Modules/xxlimited.c - platform/external/python/cpython3 - Git at Google

 /* Use this file as a template to start implementing a module that
    also declares object types. All occurrences of 'Xxo' should be changed
    to something reasonable for your objects. After that, all other
    occurrences of 'xx' should be changed to something reasonable for your
    module. If your module is named foo your source file should be named
    foo.c or foomodule.c.

    You will probably want to delete all references to 'x_attr' and add
    your own types of attributes instead.  Maybe you want to name your
    local variables other than 'self'.  If your object type is needed in
    other files, you'll have to create a file "foobarobject.h"; see
    floatobject.h for an example.

    This module roughly corresponds to::

       class Xxo:
          """A class that explicitly stores attributes in an internal dict"""

           def __init__(self):
               # In the C class, "_x_attr" is not accessible from Python code
               self._x_attr = {}
               self._x_exports = 0

           def __getattr__(self, name):
               return self._x_attr[name]

           def __setattr__(self, name, value):
               self._x_attr[name] = value

           def __delattr__(self, name):
               del self._x_attr[name]

           @property
           def x_exports(self):
               """Return the number of times an internal buffer is exported."""
               # Each Xxo instance has a 10-byte buffer that can be
               # accessed via the buffer interface (e.g. `memoryview`).
               return self._x_exports

           def demo(o, /):
               if isinstance(o, str):
                   return o
               elif isinstance(o, Xxo):
                   return o
               else:
                   raise Error('argument must be str or Xxo')

       class Error(Exception):
           """Exception raised by the xxlimited module"""

       def foo(i: int, j: int, /):
           """Return the sum of i and j."""
           # Unlike this pseudocode, the C function will *only* work with
           # integers and perform C long int arithmetic
           return i + j

       def new():
           return Xxo()

       def Str(str):
           # A trivial subclass of a built-in type
           pass
    */

 #define Py_LIMITED_API 0x030b0000

 #include "Python.h"
 #include <string.h>

 #define BUFSIZE 10

 // Module state
 typedef struct {
     PyObject *Xxo_Type;    // Xxo class
     PyObject *Error_Type;       // Error class
 } xx_state;


 /* Xxo objects */

 // Instance state
 typedef struct {
     PyObject_HEAD
     PyObject            *x_attr;           /* Attributes dictionary */
     char                x_buffer[BUFSIZE]; /* buffer for Py_buffer */
     Py_ssize_t          x_exports;         /* how many buffer are exported */
 } XxoObject;

 // XXX: no good way to do this yet
 // #define XxoObject_Check(v)      Py_IS_TYPE(v, Xxo_Type)

 static XxoObject *
 newXxoObject(PyObject *module)
 {
     xx_state *state = PyModule_GetState(module);
     if (state == NULL) {
         return NULL;
     }
     XxoObject *self;
     self = PyObject_GC_New(XxoObject, (PyTypeObject*)state->Xxo_Type);
     if (self == NULL) {
         return NULL;
     }
     self->x_attr = NULL;
     memset(self->x_buffer, 0, BUFSIZE);
     self->x_exports = 0;
     return self;
 }

 /* Xxo finalization */

 static int
 Xxo_traverse(XxoObject *self, visitproc visit, void *arg)
 {
     // Visit the type
     Py_VISIT(Py_TYPE(self));

     // Visit the attribute dict
     Py_VISIT(self->x_attr);
     return 0;
 }

 static int
 Xxo_clear(XxoObject *self)
 {
     Py_CLEAR(self->x_attr);
     return 0;
 }

 static void
 Xxo_finalize(XxoObject *self)
 {
     Py_CLEAR(self->x_attr);
 }

 static void
 Xxo_dealloc(XxoObject *self)
 {
     Xxo_finalize(self);
     PyTypeObject *tp = Py_TYPE(self);
     freefunc free = PyType_GetSlot(tp, Py_tp_free);
     free(self);
     Py_DECREF(tp);
 }


