classobject.c

python s60 1.4.5版本的源代码

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

/* Class object implementation */

#include "Python.h"
#include "structmember.h"

#define TP_DESCR_GET(t) \
    (PyType_HasFeature(t, Py_TPFLAGS_HAVE_CLASS) ? (t)->tp_descr_get : NULL)


/* Forward */
static PyObject *class_lookup(PyClassObject *, PyObject *,
			      PyClassObject **);
static PyObject *instance_getattr1(PyInstanceObject *, PyObject *);
static PyObject *instance_getattr2(PyInstanceObject *, PyObject *);

#ifndef SYMBIAN
static PyObject *getattrstr, *setattrstr, *delattrstr;
#else
#define getattrstr (pyglobals->getattrstr)
#define setattrstr (pyglobals->setattrstr)
#define delattrstr (pyglobals->delattrstr)
#endif

DL_EXPORT(PyObject *)
PyClass_New(PyObject *bases, PyObject *dict, PyObject *name)
     /* bases is NULL or tuple of classobjects! */
{
	PyClassObject *op, *dummy;
#ifndef SYMBIAN
	static PyObject *docstr, *modstr, *namestr;
#else
#define docstr (pyglobals->docstr)
#define modstr (pyglobals->modstr)
#define namestr (pyglobals->classobject_namestr)
	SPy_Python_globals* pyglobals = PYTHON_GLOBALS; // avoid TLS reads
#endif

	if (docstr == NULL) {
		docstr= PyString_InternFromString("__doc__");
		if (docstr == NULL)
			return NULL;
	}
	if (modstr == NULL) {
		modstr= PyString_InternFromString("__module__");
		if (modstr == NULL)
			return NULL;
	}
	if (namestr == NULL) {
		namestr= PyString_InternFromString("__name__");
		if (namestr == NULL)
			return NULL;
	}
	if (name == NULL || !PyString_Check(name)) {
		PyErr_SetString(PyExc_TypeError,
				"PyClass_New: name must be a string");
		return NULL;
	}
	if (dict == NULL || !PyDict_Check(dict)) {
		PyErr_SetString(PyExc_TypeError,
				"PyClass_New: dict must be a dictionary");
		return NULL;
	}
	if (PyDict_GetItem(dict, docstr) == NULL) {
		if (PyDict_SetItem(dict, docstr, Py_None) < 0)
			return NULL;
	}
	if (PyDict_GetItem(dict, modstr) == NULL) {
		PyObject *globals = PyEval_GetGlobals();
		if (globals != NULL) {
			PyObject *modname = PyDict_GetItem(globals, namestr);
			if (modname != NULL) {
				if (PyDict_SetItem(dict, modstr, modname) < 0)
					return NULL;
			}
		}
	}
	if (bases == NULL) {
		bases = PyTuple_New(0);
		if (bases == NULL)
			return NULL;
	}
	else {
		int i, n;
		PyObject *base;
		if (!PyTuple_Check(bases)) {
			PyErr_SetString(PyExc_TypeError,
					"PyClass_New: bases must be a tuple");
			return NULL;
		}
		n = PyTuple_Size(bases);
		for (i = 0; i < n; i++) {
			base = PyTuple_GET_ITEM(bases, i);
			if (!PyClass_Check(base)) {
				if (PyCallable_Check(
					(PyObject *) base->ob_type))
					return PyObject_CallFunction(
						(PyObject *) base->ob_type,
						"OOO",
						name,
						bases,
						dict);
				PyErr_SetString(PyExc_TypeError,
					"PyClass_New: base must be a class");
				return NULL;
			}
		}
		Py_INCREF(bases);
	}
	op = PyObject_GC_New(PyClassObject, &PyClass_Type);
	if (op == NULL) {
		Py_DECREF(bases);
		return NULL;
	}
	op->cl_bases = bases;
	Py_INCREF(dict);
	op->cl_dict = dict;
	Py_XINCREF(name);
	op->cl_name = name;
	if (getattrstr == NULL) {
		getattrstr = PyString_InternFromString("__getattr__");
		setattrstr = PyString_InternFromString("__setattr__");
		delattrstr = PyString_InternFromString("__delattr__");
	}
	op->cl_getattr = class_lookup(op, getattrstr, &dummy);
	op->cl_setattr = class_lookup(op, setattrstr, &dummy);
	op->cl_delattr = class_lookup(op, delattrstr, &dummy);
	Py_XINCREF(op->cl_getattr);
	Py_XINCREF(op->cl_setattr);
	Py_XINCREF(op->cl_delattr);
	_PyObject_GC_TRACK(op);
	return (PyObject *) op;
}

