Objects/moduleobject.c

   1
   2 /* Module object implementation */
   3
   4 #include "Python.h"
   5 #include "structmember.h"
   6
   7 typedef struct {
   8         PyObject_HEAD
   9         PyObject *md_dict;
  10 } PyModuleObject;
  11
  12 static PyMemberDef module_members[] = {
  13         {"__dict__", T_OBJECT, offsetof(PyModuleObject, md_dict), READONLY},
  14         {0}
  15 };
  16
  17 PyObject *
  18 PyModule_New(const char *name)
  19 {
  20         PyModuleObject *m;
  21         PyObject *nameobj;
  22         m = PyObject_GC_New(PyModuleObject, &PyModule_Type);
  23         if (m == NULL)
  24                 return NULL;
  25         nameobj = PyString_FromString(name);
  26         m->md_dict = PyDict_New();
  27         if (m->md_dict == NULL || nameobj == NULL)
  28                 goto fail;
  29         if (PyDict_SetItemString(m->md_dict, "__name__", nameobj) != 0)
  30                 goto fail;
  31         if (PyDict_SetItemString(m->md_dict, "__doc__", Py_None) != 0)
  32                 goto fail;
  33         Py_DECREF(nameobj);
  34         PyObject_GC_Track(m);
  35         return (PyObject *)m;
  36
  37  fail:
  38         Py_XDECREF(nameobj);
  39         Py_DECREF(m);
  40         return NULL;
  41 }
  42
  43 PyObject *
  44 PyModule_GetDict(PyObject *m)
  45 {
  46         PyObject *d;
  47         if (!PyModule_Check(m)) {
  48                 PyErr_BadInternalCall();
  49                 return NULL;
  50         }
  51         d = ((PyModuleObject *)m) -> md_dict;
  52         if (d == NULL)
  53                 ((PyModuleObject *)m) -> md_dict = d = PyDict_New();
  54         return d;
  55 }
  56
  57 char *
  58 PyModule_GetName(PyObject *m)
  59 {
  60         PyObject *d;
  61         PyObject *nameobj;
  62         if (!PyModule_Check(m)) {
  63                 PyErr_BadArgument();
  64                 return NULL;
  65         }
  66         d = ((PyModuleObject *)m)->md_dict;
  67         if (d == NULL ||
  68             (nameobj = PyDict_GetItemString(d, "__name__")) == NULL ||
  69             !PyString_Check(nameobj))
  70         {
  71                 PyErr_SetString(PyExc_SystemError, "nameless module");
  72                 return NULL;
  73         }
  74         return PyString_AsString(nameobj);
  75 }
  76
  77 char *
  78 PyModule_GetFilename(PyObject *m)
  79 {
  80         PyObject *d;
  81         PyObject *fileobj;
  82         if (!PyModule_Check(m)) {
  83                 PyErr_BadArgument();
  84                 return NULL;
  85         }
  86         d = ((PyModuleObject *)m)->md_dict;
  87         if (d == NULL ||
  88             (fileobj = PyDict_GetItemString(d, "__file__")) == NULL ||
  89             !PyString_Check(fileobj))
  90         {
  91                 PyErr_SetString(PyExc_SystemError, "module filename missing");
  92                 return NULL;
  93         }
  94         return PyString_AsString(fileobj);
  95 }
  96
  97 void
  98 _PyModule_Clear(PyObject *m)
  99 {
 100         /* To make the execution order of destructors for global
 101            objects a bit more predictable, we first zap all objects
 102            whose name starts with a single underscore, before we clear
 103            the entire dictionary.  We zap them by replacing them with
 104            None, rather than deleting them from the dictionary, to
 105            avoid rehashing the dictionary (to some extent). */
 106
 107         Py_ssize_t pos;
 108         PyObject *key, *value;
 109         PyObject *d;
 110
 111         d = ((PyModuleObject *)m)->md_dict;
 112         if (d == NULL)
 113                 return;
 114
 115         /* First, clear only names starting with a single underscore */
 116         pos = 0;
 117         while (PyDict_Next(d, &pos, &key, &value)) {
 118                 if (value != Py_None && PyString_Check(key)) {
 119                         char *s = PyString_AsString(key);
 120                         if (s[0] == '_' && s[1] != '_') {
 121                                 if (Py_VerboseFlag > 1)
 122                                     PySys_WriteStderr("#   clear[1] %s\n", s);
 123                                 PyDict_SetItem(d, key, Py_None);
 124                         }
 125                 }
 126         }
 127
 128         /* Next, clear all names except for __builtins__ */
 129         pos = 0;
 130         while (PyDict_Next(d, &pos, &key, &value)) {
 131                 if (value != Py_None && PyString_Check(key)) {
 132                         char *s = PyString_AsString(key);
 133                         if (s[0] != '_' || strcmp(s, "__builtins__") != 0) {
 134                                 if (Py_VerboseFlag > 1)
 135                                     PySys_WriteStderr("#   clear[2] %s\n", s);
 136                                 PyDict_SetItem(d, key, Py_None);
 137                         }
 138                 }
 139         }
 140
 141         /* Note: we leave __builtins__ in place, so that destructors
 142            of non-global objects defined in this module can still use
 143            builtins, in particularly 'None'. */
 144
 145 }
 146
 147 /* Methods */
