typeobject.c

python s60 1.4.5版本的源代码

/* Portions Copyright (c) 2005-2006 Nokia Corporation */

/* Type object implementation */

#include "Python.h"
#include "structmember.h"
#include <ctype.h>

/* The *real* layout of a type object when allocated on the heap */
/* XXX Should we publish this in a header file? */
typedef struct {
	PyTypeObject type;
	PyNumberMethods as_number;
	PySequenceMethods as_sequence;
	PyMappingMethods as_mapping;
	PyBufferProcs as_buffer;
	PyObject *name, *slots;
	PyMemberDef members[1];
} etype;

const static PyMemberDef type_members[] = {
	{"__basicsize__", T_INT, offsetof(PyTypeObject,tp_basicsize),READONLY},
	{"__itemsize__", T_INT, offsetof(PyTypeObject, tp_itemsize), READONLY},
	{"__flags__", T_LONG, offsetof(PyTypeObject, tp_flags), READONLY},
	{"__weakrefoffset__", T_LONG,
	 offsetof(PyTypeObject, tp_weaklistoffset), READONLY},
	{"__base__", T_OBJECT, offsetof(PyTypeObject, tp_base), READONLY},
	{"__dictoffset__", T_LONG,
	 offsetof(PyTypeObject, tp_dictoffset), READONLY},
	{"__bases__", T_OBJECT, offsetof(PyTypeObject, tp_bases), READONLY},
	{"__mro__", T_OBJECT, offsetof(PyTypeObject, tp_mro), READONLY},
	{0}
};

static PyObject *
type_name(PyTypeObject *type, void *context)
{
	char *s;

	s = strrchr(type->tp_name, '.');
	if (s == NULL)
		s = type->tp_name;
	else
		s++;
	return PyString_FromString(s);
}

static PyObject *
type_module(PyTypeObject *type, void *context)
{
	PyObject *mod;
	char *s;

	s = strrchr(type->tp_name, '.');
	if (s != NULL)
		return PyString_FromStringAndSize(type->tp_name,
						  (int)(s - type->tp_name));
	if (!(type->tp_flags & Py_TPFLAGS_HEAPTYPE))
		return PyString_FromString("__builtin__");
	mod = PyDict_GetItemString(type->tp_dict, "__module__");
	if (mod != NULL && PyString_Check(mod)) {
		Py_INCREF(mod);
		return mod;
	}
	PyErr_SetString(PyExc_AttributeError, "__module__");
	return NULL;
}

static int
type_set_module(PyTypeObject *type, PyObject *value, void *context)
{
	if (!(type->tp_flags & Py_TPFLAGS_HEAPTYPE) ||
	    strrchr(type->tp_name, '.')) {
		PyErr_Format(PyExc_TypeError,
			     "can't set %s.__module__", type->tp_name);
		return -1;
	}
	if (!value) {
		PyErr_Format(PyExc_TypeError,
			     "can't delete %s.__module__", type->tp_name);
		return -1;
	}
	return PyDict_SetItemString(type->tp_dict, "__module__", value);
}

static PyObject *
type_dict(PyTypeObject *type, void *context)
{
	if (type->tp_dict == NULL) {
		Py_INCREF(Py_None);
		return Py_None;
	}
	return PyDictProxy_New(type->tp_dict);
}

static PyObject *
type_get_doc(PyTypeObject *type, void *context)
{
	PyObject *result;
	if (!(type->tp_flags & Py_TPFLAGS_HEAPTYPE) && type->tp_doc != NULL)
		return PyString_FromString(type->tp_doc);
	result = PyDict_GetItemString(type->tp_dict, "__doc__");
	if (result == NULL) {
		result = Py_None;
		Py_INCREF(result);
	}
	else if (result->ob_type->tp_descr_get) {
		result = result->ob_type->tp_descr_get(result, NULL,
						       (PyObject *)type);
	}
	else {
		Py_INCREF(result);
	}
	return result;
}