DL_EXPORT(PyObject *)
PyMethod_Function(PyObject *im)
{
	if (!PyMethod_Check(im)) {
		PyErr_BadInternalCall();
		return NULL;
	}
	return ((PyMethodObject *)im)->im_func;
}

DL_EXPORT(PyObject *)
PyMethod_Self(PyObject *im)
{
	if (!PyMethod_Check(im)) {
		PyErr_BadInternalCall();
		return NULL;
	}
	return ((PyMethodObject *)im)->im_self;
}

DL_EXPORT(PyObject *)
PyMethod_Class(PyObject *im)
{
	if (!PyMethod_Check(im)) {
		PyErr_BadInternalCall();
		return NULL;
	}
	return ((PyMethodObject *)im)->im_class;
}

static PyObject *
class_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
	PyObject *name, *bases, *dict;
	static const char *const kwlist[] = {"name", "bases", "dict", 0};

	if (!PyArg_ParseTupleAndKeywords(args, kwds, "SOO", kwlist,
					 &name, &bases, &dict))
		return NULL;
	return PyClass_New(bases, dict, name);
}

/* Class methods */

static void
class_dealloc(PyClassObject *op)
{
	_PyObject_GC_UNTRACK(op);
	Py_DECREF(op->cl_bases);
	Py_DECREF(op->cl_dict);
	Py_XDECREF(op->cl_name);
	Py_XDECREF(op->cl_getattr);
	Py_XDECREF(op->cl_setattr);
	Py_XDECREF(op->cl_delattr);
	PyObject_GC_Del(op);
}

static PyObject *
class_lookup(PyClassObject *cp, PyObject *name, PyClassObject **pclass)
{
	int i, n;
	PyObject *value = PyDict_GetItem(cp->cl_dict, name);
	if (value != NULL) {
		*pclass = cp;
		return value;
	}
	n = PyTuple_Size(cp->cl_bases);
	for (i = 0; i < n; i++) {
		/* XXX What if one of the bases is not a class? */
		PyObject *v = class_lookup(
			(PyClassObject *)
			PyTuple_GetItem(cp->cl_bases, i), name, pclass);
		if (v != NULL)
			return v;
	}
	return NULL;
}

static PyObject *
class_getattr(register PyClassObject *op, PyObject *name)
{
	register PyObject *v;
	register char *sname = PyString_AsString(name);
	PyClassObject *class;
	descrgetfunc f;

	if (sname[0] == '_' && sname[1] == '_') {
		if (strcmp(sname, "__dict__") == 0) {
			if (PyEval_GetRestricted()) {
				PyErr_SetString(PyExc_RuntimeError,
			   "class.__dict__ not accessible in restricted mode");
				return NULL;
			}
			Py_INCREF(op->cl_dict);
			return op->cl_dict;
		}
		if (strcmp(sname, "__bases__") == 0) {
			Py_INCREF(op->cl_bases);
			return op->cl_bases;
		}
		if (strcmp(sname, "__name__") == 0) {
			if (op->cl_name == NULL)
				v = Py_None;
			else
				v = op->cl_name;
			Py_INCREF(v);
			return v;
		}
	}
	v = class_lookup(op, name, &class);
	if (v == NULL) {
		PyErr_Format(PyExc_AttributeError,
			     "class %.50s has no attribute '%.400s'",
			     PyString_AS_STRING(op->cl_name), sname);
		return NULL;
	}
	f = TP_DESCR_GET(v->ob_type);
	if (f == NULL)
		Py_INCREF(v);
	else
		v = f(v, (PyObject *)NULL, (PyObject *)op);
	return v;
}

