Modules/_dbmmodule.c

   1
   2 /* DBM module using dictionary interface */
   3
   4
   5 #define PY_SSIZE_T_CLEAN
   6 #include "Python.h"
   7
   8 #include <sys/types.h>
   9 #include <sys/stat.h>
  10 #include <fcntl.h>
  11
  12 /* Some Linux systems install gdbm/ndbm.h, but not ndbm.h.  This supports
  13  * whichever configure was able to locate.
  14  */
  15 #if defined(HAVE_NDBM_H)
  16 #include <ndbm.h>
  17 #if defined(PYOS_OS2) && !defined(PYCC_GCC)
  18 static char *which_dbm = "ndbm";
  19 #else
  20 static char *which_dbm = "GNU gdbm";  /* EMX port of GDBM */
  21 #endif
  22 #elif defined(HAVE_GDBM_NDBM_H)
  23 #include <gdbm/ndbm.h>
  24 static char *which_dbm = "GNU gdbm";
  25 #elif defined(HAVE_GDBM_DASH_NDBM_H)
  26 #include <gdbm-ndbm.h>
  27 static char *which_dbm = "GNU gdbm";
  28 #elif defined(HAVE_BERKDB_H)
  29 #include <db.h>
  30 static char *which_dbm = "Berkeley DB";
  31 #else
  32 #error "No ndbm.h available!"
  33 #endif
  34
  35 typedef struct {
  36     PyObject_HEAD
  37     int di_size;        /* -1 means recompute */
  38     DBM *di_dbm;
  39 } dbmobject;
  40
  41 static PyTypeObject Dbmtype;
  42
  43 #define is_dbmobject(v) (Py_TYPE(v) == &Dbmtype)
  44 #define check_dbmobject_open(v) if ((v)->di_dbm == NULL) \
  45                { PyErr_SetString(DbmError, "DBM object has already been closed"); \
  46                  return NULL; }
  47
  48 static PyObject *DbmError;
  49
  50 static PyObject *
  51 newdbmobject(char *file, int flags, int mode)
  52 {
  53     dbmobject *dp;
  54
  55     dp = PyObject_New(dbmobject, &Dbmtype);
  56     if (dp == NULL)
  57         return NULL;
  58     dp->di_size = -1;
  59     if ( (dp->di_dbm = dbm_open(file, flags, mode)) == 0 ) {
  60         PyErr_SetFromErrno(DbmError);
  61         Py_DECREF(dp);
  62         return NULL;
  63     }
  64     return (PyObject *)dp;
  65 }
  66
  67 /* Methods */
  68
  69 static void
  70 dbm_dealloc(register dbmobject *dp)
  71 {
  72     if ( dp->di_dbm )
  73         dbm_close(dp->di_dbm);
  74     PyObject_Del(dp);
  75 }
  76
  77 static Py_ssize_t
  78 dbm_length(dbmobject *dp)
  79 {
  80     if (dp->di_dbm == NULL) {
  81              PyErr_SetString(DbmError, "DBM object has already been closed");
  82              return -1;
  83     }
  84     if ( dp->di_size < 0 ) {
  85         datum key;
  86         int size;
  87
  88         size = 0;
  89         for ( key=dbm_firstkey(dp->di_dbm); key.dptr;
  90               key = dbm_nextkey(dp->di_dbm))
  91             size++;
  92         dp->di_size = size;
  93     }
  94     return dp->di_size;
  95 }
  96
  97 static PyObject *
  98 dbm_subscript(dbmobject *dp, register PyObject *key)
  99 {
 100     datum drec, krec;
 101     Py_ssize_t tmp_size;
 102
 103     if (!PyArg_Parse(key, "s#", &krec.dptr, &tmp_size) )
 104         return NULL;
 105
 106     krec.dsize = tmp_size;
 107     check_dbmobject_open(dp);
 108     drec = dbm_fetch(dp->di_dbm, krec);
 109     if ( drec.dptr == 0 ) {
 110         PyErr_SetObject(PyExc_KeyError, key);
 111         return NULL;
 112     }
 113     if ( dbm_error(dp->di_dbm) ) {
 114         dbm_clearerr(dp->di_dbm);
 115         PyErr_SetString(DbmError, "");
 116         return NULL;
 117     }
 118     return PyBytes_FromStringAndSize(drec.dptr, drec.dsize);
 119 }
 120
 121 static int
 122 dbm_ass_sub(dbmobject *dp, PyObject *v, PyObject *w)
 123 {
 124     datum krec, drec;
 125     Py_ssize_t tmp_size;
 126
 127     if ( !PyArg_Parse(v, "s#", &krec.dptr, &tmp_size) ) {
