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482 lines (438 loc) · 11 KB
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Copy pathclassobject.c
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482 lines (438 loc) · 11 KB
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/* Class object implementation (dead now except for methods) */
#include "Python.h"
#include "structmember.h"
#define TP_DESCR_GET(t) ((t)->tp_descr_get)
PyObject *
PyMethod_Function(PyObject *im)
{
if (!PyMethod_Check(im)) {
PyErr_BadInternalCall();
return NULL;
}
return ((PyMethodObject *)im)->im_func;
}
PyObject *
PyMethod_Self(PyObject *im)
{
if (!PyMethod_Check(im)) {
PyErr_BadInternalCall();
return NULL;
}
return ((PyMethodObject *)im)->im_self;
}
PyObject *
PyMethod_Class(PyObject *im)
{
if (!PyMethod_Check(im)) {
PyErr_BadInternalCall();
return NULL;
}
return ((PyMethodObject *)im)->im_class;
}
/* Method objects are used for two purposes:
(a) as bound instance methods (returned by instancename.methodname)
(b) as unbound methods (returned by ClassName.methodname)
In case (b), im_self is NULL
*/
static PyMethodObject *free_list;
PyObject *
PyMethod_New(PyObject *func, PyObject *self, PyObject *klass)
{
register PyMethodObject *im;
if (!PyCallable_Check(func)) {
PyErr_BadInternalCall();
return NULL;
}
im = free_list;
if (im != NULL) {
free_list = (PyMethodObject *)(im->im_self);
PyObject_INIT(im, &PyMethod_Type);
}
else {
im = PyObject_GC_New(PyMethodObject, &PyMethod_Type);
if (im == NULL)
return NULL;
}
im->im_weakreflist = NULL;
Py_INCREF(func);
im->im_func = func;
Py_XINCREF(self);
im->im_self = self;
Py_XINCREF(klass);
im->im_class = klass;
_PyObject_GC_TRACK(im);
return (PyObject *)im;
}
/* Descriptors for PyMethod attributes */
/* im_class, im_func and im_self are stored in the PyMethod object */
#define OFF(x) offsetof(PyMethodObject, x)
static PyMemberDef method_memberlist[] = {
{"im_class", T_OBJECT, OFF(im_class), READONLY|RESTRICTED,
"the class associated with a method"},
{"im_func", T_OBJECT, OFF(im_func), READONLY|RESTRICTED,
"the function (or other callable) implementing a method"},
{"im_self", T_OBJECT, OFF(im_self), READONLY|RESTRICTED,
"the instance to which a method is bound; None for unbound methods"},
{NULL} /* Sentinel */
};
/* Christian Tismer argued convincingly that method attributes should
(nearly) always override function attributes.
The one exception is __doc__; there's a default __doc__ which
should only be used for the class, not for instances */
static PyObject *
method_get_doc(PyMethodObject *im, void *context)
{
static PyObject *docstr;
if (docstr == NULL) {
docstr= PyString_InternFromString("__doc__");
if (docstr == NULL)
return NULL;
}
return PyObject_GetAttr(im->im_func, docstr);
}
static PyGetSetDef method_getset[] = {
{"__doc__", (getter)method_get_doc, NULL, NULL},
{0}
};
static PyObject *
method_getattro(PyObject *obj, PyObject *name)
{
PyMethodObject *im = (PyMethodObject *)obj;
PyTypeObject *tp = obj->ob_type;
PyObject *descr = NULL;
{
if (tp->tp_dict == NULL) {
if (PyType_Ready(tp) < 0)
return NULL;
}
descr = _PyType_Lookup(tp, name);
}
if (descr != NULL) {
descrgetfunc f = TP_DESCR_GET(descr->ob_type);
if (f != NULL)
return f(descr, obj, (PyObject *)obj->ob_type);
else {
Py_INCREF(descr);
return descr;
}
}
return PyObject_GetAttr(im->im_func, name);
}
PyDoc_STRVAR(method_doc,
"method(function, instance, class)\n\
\n\
Create an instance method object.");
static PyObject *
method_new(PyTypeObject* type, PyObject* args, PyObject *kw)
{
