mirror of https://github.com/python/cpython.git
348 lines
7.6 KiB
C
348 lines
7.6 KiB
C
/***********************************************************
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Copyright 1991, 1992, 1993 by Stichting Mathematisch Centrum,
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Amsterdam, The Netherlands.
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All Rights Reserved
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Permission to use, copy, modify, and distribute this software and its
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documentation for any purpose and without fee is hereby granted,
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provided that the above copyright notice appear in all copies and that
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both that copyright notice and this permission notice appear in
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supporting documentation, and that the names of Stichting Mathematisch
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Centrum or CWI not be used in advertising or publicity pertaining to
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distribution of the software without specific, written prior permission.
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STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
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THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE
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FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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******************************************************************/
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/* Access object implementation */
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/* XXX TO DO LIST
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- need a "super user" mechanism for debugger etc.
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- __init__ and __del__ (and all other similar methods)
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should be usable even when private, not ignored
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- "from foo import bar" should check access of bar
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*/
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#include "allobjects.h"
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#include "structmember.h"
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#include "modsupport.h" /* For getargs() etc. */
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typedef struct {
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OB_HEAD
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object *ac_value;
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object *ac_owner;
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typeobject *ac_type;
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int ac_mode;
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} accessobject;
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/* Forward */
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static int typecheck PROTO((object *, typeobject *));
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static int ownercheck PROTO((object *, object *, int, int));
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object *
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newaccessobject(value, owner, type, mode)
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object *value;
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object *owner;
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typeobject *type;
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int mode;
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{
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accessobject *ap;
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if (!typecheck(value, type)) {
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err_setstr(AccessError,
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"access: initial value has inappropriate type");
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return NULL;
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}
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ap = NEWOBJ(accessobject, &Accesstype);
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if (ap == NULL)
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return NULL;
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XINCREF(value);
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ap->ac_value = value;
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XINCREF(owner);
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ap->ac_owner = owner;
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XINCREF(type);
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ap->ac_type = (typeobject *)type;
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ap->ac_mode = mode;
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return (object *)ap;
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}
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object *
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cloneaccessobject(op)
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object *op;
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{
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register accessobject *ap;
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if (!is_accessobject(op)) {
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err_badcall();
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return NULL;
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}
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ap = (accessobject *)op;
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return newaccessobject(ap->ac_value, ap->ac_owner,
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ap->ac_type, ap->ac_mode);
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}
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void
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setaccessowner(op, owner)
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object *op;
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object *owner;
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{
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register accessobject *ap;
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if (!is_accessobject(op))
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return; /* XXX no error */
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ap = (accessobject *)op;
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XDECREF(ap->ac_owner);
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XINCREF(owner);
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ap->ac_owner = owner;
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}
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int
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hasaccessvalue(op)
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object *op;
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{
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if (!is_accessobject(op))
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return 0;
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return ((accessobject *)op)->ac_value != NULL;
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}
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object *
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getaccessvalue(op, owner)
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object *op;
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object *owner;
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{
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register accessobject *ap;
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if (!is_accessobject(op)) {
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err_badcall();
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return NULL;
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}
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ap = (accessobject *)op;
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if (!ownercheck(owner, ap->ac_owner, AC_R, ap->ac_mode)) {
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err_setstr(AccessError, "read access denied");
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return NULL;
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}
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if (ap->ac_value == NULL) {
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err_setstr(AccessError, "no current value");
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return NULL;
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}
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INCREF(ap->ac_value);
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return ap->ac_value;
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}
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int
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setaccessvalue(op, owner, value)
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object *op;
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object *owner;
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object *value;
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{
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register accessobject *ap;
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if (!is_accessobject(op)) {
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err_badcall();
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return -1;
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}
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ap = (accessobject *)op;
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if (!ownercheck(owner, ap->ac_owner, AC_W, ap->ac_mode)) {
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err_setstr(AccessError, "write access denied");
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return -1;
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}
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if (!typecheck(value, ap->ac_type)) {
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err_setstr(AccessError, "assign value of inappropriate type");
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return -1;
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}
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if (value == NULL) { /* Delete it */
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if (ap->ac_value == NULL) {
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err_setstr(AccessError, "no current value");
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return -1;
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}
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DECREF(ap->ac_value);
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ap->ac_value = NULL;
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return 0;
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}
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XDECREF(ap->ac_value);
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INCREF(value);
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ap->ac_value = value;
