object.c

python s60 1.4.5版本的源代码

/* Portions Copyright (c) 2005 Nokia Corporation */

/* Generic object operations; and implementation of None (NoObject) */

#include "Python.h"

#ifdef macintosh
#include "macglue.h"
#endif

/* just for trashcan: */
#include "compile.h"
#include "frameobject.h"
#include "traceback.h"


#if defined( Py_TRACE_REFS ) || defined( Py_REF_DEBUG )
DL_IMPORT(long) _Py_RefTotal;
#endif

#ifndef SYMBIAN
DL_IMPORT(int) Py_DivisionWarningFlag;
#endif

/* Object allocation routines used by NEWOBJ and NEWVAROBJ macros.
   These are used by the individual routines for object creation.
   Do not call them otherwise, they do not initialize the object! */

#ifdef COUNT_ALLOCS
const static PyTypeObject *type_list;
extern int tuple_zero_allocs, fast_tuple_allocs;
extern int quick_int_allocs, quick_neg_int_allocs;
extern int null_strings, one_strings;
DL_EXPORT(void)
dump_counts(void)
{
	PyTypeObject *tp;

	for (tp = type_list; tp; tp = tp->tp_next)
		fprintf(stderr, "%s alloc'd: %d, freed: %d, max in use: %d\n",
			tp->tp_name, tp->tp_allocs, tp->tp_frees,
			tp->tp_maxalloc);
	fprintf(stderr, "fast tuple allocs: %d, empty: %d\n",
		fast_tuple_allocs, tuple_zero_allocs);
	fprintf(stderr, "fast int allocs: pos: %d, neg: %d\n",
		quick_int_allocs, quick_neg_int_allocs);
	fprintf(stderr, "null strings: %d, 1-strings: %d\n",
		null_strings, one_strings);
}

DL_EXPORT(PyObject *)
get_counts(void)
{
	PyTypeObject *tp;
	PyObject *result;
	PyObject *v;

	result = PyList_New(0);
	if (result == NULL)
		return NULL;
	for (tp = type_list; tp; tp = tp->tp_next) {
		v = Py_BuildValue("(siii)", tp->tp_name, tp->tp_allocs,
				  tp->tp_frees, tp->tp_maxalloc);
		if (v == NULL) {
			Py_DECREF(result);
			return NULL;
		}
		if (PyList_Append(result, v) < 0) {
			Py_DECREF(v);
			Py_DECREF(result);
			return NULL;
		}
		Py_DECREF(v);
	}
	return result;
}

DL_EXPORT(void)
inc_count(PyTypeObject *tp)
{
	if (tp->tp_allocs == 0) {
		/* first time; insert in linked list */
		if (tp->tp_next != NULL) /* sanity check */
			Py_FatalError("XXX inc_count sanity check");
		tp->tp_next = type_list;
		/* Note that as of Python 2.2, heap-allocated type objects
		 * can go away, but this code requires that they stay alive
		 * until program exit.  That's why we're careful with
		 * refcounts here.  type_list gets a new reference to tp,
		 * while ownership of the reference type_list used to hold
		 * (if any) was transferred to tp->tp_next in the line above.
		 * tp is thus effectively immortal after this.
		 */
		Py_INCREF(tp);
		type_list = tp;
	}
	tp->tp_allocs++;
	if (tp->tp_allocs - tp->tp_frees > tp->tp_maxalloc)
		tp->tp_maxalloc = tp->tp_allocs - tp->tp_frees;
}
#endif

DL_EXPORT(PyObject *)
PyObject_Init(PyObject *op, PyTypeObject *tp)
{
	if (op == NULL)
		return PyErr_NoMemory();
	/* Any changes should be reflected in PyObject_INIT (objimpl.h) */
	op->ob_type = tp;
	_Py_NewReference(op);
	return op;
}

DL_EXPORT(PyVarObject *)
PyObject_InitVar(PyVarObject *op, PyTypeObject *tp, int size)
{
	if (op == NULL)
		return (PyVarObject *) PyErr_NoMemory();
	/* Any changes should be reflected in PyObject_INIT_VAR */
	op->ob_size = size;
	op->ob_type = tp;
	_Py_NewReference((PyObject *)op);
	return op;
}

