/* Module object implementation */

#include "Python.h"

#include "structmember.h"

typedef struct {

	PyObject_HEAD

	PyObject *md_dict;

} PyModuleObject;

static PyMemberDef module_members[] = {

	{"__dict__", T_OBJECT, offsetof(PyModuleObject, md_dict), READONLY},

	{0}

};

PyObject *

PyModule_New(const char *name)

{

	PyModuleObject *m;

	PyObject *nameobj;

	m = PyObject_GC_New(PyModuleObject, &PyModule_Type);

	if (m == NULL)

		return NULL;

	nameobj = PyString_FromString(name);

	m->md_dict = PyDict_New();

	if (m->md_dict == NULL || nameobj == NULL)

		goto fail;

	if (PyDict_SetItemString(m->md_dict, "__name__", nameobj) != 0)

		goto fail;

	if (PyDict_SetItemString(m->md_dict, "__doc__", Py_None) != 0)

		goto fail;

	if (PyDict_SetItemString(m->md_dict, "__package__", Py_None) != 0)

		goto fail;

	Py_DECREF(nameobj);

	PyObject_GC_Track(m);

	return (PyObject *)m;

 fail:

	Py_XDECREF(nameobj);

	Py_DECREF(m);

	return NULL;

}

PyObject *

PyModule_GetDict(PyObject *m)

{

	PyObject *d;

	if (!PyModule_Check(m)) {

		PyErr_BadInternalCall();

		return NULL;

	}

	d = ((PyModuleObject *)m) -> md_dict;

	if (d == NULL)

		((PyModuleObject *)m) -> md_dict = d = PyDict_New();

	return d;

}

char *

PyModule_GetName(PyObject *m)

{

	PyObject *d;

	PyObject *nameobj;

	if (!PyModule_Check(m)) {

		PyErr_BadArgument();

		return NULL;

	}

	d = ((PyModuleObject *)m)->md_dict;

	if (d == NULL ||

	    (nameobj = PyDict_GetItemString(d, "__name__")) == NULL ||

	    !PyString_Check(nameobj))

	{

		PyErr_SetString(PyExc_SystemError, "nameless module");

		return NULL;

	}

	return PyString_AsString(nameobj);

}

char *

PyModule_GetFilename(PyObject *m)

{

	PyObject *d;

	PyObject *fileobj;

	if (!PyModule_Check(m)) {

		PyErr_BadArgument();

		return NULL;

	}

	d = ((PyModuleObject *)m)->md_dict;

	if (d == NULL ||

	    (fileobj = PyDict_GetItemString(d, "__file__")) == NULL ||

	    !PyString_Check(fileobj))

	{

		PyErr_SetString(PyExc_SystemError, "module filename missing");

		return NULL;

	}

	return PyString_AsString(fileobj);

}

void

_PyModule_Clear(PyObject *m)

{

	/* To make the execution order of destructors for global

	   objects a bit more predictable, we first zap all objects

	   whose name starts with a single underscore, before we clear

	   the entire dictionary.  We zap them by replacing them with

	   None, rather than deleting them from the dictionary, to

	   avoid rehashing the dictionary (to some extent). */

	Py_ssize_t pos;

	PyObject *key, *value;

	PyObject *d;

	d = ((PyModuleObject *)m)->md_dict;

	if (d == NULL)

		return;

	/* First, clear only names starting with a single underscore */

	pos = 0;

	while (PyDict_Next(d, &pos, &key, &value)) {

		if (value != Py_None && PyString_Check(key)) {

			char *s = PyString_AsString(key);

			if (s[0] == '_' && s[1] != '_') {

				if (Py_VerboseFlag > 1)

				    PySys_WriteStderr("#   clear[1] %s\n", s);

				PyDict_SetItem(d, key, Py_None);

			}

		}

	}

	/* Next, clear all names except for __builtins__ */

	pos = 0;

	while (PyDict_Next(d, &pos, &key, &value)) {

		if (value != Py_None && PyString_Check(key)) {

			char *s = PyString_AsString(key);

			if (s[0] != '_' || strcmp(s, "__builtins__") != 0) {

				if (Py_VerboseFlag > 1)