PyObject *func;
PyObject *self;
PyObject *classObj = NULL;
if (!_PyArg_NoKeywords("instancemethod", kw))
return NULL;
if (!PyArg_UnpackTuple(args, "method", 2, 3,
&func, &self, &classObj))
return NULL;
if (!PyCallable_Check(func)) {
PyErr_SetString(PyExc_TypeError,
"first argument must be callable");
return NULL;
}
if (self == Py_None)
self = NULL;
if (self == NULL && classObj == NULL) {
PyErr_SetString(PyExc_TypeError,
"unbound methods must have non-NULL im_class");
return NULL;
}
return PyMethod_New(func, self, classObj);
}
static void
method_dealloc(register PyMethodObject *im)
{
_PyObject_GC_UNTRACK(im);
if (im->im_weakreflist != NULL)
PyObject_ClearWeakRefs((PyObject *)im);
Py_DECREF(im->im_func);
Py_XDECREF(im->im_self);
Py_XDECREF(im->im_class);
im->im_self = (PyObject *)free_list;
free_list = im;
}
static PyObject *
method_richcompare(PyObject *self, PyObject *other, int op)
{
PyMethodObject *a, *b;
PyObject *res;
int eq;
if ((op != Py_EQ && op != Py_NE) ||
!PyMethod_Check(self) ||
!PyMethod_Check(other))
{
Py_INCREF(Py_NotImplemented);
return Py_NotImplemented;
}
a = (PyMethodObject *)self;
b = (PyMethodObject *)other;
eq = PyObject_RichCompareBool(a->im_func, b->im_func, Py_EQ);
if (eq == 1) {
if (a->im_self == NULL || b->im_self == NULL)
eq = a->im_self == b->im_self;
else
eq = PyObject_RichCompareBool(a->im_self, b->im_self,
Py_EQ);
}
if (eq < 0)
return NULL;
if (op == Py_EQ)
res = eq ? Py_True : Py_False;
else
res = eq ? Py_False : Py_True;
Py_INCREF(res);
return res;
}
static PyObject *
method_repr(PyMethodObject *a)
{
PyObject *self = a->im_self;
PyObject *func = a->im_func;
PyObject *klass = a->im_class;
PyObject *funcname = NULL, *klassname = NULL, *result = NULL;
char *sfuncname = "?", *sklassname = "?";
funcname = PyObject_GetAttrString(func, "__name__");
if (funcname == NULL) {
if (!PyErr_ExceptionMatches(PyExc_AttributeError))
return NULL;
PyErr_Clear();
}
else if (!PyString_Check(funcname)) {
Py_DECREF(funcname);
funcname = NULL;
}
else
sfuncname = PyString_AS_STRING(funcname);
if (klass == NULL)
klassname = NULL;
else {
klassname = PyObject_GetAttrString(klass, "__name__");
if (klassname == NULL) {
if (!PyErr_ExceptionMatches(PyExc_AttributeError))
return NULL;
PyErr_Clear();
}
else if (!PyString_Check(klassname)) {
Py_DECREF(klassname);
klassname = NULL;
}
else
sklassname = PyString_AS_STRING(klassname);
}
if (self == NULL)
result = PyUnicode_FromFormat("<unbound method %s.%s>",
sklassname, sfuncname);
else {
/* XXX Shouldn't use repr()/%R here! */
result = PyUnicode_FromFormat("<bound method %s.%s of %R>",
sklassname, sfuncname, self);
}
Py_XDECREF(funcname);
Py_XDECREF(klassname);
return result;
}
static long
method_hash(PyMethodObject *a)
{
long x, y;
if (a->im_self == NULL)
x = PyObject_Hash(Py_None);
else
x = PyObject_Hash(a->im_self);
if (x == -1)
return -1;
y = PyObject_Hash(a->im_func);
if (y == -1)
return -1;
x = x ^ y;
if (x == -1)
x = -2;
return x;
}
static int
method_traverse(PyMethodObject *im, visitproc visit, void *arg)
{
Py_VISIT(im->im_func);
Py_VISIT(im->im_self);
Py_VISIT(im->im_class);
return 0;
}
static void
getclassname(PyObject *klass, char *buf, int bufsize)
{
PyObject *name;
assert(bufsize > 1);
strcpy(buf, "?"); /* Default outcome */
if (klass == NULL)
return;
name = PyObject_GetAttrString(klass, "__name__");
if (name == NULL) {
/* This function cannot return an exception */
PyErr_Clear();
return;
}
if (PyString_Check(name)) {
strncpy(buf, PyString_AS_STRING(name), bufsize);
buf[bufsize-1] = '\0';
}
Py_DECREF(name);
}
static void
