mirror of
https://github.com/python/cpython.git
synced 2025-07-31 07:04:42 +00:00
0741a60ca7
merged into the 2.5 maintenance branch: - self->statement was not checked while fetching data, which could lead to crashes if you used the pysqlite API in unusual ways. Closing the cursor and continuing to fetch data was enough. - Converters are stored in a converters dictionary. The converter name is uppercased first. The old upper-casing algorithm was wrong and was replaced by a simple call to the Python string's upper() method instead. -Applied patch by Glyph Lefkowitz that fixes the problem with subsequent SQLITE_SCHEMA errors. - Improvement to the row type: rows can now be iterated over and have a keys() method. This improves compatibility with both tuple and dict a lot. - A bugfix for the subsecond resolution in timestamps. - Corrected the way the flags PARSE_DECLTYPES and PARSE_COLNAMES are checked for. Now they work as documented. - gcc on Linux sucks. It exports all symbols by default in shared libraries, so if symbols are not unique it can lead to problems with symbol lookup. pysqlite used to crash under Apache when mod_cache was enabled because both modules had the symbol cache_init. I fixed this by applying the prefix pysqlite_ almost everywhere. Sigh.
375 lines
13 KiB
C
375 lines
13 KiB
C
/* cache .c - a LRU cache
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*
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* Copyright (C) 2004-2006 Gerhard Häring <gh@ghaering.de>
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*
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* This file is part of pysqlite.
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*
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the authors be held liable for any damages
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* arising from the use of this software.
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*
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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*
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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*/
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#include "cache.h"
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#include <limits.h>
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/* only used internally */
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pysqlite_Node* pysqlite_new_node(PyObject* key, PyObject* data)
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{
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pysqlite_Node* node;
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node = (pysqlite_Node*) (pysqlite_NodeType.tp_alloc(&pysqlite_NodeType, 0));
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if (!node) {
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return NULL;
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}
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Py_INCREF(key);
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node->key = key;
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Py_INCREF(data);
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node->data = data;
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node->prev = NULL;
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node->next = NULL;
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return node;
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}
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void pysqlite_node_dealloc(pysqlite_Node* self)
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{
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Py_DECREF(self->key);
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Py_DECREF(self->data);
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self->ob_type->tp_free((PyObject*)self);
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}
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int pysqlite_cache_init(pysqlite_Cache* self, PyObject* args, PyObject* kwargs)
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{
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PyObject* factory;
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int size = 10;
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self->factory = NULL;
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if (!PyArg_ParseTuple(args, "O|i", &factory, &size)) {
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return -1;
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}
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/* minimum cache size is 5 entries */
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if (size < 5) {
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size = 5;
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}
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self->size = size;
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self->first = NULL;
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self->last = NULL;
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self->mapping = PyDict_New();
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if (!self->mapping) {
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return -1;
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}
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Py_INCREF(factory);
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self->factory = factory;
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self->decref_factory = 1;
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return 0;
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}
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void pysqlite_cache_dealloc(pysqlite_Cache* self)
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{
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pysqlite_Node* node;
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pysqlite_Node* delete_node;
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if (!self->factory) {
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/* constructor failed, just get out of here */
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return;
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}
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/* iterate over all nodes and deallocate them */
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node = self->first;
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while (node) {
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delete_node = node;
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node = node->next;
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Py_DECREF(delete_node);
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}
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if (self->decref_factory) {
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Py_DECREF(self->factory);
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}
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Py_DECREF(self->mapping);
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self->ob_type->tp_free((PyObject*)self);
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}
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PyObject* pysqlite_cache_get(pysqlite_Cache* self, PyObject* args)
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{
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PyObject* key = args;
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pysqlite_Node* node;
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pysqlite_Node* ptr;
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PyObject* data;
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node = (pysqlite_Node*)PyDict_GetItem(self->mapping, key);
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if (node) {
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/* an entry for this key already exists in the cache */
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/* increase usage counter of the node found */
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if (node->count < LONG_MAX) {
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node->count++;
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}
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/* if necessary, reorder entries in the cache by swapping positions */
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if (node->prev && node->count > node->prev->count) {
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ptr = node->prev;
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while (ptr->prev && node->count > ptr->prev->count) {
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ptr = ptr->prev;
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}
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if (node->next) {
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node->next->prev = node->prev;
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} else {
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self->last = node->prev;
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}
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if (node->prev) {
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node->prev->next = node->next;
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}
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if (ptr->prev) {
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ptr->prev->next = node;
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} else {
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self->first = node;
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}
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node->next = ptr;
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node->prev = ptr->prev;
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if (!node->prev) {
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self->first = node;
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}
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ptr->prev = node;
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}
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} else {
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/* There is no entry for this key in the cache, yet. We'll insert a new
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* entry in the cache, and make space if necessary by throwing the
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* least used item out of the cache. */
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if (PyDict_Size(self->mapping) == self->size) {
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if (self->last) {
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node = self->last;
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if (PyDict_DelItem(self->mapping, self->last->key) != 0) {
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return NULL;
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}
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if (node->prev) {
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node->prev->next = NULL;
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}
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self->last = node->prev;
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node->prev = NULL;
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Py_DECREF(node);
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}
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}
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data = PyObject_CallFunction(self->factory, "O", key);
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if (!data) {
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return NULL;
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}
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node = pysqlite_new_node(key, data);
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if (!node) {
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return NULL;
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}
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node->prev = self->last;