 /* Xxo attribute handling */

 static PyObject *
 Xxo_getattro(XxoObject *self, PyObject *name)
 {
     if (self->x_attr != NULL) {
         PyObject *v = PyDict_GetItemWithError(self->x_attr, name);
         if (v != NULL) {
             Py_INCREF(v);
             return v;
         }
         else if (PyErr_Occurred()) {
             return NULL;
         }
     }
     return PyObject_GenericGetAttr((PyObject *)self, name);
 }

 static int
 Xxo_setattro(XxoObject *self, PyObject *name, PyObject *v)
 {
     if (self->x_attr == NULL) {
         // prepare the attribute dict
         self->x_attr = PyDict_New();
         if (self->x_attr == NULL) {
             return -1;
         }
     }
     if (v == NULL) {
         // delete an attribute
         int rv = PyDict_DelItem(self->x_attr, name);
         if (rv < 0 && PyErr_ExceptionMatches(PyExc_KeyError)) {
             PyErr_SetString(PyExc_AttributeError,
                 "delete non-existing Xxo attribute");
             return -1;
         }
         return rv;
     }
     else {
         // set an attribute
         return PyDict_SetItem(self->x_attr, name, v);
     }
 }

 /* Xxo methods */

 static PyObject *
 Xxo_demo(XxoObject *self, PyTypeObject *defining_class,
          PyObject **args, Py_ssize_t nargs, PyObject *kwnames)
 {
     if (kwnames != NULL && PyObject_Length(kwnames)) {
         PyErr_SetString(PyExc_TypeError, "demo() takes no keyword arguments");
         return NULL;
     }
     if (nargs != 1) {
         PyErr_SetString(PyExc_TypeError, "demo() takes exactly 1 argument");
         return NULL;
     }

     PyObject *o = args[0];

     /* Test if the argument is "str" */
     if (PyUnicode_Check(o)) {
         Py_INCREF(o);
         return o;
     }

     /* test if the argument is of the Xxo class */
     if (PyObject_TypeCheck(o, defining_class)) {
         Py_INCREF(o);
         return o;
     }

     Py_INCREF(Py_None);
     return Py_None;
 }

 static PyMethodDef Xxo_methods[] = {
     {"demo",            (PyCFunction)(void(*)(void))Xxo_demo,
      METH_METHOD | METH_FASTCALL | METH_KEYWORDS, PyDoc_STR("demo(o) -> o")},
     {NULL,              NULL}           /* sentinel */
 };

 /* Xxo buffer interface */

 static int
 Xxo_getbuffer(XxoObject *self, Py_buffer *view, int flags)
 {
     int res = PyBuffer_FillInfo(view, (PyObject*)self,
                                (void *)self->x_buffer, BUFSIZE,
                                0, flags);
     if (res == 0) {
         self->x_exports++;
     }
     return res;
 }

 static void
 Xxo_releasebuffer(XxoObject *self, Py_buffer *view)
 {
     self->x_exports--;
 }

 static PyObject *
 Xxo_get_x_exports(XxoObject *self, void *c)
 {
     return PyLong_FromSsize_t(self->x_exports);
 }

 /* Xxo type definition */

 PyDoc_STRVAR(Xxo_doc,
              "A class that explicitly stores attributes in an internal dict");

 static PyGetSetDef Xxo_getsetlist[] = {
     {"x_exports", (getter) Xxo_get_x_exports, NULL, NULL},
     {NULL},
 };


 static PyType_Slot Xxo_Type_slots[] = {
     {Py_tp_doc, (char *)Xxo_doc},
     {Py_tp_traverse, Xxo_traverse},
     {Py_tp_clear, Xxo_clear},
     {Py_tp_finalize, Xxo_finalize},
     {Py_tp_dealloc, Xxo_dealloc},
     {Py_tp_getattro, Xxo_getattro},
     {Py_tp_setattro, Xxo_setattro},
     {Py_tp_methods, Xxo_methods},
     {Py_bf_getbuffer, Xxo_getbuffer},
     {Py_bf_releasebuffer, Xxo_releasebuffer},
     {Py_tp_getset, Xxo_getsetlist},
     {0, 0},  /* sentinel */
 };

 static PyType_Spec Xxo_Type_spec = {
     .name = "xxlimited.Xxo",
     .basicsize = sizeof(XxoObject),
     .flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
     .slots = Xxo_Type_slots,
 };