const static PyGetSetDef type_getsets[] = {
	{"__name__", (getter)type_name, NULL, NULL},
	{"__module__", (getter)type_module, (setter)type_set_module, NULL},
	{"__dict__",  (getter)type_dict,  NULL, NULL},
	{"__doc__", (getter)type_get_doc, NULL, NULL},
	{0}
};

static int
type_compare(PyObject *v, PyObject *w)
{
	/* This is called with type objects only. So we
	   can just compare the addresses. */
	Py_uintptr_t vv = (Py_uintptr_t)v;
	Py_uintptr_t ww = (Py_uintptr_t)w;
	return (vv < ww) ? -1 : (vv > ww) ? 1 : 0;
}

static PyObject *
type_repr(PyTypeObject *type)
{
	PyObject *mod, *name, *rtn;
	char *kind;

	mod = type_module(type, NULL);
	if (mod == NULL)
		PyErr_Clear();
	else if (!PyString_Check(mod)) {
		Py_DECREF(mod);
		mod = NULL;
	}
	name = type_name(type, NULL);
	if (name == NULL)
		return NULL;

	if (type->tp_flags & Py_TPFLAGS_HEAPTYPE)
		kind = "class";
	else
		kind = "type";

	if (mod != NULL && strcmp(PyString_AS_STRING(mod), "__builtin__")) {
		rtn = PyString_FromFormat("<%s '%s.%s'>",
					  kind,
					  PyString_AS_STRING(mod),
					  PyString_AS_STRING(name));
	}
	else
		rtn = PyString_FromFormat("<%s '%s'>", kind, type->tp_name);

	Py_XDECREF(mod);
	Py_DECREF(name);
	return rtn;
}

static PyObject *
type_call(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
	PyObject *obj;

	if (type->tp_new == NULL) {
		PyErr_Format(PyExc_TypeError,
			     "cannot create '%.100s' instances",
			     type->tp_name);
		return NULL;
	}

	obj = type->tp_new(type, args, kwds);
	if (obj != NULL) {
		/* Ugly exception: when the call was type(something),
		   don't call tp_init on the result. */
		if (type == &PyType_Type &&
		    PyTuple_Check(args) && PyTuple_GET_SIZE(args) == 1 &&
		    (kwds == NULL ||
		     (PyDict_Check(kwds) && PyDict_Size(kwds) == 0)))
			return obj;
		/* If the returned object is not an instance of type,
		   it won't be initialized. */
		if (!PyType_IsSubtype(obj->ob_type, type))
			return obj;
		type = obj->ob_type;
		if (PyType_HasFeature(type, Py_TPFLAGS_HAVE_CLASS) &&
		    type->tp_init != NULL &&
		    type->tp_init(obj, args, kwds) < 0) {
			Py_DECREF(obj);
			obj = NULL;
		}
	}
	return obj;
}

DL_EXPORT(PyObject *)
PyType_GenericAlloc(PyTypeObject *type, int nitems)
{
	PyObject *obj;
	const size_t size = _PyObject_VAR_SIZE(type, nitems);

	if (PyType_IS_GC(type))
		obj = _PyObject_GC_Malloc(type, nitems);
	else
		obj = PyObject_MALLOC(size);

	if (obj == NULL)
		return PyErr_NoMemory();

	memset(obj, '\0', size);

	if (type->tp_flags & Py_TPFLAGS_HEAPTYPE)
		Py_INCREF(type);

	if (type->tp_itemsize == 0)
		PyObject_INIT(obj, type);
	else
		(void) PyObject_INIT_VAR((PyVarObject *)obj, type, nitems);

	if (PyType_IS_GC(type))
		_PyObject_GC_TRACK(obj);
	return obj;
}

DL_EXPORT(PyObject *)
PyType_GenericNew(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
	return type->tp_alloc(type, 0);
}