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Py_DECREF(data);
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if (PyDict_SetItem(self->mapping, key, (PyObject*)node) != 0) {
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Py_DECREF(node);
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return NULL;
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}
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if (self->last) {
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self->last->next = node;
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} else {
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self->first = node;
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}
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self->last = node;
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}
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Py_INCREF(node->data);
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return node->data;
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}
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PyObject* pysqlite_cache_display(pysqlite_Cache* self, PyObject* args)
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{
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pysqlite_Node* ptr;
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PyObject* prevkey;
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PyObject* nextkey;
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PyObject* fmt_args;
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PyObject* template;
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PyObject* display_str;
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ptr = self->first;
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while (ptr) {
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if (ptr->prev) {
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prevkey = ptr->prev->key;
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} else {
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prevkey = Py_None;
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}
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Py_INCREF(prevkey);
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if (ptr->next) {
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nextkey = ptr->next->key;
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} else {
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nextkey = Py_None;
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}
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Py_INCREF(nextkey);
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fmt_args = Py_BuildValue("OOO", prevkey, ptr->key, nextkey);
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if (!fmt_args) {
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return NULL;
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}
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template = PyString_FromString("%s <- %s ->%s\n");
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if (!template) {
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return NULL;
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}
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display_str = PyString_Format(template, fmt_args);
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Py_DECREF(template);
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Py_DECREF(fmt_args);
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if (!display_str) {
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return NULL;
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}
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PyObject_Print(display_str, stdout, Py_PRINT_RAW);
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Py_DECREF(display_str);
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Py_DECREF(prevkey);
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Py_DECREF(nextkey);
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ptr = ptr->next;
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}
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Py_INCREF(Py_None);
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return Py_None;
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}
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static PyMethodDef cache_methods[] = {
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{"get", (PyCFunction)pysqlite_cache_get, METH_O,
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PyDoc_STR("Gets an entry from the cache or calls the factory function to produce one.")},
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{"display", (PyCFunction)pysqlite_cache_display, METH_NOARGS,
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PyDoc_STR("For debugging only.")},
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{NULL, NULL}
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};
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PyTypeObject pysqlite_NodeType = {
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PyObject_HEAD_INIT(NULL)
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0, /* ob_size */
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MODULE_NAME "Node", /* tp_name */
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sizeof(pysqlite_Node), /* tp_basicsize */
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0, /* tp_itemsize */
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(destructor)pysqlite_node_dealloc, /* tp_dealloc */
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0, /* tp_print */
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0, /* tp_getattr */
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0, /* tp_setattr */
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0, /* tp_compare */
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0, /* tp_repr */
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0, /* tp_as_number */
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0, /* tp_as_sequence */
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0, /* tp_as_mapping */
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0, /* tp_hash */
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0, /* tp_call */
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0, /* tp_str */
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0, /* tp_getattro */
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0, /* tp_setattro */
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0, /* tp_as_buffer */
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Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE, /* tp_flags */
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0, /* tp_doc */
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0, /* tp_traverse */
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0, /* tp_clear */
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0, /* tp_richcompare */
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0, /* tp_weaklistoffset */
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0, /* tp_iter */
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0, /* tp_iternext */
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0, /* tp_methods */
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0, /* tp_members */
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0, /* tp_getset */
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0, /* tp_base */
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0, /* tp_dict */
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0, /* tp_descr_get */
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0, /* tp_descr_set */
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0, /* tp_dictoffset */
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(initproc)0, /* tp_init */
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0, /* tp_alloc */
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0, /* tp_new */
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0 /* tp_free */
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};
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PyTypeObject pysqlite_CacheType = {
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PyObject_HEAD_INIT(NULL)
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0, /* ob_size */
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MODULE_NAME ".Cache", /* tp_name */
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sizeof(pysqlite_Cache), /* tp_basicsize */
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0, /* tp_itemsize */
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(destructor)pysqlite_cache_dealloc, /* tp_dealloc */
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0, /* tp_print */
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0, /* tp_getattr */
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0, /* tp_setattr */
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0, /* tp_compare */
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0, /* tp_repr */
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0, /* tp_as_number */
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0, /* tp_as_sequence */
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0, /* tp_as_mapping */
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0, /* tp_hash */
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0, /* tp_call */
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0, /* tp_str */
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0, /* tp_getattro */
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0, /* tp_setattro */
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0, /* tp_as_buffer */
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Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE, /* tp_flags */
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0, /* tp_doc */
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0, /* tp_traverse */
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0, /* tp_clear */
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0, /* tp_richcompare */
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0, /* tp_weaklistoffset */
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0, /* tp_iter */
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0, /* tp_iternext */
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cache_methods, /* tp_methods */
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0, /* tp_members */
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0, /* tp_getset */
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0, /* tp_base */
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0, /* tp_dict */
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0, /* tp_descr_get */
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0, /* tp_descr_set */
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0, /* tp_dictoffset */
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(initproc)pysqlite_cache_init, /* tp_init */
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0, /* tp_alloc */
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0, /* tp_new */
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0 /* tp_free */
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};
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extern int pysqlite_cache_setup_types(void)
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{
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int rc;
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pysqlite_NodeType.tp_new = PyType_GenericNew;
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pysqlite_CacheType.tp_new = PyType_GenericNew;
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rc = PyType_Ready(&pysqlite_NodeType);
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if (rc < 0) {
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return rc;
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}
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rc = PyType_Ready(&pysqlite_CacheType);
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return rc;
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}
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