 /* Str type definition*/

 static PyType_Slot Str_Type_slots[] = {
     {0, 0},  /* sentinel */
 };

 static PyType_Spec Str_Type_spec = {
     .name = "xxlimited.Str",
     .basicsize = 0,
     .flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
     .slots = Str_Type_slots,
 };


 /* Function of two integers returning integer (with C "long int" arithmetic) */

 PyDoc_STRVAR(xx_foo_doc,
 "foo(i,j)\n\
 \n\
 Return the sum of i and j.");

 static PyObject *
 xx_foo(PyObject *module, PyObject *args)
 {
     long i, j;
     long res;
     if (!PyArg_ParseTuple(args, "ll:foo", &i, &j))
         return NULL;
     res = i+j; /* XXX Do something here */
     return PyLong_FromLong(res);
 }


 /* Function of no arguments returning new Xxo object */

 static PyObject *
 xx_new(PyObject *module, PyObject *Py_UNUSED(unused))
 {
     XxoObject *rv;

     rv = newXxoObject(module);
     if (rv == NULL)
         return NULL;
     return (PyObject *)rv;
 }


 /* List of functions defined in the module */

 static PyMethodDef xx_methods[] = {
     {"foo",             xx_foo,         METH_VARARGS,
         xx_foo_doc},
     {"new",             xx_new,         METH_NOARGS,
         PyDoc_STR("new() -> new Xx object")},
     {NULL,              NULL}           /* sentinel */
 };


 /* The module itself */

 PyDoc_STRVAR(module_doc,
 "This is a template module just for instruction.");

 static int
 xx_modexec(PyObject *m)
 {
     xx_state *state = PyModule_GetState(m);

     state->Error_Type = PyErr_NewException("xxlimited.Error", NULL, NULL);
     if (state->Error_Type == NULL) {
         return -1;
     }
     if (PyModule_AddType(m, (PyTypeObject*)state->Error_Type) < 0) {
         return -1;
     }

     state->Xxo_Type = PyType_FromModuleAndSpec(m, &Xxo_Type_spec, NULL);
     if (state->Xxo_Type == NULL) {
         return -1;
     }
     if (PyModule_AddType(m, (PyTypeObject*)state->Xxo_Type) < 0) {
         return -1;
     }

     // Add the Str type. It is not needed from C code, so it is only
     // added to the module dict.
     // It does not inherit from "object" (PyObject_Type), but from "str"
     // (PyUnincode_Type).
     PyObject *Str_Type = PyType_FromModuleAndSpec(
         m, &Str_Type_spec, (PyObject *)&PyUnicode_Type);
     if (Str_Type == NULL) {
         return -1;
     }
     if (PyModule_AddType(m, (PyTypeObject*)Str_Type) < 0) {
         return -1;
     }
     Py_DECREF(Str_Type);

     return 0;
 }

 static PyModuleDef_Slot xx_slots[] = {
     {Py_mod_exec, xx_modexec},
     {0, NULL}
 };

 static int
 xx_traverse(PyObject *module, visitproc visit, void *arg)
 {
     xx_state *state = PyModule_GetState(module);
     Py_VISIT(state->Xxo_Type);
     Py_VISIT(state->Error_Type);
     return 0;
 }

 static int
 xx_clear(PyObject *module)
 {
     xx_state *state = PyModule_GetState(module);
     Py_CLEAR(state->Xxo_Type);
     Py_CLEAR(state->Error_Type);
     return 0;
 }

 static struct PyModuleDef xxmodule = {
     PyModuleDef_HEAD_INIT,
     .m_name = "xxlimited",
     .m_doc = module_doc,
     .m_size = sizeof(xx_state),
     .m_methods = xx_methods,
     .m_slots = xx_slots,
     .m_traverse = xx_traverse,
     .m_clear = xx_clear,
     /* m_free is not necessary here: xx_clear clears all references,
      * and the module state is deallocated along with the module.
      */
 };


 /* Export function for the module (*must* be called PyInit_xx) */

 PyMODINIT_FUNC
 PyInit_xxlimited(void)
 {
     return PyModuleDef_Init(&xxmodule);
 }
	/* Use this file as a template to start implementing a module that
	also declares object types. All occurrences of 'Xxo' should be changed
	to something reasonable for your objects. After that, all other
	occurrences of 'xx' should be changed to something reasonable for your
	module. If your module is named foo your source file should be named
	foo.c or foomodule.c.