static void
set_slot(PyObject **slot, PyObject *v)
{
	PyObject *temp = *slot;
	Py_XINCREF(v);
	*slot = v;
	Py_XDECREF(temp);
}

static void
set_attr_slots(PyClassObject *c)
{
	PyClassObject *dummy;
#ifdef SYMBIAN
	SPy_Python_globals* pyglobals = PYTHON_GLOBALS; //  avoid TLS reads
#endif
	set_slot(&c->cl_getattr, class_lookup(c, getattrstr, &dummy));
	set_slot(&c->cl_setattr, class_lookup(c, setattrstr, &dummy));
	set_slot(&c->cl_delattr, class_lookup(c, delattrstr, &dummy));
}

static char *
set_dict(PyClassObject *c, PyObject *v)
{
	if (v == NULL || !PyDict_Check(v))
		return "__dict__ must be a dictionary object";
	set_slot(&c->cl_dict, v);
	set_attr_slots(c);
	return "";
}

static char *
set_bases(PyClassObject *c, PyObject *v)
{
	int i, n;

	if (v == NULL || !PyTuple_Check(v))
		return "__bases__ must be a tuple object";
	n = PyTuple_Size(v);
	for (i = 0; i < n; i++) {
		PyObject *x = PyTuple_GET_ITEM(v, i);
		if (!PyClass_Check(x))
			return "__bases__ items must be classes";
		if (PyClass_IsSubclass(x, (PyObject *)c))
			return "a __bases__ item causes an inheritance cycle";
	}
	set_slot(&c->cl_bases, v);
	set_attr_slots(c);
	return "";
}

static char *
set_name(PyClassObject *c, PyObject *v)
{
	if (v == NULL || !PyString_Check(v))
		return "__name__ must be a string object";
	if (strlen(PyString_AS_STRING(v)) != (size_t)PyString_GET_SIZE(v))
		return "__name__ must not contain null bytes";
	set_slot(&c->cl_name, v);
	return "";
}

static int
class_setattr(PyClassObject *op, PyObject *name, PyObject *v)
{
	char *sname;
	if (PyEval_GetRestricted()) {
		PyErr_SetString(PyExc_RuntimeError,
			   "classes are read-only in restricted mode");
		return -1;
	}
	sname = PyString_AsString(name);
	if (sname[0] == '_' && sname[1] == '_') {
		int n = PyString_Size(name);
		if (sname[n-1] == '_' && sname[n-2] == '_') {
			char *err = NULL;
			if (strcmp(sname, "__dict__") == 0)
				err = set_dict(op, v);
			else if (strcmp(sname, "__bases__") == 0)
				err = set_bases(op, v);
			else if (strcmp(sname, "__name__") == 0)
				err = set_name(op, v);
			else if (strcmp(sname, "__getattr__") == 0)
				set_slot(&op->cl_getattr, v);
			else if (strcmp(sname, "__setattr__") == 0)
				set_slot(&op->cl_setattr, v);
			else if (strcmp(sname, "__delattr__") == 0)
				set_slot(&op->cl_delattr, v);
			/* For the last three, we fall through to update the
			   dictionary as well. */
			if (err != NULL) {
				if (*err == '\0')
					return 0;
				PyErr_SetString(PyExc_TypeError, err);
				return -1;
			}
		}
	}
	if (v == NULL) {
		int rv = PyDict_DelItem(op->cl_dict, name);
		if (rv < 0)
			PyErr_Format(PyExc_AttributeError,
				     "class %.50s has no attribute '%.400s'",
				     PyString_AS_STRING(op->cl_name), sname);
		return rv;
	}
	else
		return PyDict_SetItem(op->cl_dict, name, v);
}

