well, no, maybe this is not a good idea.
+             * It would become a leak in case of dynamic
+             * classes generated in a loop (think namedtuples). */
+
+            /* key = PyTuple_Pack(2, (PyObject*)type, proto);
+             * PyDict_SetItem(psyco_adapters, key, adapter);
+             * Py_DECREF(key);
+             */
+            return adapter;
+        }
+    }
+    return Py_None;
+}
+
+
+/* microprotocols_adapt - adapt an object to the built-in protocol */
+
+PyObject *
+microprotocols_adapt(PyObject *obj, PyObject *proto, PyObject *alt)
+{
+    PyObject *adapter, *adapted, *key, *meth;
+    char buffer[256];
+
+    /* we don't check for exact type conformance as specified in PEP 246
+       because the ISQLQuote type is abstract and there is no way to get a
+       quotable object to be its instance */
+
+    Dprintf("microprotocols_adapt: trying to adapt %s",
+        Py_TYPE(obj)->tp_name);
+
+    /* look for an adapter in the registry */
+    if (!(key = PyTuple_Pack(2, Py_TYPE(obj), proto))) { return NULL; }
+    adapter = PyDict_GetItem(psyco_adapters, key);
+    Py_DECREF(key);
+    if (adapter) {
+        adapted = PyObject_CallFunctionObjArgs(adapter, obj, NULL);
+        return adapted;
+    }
+
+    /* try to have the protocol adapt this object*/
+    if ((meth = PyObject_GetAttrString(proto, "__adapt__"))) {
+        adapted = PyObject_CallFunctionObjArgs(meth, obj, NULL);
+        Py_DECREF(meth);
+        if (adapted && adapted != Py_None) return adapted;
+        Py_XDECREF(adapted);
+        if (PyErr_Occurred()) {
+            if (PyErr_ExceptionMatches(PyExc_TypeError)) {
+               PyErr_Clear();
+            } else {
+                return NULL;
+            }
+        }
+    }
+    else {
+        /* proto.__adapt__ not found. */
+        PyErr_Clear();
+    }
+
+    /* then try to have the object adapt itself */
+    if ((meth = PyObject_GetAttrString(obj, "__conform__"))) {
+        adapted = PyObject_CallFunctionObjArgs(meth, proto, NULL);
+        Py_DECREF(meth);
+        if (adapted && adapted != Py_None) return adapted;
+        Py_XDECREF(adapted);
+        if (PyErr_Occurred()) {
+            if (PyErr_ExceptionMatches(PyExc_TypeError)) {
+               PyErr_Clear();
+            } else {
+                return NULL;
+            }
+        }
+    }
+    else {
+        /* obj.__conform__ not found. */
+        PyErr_Clear();
+    }
+
+    /* Finally check if a superclass can be adapted and use the same adapter. */
+    if (!(adapter = _get_superclass_adapter(obj, proto))) {
+        return NULL;
+    }
+    if (Py_None != adapter) {
+        adapted = PyObject_CallFunctionObjArgs(adapter, obj, NULL);
+        return adapted;
+    }
+
+    /* else set the right exception and return NULL */
+    PyOS_snprintf(buffer, 255, "can't adapt type '%s'",
+        Py_TYPE(obj)->tp_name);
+    psyco_set_error(ProgrammingError, NULL, buffer);
+    return NULL;
+}
+
+/* microprotocol_getquoted - utility function that adapt and call getquoted.
+ *
+ * Return a bytes string, NULL on error.
+ */
+
+PyObject *
+microprotocol_getquoted(PyObject *obj, connectionObject *conn)
+{
+    PyObject *res = NULL;
+    PyObject *prepare = NULL;
+    PyObject *adapted;
+
+    if (!(adapted = microprotocols_adapt(obj, (PyObject*)&isqlquoteType, NULL))) {
+       goto exit;
+    }
+
+    Dprintf("microprotocol_getquoted: adapted to %s",
+        Py_TYPE(adapted)->tp_name);
+
+    /* if requested prepare the object passing it the connection */
+    if (conn) {
+        if ((prepare = PyObject_GetAttrString(adapted, "prepare"))) {
+            res = PyObject_CallFunctionObjArgs(
+                prepare, (PyObject *)conn, NULL);
+            if (res) {
+                Py_DECREF(res);
+                res = NULL;
+            } else {
+                goto exit;
+            }
+        }
+        else {
+            /* adapted.prepare not found */
+            PyErr_Clear();
+        }
+    }
+
+    /* call the getquoted method on adapted (that should exist because we
+       adapted to the right protocol) */
+    res = PyObject_CallMethod(adapted, "getquoted", NULL);
+
+    /* Convert to bytes. */
+    if (res && PyUnicode_CheckExact(res)) {
+        PyObject *b;
+        b = conn_encode(conn, res);
+        Py_DECREF(res);
+        res = b;
+    }
+
+exit:
+    Py_XDECREF(adapted);
+    Py_XDECREF(prepare);
+
+    /* we return res with one extra reference, the caller shall free it */
+    return res;
+}
+
+
+/** module-level functions **/
+
+PyObject *
+psyco_microprotocols_adapt(cursorObject *self, PyObject *args)
+{
+    PyObject *obj, *alt = NULL;
+    PyObject *proto = (PyObject*)&isqlquoteType;
+
+    if (!PyArg_ParseTuple(args, "O|OO", &obj, &proto, &alt)) return NULL;
+    return microprotocols_adapt(obj, proto, alt);
+}