 128         PyErr_SetString(PyExc_TypeError,
 129                         "dbm mappings have bytes or string keys only");
 130         return -1;
 131     }
 132     krec.dsize = tmp_size;
 133     if (dp->di_dbm == NULL) {
 134              PyErr_SetString(DbmError, "DBM object has already been closed");
 135              return -1;
 136     }
 137     dp->di_size = -1;
 138     if (w == NULL) {
 139         if ( dbm_delete(dp->di_dbm, krec) < 0 ) {
 140             dbm_clearerr(dp->di_dbm);
 141             PyErr_SetObject(PyExc_KeyError, v);
 142             return -1;
 143         }
 144     } else {
 145         if ( !PyArg_Parse(w, "s#", &drec.dptr, &tmp_size) ) {
 146             PyErr_SetString(PyExc_TypeError,
 147                  "dbm mappings have byte or string elements only");
 148             return -1;
 149         }
 150         drec.dsize = tmp_size;
 151         if ( dbm_store(dp->di_dbm, krec, drec, DBM_REPLACE) < 0 ) {
 152             dbm_clearerr(dp->di_dbm);
 153             PyErr_SetString(DbmError,
 154                             "cannot add item to database");
 155             return -1;
 156         }
 157     }
 158     if ( dbm_error(dp->di_dbm) ) {
 159         dbm_clearerr(dp->di_dbm);
 160         PyErr_SetString(DbmError, "");
 161         return -1;
 162     }
 163     return 0;
 164 }
 165
 166 static PyMappingMethods dbm_as_mapping = {
 167     (lenfunc)dbm_length,                /*mp_length*/
 168     (binaryfunc)dbm_subscript,          /*mp_subscript*/
 169     (objobjargproc)dbm_ass_sub,         /*mp_ass_subscript*/
 170 };
 171
 172 static PyObject *
 173 dbm__close(register dbmobject *dp, PyObject *unused)
 174 {
 175     if (dp->di_dbm)
 176         dbm_close(dp->di_dbm);
 177     dp->di_dbm = NULL;
 178     Py_INCREF(Py_None);
 179     return Py_None;
 180 }
 181
 182 static PyObject *
 183 dbm_keys(register dbmobject *dp, PyObject *unused)
 184 {
 185     register PyObject *v, *item;
 186     datum key;
 187     int err;
 188
 189     check_dbmobject_open(dp);
 190     v = PyList_New(0);
 191     if (v == NULL)
 192         return NULL;
 193     for (key = dbm_firstkey(dp->di_dbm); key.dptr;
 194          key = dbm_nextkey(dp->di_dbm)) {
 195         item = PyBytes_FromStringAndSize(key.dptr, key.dsize);
 196         if (item == NULL) {
 197             Py_DECREF(v);
 198             return NULL;
 199         }
 200         err = PyList_Append(v, item);
 201         Py_DECREF(item);
 202         if (err != 0) {
 203             Py_DECREF(v);
 204             return NULL;
 205         }
 206     }
 207     return v;
 208 }
 209
 210 static int
 211 dbm_contains(PyObject *self, PyObject *arg)
 212 {
 213     dbmobject *dp = (dbmobject *)self;
 214     datum key, val;
 215
 216     if ((dp)->di_dbm == NULL) {
 217         PyErr_SetString(DbmError,
 218                         "DBM object has already been closed");
 219          return -1;
 220     }
 221     if (PyUnicode_Check(arg)) {
 222         arg = _PyUnicode_AsDefaultEncodedString(arg, NULL);
 223         if (arg == NULL)
 224             return -1;
 225     }
 226     if (!PyBytes_Check(arg)) {
 227         PyErr_Format(PyExc_TypeError,
 228                      "dbm key must be string, not %.100s",
 229                      arg->ob_type->tp_name);
 230         return -1;
 231     }
 232     key.dptr = PyBytes_AS_STRING(arg);
 233     key.dsize = PyBytes_GET_SIZE(arg);
 234     val = dbm_fetch(dp->di_dbm, key);
 235     return val.dptr != NULL;
 236 }
 237
 238 static PySequenceMethods dbm_as_sequence = {
