Modules/dbmmodule.c

   1
   2 /* DBM module using dictionary interface */
   3
   4
   5 #include "Python.h"
   6
   7 #include <sys/types.h>
   8 #include <sys/stat.h>
   9 #include <fcntl.h>
  10
  11 /* Some Linux systems install gdbm/ndbm.h, but not ndbm.h.  This supports
  12  * whichever configure was able to locate.
  13  */
  14 #if defined(HAVE_NDBM_H)
  15 #include <ndbm.h>
  16 #if defined(PYOS_OS2) && !defined(PYCC_GCC)
  17 static char *which_dbm = "ndbm";
  18 #else
  19 static char *which_dbm = "GNU gdbm";  /* EMX port of GDBM */
  20 #endif
  21 #elif defined(HAVE_GDBM_NDBM_H)
  22 #include <gdbm/ndbm.h>
  23 static char *which_dbm = "GNU gdbm";
  24 #elif defined(HAVE_GDBM_DASH_NDBM_H)
  25 #include <gdbm-ndbm.h>
  26 static char *which_dbm = "GNU gdbm";
  27 #elif defined(HAVE_BERKDB_H)
  28 #include <db.h>
  29 static char *which_dbm = "Berkeley DB";
  30 #else
  31 #error "No ndbm.h available!"
  32 #endif
  33
  34 typedef struct {
  35         PyObject_HEAD
  36         int di_size;    /* -1 means recompute */
  37         DBM *di_dbm;
  38 } dbmobject;
  39
  40 static PyTypeObject Dbmtype;
  41
  42 #define is_dbmobject(v) (Py_TYPE(v) == &Dbmtype)
  43 #define check_dbmobject_open(v) if ((v)->di_dbm == NULL) \
  44                { PyErr_SetString(DbmError, "DBM object has already been closed"); \
  45                  return NULL; }
  46
  47 static PyObject *DbmError;
  48
  49 static PyObject *
  50 newdbmobject(char *file, int flags, int mode)
  51 {
  52         dbmobject *dp;
  53
  54         dp = PyObject_New(dbmobject, &Dbmtype);
  55         if (dp == NULL)
  56                 return NULL;
  57         dp->di_size = -1;
  58         if ( (dp->di_dbm = dbm_open(file, flags, mode)) == 0 ) {
  59                 PyErr_SetFromErrno(DbmError);
  60                 Py_DECREF(dp);
  61                 return NULL;
  62         }
  63         return (PyObject *)dp;
  64 }
  65
  66 /* Methods */
  67
  68 static void
  69 dbm_dealloc(register dbmobject *dp)
  70 {
  71         if ( dp->di_dbm )
  72                 dbm_close(dp->di_dbm);
  73         PyObject_Del(dp);
  74 }
  75
  76 static Py_ssize_t
  77 dbm_length(dbmobject *dp)
  78 {
  79         if (dp->di_dbm == NULL) {
  80                  PyErr_SetString(DbmError, "DBM object has already been closed");
  81                  return -1;
  82         }
  83         if ( dp->di_size < 0 ) {
  84                 datum key;
  85                 int size;
  86
  87                 size = 0;
  88                 for ( key=dbm_firstkey(dp->di_dbm); key.dptr;
  89                       key = dbm_nextkey(dp->di_dbm))
  90                         size++;
  91                 dp->di_size = size;
  92         }
  93         return dp->di_size;
  94 }
  95
  96 static PyObject *
  97 dbm_subscript(dbmobject *dp, register PyObject *key)
  98 {
  99         datum drec, krec;
 100         int tmp_size;
 101
 102         if (!PyArg_Parse(key, "s#", &krec.dptr, &tmp_size) )
 103                 return NULL;
 104
 105         krec.dsize = tmp_size;
 106         check_dbmobject_open(dp);
 107         drec = dbm_fetch(dp->di_dbm, krec);
 108         if ( drec.dptr == 0 ) {
 109                 PyErr_SetString(PyExc_KeyError,
 110                                 PyString_AS_STRING((PyStringObject *)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 PyString_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         int tmp_size;
 126
 127         if ( !PyArg_Parse(v, "s#", &krec.dptr, &tmp_size) ) {
 128                 PyErr_SetString(PyExc_TypeError,
 129                                 "dbm mappings have string indices 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_SetString(PyExc_KeyError,
 142                                       PyString_AS_STRING((PyStringObject *)v));
 143                         return -1;
 144                 }
 145         } else {
 146                 if ( !PyArg_Parse(w, "s#", &drec.dptr, &tmp_size) ) {
 147                         PyErr_SetString(PyExc_TypeError,
 148                                      "dbm mappings have string elements only");
 149                         return -1;
 150                 }
