/* 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 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;

}

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;

}

Py_XINCREF(res);

}

else {

res = do_richcmp(v, w, op);

delete_token(token);

}

goto Done;

}

/* No nesting extremism.

If the types are equal, and not old-style instances, try to

get out cheap (don't bother with coercions etc.). */

if (v->ob_type == w->ob_type && !PyInstance_Check(v)) {

cmpfunc fcmp;

richcmpfunc frich = RICHCOMPARE(v->ob_type);

/* If the type has richcmp, try it first. try_rich_compare

tries it two-sided, which is not needed since we've a

single type only. */

if (frich != NULL) {

res = (*frich)(v, w, op);

if (res != Py_NotImplemented)

goto Done;

Py_DECREF(res);

}

/* No richcmp, or this particular richmp not implemented.

Try 3-way cmp. */

fcmp = v->ob_type->tp_compare;

if (fcmp != NULL) {

int c = (*fcmp)(v, w);

c = adjust_tp_compare(c);

if (c == -2) {

res = NULL;

goto Done;

}

res = convert_3way_to_object(op, c);

goto Done;

}

}

/* Fast path not taken, or couldn't deliver a useful result. */

res = do_richcmp(v, w, op);

Done:

compare_nesting--;