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/* statement.c - the statement type
*
* Copyright (C) 2005-2010 Gerhard Häring <gh@ghaering.de>
*
* This file is part of pysqlite.
*
* 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 "connection.h"
#include "statement.h"
#include "util.h"
/* prototypes */
static const char *lstrip_sql(const char *sql);
pysqlite_Statement *
pysqlite_statement_create(pysqlite_Connection *connection, PyObject *sql)
{
pysqlite_state *state = connection->state;
assert(PyUnicode_Check(sql));
Py_ssize_t size;
const char *sql_cstr = PyUnicode_AsUTF8AndSize(sql, &size);
if (sql_cstr == NULL) {
return NULL;
}
sqlite3 *db = connection->db;
int max_length = sqlite3_limit(db, SQLITE_LIMIT_SQL_LENGTH, -1);
if (size > max_length) {
PyErr_SetString(connection->DataError,
"query string is too large");
return NULL;
}
if (strlen(sql_cstr) != (size_t)size) {
PyErr_SetString(connection->ProgrammingError,
"the query contains a null character");
return NULL;
}
sqlite3_stmt *stmt;
const char *tail;
int rc;
Py_BEGIN_ALLOW_THREADS
rc = sqlite3_prepare_v2(db, sql_cstr, (int)size + 1, &stmt, &tail);
Py_END_ALLOW_THREADS
if (rc != SQLITE_OK) {
_pysqlite_seterror(state, db);
return NULL;
}
if (lstrip_sql(tail) != NULL) {
PyErr_SetString(connection->ProgrammingError,
"You can only execute one statement at a time.");
goto error;
}
/* Determine if the statement is a DML statement.
SELECT is the only exception. See #9924. */
int is_dml = 0;
const char *p = lstrip_sql(sql_cstr);
if (p != NULL) {
is_dml = (PyOS_strnicmp(p, "insert", 6) == 0)
|| (PyOS_strnicmp(p, "update", 6) == 0)
|| (PyOS_strnicmp(p, "delete", 6) == 0)
|| (PyOS_strnicmp(p, "replace", 7) == 0);
}
pysqlite_Statement *self = PyObject_GC_New(pysqlite_Statement,
state->StatementType);
if (self == NULL) {
goto error;
}
self->st = stmt;
self->is_dml = is_dml;
PyObject_GC_Track(self);
return self;
error:
(void)sqlite3_finalize(stmt);
return NULL;
}
static void
stmt_dealloc(pysqlite_Statement *self)
{
PyTypeObject *tp = Py_TYPE(self);
PyObject_GC_UnTrack(self);
if (self->st) {
Py_BEGIN_ALLOW_THREADS
sqlite3_finalize(self->st);
Py_END_ALLOW_THREADS
self->st = 0;
}
tp->tp_free(self);
Py_DECREF(tp);
}
static int
stmt_traverse(pysqlite_Statement *self, visitproc visit, void *arg)
{
Py_VISIT(Py_TYPE(self));
return 0;
}
/*
* Strip leading whitespace and comments from incoming SQL (null terminated C
* string) and return a pointer to the first non-whitespace, non-comment
* character.
*
* This is used to check if somebody tries to execute more than one SQL query
* with one execute()/executemany() command, which the DB-API don't allow.
*
* It is also used to harden DML query detection.
*/
static inline const char *
lstrip_sql(const char *sql)
{
// This loop is borrowed from the SQLite source code.
for (const char *pos = sql; *pos; pos++) {
switch (*pos) {
case ' ':
case '\t':
case '\f':
case '\n':
case '\r':
// Skip whitespace.
break;
case '-':
// Skip line comments.
if (pos[1] == '-') {
pos += 2;
while (pos[0] && pos[0] != '\n') {
pos++;
}
if (pos[0] == '\0') {
return NULL;
}
continue;
}
return pos;
case '/':
// Skip C style comments.
if (pos[1] == '*') {
pos += 2;
while (pos[0] && (pos[0] != '*' || pos[1] != '/')) {
pos++;
}
if (pos[0] == '\0') {
return NULL;
}
pos++;
continue;
}
return pos;
default:
return pos;
}
}
return NULL;
}
static PyType_Slot stmt_slots[] = {
{Py_tp_dealloc, stmt_dealloc},
{Py_tp_traverse, stmt_traverse},
{0, NULL},
};
static PyType_Spec stmt_spec = {
.name = MODULE_NAME ".Statement",
.basicsize = sizeof(pysqlite_Statement),
.flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
Py_TPFLAGS_IMMUTABLETYPE | Py_TPFLAGS_DISALLOW_INSTANTIATION),
.slots = stmt_slots,
};
int
pysqlite_statement_setup_types(PyObject *module)
{
PyObject *type = PyType_FromModuleAndSpec(module, &stmt_spec, NULL);
if (type == NULL) {
return -1;
}
pysqlite_state *state = pysqlite_get_state(module);
state->StatementType = (PyTypeObject *)type;
return 0;
}
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