DL_EXPORT(PyObject *)
_PyObject_New(PyTypeObject *tp)
{
	PyObject *op;
	op = (PyObject *) PyObject_MALLOC(_PyObject_SIZE(tp));
	if (op == NULL)
		return PyErr_NoMemory();
	return PyObject_INIT(op, tp);
}

DL_EXPORT(PyVarObject *)
_PyObject_NewVar(PyTypeObject *tp, int nitems)
{
	PyVarObject *op;
	const size_t size = _PyObject_VAR_SIZE(tp, nitems);
	op = (PyVarObject *) PyObject_MALLOC(size);
	if (op == NULL)
		return (PyVarObject *)PyErr_NoMemory();
	return PyObject_INIT_VAR(op, tp, nitems);
}

DL_EXPORT(void)
_PyObject_Del(PyObject *op)
{
	PyObject_FREE(op);
}

DL_EXPORT(int)
PyObject_Print(PyObject *op, FILE *fp, int flags)
{
	int ret = 0;
	if (PyErr_CheckSignals())
		return -1;
#ifdef USE_STACKCHECK
	if (PyOS_CheckStack()) {
		PyErr_SetString(PyExc_MemoryError, "stack overflow");
		return -1;
	}
#endif
	clearerr(fp); /* Clear any previous error condition */
	if (op == NULL) {
		fprintf(fp, "<nil>");
	}
	else {
		if (op->ob_refcnt <= 0)
			fprintf(fp, "<refcnt %u at %p>",
				op->ob_refcnt, op);
		else if (op->ob_type->tp_print == NULL) {
			PyObject *s;
			if (flags & Py_PRINT_RAW)
				s = PyObject_Str(op);
			else
				s = PyObject_Repr(op);
			if (s == NULL)
				ret = -1;
			else {
				ret = PyObject_Print(s, fp, Py_PRINT_RAW);
			}
			Py_XDECREF(s);
		}
		else
			ret = (*op->ob_type->tp_print)(op, fp, flags);
	}
	if (ret == 0) {
		if (ferror(fp)) {
			PyErr_SetFromErrno(PyExc_IOError);
			clearerr(fp);
			ret = -1;
		}
	}
	return ret;
}

/* For debugging convenience.  See Misc/gdbinit for some useful gdb hooks */
DL_EXPORT(void)
_PyObject_Dump(PyObject* op)
{
	if (op == NULL)
		fprintf(stderr, "NULL\n");
	else {
		fprintf(stderr, "object  : ");
		(void)PyObject_Print(op, stderr, 0);
		fprintf(stderr, "\n"
			"type    : %s\n"
			"refcount: %d\n"
			"address : %p\n",
			op->ob_type==NULL ? "NULL" : op->ob_type->tp_name,
			op->ob_refcnt,
			op);
	}
}

DL_EXPORT(PyObject *)
PyObject_Repr(PyObject *v)
{
	if (PyErr_CheckSignals())
		return NULL;
#ifdef USE_STACKCHECK
	if (PyOS_CheckStack()) {
		PyErr_SetString(PyExc_MemoryError, "stack overflow");
		return NULL;
	}
#endif
	if (v == NULL)
		return PyString_FromString("<NULL>");
	else if (v->ob_type->tp_repr == NULL)
		return PyString_FromFormat("<%s object at %p>",
					   v->ob_type->tp_name, v);
	else {
		PyObject *res;
		res = (*v->ob_type->tp_repr)(v);
		if (res == NULL)
			return NULL;
#ifdef Py_USING_UNICODE
		if (PyUnicode_Check(res)) {
			PyObject* str;
			str = PyUnicode_AsUnicodeEscapeString(res);
			Py_DECREF(res);
			if (str)
				res = str;
			else
				return NULL;
		}
#endif
		if (!PyString_Check(res)) {
			PyErr_Format(PyExc_TypeError,
				     "__repr__ returned non-string (type %.200s)",
				     res->ob_type->tp_name);
			Py_DECREF(res);
			return NULL;
		}
		return res;
	}
}