getinstclassname(PyObject *inst, char *buf, int bufsize)
{
PyObject *klass;
if (inst == NULL) {
assert(bufsize > 0 && (size_t)bufsize > strlen("nothing"));
strcpy(buf, "nothing");
return;
}
klass = PyObject_GetAttrString(inst, "__class__");
if (klass == NULL) {
/* This function cannot return an exception */
PyErr_Clear();
klass = (PyObject *)(inst->ob_type);
Py_INCREF(klass);
}
getclassname(klass, buf, bufsize);
Py_XDECREF(klass);
}
static PyObject *
method_call(PyObject *func, PyObject *arg, PyObject *kw)
{
PyObject *self = PyMethod_GET_SELF(func);
PyObject *klass = PyMethod_GET_CLASS(func);
PyObject *result;
func = PyMethod_GET_FUNCTION(func);
if (self == NULL) {
/* Unbound methods must be called with an instance of
the class (or a derived class) as first argument */
int ok;
if (PyTuple_Size(arg) >= 1)
self = PyTuple_GET_ITEM(arg, 0);
if (self == NULL)
ok = 0;
else {
ok = PyObject_IsInstance(self, klass);
if (ok < 0)
return NULL;
}
if (!ok) {
char clsbuf[256];
char instbuf[256];
getclassname(klass, clsbuf, sizeof(clsbuf));
getinstclassname(self, instbuf, sizeof(instbuf));
PyErr_Format(PyExc_TypeError,
"unbound method %s%s must be called with "
"%s instance as first argument "
"(got %s%s instead)",
PyEval_GetFuncName(func),
PyEval_GetFuncDesc(func),
clsbuf,
instbuf,
self == NULL ? "" : " instance");
return NULL;
}
Py_INCREF(arg);
}
else {
Py_ssize_t argcount = PyTuple_Size(arg);
PyObject *newarg = PyTuple_New(argcount + 1);
int i;
if (newarg == NULL)
return NULL;
Py_INCREF(self);
PyTuple_SET_ITEM(newarg, 0, self);
for (i = 0; i < argcount; i++) {
PyObject *v = PyTuple_GET_ITEM(arg, i);
Py_XINCREF(v);
PyTuple_SET_ITEM(newarg, i+1, v);
}
arg = newarg;
}
result = PyObject_Call((PyObject *)func, arg, kw);
Py_DECREF(arg);
return result;
}
static PyObject *
method_descr_get(PyObject *meth, PyObject *obj, PyObject *cls)
{
/* Don't rebind an already bound method, or an unbound method
of a class that's not a base class of cls. */
if (PyMethod_GET_SELF(meth) != NULL) {
/* Already bound */
Py_INCREF(meth);
return meth;
}
/* No, it is an unbound method */
if (PyMethod_GET_CLASS(meth) != NULL && cls != NULL) {
/* Do subclass test. If it fails, return meth unchanged. */
int ok = PyObject_IsSubclass(cls, PyMethod_GET_CLASS(meth));
if (ok < 0)
return NULL;
if (!ok) {
Py_INCREF(meth);
return meth;
}
}
/* Bind it to obj */
return PyMethod_New(PyMethod_GET_FUNCTION(meth), obj, cls);
}
PyTypeObject PyMethod_Type = {
PyObject_HEAD_INIT(&PyType_Type)
0,
"method",
sizeof(PyMethodObject),
0,
(destructor)method_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_compare */
(reprfunc)method_repr, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
(hashfunc)method_hash, /* tp_hash */
method_call, /* tp_call */
0, /* tp_str */
method_getattro, /* tp_getattro */
PyObject_GenericSetAttr, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
method_doc, /* tp_doc */
(traverseproc)method_traverse, /* tp_traverse */
0, /* tp_clear */
method_richcompare, /* tp_richcompare */
offsetof(PyMethodObject, im_weakreflist), /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
0, /* tp_methods */
method_memberlist, /* tp_members */
method_getset, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
method_descr_get, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
0, /* tp_init */
0, /* tp_alloc */
method_new, /* tp_new */
};
/* Clear out the free list */
void
PyMethod_Fini(void)
{
while (free_list) {
PyMethodObject *im = free_list;
free_list = (PyMethodObject *)(im->im_self);
PyObject_GC_Del(im);
}
}