	You will probably want to delete all references to 'x_attr' and add
	your own types of attributes instead. Maybe you want to name your
	local variables other than 'self'. If your object type is needed in
	other files, you'll have to create a file "foobarobject.h"; see
	floatobject.h for an example.

	This module roughly corresponds to::

	class Xxo:
	"""A class that explicitly stores attributes in an internal dict"""

	def __init__(self):
	# In the C class, "_x_attr" is not accessible from Python code
	self._x_attr = {}
	self._x_exports = 0

	def __getattr__(self, name):
	return self._x_attr[name]

	def __setattr__(self, name, value):
	self._x_attr[name] = value

	def __delattr__(self, name):
	del self._x_attr[name]

	@property
	def x_exports(self):
	"""Return the number of times an internal buffer is exported."""
	# Each Xxo instance has a 10-byte buffer that can be
	# accessed via the buffer interface (e.g. `memoryview`).
	return self._x_exports

	def demo(o, /):
	if isinstance(o, str):
	return o
	elif isinstance(o, Xxo):
	return o
	else:
	raise Error('argument must be str or Xxo')

	class Error(Exception):
	"""Exception raised by the xxlimited module"""

	def foo(i: int, j: int, /):
	"""Return the sum of i and j."""
	# Unlike this pseudocode, the C function will only work with
	# integers and perform C long int arithmetic
	return i + j

	def new():
	return Xxo()

	def Str(str):
	# A trivial subclass of a built-in type
	pass
	*/

	#define Py_LIMITED_API 0x030b0000

	#include "Python.h"
	#include <string.h>

	#define BUFSIZE 10

	// Module state
	typedef struct {
	PyObject *Xxo_Type; // Xxo class
	PyObject *Error_Type; // Error class
	} xx_state;


	/* Xxo objects */

	// Instance state
	typedef struct {
	PyObject_HEAD
	PyObject x_attr; / Attributes dictionary */
	char x_buffer[BUFSIZE]; /* buffer for Py_buffer */
	Py_ssize_t x_exports; /* how many buffer are exported */
	} XxoObject;

	// XXX: no good way to do this yet
	// #define XxoObject_Check(v) Py_IS_TYPE(v, Xxo_Type)

	static XxoObject *
	newXxoObject(PyObject *module)
	{
	xx_state *state = PyModule_GetState(module);
	if (state == NULL) {
	return NULL;
	}
	XxoObject *self;
	self = PyObject_GC_New(XxoObject, (PyTypeObject*)state->Xxo_Type);
	if (self == NULL) {
	return NULL;
	}
	self->x_attr = NULL;
	memset(self->x_buffer, 0, BUFSIZE);
	self->x_exports = 0;
	return self;
	}

	/* Xxo finalization */

	static int
	Xxo_traverse(XxoObject self, visitproc visit, void arg)
	{
	// Visit the type
	Py_VISIT(Py_TYPE(self));

	// Visit the attribute dict
	Py_VISIT(self->x_attr);
	return 0;
	}

	static int
	Xxo_clear(XxoObject *self)
	{
	Py_CLEAR(self->x_attr);
	return 0;
	}

	static void
	Xxo_finalize(XxoObject *self)
	{
	Py_CLEAR(self->x_attr);
	}

	static void
	Xxo_dealloc(XxoObject *self)
	{
	Xxo_finalize(self);
	PyTypeObject *tp = Py_TYPE(self);
	freefunc free = PyType_GetSlot(tp, Py_tp_free);
	free(self);
	Py_DECREF(tp);
	}