static PyObject *
class_repr(PyClassObject *op)
{
	PyObject *mod = PyDict_GetItemString(op->cl_dict, "__module__");
	char *name;
	if (op->cl_name == NULL || !PyString_Check(op->cl_name))
		name = "?";
	else
		name = PyString_AsString(op->cl_name);
	if (mod == NULL || !PyString_Check(mod))
		return PyString_FromFormat("<class ?.%s at %p>", name, op);
	else
		return PyString_FromFormat("<class %s.%s at %p>",
					   PyString_AsString(mod),
					   name, op);
}

static PyObject *
class_str(PyClassObject *op)
{
	PyObject *mod = PyDict_GetItemString(op->cl_dict, "__module__");
	PyObject *name = op->cl_name;
	PyObject *res;
	int m, n;

	if (name == NULL || !PyString_Check(name))
		return class_repr(op);
	if (mod == NULL || !PyString_Check(mod)) {
		Py_INCREF(name);
		return name;
	}
	m = PyString_Size(mod);
	n = PyString_Size(name);
	res = PyString_FromStringAndSize((char *)NULL, m+1+n);
	if (res != NULL) {
		char *s = PyString_AsString(res);
		memcpy(s, PyString_AsString(mod), m);
		s += m;
		*s++ = '.';
		memcpy(s, PyString_AsString(name), n);
	}
	return res;
}

static int
class_traverse(PyClassObject *o, visitproc visit, void *arg)
{
	int err;
	if (o->cl_bases) {
		err = visit(o->cl_bases, arg);
		if (err)
			return err;
	}
	if (o->cl_dict) {
		err = visit(o->cl_dict, arg);
		if (err)
			return err;
	}
	if (o->cl_name) {
		err = visit(o->cl_name, arg);
		if (err)
			return err;
	}
	if (o->cl_getattr) {
		err = visit(o->cl_getattr, arg);
		if (err)
			return err;
	}
	if (o->cl_setattr) {
		err = visit(o->cl_setattr, arg);
		if (err)
			return err;
	}
	if (o->cl_delattr) {
		err = visit(o->cl_delattr, arg);
		if (err)
			return err;
	}
	return 0;
}

#ifndef SYMBIAN
PyTypeObject PyClass_Type = {
	PyObject_HEAD_INIT(&PyType_Type)
#else
const PyTypeObject c_PyClass_Type = {
	PyObject_HEAD_INIT(NULL)
#endif
	0,
	"class",
	sizeof(PyClassObject),
	0,
	(destructor)class_dealloc,		/* tp_dealloc */
	0,					/* tp_print */
	0,					/* tp_getattr */
	0,					/* tp_setattr */
	0,					/* tp_compare */
	(reprfunc)class_repr,			/* tp_repr */
	0,					/* tp_as_number */
	0,					/* tp_as_sequence */
	0,					/* tp_as_mapping */
	0,					/* tp_hash */
	PyInstance_New,				/* tp_call */
	(reprfunc)class_str,			/* tp_str */
	(getattrofunc)class_getattr,		/* tp_getattro */
	(setattrofunc)class_setattr,		/* tp_setattro */
	0,					/* tp_as_buffer */
	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
	0,					/* tp_doc */
	(traverseproc)class_traverse,		/* tp_traverse */
 	0,					/* tp_clear */
	0,					/* tp_richcompare */
	0,					/* tp_weaklistoffset */
	0,					/* tp_iter */
	0,					/* tp_iternext */
	0,					/* tp_methods */
	0,					/* tp_members */
	0,					/* tp_getset */
	0,					/* tp_base */
	0,					/* tp_dict */
	0,					/* tp_descr_get */
	0,					/* tp_descr_set */
	0,					/* tp_dictoffset */
	0,					/* tp_init */
	0,					/* tp_alloc */
	class_new,				/* tp_new */
};

DL_EXPORT(int)
PyClass_IsSubclass(PyObject *class, PyObject *base)
{
	int i, n;
	PyClassObject *cp;
	if (class == base)
		return 1;
	if (class == NULL || !PyClass_Check(class))