view Python/symtable.c @ 17337:96ea0eccdb31 legacy-trunk

SF patch #413552 - Premature decref on object Jeffery Collins pointed out that filterstring decrefs a character object before it's done using it. This works by accident today because another module always happens to have an active reference too at the time. The accident doesn't work after his Pippy modifications, and since it *is* an accident even in the mainline Python, it should work by design there too. The patch accomplishes that.
author Tim Peters <tim.peters@gmail.com>
date Sat, 07 Apr 2001 20:34:48 +0000
parents 08d937107fe6
children 568c75dd5078 7bc473b2c654
line wrap: on
line source

#include "Python.h"
#include "compile.h"
#include "symtable.h"
#include "graminit.h"
#include "structmember.h"

PyObject *
PySymtableEntry_New(struct symtable *st, char *name, int type, int lineno)
{
	PySymtableEntryObject *ste = NULL;
	PyObject *k, *v;

	k = PyInt_FromLong(st->st_nscopes++);
	if (k == NULL)
		goto fail;
	v = PyDict_GetItem(st->st_symbols, k);
	if (v) /* XXX could check that name, type, lineno match */ {
		Py_INCREF(v);
		return v;
	}
	
	ste = (PySymtableEntryObject *)PyObject_New(PySymtableEntryObject,
						    &PySymtableEntry_Type);
	ste->ste_table = st;
	ste->ste_id = k;

	v = PyString_FromString(name);
	if (v == NULL)
		goto fail;
	ste->ste_name = v;
	
	v = PyDict_New();
	if (v == NULL)
	    goto fail;
	ste->ste_symbols = v;

	v = PyList_New(0);
	if (v == NULL)
	    goto fail;
	ste->ste_varnames = v;

	v = PyList_New(0);
	if (v == NULL)
	    goto fail;
	ste->ste_children = v;

	ste->ste_optimized = 0;
	ste->ste_lineno = lineno;
	switch (type) {
	case funcdef:
	case lambdef:
		ste->ste_type = TYPE_FUNCTION;
		break;
	case classdef:
		ste->ste_type = TYPE_CLASS;
		break;
	case single_input:
	case eval_input:
	case file_input:
		ste->ste_type = TYPE_MODULE;
		break;
	}

	if (st->st_cur == NULL)
		ste->ste_nested = 0;
	else if (st->st_cur->ste_nested 
		 || st->st_cur->ste_type == TYPE_FUNCTION)
		ste->ste_nested = 1;
	else
		ste->ste_nested = 0;
	ste->ste_child_free = 0;

	if (PyDict_SetItem(st->st_symbols, ste->ste_id, (PyObject *)ste) < 0)
	    goto fail;
	
	return (PyObject *)ste;
 fail:
	Py_XDECREF(ste);
	return NULL;
}

static PyObject *
ste_repr(PySymtableEntryObject *ste)
{
	char buf[256];

	sprintf(buf, "<symtable entry %.100s(%ld), line %d>",
		PyString_AS_STRING(ste->ste_name),
		PyInt_AS_LONG(ste->ste_id),
		ste->ste_lineno);
	return PyString_FromString(buf);
}

static void
ste_dealloc(PySymtableEntryObject *ste)
{
	ste->ste_table = NULL;
	Py_XDECREF(ste->ste_id);
	Py_XDECREF(ste->ste_name);
	Py_XDECREF(ste->ste_symbols);
	Py_XDECREF(ste->ste_varnames);
	Py_XDECREF(ste->ste_children);
	PyObject_Del(ste);
}

#define OFF(x) offsetof(PySymtableEntryObject, x)

static struct memberlist ste_memberlist[] = {
	{"id",       T_OBJECT, OFF(ste_id), READONLY},
	{"name",     T_OBJECT, OFF(ste_name), READONLY},
	{"symbols",  T_OBJECT, OFF(ste_symbols), READONLY},
	{"varnames", T_OBJECT, OFF(ste_varnames), READONLY},
	{"children", T_OBJECT, OFF(ste_children), READONLY},
	{"type",     T_INT,    OFF(ste_type), READONLY},
	{"lineno",   T_INT,    OFF(ste_lineno), READONLY},
	{"optimized",T_INT,    OFF(ste_optimized), READONLY},
	{"nested",   T_INT,    OFF(ste_nested), READONLY},
	{NULL}
};

static PyObject *
ste_getattr(PySymtableEntryObject *ste, char *name)
{
	return PyMember_Get((char *)ste, ste_memberlist, name);
}

PyTypeObject PySymtableEntry_Type = {
	PyObject_HEAD_INIT(&PyType_Type)
	0,
	"symtable entry",
	sizeof(PySymtableEntryObject),
	0,
	(destructor)ste_dealloc,                /* tp_dealloc */
	0,                                      /* tp_print */
	(getattrfunc)ste_getattr,               /* tp_getattr */
	0,					/* tp_setattr */
	0,			                /* tp_compare */
	(reprfunc)ste_repr,			/* tp_repr */
	0,					/* tp_as_number */
	0,			                /* tp_as_sequence */
	0,					/* tp_as_mapping */
	0,					/* tp_hash */
	0,					/* tp_call */
	0,					/* tp_str */
	0,					/* tp_getattro */
	0,					/* tp_setattro */
	0,					/* tp_as_buffer */
	Py_TPFLAGS_DEFAULT,	                /* tp_flags */
 	0,					/* tp_doc */
};