 151                 drec.dsize = tmp_size;
 152                 if ( dbm_store(dp->di_dbm, krec, drec, DBM_REPLACE) < 0 ) {
 153                         dbm_clearerr(dp->di_dbm);
 154                         PyErr_SetString(DbmError,
 155                                         "cannot add item to database");
 156                         return -1;
 157                 }
 158         }
 159         if ( dbm_error(dp->di_dbm) ) {
 160                 dbm_clearerr(dp->di_dbm);
 161                 PyErr_SetString(DbmError, "");
 162                 return -1;
 163         }
 164         return 0;
 165 }
 166
 167 static int
 168 dbm_contains(register dbmobject *dp, PyObject *v)
 169 {
 170         datum key, val;
 171
 172         if (PyString_AsStringAndSize(v, (char **)&key.dptr,
 173                                      (Py_ssize_t *)&key.dsize)) {
 174                 return -1;
 175         }
 176
 177         /* Expand check_dbmobject_open to return -1 */
 178         if (dp->di_dbm == NULL) {
 179                 PyErr_SetString(DbmError, "DBM object has already been closed");
 180                 return -1;
 181         }
 182         val = dbm_fetch(dp->di_dbm, key);
 183         return val.dptr != NULL;
 184 }
 185
 186 static PySequenceMethods dbm_as_sequence = {
 187     (lenfunc)dbm_length,        /*_length*/
 188     0,                          /*sq_concat*/
 189     0,                          /*sq_repeat*/
 190     0,                          /*sq_item*/
 191     0,                          /*sq_slice*/
 192     0,                          /*sq_ass_item*/
 193     0,                          /*sq_ass_slice*/
 194     (objobjproc)dbm_contains,   /*sq_contains*/
 195     0,                          /*sq_inplace_concat*/
 196     0                           /*sq_inplace_repeat*/
 197 };
 198
 199 static PyMappingMethods dbm_as_mapping = {
 200         (lenfunc)dbm_length,            /*mp_length*/
 201         (binaryfunc)dbm_subscript,      /*mp_subscript*/
 202         (objobjargproc)dbm_ass_sub,     /*mp_ass_subscript*/
 203 };
 204
 205 static PyObject *
 206 dbm__close(register dbmobject *dp, PyObject *unused)
 207 {
 208         if (dp->di_dbm)
 209                 dbm_close(dp->di_dbm);
 210         dp->di_dbm = NULL;
 211         Py_INCREF(Py_None);
 212         return Py_None;
 213 }
 214
 215 static PyObject *
 216 dbm_keys(register dbmobject *dp, PyObject *unused)
 217 {
 218         register PyObject *v, *item;
 219         datum key;
 220         int err;
 221
 222         check_dbmobject_open(dp);
 223         v = PyList_New(0);
 224         if (v == NULL)
 225                 return NULL;
 226         for (key = dbm_firstkey(dp->di_dbm); key.dptr;
 227              key = dbm_nextkey(dp->di_dbm)) {
 228                 item = PyString_FromStringAndSize(key.dptr, key.dsize);
 229                 if (item == NULL) {
 230                         Py_DECREF(v);
 231                         return NULL;
 232                 }
 233                 err = PyList_Append(v, item);
 234                 Py_DECREF(item);
 235                 if (err != 0) {
 236                         Py_DECREF(v);
 237                         return NULL;
 238                 }
 239         }
 240         return v;
 241 }
 242
 243 static PyObject *
 244 dbm_has_key(register dbmobject *dp, PyObject *args)
 245 {
 246         char *tmp_ptr;
 247         datum key, val;
 248         int tmp_size;
 249
 250         if (!PyArg_ParseTuple(args, "s#:has_key", &tmp_ptr, &tmp_size))
 251                 return NULL;
 252         key.dptr = tmp_ptr;
 253         key.dsize = tmp_size;
 254         check_dbmobject_open(dp);
 255         val = dbm_fetch(dp->di_dbm, key);
 256         return PyInt_FromLong(val.dptr != NULL);
 257 }
 258
 259 static PyObject *
 260 dbm_get(register dbmobject *dp, PyObject *args)
 261 {
 262         datum key, val;
 263         PyObject *defvalue = Py_None;
 264         char *tmp_ptr;
 265         int tmp_size;
 266
 267         if (!PyArg_ParseTuple(args, "s#|O:get",
 268                               &tmp_ptr, &tmp_size, &defvalue))
 269                 return NULL;
 270         key.dptr = tmp_ptr;