	/* Xxo attribute handling */

	static PyObject *
	Xxo_getattro(XxoObject self, PyObject name)
	{
	if (self->x_attr != NULL) {
	PyObject *v = PyDict_GetItemWithError(self->x_attr, name);
	if (v != NULL) {
	Py_INCREF(v);
	return v;
	}
	else if (PyErr_Occurred()) {
	return NULL;
	}
	}
	return PyObject_GenericGetAttr((PyObject *)self, name);
	}

	static int
	Xxo_setattro(XxoObject self, PyObject name, PyObject *v)
	{
	if (self->x_attr == NULL) {
	// prepare the attribute dict
	self->x_attr = PyDict_New();
	if (self->x_attr == NULL) {
	return -1;
	}
	}
	if (v == NULL) {
	// delete an attribute
	int rv = PyDict_DelItem(self->x_attr, name);
	if (rv < 0 && PyErr_ExceptionMatches(PyExc_KeyError)) {
	PyErr_SetString(PyExc_AttributeError,
	"delete non-existing Xxo attribute");
	return -1;
	}
	return rv;
	}
	else {
	// set an attribute
	return PyDict_SetItem(self->x_attr, name, v);
	}
	}

	/* Xxo methods */

	static PyObject *
	Xxo_demo(XxoObject self, PyTypeObject defining_class,
	PyObject *args, Py_ssize_t nargs, PyObject kwnames)
	{
	if (kwnames != NULL && PyObject_Length(kwnames)) {
	PyErr_SetString(PyExc_TypeError, "demo() takes no keyword arguments");
	return NULL;
	}
	if (nargs != 1) {
	PyErr_SetString(PyExc_TypeError, "demo() takes exactly 1 argument");
	return NULL;
	}

	PyObject *o = args[0];

	/* Test if the argument is "str" */
	if (PyUnicode_Check(o)) {
	Py_INCREF(o);
	return o;
	}

	/* test if the argument is of the Xxo class */
	if (PyObject_TypeCheck(o, defining_class)) {
	Py_INCREF(o);
	return o;
	}

	Py_INCREF(Py_None);
	return Py_None;
	}

	static PyMethodDef Xxo_methods[] = {
	{"demo", (PyCFunction)(void(*)(void))Xxo_demo,
	METH_METHOD \| METH_FASTCALL \| METH_KEYWORDS, PyDoc_STR("demo(o) -> o")},
	{NULL, NULL} /* sentinel */
	};

	/* Xxo buffer interface */

	static int
	Xxo_getbuffer(XxoObject self, Py_buffer view, int flags)
	{
	int res = PyBuffer_FillInfo(view, (PyObject*)self,
	(void *)self->x_buffer, BUFSIZE,
	0, flags);
	if (res == 0) {
	self->x_exports++;
	}
	return res;
	}

	static void
	Xxo_releasebuffer(XxoObject self, Py_buffer view)
	{
	self->x_exports--;
	}

	static PyObject *
	Xxo_get_x_exports(XxoObject self, void c)
	{
	return PyLong_FromSsize_t(self->x_exports);
	}

	/* Xxo type definition */

	PyDoc_STRVAR(Xxo_doc,
	"A class that explicitly stores attributes in an internal dict");

	static PyGetSetDef Xxo_getsetlist[] = {
	{"x_exports", (getter) Xxo_get_x_exports, NULL, NULL},
	{NULL},
	};


	static PyType_Slot Xxo_Type_slots[] = {
	{Py_tp_doc, (char *)Xxo_doc},
	{Py_tp_traverse, Xxo_traverse},
	{Py_tp_clear, Xxo_clear},
	{Py_tp_finalize, Xxo_finalize},
	{Py_tp_dealloc, Xxo_dealloc},
	{Py_tp_getattro, Xxo_getattro},
	{Py_tp_setattro, Xxo_setattro},
	{Py_tp_methods, Xxo_methods},
	{Py_bf_getbuffer, Xxo_getbuffer},
	{Py_bf_releasebuffer, Xxo_releasebuffer},
	{Py_tp_getset, Xxo_getsetlist},
	{0, 0}, /* sentinel */
	};

	static PyType_Spec Xxo_Type_spec = {
	.name = "xxlimited.Xxo",
	.basicsize = sizeof(XxoObject),
	.flags = Py_TPFLAGS_DEFAULT \| Py_TPFLAGS_HAVE_GC,
	.slots = Xxo_Type_slots,
	};