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return 0;
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}
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static int
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typecheck(value, type)
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object *value;
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typeobject *type;
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{
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object *x;
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if (value == NULL || type == NULL)
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return 1; /* No check */
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if (value->ob_type == type)
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return 1; /* Exact match */
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if (type == &Anynumbertype) {
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if (value->ob_type->tp_as_number == NULL)
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return 0;
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if (!is_instanceobject(value))
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return 1;
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/* For instances, make sure it really looks like a number */
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x = getattr(value, "__sub__");
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if (x == NULL) {
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err_clear();
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return 0;
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}
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DECREF(x);
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return 1;
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}
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if (type == &Anysequencetype) {
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if (value->ob_type->tp_as_sequence == NULL)
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return 0;
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if (!is_instanceobject(value))
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return 1;
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/* For instances, make sure it really looks like a sequence */
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x = getattr(value, "__getslice__");
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if (x == NULL) {
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err_clear();
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return 0;
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}
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DECREF(x);
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return 1;
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}
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if (type == &Anymappingtype) {
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if (value->ob_type->tp_as_mapping == NULL)
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return 0;
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if (!is_instanceobject(value))
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return 1;
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/* For instances, make sure it really looks like a mapping */
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x = getattr(value, "__getitem__");
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if (x == NULL) {
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err_clear();
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return 0;
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}
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DECREF(x);
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return 1;
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}
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return 0;
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}
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static int
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ownercheck(caller, owner, access, mode)
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object *caller;
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object *owner;
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int access;
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int mode;
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{
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int mask = AC_PUBLIC;
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if (owner != NULL) {
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if (caller == owner)
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mask |= AC_PRIVATE | AC_PROTECTED;
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else if (is_classobject(owner) && issubclass(caller, owner))
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mask |= AC_PROTECTED;
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}
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return access & mode & mask;
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}
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/* Access methods */
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static void
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access_dealloc(ap)
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accessobject *ap;
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{
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XDECREF(ap->ac_value);
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XDECREF(ap->ac_owner);
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XDECREF(ap->ac_type);
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DEL(ap);
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}
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#define OFF(x) offsetof(accessobject, x)
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static struct memberlist access_memberlist[] = {
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{"ac_value", T_OBJECT, OFF(ac_value)},
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{"ac_owner", T_OBJECT, OFF(ac_owner)},
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{"ac_type", T_OBJECT, OFF(ac_type)},
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{"ac_mode", T_INT, OFF(ac_mode)},
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{NULL} /* Sentinel */
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};
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static object *
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access_getattr(ap, name)
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accessobject *ap;
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char *name;
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{
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return getmember((char *)ap, access_memberlist, name);
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}
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static object *
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access_repr(ap)
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accessobject *ap;
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{
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char buf[300];
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char buf2[20];
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char *ownername;
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typeobject *type = ap->ac_type;
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if (is_classobject(ap->ac_owner)) {
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ownername =
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getstringvalue(((classobject *)ap->ac_owner)->cl_name);
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}
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else {
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sprintf(buf2, "0x%lx", (long)ap->ac_owner);
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ownername = buf2;
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}
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sprintf(buf,
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"<access object, value 0x%lx, owner %.100s, type %.100s, mode %04o>",
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(long)(ap->ac_value),
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ownername,
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type ? type->tp_name : "-",
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ap->ac_mode);
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return newstringobject(buf);
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}
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typeobject Accesstype = {
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OB_HEAD_INIT(&Typetype)
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0, /*ob_size*/
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"access", /*tp_name*/
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sizeof(accessobject), /*tp_size*/
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0, /*tp_itemsize*/
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/* methods */
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access_dealloc, /*tp_dealloc*/
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0, /*tp_print*/
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access_getattr, /*tp_getattr*/
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0, /*tp_setattr*/
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0, /*tp_compare*/
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access_repr, /*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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};
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/* Pseudo type objects to indicate collections of types */
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/* XXX This should be replaced by a more general "subclassing"
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XXX mechanism for type objects... */
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typeobject Anynumbertype = {
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OB_HEAD_INIT(&Typetype)
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0, /*ob_size*/
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"*number*", /*tp_name*/
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};
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/* XXX Should really distinguish mutable and immutable sequences as well */
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typeobject Anysequencetype = {
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OB_HEAD_INIT(&Typetype)
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0, /*ob_size*/
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"*sequence*", /*tp_name*/
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};
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typeobject Anymappingtype = {
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OB_HEAD_INIT(&Typetype)
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0, /*ob_size*/
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"*mapping*", /*tp_name*/
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};
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