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2228 lines (2004 loc) · 51.7 KB
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Copy pathobject.c
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2228 lines (2004 loc) · 51.7 KB
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/* Generic object operations; and implementation of None (NoObject) */
#include "Python.h"
#ifdef macintosh
#include "macglue.h"
#endif
#ifdef Py_REF_DEBUG
long _Py_RefTotal;
#endif
int Py_DivisionWarningFlag;
/* 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 Py_TRACE_REFS
/* Head of circular doubly-linked list of all objects. These are linked
* together via the _ob_prev and _ob_next members of a PyObject, which
* exist only in a Py_TRACE_REFS build.
*/
static PyObject refchain = {&refchain, &refchain};
/* Insert op at the front of the list of all objects. If force is true,
* op is added even if _ob_prev and _ob_next are non-NULL already. If
* force is false amd _ob_prev or _ob_next are non-NULL, do nothing.
* force should be true if and only if op points to freshly allocated,
* uninitialized memory, or you've unlinked op from the list and are
* relinking it into the front.
* Note that objects are normally added to the list via _Py_NewReference,
* which is called by PyObject_Init. Not all objects are initialized that
* way, though; exceptions include statically allocated type objects, and
* statically allocated singletons (like Py_True and Py_None).
*/
void
_Py_AddToAllObjects(PyObject *op, int force)
{
#ifdef Py_DEBUG
if (!force) {
/* If it's initialized memory, op must be in or out of
* the list unambiguously.
*/
assert((op->_ob_prev == NULL) == (op->_ob_next == NULL));
}
#endif
if (force || op->_ob_prev == NULL) {
op->_ob_next = refchain._ob_next;
op->_ob_prev = &refchain;
refchain._ob_next->_ob_prev = op;
refchain._ob_next = op;
}
}
#endif /* Py_TRACE_REFS */
#ifdef COUNT_ALLOCS
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;
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);
}
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;
}
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;
#ifdef Py_TRACE_REFS
/* Also insert in the doubly-linked list of all objects,
* if not already there.
*/
_Py_AddToAllObjects((PyObject *)tp, 0);
#endif
}
tp->tp_allocs++;
if (tp->tp_allocs - tp->tp_frees > tp->tp_maxalloc)
tp->tp_maxalloc = tp->tp_allocs - tp->tp_frees;
}
#endif
#ifdef Py_REF_DEBUG
/* Log a fatal error; doesn't return. */
void
_Py_NegativeRefcount(const char *fname, int lineno, PyObject *op)
{
char buf[300];
PyOS_snprintf(buf, sizeof(buf),
"%s:%i object at %p has negative ref count %i",
fname, lineno, op, op->ob_refcnt);
Py_FatalError(buf);
}
#endif /* Py_REF_DEBUG */
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;
}
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;
}
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);
}
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);
}
/* for binary compatibility with 2.2 */
#undef _PyObject_Del
void
_PyObject_Del(PyObject *op)
{
PyObject_FREE(op);
}
/* Implementation of PyObject_Print with recursion checking */
static int
internal_print(PyObject *op, FILE *fp, int flags, int nesting)
{
int ret = 0;
if (nesting > 10) {
PyErr_SetString(PyExc_RuntimeError, "print recursion");
return -1;
}
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 = internal_print(s, fp, Py_PRINT_RAW,
nesting+1);
}
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;
}
int
PyObject_Print(PyObject *op, FILE *fp, int flags)
{
return internal_print(op, fp, flags, 0);
}
/* For debugging convenience. See Misc/gdbinit for some useful gdb hooks */
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);
}
}
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;
}
}
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
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;
static PyObject *unicodestr;
/* 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
/* Helper to warn about deprecated tp_compare return values. Return:
-2 for an exception;
-1 if v < w;
0 if v == w;
1 if v > w.
(This function cannot return 2.)
*/
static int
adjust_tp_compare(int c)
{
if (PyErr_Occurred()) {
if (c != -1 && c != -2) {
PyObject *t, *v, *tb;
PyErr_Fetch(&t, &v, &tb);
if (PyErr_Warn(PyExc_RuntimeWarning,
"tp_compare didn't return -1 or -2 "
"for exception") < 0) {
Py_XDECREF(t);
Py_XDECREF(v);
Py_XDECREF(tb);
}
else
PyErr_Restore(t, v, tb);
}
return -2;
}
else if (c < -1 || c > 1) {
if (PyErr_Warn(PyExc_RuntimeWarning,
"tp_compare didn't return -1, 0 or 1") < 0)
return -2;
else
return c < -1 ? -1 : 1;
}
else {
assert(c >= -1 && c <= 1);
return c;
}
}
/* 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 */
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)
{
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);
return adjust_tp_compare(c);
}
/* 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);
return adjust_tp_compare(c);
}
/* 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);
c = adjust_tp_compare(c);
if (c >= -1)
return -c; /* Swapped! */
else
return c;
}
/* 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;
char *vname, *wname;
if (v->ob_type == w->ob_type) {
/* When comparing these pointers, they must be cast to
* integer types (i.e. Py_uintptr_t, our spelling of C9X's
* uintptr_t). ANSI specifies that pointer compares other
* than == and != to non-related structures are undefined.