				    PySys_WriteStderr("#   clear[2] %s\n", s);

				PyDict_SetItem(d, key, Py_None);

			}

		}

	}

	/* Note: we leave __builtins__ in place, so that destructors

	   of non-global objects defined in this module can still use

	   builtins, in particularly 'None'. */

}

/* Methods */

static int

module_init(PyModuleObject *m, PyObject *args, PyObject *kwds)

{

	static char *kwlist[] = {"name", "doc", NULL};

	PyObject *dict, *name = Py_None, *doc = Py_None;

	if (!PyArg_ParseTupleAndKeywords(args, kwds, "S|O:module.__init__",

                                         kwlist, &name, &doc))

		return -1;

	dict = m->md_dict;

	if (dict == NULL) {

		dict = PyDict_New();

		if (dict == NULL)

			return -1;

		m->md_dict = dict;

	}

	if (PyDict_SetItemString(dict, "__name__", name) < 0)

		return -1;

	if (PyDict_SetItemString(dict, "__doc__", doc) < 0)

		return -1;

	return 0;

}

static void

module_dealloc(PyModuleObject *m)

{

	PyObject_GC_UnTrack(m);

	if (m->md_dict != NULL) {

		_PyModule_Clear((PyObject *)m);

		Py_DECREF(m->md_dict);

	}

	Py_TYPE(m)->tp_free((PyObject *)m);

}

static PyObject *

module_repr(PyModuleObject *m)

{

	char *name;

	char *filename;

	name = PyModule_GetName((PyObject *)m);

	if (name == NULL) {

		PyErr_Clear();

		name = "?";

	}

	filename = PyModule_GetFilename((PyObject *)m);

	if (filename == NULL) {

		PyErr_Clear();

		return PyString_FromFormat("<module '%s' (built-in)>", name);

	}

	return PyString_FromFormat("<module '%s' from '%s'>", name, filename);

}

/* We only need a traverse function, no clear function: If the module

   is in a cycle, md_dict will be cleared as well, which will break

   the cycle. */

static int

module_traverse(PyModuleObject *m, visitproc visit, void *arg)

{

	Py_VISIT(m->md_dict);

	return 0;

}

PyDoc_STRVAR(module_doc,

"module(name[, doc])\n\

\n\

Create a module object.\n\

The name must be a string; the optional doc argument can have any type.");

PyTypeObject PyModule_Type = {

	PyVarObject_HEAD_INIT(&PyType_Type, 0)

	"module",				/* tp_name */

	sizeof(PyModuleObject),			/* tp_size */

	0,					/* tp_itemsize */

	(destructor)module_dealloc,		/* tp_dealloc */

	0,					/* tp_print */

	0,					/* tp_getattr */

	0,					/* tp_setattr */

	0,					/* tp_compare */

	(reprfunc)module_repr,			/* tp_repr */

	0,					/* tp_as_number */

	0,					/* tp_as_sequence */

	0,					/* tp_as_mapping */

	0,					/* tp_hash */

	0,					/* tp_call */

	0,					/* tp_str */

	PyObject_GenericGetAttr,		/* tp_getattro */

	PyObject_GenericSetAttr,		/* tp_setattro */

	0,					/* tp_as_buffer */

	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |

		Py_TPFLAGS_BASETYPE,		/* tp_flags */

	module_doc,				/* tp_doc */

	(traverseproc)module_traverse,		/* tp_traverse */

	0,					/* tp_clear */

	0,					/* tp_richcompare */

	0,					/* tp_weaklistoffset */

	0,					/* tp_iter */

	0,					/* tp_iternext */

	0,					/* tp_methods */

	module_members,				/* tp_members */

	0,					/* tp_getset */

	0,					/* tp_base */

	0,					/* tp_dict */

	0,					/* tp_descr_get */

	0,					/* tp_descr_set */

	offsetof(PyModuleObject, md_dict),	/* tp_dictoffset */

	(initproc)module_init,			/* tp_init */

	PyType_GenericAlloc,			/* tp_alloc */

	PyType_GenericNew,			/* tp_new */

	PyObject_GC_Del,		        /* tp_free */

};