/* Helpers for subtyping */

static int
traverse_slots(PyTypeObject *type, PyObject *self, visitproc visit, void *arg)
{
	int i, n;
	PyMemberDef *mp;

	n = type->ob_size;
	mp = ((etype *)type)->members;
	for (i = 0; i < n; i++, mp++) {
		if (mp->type == T_OBJECT_EX) {
			char *addr = (char *)self + mp->offset;
			PyObject *obj = *(PyObject **)addr;
			if (obj != NULL) {
				int err = visit(obj, arg);
				if (err)
					return err;
			}
		}
	}
	return 0;
}

static int
subtype_traverse(PyObject *self, visitproc visit, void *arg)
{
	PyTypeObject *type, *base;
	traverseproc basetraverse;

	/* Find the nearest base with a different tp_traverse,
	   and traverse slots while we're at it */
	type = self->ob_type;
	base = type;
	while ((basetraverse = base->tp_traverse) == subtype_traverse) {
		if (base->ob_size) {
			int err = traverse_slots(base, self, visit, arg);
			if (err)
				return err;
		}
		base = base->tp_base;
		assert(base);
	}

	if (type->tp_dictoffset != base->tp_dictoffset) {
		PyObject **dictptr = _PyObject_GetDictPtr(self);
		if (dictptr && *dictptr) {
			int err = visit(*dictptr, arg);
			if (err)
				return err;
		}
	}

	if (type->tp_flags & Py_TPFLAGS_HEAPTYPE) {
		/* For a heaptype, the instances count as references
		   to the type.  Traverse the type so the collector
		   can find cycles involving this link. */
		int err = visit((PyObject *)type, arg);
		if (err)
			return err;
	}

	if (basetraverse)
		return basetraverse(self, visit, arg);
	return 0;
}

static void
clear_slots(PyTypeObject *type, PyObject *self)
{
	int i, n;
	PyMemberDef *mp;

	n = type->ob_size;
	mp = ((etype *)type)->members;
	for (i = 0; i < n; i++, mp++) {
		if (mp->type == T_OBJECT_EX && !(mp->flags & READONLY)) {
			char *addr = (char *)self + mp->offset;
			PyObject *obj = *(PyObject **)addr;
			if (obj != NULL) {
				Py_DECREF(obj);
				*(PyObject **)addr = NULL;
			}
		}
	}
}

static int
subtype_clear(PyObject *self)
{
	PyTypeObject *type, *base;
	inquiry baseclear;

	/* Find the nearest base with a different tp_clear
	   and clear slots while we're at it */
	type = self->ob_type;
	base = type;
	while ((baseclear = base->tp_clear) == subtype_clear) {
		if (base->ob_size)
			clear_slots(base, self);
		base = base->tp_base;
		assert(base);
	}

	/* There's no need to clear the instance dict (if any);
	   the collector will call its tp_clear handler. */

	if (baseclear)
		return baseclear(self);
	return 0;
}

staticforward PyObject *lookup_maybe(PyObject *, char *, PyObject **);

static int
call_finalizer(PyObject *self)
{
#ifndef SYMBIAN
  	static PyObject *del_str = NULL;
#else
#define del_str (PYTHON_GLOBALS->finalizer_del_str)
#endif
	PyObject *del, *res;
	PyObject *error_type, *error_value, *error_traceback;

	/* Temporarily resurrect the object. */
#ifdef Py_TRACE_REFS
#ifndef Py_REF_DEBUG
#   error "Py_TRACE_REFS defined but Py_REF_DEBUG not."
#endif
	/* much too complicated if Py_TRACE_REFS defined */
	_Py_NewReference((PyObject *)self);
#ifdef COUNT_ALLOCS
	/* compensate for boost in _Py_NewReference; note that
	 * _Py_RefTotal was also boosted; we'll knock that down later.
	 */
	self->ob_type->tp_allocs--;
#endif
#else /* !Py_TRACE_REFS */
	/* Py_INCREF boosts _Py_RefTotal if Py_REF_DEBUG is defined */
	Py_INCREF(self);
#endif /* !Py_TRACE_REFS */

	/* Save the current exception, if any. */
	PyErr_Fetch(&error_type, &error_value, &error_traceback);