*/
Py_uintptr_t vv = (Py_uintptr_t)v;
Py_uintptr_t ww = (Py_uintptr_t)w;
return (vv < ww) ? -1 : (vv > ww) ? 1 : 0;
}
#ifdef Py_USING_UNICODE
/* Special case for Unicode */
if (PyUnicode_Check(v) || PyUnicode_Check(w)) {
c = PyUnicode_Compare(v, w);
if (!PyErr_Occurred())
return c;
/* TypeErrors are ignored: if Unicode coercion fails due
to one of the arguments not having the right type, we
continue as defined by the coercion protocol (see
above). Luckily, decoding errors are reported as
ValueErrors and are not masked by this technique. */
if (!PyErr_ExceptionMatches(PyExc_TypeError))
return -2;
PyErr_Clear();
}
#endif
/* None is smaller than anything */
if (v == Py_None)
return -1;
if (w == Py_None)
return 1;
/* different type: compare type names; numbers are smaller */
if (PyNumber_Check(v))
vname = "";
else
vname = v->ob_type->tp_name;
if (PyNumber_Check(w))
wname = "";
else
wname = w->ob_type->tp_name;
c = strcmp(vname, wname);
if (c < 0)
return -1;
if (c > 0)
return 1;
/* Same type name, or (more likely) incomparable numeric types */
return ((Py_uintptr_t)(v->ob_type) < (
Py_uintptr_t)(w->ob_type)) ? -1 : 1;
}
#define CHECK_TYPES(o) PyType_HasFeature((o)->ob_type, Py_TPFLAGS_CHECKTYPES)
/* Do a 3-way comparison, by hook or by crook. Return:
-2 for an exception (but see below);
-1 if v < w;
0 if v == w;
1 if v > w;
BUT: if the object implements a tp_compare function, it returns
whatever this function returns (whether with an exception or not).
*/
static int
do_cmp(PyObject *v, PyObject *w)
{
int c;
cmpfunc f;
if (v->ob_type == w->ob_type
&& (f = v->ob_type->tp_compare) != NULL) {
c = (*f)(v, w);
if (PyInstance_Check(v)) {
/* Instance tp_compare has a different signature.
But if it returns undefined we fall through. */
if (c != 2)
return c;
/* Else fall through to try_rich_to_3way_compare() */
}
else
return adjust_tp_compare(c);
}
/* We only get here if one of the following is true:
a) v and w have different types
b) v and w have the same type, which doesn't have tp_compare
c) v and w are instances, and either __cmp__ is not defined or
__cmp__ returns NotImplemented
*/
c = try_rich_to_3way_compare(v, w);
if (c < 2)
return c;
c = try_3way_compare(v, w);
if (c < 2)
return c;
return default_3way_compare(v, w);
}
/* compare_nesting is incremented before calling compare (for
some types) and decremented on exit. If the count exceeds the
nesting limit, enable code to detect circular data structures.
This is a tunable parameter that should only affect the performance
of comparisons, nothing else. Setting it high makes comparing deeply
nested non-cyclical data structures faster, but makes comparing cyclical
data structures slower.
*/
#define NESTING_LIMIT 20
static int compare_nesting = 0;
static PyObject*
get_inprogress_dict(void)
{
static PyObject *key;
PyObject *tstate_dict, *inprogress;
if (key == NULL) {
key = PyString_InternFromString("cmp_state");
if (key == NULL)
return NULL;
}
tstate_dict = PyThreadState_GetDict();
if (tstate_dict == NULL) {
PyErr_BadInternalCall();
return NULL;
}
inprogress = PyDict_GetItem(tstate_dict, key);
if (inprogress == NULL) {
inprogress = PyDict_New();
if (inprogress == NULL)
return NULL;
if (PyDict_SetItem(tstate_dict, key, inprogress) == -1) {
Py_DECREF(inprogress);
return NULL;
}
Py_DECREF(inprogress);
}
return inprogress;
}
/* If the comparison "v op w" is already in progress in this thread, returns
* a borrowed reference to Py_None (the caller must not decref).
* If it's not already in progress, returns "a token" which must eventually
* be passed to delete_token(). The caller must not decref this either
* (delete_token decrefs it). The token must not survive beyond any point
* where v or w may die.
* If an error occurs (out-of-memory), returns NULL.