DL_EXPORT(PyObject *)
PyObject_Str(PyObject *v)
{
	PyObject *res;

	if (v == NULL)
		return PyString_FromString("<NULL>");
	if (PyString_CheckExact(v)) {
		Py_INCREF(v);
		return v;
	}
	if (v->ob_type->tp_str == NULL)
		return PyObject_Repr(v);

	res = (*v->ob_type->tp_str)(v);
	if (res == NULL)
		return NULL;
#ifdef Py_USING_UNICODE
	if (PyUnicode_Check(res)) {
		PyObject* str;
		str = PyUnicode_AsEncodedString(res, NULL, NULL);
		Py_DECREF(res);
		if (str)
			res = str;
		else
		    	return NULL;
	}
#endif
	if (!PyString_Check(res)) {
		PyErr_Format(PyExc_TypeError,
			     "__str__ returned non-string (type %.200s)",
			     res->ob_type->tp_name);
		Py_DECREF(res);
		return NULL;
	}
	return res;
}

#ifdef Py_USING_UNICODE
DL_EXPORT(PyObject *)
PyObject_Unicode(PyObject *v)
{
	PyObject *res;

	if (v == NULL)
		res = PyString_FromString("<NULL>");
	if (PyUnicode_CheckExact(v)) {
		Py_INCREF(v);
		return v;
	}
	if (PyUnicode_Check(v)) {
		/* For a Unicode subtype that's not a Unicode object,
		   return a true Unicode object with the same data. */
		return PyUnicode_FromUnicode(PyUnicode_AS_UNICODE(v),
					     PyUnicode_GET_SIZE(v));
	}
	if (PyString_Check(v)) {
		Py_INCREF(v);
	    	res = v;
    	}
	else {
		PyObject *func;
#ifndef SYMBIAN
		static PyObject *unicodestr;
#else
#define unicodestr (PYTHON_GLOBALS->unicodestr)
#endif
		/* XXX As soon as we have a tp_unicode slot, we should
		       check this before trying the __unicode__
		       method. */
		if (unicodestr == NULL) {
			unicodestr = PyString_InternFromString(
						       "__unicode__");
			if (unicodestr == NULL)
				return NULL;
		}
		func = PyObject_GetAttr(v, unicodestr);
		if (func != NULL) {
		    	res = PyEval_CallObject(func, (PyObject *)NULL);
			Py_DECREF(func);
		}
		else {
			PyErr_Clear();
			if (v->ob_type->tp_str != NULL)
				res = (*v->ob_type->tp_str)(v);
			else
				res = PyObject_Repr(v);
		}
	}
	if (res == NULL)
		return NULL;
	if (!PyUnicode_Check(res)) {
		PyObject *str;
		str = PyUnicode_FromEncodedObject(res, NULL, "strict");
		Py_DECREF(res);
		if (str)
			res = str;
		else
		    	return NULL;
	}
	return res;
}
#endif


/* Macro to get the tp_richcompare field of a type if defined */
#define RICHCOMPARE(t) (PyType_HasFeature((t), Py_TPFLAGS_HAVE_RICHCOMPARE) \
                         ? (t)->tp_richcompare : NULL)

/* Map rich comparison operators to their swapped version, e.g. LT --> GT */
const static int swapped_op[] = {Py_GT, Py_GE, Py_EQ, Py_NE, Py_LT, Py_LE};

/* Try a genuine rich comparison, returning an object.  Return:
   NULL for exception;
   NotImplemented if this particular rich comparison is not implemented or
     undefined;
   some object not equal to NotImplemented if it is implemented
     (this latter object may not be a Boolean).
*/
static PyObject *
try_rich_compare(PyObject *v, PyObject *w, int op)
{
	richcmpfunc f;
	PyObject *res;

	if (v->ob_type != w->ob_type &&
	    PyType_IsSubtype(w->ob_type, v->ob_type) &&
	    (f = RICHCOMPARE(w->ob_type)) != NULL) {
		res = (*f)(w, v, swapped_op[op]);
		if (res != Py_NotImplemented)
			return res;
		Py_DECREF(res);
	}
	if ((f = RICHCOMPARE(v->ob_type)) != NULL) {
		res = (*f)(v, w, op);
		if (res != Py_NotImplemented)
			return res;
		Py_DECREF(res);
	}
	if ((f = RICHCOMPARE(w->ob_type)) != NULL) {
		return (*f)(w, v, swapped_op[op]);
	}
	res = Py_NotImplemented;
	Py_INCREF(res);
	return res;
}