 271         key.dsize = tmp_size;
 272         check_dbmobject_open(dp);
 273         val = dbm_fetch(dp->di_dbm, key);
 274         if (val.dptr != NULL)
 275                 return PyString_FromStringAndSize(val.dptr, val.dsize);
 276         else {
 277                 Py_INCREF(defvalue);
 278                 return defvalue;
 279         }
 280 }
 281
 282 static PyObject *
 283 dbm_setdefault(register dbmobject *dp, PyObject *args)
 284 {
 285         datum key, val;
 286         PyObject *defvalue = NULL;
 287         char *tmp_ptr;
 288         int tmp_size;
 289
 290         if (!PyArg_ParseTuple(args, "s#|S:setdefault",
 291                               &tmp_ptr, &tmp_size, &defvalue))
 292                 return NULL;
 293         key.dptr = tmp_ptr;
 294         key.dsize = tmp_size;
 295         check_dbmobject_open(dp);
 296         val = dbm_fetch(dp->di_dbm, key);
 297         if (val.dptr != NULL)
 298                 return PyString_FromStringAndSize(val.dptr, val.dsize);
 299         if (defvalue == NULL) {
 300                 defvalue = PyString_FromStringAndSize(NULL, 0);
 301                 if (defvalue == NULL)
 302                         return NULL;
 303         }
 304         else
 305                 Py_INCREF(defvalue);
 306         val.dptr = PyString_AS_STRING(defvalue);
 307         val.dsize = PyString_GET_SIZE(defvalue);
 308         if (dbm_store(dp->di_dbm, key, val, DBM_INSERT) < 0) {
 309                 dbm_clearerr(dp->di_dbm);
 310                 PyErr_SetString(DbmError, "cannot add item to database");
 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         {"has_key",     (PyCFunction)dbm_has_key,       METH_VARARGS,
 322          "has_key(key} -> boolean\nReturn true iff key is in the database."},
 323         {"get",         (PyCFunction)dbm_get,           METH_VARARGS,
 324          "get(key[, default]) -> value\n"
 325          "Return the value for key if present, otherwise default."},
 326         {"setdefault",  (PyCFunction)dbm_setdefault,    METH_VARARGS,
 327          "setdefault(key[, default]) -> value\n"
 328          "Return the value for key if present, otherwise default.  If key\n"
 329          "is not in the database, it is inserted with default as the value."},
 330         {NULL,          NULL}           /* sentinel */
 331 };
 332
 333 static PyObject *
 334 dbm_getattr(dbmobject *dp, char *name)
 335 {
 336         return Py_FindMethod(dbm_methods, (PyObject *)dp, name);
 337 }
 338
 339 static PyTypeObject Dbmtype = {
 340         PyVarObject_HEAD_INIT(NULL, 0)
 341         "dbm.dbm",
 342         sizeof(dbmobject),
 343         0,
 344         (destructor)dbm_dealloc,  /*tp_dealloc*/
 345         0,                        /*tp_print*/
 346         (getattrfunc)dbm_getattr, /*tp_getattr*/
 347         0,                        /*tp_setattr*/
 348         0,                        /*tp_compare*/
 349         0,                        /*tp_repr*/
 350         0,                        /*tp_as_number*/
 351     &dbm_as_sequence,     /*tp_as_sequence*/
 352         &dbm_as_mapping,          /*tp_as_mapping*/
 353     0,                    /*tp_hash*/
 354     0,                    /*tp_call*/
 355     0,                    /*tp_str*/
 356     0,                    /*tp_getattro*/
 357     0,                    /*tp_setattro*/
 358     0,                    /*tp_as_buffer*/
 359     Py_TPFLAGS_DEFAULT,   /*tp_xxx4*/
 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 PyMODINIT_FUNC
 400 initdbm(void) {
 401         PyObject *m, *d, *s;
 402
 403         Dbmtype.ob_type = &PyType_Type;
 404         m = Py_InitModule("dbm", dbmmodule_methods);
 405         if (m == NULL)
 406                 return;
 407         d = PyModule_GetDict(m);
 408         if (DbmError == NULL)
 409                 DbmError = PyErr_NewException("dbm.error", NULL, NULL);
 410         s = PyString_FromString(which_dbm);
 411         if (s != NULL) {
 412                 PyDict_SetItemString(d, "library", s);
 413                 Py_DECREF(s);
 414         }
 415         if (DbmError != NULL)
 416                 PyDict_SetItemString(d, "error", DbmError);
 417 }