 148
 149 static int
 150 module_init(PyModuleObject *m, PyObject *args, PyObject *kwds)
 151 {
 152         static char *kwlist[] = {"name", "doc", NULL};
 153         PyObject *dict, *name = Py_None, *doc = Py_None;
 154         if (!PyArg_ParseTupleAndKeywords(args, kwds, "S|O:module.__init__",
 155                                          kwlist, &name, &doc))
 156                 return -1;
 157         dict = m->md_dict;
 158         if (dict == NULL) {
 159                 dict = PyDict_New();
 160                 if (dict == NULL)
 161                         return -1;
 162                 m->md_dict = dict;
 163         }
 164         if (PyDict_SetItemString(dict, "__name__", name) < 0)
 165                 return -1;
 166         if (PyDict_SetItemString(dict, "__doc__", doc) < 0)
 167                 return -1;
 168         return 0;
 169 }
 170
 171 static void
 172 module_dealloc(PyModuleObject *m)
 173 {
 174         PyObject_GC_UnTrack(m);
 175         if (m->md_dict != NULL) {
 176                 _PyModule_Clear((PyObject *)m);
 177                 Py_DECREF(m->md_dict);
 178         }
 179         m->ob_type->tp_free((PyObject *)m);
 180 }
 181
 182 static PyObject *
 183 module_repr(PyModuleObject *m)
 184 {
 185         char *name;
 186         char *filename;
 187
 188         name = PyModule_GetName((PyObject *)m);
 189         if (name == NULL) {
 190                 PyErr_Clear();
 191                 name = "?";
 192         }
 193         filename = PyModule_GetFilename((PyObject *)m);
 194         if (filename == NULL) {
 195                 PyErr_Clear();
 196                 return PyString_FromFormat("<module '%s' (built-in)>", name);
 197         }
 198         return PyString_FromFormat("<module '%s' from '%s'>", name, filename);
 199 }
 200
 201 /* We only need a traverse function, no clear function: If the module
 202    is in a cycle, md_dict will be cleared as well, which will break
 203    the cycle. */
 204 static int
 205 module_traverse(PyModuleObject *m, visitproc visit, void *arg)
 206 {
 207         Py_VISIT(m->md_dict);
 208         return 0;
 209 }
 210
 211 PyDoc_STRVAR(module_doc,
 212 "module(name[, doc])\n\
 213 \n\
 214 Create a module object.\n\
 215 The name must be a string; the optional doc argument can have any type.");
 216
 217 PyTypeObject PyModule_Type = {
 218         PyObject_HEAD_INIT(&PyType_Type)
 219         0,                                      /* ob_size */
 220         "module",                               /* tp_name */
 221         sizeof(PyModuleObject),                 /* tp_size */
 222         0,                                      /* tp_itemsize */
 223         (destructor)module_dealloc,             /* tp_dealloc */
 224         0,                                      /* tp_print */
 225         0,                                      /* tp_getattr */
 226         0,                                      /* tp_setattr */
 227         0,                                      /* tp_compare */
 228         (reprfunc)module_repr,                  /* tp_repr */
 229         0,                                      /* tp_as_number */
 230         0,                                      /* tp_as_sequence */
 231         0,                                      /* tp_as_mapping */
 232         0,                                      /* tp_hash */
 233         0,                                      /* tp_call */
 234         0,                                      /* tp_str */
 235         PyObject_GenericGetAttr,                /* tp_getattro */
 236         PyObject_GenericSetAttr,                /* tp_setattro */
 237         0,                                      /* tp_as_buffer */
 238         Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
 239                 Py_TPFLAGS_BASETYPE,            /* tp_flags */
 240         module_doc,                             /* tp_doc */
 241         (traverseproc)module_traverse,          /* tp_traverse */
 242         0,                                      /* tp_clear */
 243         0,                                      /* tp_richcompare */
 244         0,                                      /* tp_weaklistoffset */
 245         0,                                      /* tp_iter */
 246         0,                                      /* tp_iternext */
 247         0,                                      /* tp_methods */
 248         module_members,                         /* tp_members */
 249         0,                                      /* tp_getset */
 250         0,                                      /* tp_base */
 251         0,                                      /* tp_dict */
 252         0,                                      /* tp_descr_get */
 253         0,                                      /* tp_descr_set */
 254         offsetof(PyModuleObject, md_dict),      /* tp_dictoffset */
 255         (initproc)module_init,                  /* tp_init */
 256         PyType_GenericAlloc,                    /* tp_alloc */
 257         PyType_GenericNew,                      /* tp_new */
 258         PyObject_GC_Del,                        /* tp_free */
 259 };