/* Try a genuine rich comparison, returning an int.  Return:
   -1 for exception (including the case where try_rich_compare() returns an
      object that's not a Boolean);
    0 if the outcome is false;
    1 if the outcome is true;
    2 if this particular rich comparison is not implemented or undefined.
*/
static int
try_rich_compare_bool(PyObject *v, PyObject *w, int op)
{
	PyObject *res;
	int ok;

	if (RICHCOMPARE(v->ob_type) == NULL && RICHCOMPARE(w->ob_type) == NULL)
		return 2; /* Shortcut, avoid INCREF+DECREF */
	res = try_rich_compare(v, w, op);
	if (res == NULL)
		return -1;
	if (res == Py_NotImplemented) {
		Py_DECREF(res);
		return 2;
	}
	ok = PyObject_IsTrue(res);
	Py_DECREF(res);
	return ok;
}

/* Try rich comparisons to determine a 3-way comparison.  Return:
   -2 for an exception;
   -1 if v  < w;
    0 if v == w;
    1 if v  > w;
    2 if this particular rich comparison is not implemented or undefined.
*/
static int
try_rich_to_3way_compare(PyObject *v, PyObject *w)
{
	const static struct { int op; int outcome; } tries[3] = {
		/* Try this operator, and if it is true, use this outcome: */
		{Py_EQ, 0},
		{Py_LT, -1},
		{Py_GT, 1},
	};
	int i;

	if (RICHCOMPARE(v->ob_type) == NULL && RICHCOMPARE(w->ob_type) == NULL)
		return 2; /* Shortcut */

	for (i = 0; i < 3; i++) {
		switch (try_rich_compare_bool(v, w, tries[i].op)) {
		case -1:
			return -2;
		case 1:
			return tries[i].outcome;
		}
	}

	return 2;
}

/* Try a 3-way comparison, returning an int.  Return:
   -2 for an exception;
   -1 if v <  w;
    0 if v == w;
    1 if v  > w;
    2 if this particular 3-way comparison is not implemented or undefined.
*/
static int
try_3way_compare(PyObject *v, PyObject *w)
{
	int c;
	cmpfunc f;

	/* Comparisons involving instances are given to instance_compare,
	   which has the same return conventions as this function. */

	f = v->ob_type->tp_compare;
	if (PyInstance_Check(v))
		return (*f)(v, w);
	if (PyInstance_Check(w))
		return (*w->ob_type->tp_compare)(v, w);

	/* If both have the same (non-NULL) tp_compare, use it. */
	if (f != NULL && f == w->ob_type->tp_compare) {
		c = (*f)(v, w);
		if (c < 0 && PyErr_Occurred())
			return -1;
		return c < 0 ? -1 : c > 0 ? 1 : 0;
	}

	/* If either tp_compare is _PyObject_SlotCompare, that's safe. */
	if (f == _PyObject_SlotCompare ||
	    w->ob_type->tp_compare == _PyObject_SlotCompare)
		return _PyObject_SlotCompare(v, w);

	/* Try coercion; if it fails, give up */
	c = PyNumber_CoerceEx(&v, &w);
	if (c < 0)
		return -2;
	if (c > 0)
		return 2;

	/* Try v's comparison, if defined */
	if ((f = v->ob_type->tp_compare) != NULL) {
		c = (*f)(v, w);
		Py_DECREF(v);
		Py_DECREF(w);
		if (c < 0 && PyErr_Occurred())
			return -2;
		return c < 0 ? -1 : c > 0 ? 1 : 0;
	}

	/* Try w's comparison, if defined */
	if ((f = w->ob_type->tp_compare) != NULL) {
		c = (*f)(w, v); /* swapped! */
		Py_DECREF(v);
		Py_DECREF(w);
		if (c < 0 && PyErr_Occurred())
			return -2;
		return c < 0 ? 1 : c > 0 ? -1 : 0; /* negated! */
	}

	/* No comparison defined */
	Py_DECREF(v);
	Py_DECREF(w);
	return 2;
}

/* Final fallback 3-way comparison, returning an int.  Return:
   -2 if an error occurred;
   -1 if v <  w;
    0 if v == w;
    1 if v >  w.
*/
static int
default_3way_compare(PyObject *v, PyObject *w)
{
	int c;