	/* Str type definition*/

	static PyType_Slot Str_Type_slots[] = {
	{0, 0}, /* sentinel */
	};

	static PyType_Spec Str_Type_spec = {
	.name = "xxlimited.Str",
	.basicsize = 0,
	.flags = Py_TPFLAGS_DEFAULT \| Py_TPFLAGS_BASETYPE,
	.slots = Str_Type_slots,
	};


	/* Function of two integers returning integer (with C "long int" arithmetic) */

	PyDoc_STRVAR(xx_foo_doc,
	"foo(i,j)\n\
	\n\
	Return the sum of i and j.");

	static PyObject *
	xx_foo(PyObject module, PyObject args)
	{
	long i, j;
	long res;
	if (!PyArg_ParseTuple(args, "ll:foo", &i, &j))
	return NULL;
	res = i+j; /* XXX Do something here */
	return PyLong_FromLong(res);
	}


	/* Function of no arguments returning new Xxo object */

	static PyObject *
	xx_new(PyObject module, PyObject Py_UNUSED(unused))
	{
	XxoObject *rv;

	rv = newXxoObject(module);
	if (rv == NULL)
	return NULL;
	return (PyObject *)rv;
	}



	/* List of functions defined in the module */

	static PyMethodDef xx_methods[] = {
	{"foo", xx_foo, METH_VARARGS,
	xx_foo_doc},
	{"new", xx_new, METH_NOARGS,
	PyDoc_STR("new() -> new Xx object")},
	{NULL, NULL} /* sentinel */
	};


	/* The module itself */

	PyDoc_STRVAR(module_doc,
	"This is a template module just for instruction.");

	static int
	xx_modexec(PyObject *m)
	{
	xx_state *state = PyModule_GetState(m);

	state->Error_Type = PyErr_NewException("xxlimited.Error", NULL, NULL);
	if (state->Error_Type == NULL) {
	return -1;
	}
	if (PyModule_AddType(m, (PyTypeObject*)state->Error_Type) < 0) {
	return -1;
	}

	state->Xxo_Type = PyType_FromModuleAndSpec(m, &Xxo_Type_spec, NULL);
	if (state->Xxo_Type == NULL) {
	return -1;
	}
	if (PyModule_AddType(m, (PyTypeObject*)state->Xxo_Type) < 0) {
	return -1;
	}

	// Add the Str type. It is not needed from C code, so it is only
	// added to the module dict.
	// It does not inherit from "object" (PyObject_Type), but from "str"
	// (PyUnincode_Type).
	PyObject *Str_Type = PyType_FromModuleAndSpec(
	m, &Str_Type_spec, (PyObject *)&PyUnicode_Type);
	if (Str_Type == NULL) {
	return -1;
	}
	if (PyModule_AddType(m, (PyTypeObject*)Str_Type) < 0) {
	return -1;
	}
	Py_DECREF(Str_Type);

	return 0;
	}

	static PyModuleDef_Slot xx_slots[] = {
	{Py_mod_exec, xx_modexec},
	{0, NULL}
	};

	static int
	xx_traverse(PyObject module, visitproc visit, void arg)
	{
	xx_state *state = PyModule_GetState(module);
	Py_VISIT(state->Xxo_Type);
	Py_VISIT(state->Error_Type);
	return 0;
	}

	static int
	xx_clear(PyObject *module)
	{
	xx_state *state = PyModule_GetState(module);
	Py_CLEAR(state->Xxo_Type);
	Py_CLEAR(state->Error_Type);
	return 0;
	}

	static struct PyModuleDef xxmodule = {
	PyModuleDef_HEAD_INIT,
	.m_name = "xxlimited",
	.m_doc = module_doc,
	.m_size = sizeof(xx_state),
	.m_methods = xx_methods,
	.m_slots = xx_slots,
	.m_traverse = xx_traverse,
	.m_clear = xx_clear,
	/* m_free is not necessary here: xx_clear clears all references,
	* and the module state is deallocated along with the module.
	*/
	};


	/* Export function for the module (must be called PyInit_xx) */

	PyMODINIT_FUNC
	PyInit_xxlimited(void)
	{
	return PyModuleDef_Init(&xxmodule);
	}