 239     0,                          /* sq_length */
 240     0,                          /* sq_concat */
 241     0,                          /* sq_repeat */
 242     0,                          /* sq_item */
 243     0,                          /* sq_slice */
 244     0,                          /* sq_ass_item */
 245     0,                          /* sq_ass_slice */
 246     dbm_contains,               /* sq_contains */
 247     0,                          /* sq_inplace_concat */
 248     0,                          /* sq_inplace_repeat */
 249 };
 250
 251 static PyObject *
 252 dbm_get(register dbmobject *dp, PyObject *args)
 253 {
 254     datum key, val;
 255     PyObject *defvalue = Py_None;
 256     char *tmp_ptr;
 257     Py_ssize_t tmp_size;
 258
 259     if (!PyArg_ParseTuple(args, "s#|O:get",
 260                           &tmp_ptr, &tmp_size, &defvalue))
 261         return NULL;
 262     key.dptr = tmp_ptr;
 263     key.dsize = tmp_size;
 264     check_dbmobject_open(dp);
 265     val = dbm_fetch(dp->di_dbm, key);
 266     if (val.dptr != NULL)
 267         return PyBytes_FromStringAndSize(val.dptr, val.dsize);
 268     else {
 269         Py_INCREF(defvalue);
 270         return defvalue;
 271     }
 272 }
 273
 274 static PyObject *
 275 dbm_setdefault(register dbmobject *dp, PyObject *args)
 276 {
 277     datum key, val;
 278     PyObject *defvalue = NULL;
 279     char *tmp_ptr;
 280     Py_ssize_t tmp_size;
 281
 282     if (!PyArg_ParseTuple(args, "s#|O:setdefault",
 283                           &tmp_ptr, &tmp_size, &defvalue))
 284         return NULL;
 285     key.dptr = tmp_ptr;
 286     key.dsize = tmp_size;
 287     check_dbmobject_open(dp);
 288     val = dbm_fetch(dp->di_dbm, key);
 289     if (val.dptr != NULL)
 290         return PyBytes_FromStringAndSize(val.dptr, val.dsize);
 291     if (defvalue == NULL) {
 292         defvalue = PyBytes_FromStringAndSize(NULL, 0);
 293         if (defvalue == NULL)
 294             return NULL;
 295         val.dptr = NULL;
 296         val.dsize = 0;
 297     }
 298     else {
 299         if ( !PyArg_Parse(defvalue, "s#", &val.dptr, &tmp_size) ) {
 300             PyErr_SetString(PyExc_TypeError,
 301                 "dbm mappings have byte string elements only");
 302             return NULL;
 303         }
 304         val.dsize = tmp_size;
 305         Py_INCREF(defvalue);
 306     }
 307     if (dbm_store(dp->di_dbm, key, val, DBM_INSERT) < 0) {
 308         dbm_clearerr(dp->di_dbm);
 309         PyErr_SetString(DbmError, "cannot add item to database");
 310         Py_DECREF(defvalue);
 311         return NULL;
 312     }
 313     return defvalue;
 314 }
 315
 316 static PyMethodDef dbm_methods[] = {
 317     {"close",           (PyCFunction)dbm__close,        METH_NOARGS,
 318      "close()\nClose the database."},
 319     {"keys",            (PyCFunction)dbm_keys,          METH_NOARGS,
 320      "keys() -> list\nReturn a list of all keys in the database."},
 321     {"get",             (PyCFunction)dbm_get,           METH_VARARGS,
 322      "get(key[, default]) -> value\n"
 323      "Return the value for key if present, otherwise default."},
 324     {"setdefault",      (PyCFunction)dbm_setdefault,    METH_VARARGS,
 325      "setdefault(key[, default]) -> value\n"
 326      "Return the value for key if present, otherwise default.  If key\n"
 327      "is not in the database, it is inserted with default as the value."},
 328     {NULL,              NULL}           /* sentinel */
 329 };
 330
 331 static PyTypeObject Dbmtype = {