	/* Execute __del__ method, if any. */
	del = lookup_maybe(self, "__del__", &del_str);
	if (del != NULL) {
		res = PyEval_CallObject(del, NULL);
		if (res == NULL)
			PyErr_WriteUnraisable(del);
		else
			Py_DECREF(res);
		Py_DECREF(del);
	}

	/* Restore the saved exception. */
	PyErr_Restore(error_type, error_value, error_traceback);

	/* Undo the temporary resurrection; can't use DECREF here, it would
	 * cause a recursive call.
	 */
#ifdef Py_REF_DEBUG
	/* _Py_RefTotal was boosted either by _Py_NewReference or
	 * Py_INCREF above.
	 */
	_Py_RefTotal--;
#endif
	if (--self->ob_refcnt > 0) {
#ifdef COUNT_ALLOCS
		self->ob_type->tp_frees--;
#endif
		/* This should still be a tracked gc'ed object. */
#ifdef WITH_CYCLE_GC
		assert(((PyGC_Head *)(self)-1)->gc.gc_next != NULL);
#endif
		return -1; /* __del__ added a reference; don't delete now */
	}
#ifdef Py_TRACE_REFS
	_Py_ForgetReference((PyObject *)self);
#ifdef COUNT_ALLOCS
	/* compensate for increment in _Py_ForgetReference */
	self->ob_type->tp_frees--;
#endif
#endif

	return 0;
#ifdef SYMBIAN
#undef del_str
#endif
}

static void
subtype_dealloc(PyObject *self)
{
	PyTypeObject *type, *base;
	destructor basedealloc;

	/* This exists so we can DECREF self->ob_type */

	if (call_finalizer(self) < 0)
		return;

	/* Find the nearest base with a different tp_dealloc
	   and clear slots while we're at it */
	type = self->ob_type;
	base = type;
	while ((basedealloc = base->tp_dealloc) == subtype_dealloc) {
		if (base->ob_size)
			clear_slots(base, self);
		base = base->tp_base;
		assert(base);
	}

	/* If we added a dict, DECREF it */
	if (type->tp_dictoffset && !base->tp_dictoffset) {
		PyObject **dictptr = _PyObject_GetDictPtr(self);
		if (dictptr != NULL) {
			PyObject *dict = *dictptr;
			if (dict != NULL) {
				Py_DECREF(dict);
				*dictptr = NULL;
			}
		}
	}

	/* If we added weaklist, we clear it */
	if (type->tp_weaklistoffset && !base->tp_weaklistoffset)
		PyObject_ClearWeakRefs(self);

	/* Finalize GC if the base doesn't do GC and we do */
	if (PyType_IS_GC(type) && !PyType_IS_GC(base))
		_PyObject_GC_UNTRACK(self);

	/* Call the base tp_dealloc() */
	assert(basedealloc);
	basedealloc(self);

	/* Can't reference self beyond this point */
	if (type->tp_flags & Py_TPFLAGS_HEAPTYPE) {
		Py_DECREF(type);
	}
}

staticforward PyTypeObject *solid_base(PyTypeObject *type);

/* type test with subclassing support */

DL_EXPORT(int)
PyType_IsSubtype(PyTypeObject *a, PyTypeObject *b)
{
	PyObject *mro;

	if (!(a->tp_flags & Py_TPFLAGS_HAVE_CLASS))
		return b == a || b == &PyBaseObject_Type;

	mro = a->tp_mro;
	if (mro != NULL) {
		/* Deal with multiple inheritance without recursion
		   by walking the MRO tuple */
		int i, n;
		assert(PyTuple_Check(mro));
		n = PyTuple_GET_SIZE(mro);
		for (i = 0; i < n; i++) {
			if (PyTuple_GET_ITEM(mro, i) == (PyObject *)b)
				return 1;
		}
		return 0;
	}
	else {
		/* a is not completely initilized yet; follow tp_base */
		do {
			if (a == b)