*/
static PyObject *
check_recursion(PyObject *v, PyObject *w, int op)
{
PyObject *inprogress;
PyObject *token;
Py_uintptr_t iv = (Py_uintptr_t)v;
Py_uintptr_t iw = (Py_uintptr_t)w;
PyObject *x, *y, *z;
inprogress = get_inprogress_dict();
if (inprogress == NULL)
return NULL;
token = PyTuple_New(3);
if (token == NULL)
return NULL;
if (iv <= iw) {
PyTuple_SET_ITEM(token, 0, x = PyLong_FromVoidPtr((void *)v));
PyTuple_SET_ITEM(token, 1, y = PyLong_FromVoidPtr((void *)w));
if (op >= 0)
op = swapped_op[op];
} else {
PyTuple_SET_ITEM(token, 0, x = PyLong_FromVoidPtr((void *)w));
PyTuple_SET_ITEM(token, 1, y = PyLong_FromVoidPtr((void *)v));
}
PyTuple_SET_ITEM(token, 2, z = PyInt_FromLong((long)op));
if (x == NULL || y == NULL || z == NULL) {
Py_DECREF(token);
return NULL;
}
if (PyDict_GetItem(inprogress, token) != NULL) {
Py_DECREF(token);
return Py_None; /* Without INCREF! */
}
if (PyDict_SetItem(inprogress, token, token) < 0) {
Py_DECREF(token);
return NULL;
}
return token;
}
static void
delete_token(PyObject *token)
{
PyObject *inprogress;
if (token == NULL || token == Py_None)
return;
inprogress = get_inprogress_dict();
if (inprogress == NULL)
PyErr_Clear();
else
PyDict_DelItem(inprogress, token);
Py_DECREF(token);
}
/* Compare v to w. Return
-1 if v < w or exception (PyErr_Occurred() true in latter case).
0 if v == w.
1 if v > w.
XXX The docs (C API manual) say the return value is undefined in case
XXX of error.
*/
int
PyObject_Compare(PyObject *v, PyObject *w)
{
PyTypeObject *vtp;
int result;
#if defined(USE_STACKCHECK)
if (PyOS_CheckStack()) {
PyErr_SetString(PyExc_MemoryError, "Stack overflow");
return -1;
}
#endif
if (v == NULL || w == NULL) {
PyErr_BadInternalCall();
return -1;
}
if (v == w)
return 0;
vtp = v->ob_type;
compare_nesting++;
if (compare_nesting > NESTING_LIMIT &&
(vtp->tp_as_mapping || vtp->tp_as_sequence) &&
!PyString_CheckExact(v) &&
!PyTuple_CheckExact(v)) {
/* try to detect circular data structures */
PyObject *token = check_recursion(v, w, -1);
if (token == NULL) {
result = -1;
}
else if (token == Py_None) {
/* already comparing these objects. assume
they're equal until shown otherwise */
result = 0;
}
else {
result = do_cmp(v, w);
delete_token(token);
}
}
else {
result = do_cmp(v, w);
}
compare_nesting--;
return result < 0 ? -1 : result;
}
/* Return (new reference to) Py_True or Py_False. */
static PyObject *
convert_3way_to_object(int op, int c)
{
PyObject *result;
switch (op) {
case Py_LT: c = c < 0; break;
case Py_LE: c = c <= 0; break;
case Py_EQ: c = c == 0; break;
case Py_NE: c = c != 0; break;
case Py_GT: c = c > 0; break;
case Py_GE: c = c >= 0; break;
}
result = c ? Py_True : Py_False;
Py_INCREF(result);
return result;
}
/* We want a rich comparison but don't have one. Try a 3-way cmp instead.
Return
NULL if error
Py_True if v op w
Py_False if not (v op w)
*/
static PyObject *
try_3way_to_rich_compare(PyObject *v, PyObject *w, int op)
{
int c;
c = try_3way_compare(v, w);
if (c >= 2)
c = default_3way_compare(v, w);
if (c <= -2)
return NULL;
return convert_3way_to_object(op, c);
}
/* Do rich comparison on v and w. Return
NULL if error
Else a new reference to an object other than Py_NotImplemented, usually(?):
Py_True if v op w
Py_False if not (v op w)
*/
static PyObject *
do_richcmp(PyObject *v, PyObject *w, int op)
{
PyObject *res;
res = try_rich_compare(v, w, op);
if (res != Py_NotImplemented)
return res;
Py_DECREF(res);
return try_3way_to_rich_compare(v, w, op);
}
/* Return:
NULL for exception;
some object not equal to NotImplemented if it is implemented
(this latter object may not be a Boolean).
*/
PyObject *
PyObject_RichCompare(PyObject *v, PyObject *w, int op)
{
PyObject *res;
assert(Py_LT <= op && op <= Py_GE);
compare_nesting++;
if (compare_nesting > NESTING_LIMIT &&
(v->ob_type->tp_as_mapping || v->ob_type->tp_as_sequence) &&
!PyString_CheckExact(v) &&
!PyTuple_CheckExact(v)) {
/* try to detect circular data structures */
PyObject *token = check_recursion(v, w, op);
if (token == NULL) {
res = NULL;
goto Done;
}
else if (token == Py_None) {
/* already comparing these objects with this operator.
assume they're equal until shown otherwise */
if (op == Py_EQ)
res = Py_True;
else if (op == Py_NE)
res = Py_False;
else {
PyErr_SetString(PyExc_ValueError,
"can't order recursive values");
res = NULL;