 332     PyVarObject_HEAD_INIT(NULL, 0)
 333     "_dbm.dbm",
 334     sizeof(dbmobject),
 335     0,
 336     (destructor)dbm_dealloc,  /*tp_dealloc*/
 337     0,                            /*tp_print*/
 338     0,                        /*tp_getattr*/
 339     0,                            /*tp_setattr*/
 340     0,                            /*tp_reserved*/
 341     0,                            /*tp_repr*/
 342     0,                            /*tp_as_number*/
 343     &dbm_as_sequence,             /*tp_as_sequence*/
 344     &dbm_as_mapping,              /*tp_as_mapping*/
 345     0,                    /*tp_hash*/
 346     0,                    /*tp_call*/
 347     0,                    /*tp_str*/
 348     0,                    /*tp_getattro*/
 349     0,                    /*tp_setattro*/
 350     0,                    /*tp_as_buffer*/
 351     Py_TPFLAGS_DEFAULT,   /*tp_flags*/
 352     0,                        /*tp_doc*/
 353     0,                        /*tp_traverse*/
 354     0,                        /*tp_clear*/
 355     0,                        /*tp_richcompare*/
 356     0,                        /*tp_weaklistoffset*/
 357     0,                        /*tp_iter*/
 358     0,                        /*tp_iternext*/
 359     dbm_methods,          /*tp_methods*/
 360 };
 361
 362 /* ----------------------------------------------------------------- */
 363
 364 static PyObject *
 365 dbmopen(PyObject *self, PyObject *args)
 366 {
 367     char *name;
 368     char *flags = "r";
 369     int iflags;
 370     int mode = 0666;
 371
 372     if ( !PyArg_ParseTuple(args, "s|si:open", &name, &flags, &mode) )
 373         return NULL;
 374     if ( strcmp(flags, "r") == 0 )
 375         iflags = O_RDONLY;
 376     else if ( strcmp(flags, "w") == 0 )
 377         iflags = O_RDWR;
 378     else if ( strcmp(flags, "rw") == 0 ) /* B/W compat */
 379         iflags = O_RDWR|O_CREAT;
 380     else if ( strcmp(flags, "c") == 0 )
 381         iflags = O_RDWR|O_CREAT;
 382     else if ( strcmp(flags, "n") == 0 )
 383         iflags = O_RDWR|O_CREAT|O_TRUNC;
 384     else {
 385         PyErr_SetString(DbmError,
 386                         "arg 2 to open should be 'r', 'w', 'c', or 'n'");
 387         return NULL;
 388     }
 389     return newdbmobject(name, iflags, mode);
 390 }
 391
 392 static PyMethodDef dbmmodule_methods[] = {
 393     { "open", (PyCFunction)dbmopen, METH_VARARGS,
 394       "open(path[, flag[, mode]]) -> mapping\n"
 395       "Return a database object."},
 396     { 0, 0 },
 397 };
 398
 399
 400 static struct PyModuleDef _dbmmodule = {
 401     PyModuleDef_HEAD_INIT,
 402     "_dbm",
 403     NULL,
 404     -1,
 405     dbmmodule_methods,
 406     NULL,
 407     NULL,
 408     NULL,
 409     NULL
 410 };
 411
 412 PyMODINIT_FUNC
 413 PyInit__dbm(void) {
 414     PyObject *m, *d, *s;
 415
 416     if (PyType_Ready(&Dbmtype) < 0)
 417         return NULL;
 418     m = PyModule_Create(&_dbmmodule);
 419     if (m == NULL)
 420         return NULL;
 421     d = PyModule_GetDict(m);
 422     if (DbmError == NULL)
 423         DbmError = PyErr_NewException("_dbm.error",
 424                                       PyExc_IOError, NULL);
 425     s = PyUnicode_FromString(which_dbm);
 426     if (s != NULL) {
 427         PyDict_SetItemString(d, "library", s);
 428         Py_DECREF(s);
 429     }
 430     if (DbmError != NULL)
 431         PyDict_SetItemString(d, "error", DbmError);
 432     if (PyErr_Occurred()) {
 433         Py_DECREF(m);
 434         m = NULL;
 435     }
 436     return m;
 437 }