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 static char *which_dbm = "ndbm";
  17 #elif defined(HAVE_DB1_NDBM_H)
  18 #include <db1/ndbm.h>
  19 static char *which_dbm = "BSD db";
  20 #elif defined(HAVE_GDBM_NDBM_H)
  21 #include <gdbm/ndbm.h>
  22 static char *which_dbm = "GNU gdbm";
  23 #else
  24 #error "No ndbm.h available!"
  25 #endif
  26
  27 typedef struct {
  28         PyObject_HEAD
  29         int di_size;    /* -1 means recompute */
  30         DBM *di_dbm;
  31 } dbmobject;
  32
  33 staticforward PyTypeObject Dbmtype;
  34
  35 #define is_dbmobject(v) ((v)->ob_type == &Dbmtype)
  36 #define check_dbmobject_open(v) if ((v)->di_dbm == NULL) \
  37                { PyErr_SetString(DbmError, "DBM object has already been closed"); \
  38                  return NULL; }
  39
  40 static PyObject *DbmError;
  41
  42 static PyObject *
  43 newdbmobject(char *file, int flags, int mode)
  44 {
  45         dbmobject *dp;
  46
  47         dp = PyObject_New(dbmobject, &Dbmtype);
  48         if (dp == NULL)
  49                 return NULL;
  50         dp->di_size = -1;
  51         if ( (dp->di_dbm = dbm_open(file, flags, mode)) == 0 ) {
  52                 PyErr_SetFromErrno(DbmError);
  53                 Py_DECREF(dp);
  54                 return NULL;
  55         }
  56         return (PyObject *)dp;
  57 }
  58
  59 /* Methods */
  60
  61 static void
  62 dbm_dealloc(register dbmobject *dp)
  63 {
  64         if ( dp->di_dbm )
  65                 dbm_close(dp->di_dbm);
  66         PyObject_Del(dp);
  67 }
  68
  69 static int
  70 dbm_length(dbmobject *dp)
  71 {
  72         if (dp->di_dbm == NULL) {
  73                  PyErr_SetString(DbmError, "DBM object has already been closed");
  74                  return -1;
  75         }
  76         if ( dp->di_size < 0 ) {
  77                 datum key;
  78                 int size;
  79
  80                 size = 0;
  81                 for ( key=dbm_firstkey(dp->di_dbm); key.dptr;
  82                       key = dbm_nextkey(dp->di_dbm))
  83                         size++;
  84                 dp->di_size = size;
  85         }
  86         return dp->di_size;
  87 }
  88
  89 static PyObject *
  90 dbm_subscript(dbmobject *dp, register PyObject *key)
  91 {
  92         datum drec, krec;
  93         int tmp_size;
  94
  95         if (!PyArg_Parse(key, "s#", &krec.dptr, &tmp_size) )
  96                 return NULL;
  97
  98         krec.dsize = tmp_size;
  99         check_dbmobject_open(dp);
 100         drec = dbm_fetch(dp->di_dbm, krec);
 101         if ( drec.dptr == 0 ) {
 102                 PyErr_SetString(PyExc_KeyError,
 103                                 PyString_AS_STRING((PyStringObject *)key));
 104                 return NULL;
 105         }
 106         if ( dbm_error(dp->di_dbm) ) {
 107                 dbm_clearerr(dp->di_dbm);
 108                 PyErr_SetString(DbmError, "");
 109                 return NULL;
 110         }
 111         return PyString_FromStringAndSize(drec.dptr, drec.dsize);
 112 }
 113
 114 static int
 115 dbm_ass_sub(dbmobject *dp, PyObject *v, PyObject *w)
 116 {
 117         datum krec, drec;
 118         int tmp_size;
 119
 120         if ( !PyArg_Parse(v, "s#", &krec.dptr, &tmp_size) ) {
 121                 PyErr_SetString(PyExc_TypeError,
 122                                 "dbm mappings have string indices only");
 123                 return -1;
 124         }
 125         krec.dsize = tmp_size;
 126         if (dp->di_dbm == NULL) {
 127                  PyErr_SetString(DbmError, "DBM object has already been closed");
 128                  return -1;
 129         }
 130         dp->di_size = -1;
 131         if (w == NULL) {
 132                 if ( dbm_delete(dp->di_dbm, krec) < 0 ) {
 133                         dbm_clearerr(dp->di_dbm);
 134                         PyErr_SetString(PyExc_KeyError,
 135                                       PyString_AS_STRING((PyStringObject *)v));
 136                         return -1;
 137                 }
 138         } else {
 139                 if ( !PyArg_Parse(w, "s#", &drec.dptr, &tmp_size) ) {
 140                         PyErr_SetString(PyExc_TypeError,
 141                                      "dbm mappings have string elements only");
 142                         return -1;
 143                 }
 144                 drec.dsize = tmp_size;
 145                 if ( dbm_store(dp->di_dbm, krec, drec, DBM_REPLACE) < 0 ) {
 146                         dbm_clearerr(dp->di_dbm);
 147                         PyErr_SetString(DbmError,
 148                                         "cannot add item to database");
 149                         return -1;
 150                 }
 151         }
 152         if ( dbm_error(dp->di_dbm) ) {
 153                 dbm_clearerr(dp->di_dbm);
 154                 PyErr_SetString(DbmError, "");
 155                 return -1;
 156         }
 157         return 0;
 158 }
 159
 160 static PyMappingMethods dbm_as_mapping = {
 161         (inquiry)dbm_length,            /*mp_length*/
 162         (binaryfunc)dbm_subscript,      /*mp_subscript*/
 163         (objobjargproc)dbm_ass_sub,     /*mp_ass_subscript*/
 164 };
 165
 166 static PyObject *
 167 dbm__close(register dbmobject *dp, PyObject *args)
 168 {
 169         if (!PyArg_ParseTuple(args, ":close"))
 170                 return NULL;
 171         if (dp->di_dbm)
 172                 dbm_close(dp->di_dbm);
 173         dp->di_dbm = NULL;
 174         Py_INCREF(Py_None);
 175         return Py_None;
 176 }
 177
 178 static PyObject *
 179 dbm_keys(register dbmobject *dp, PyObject *args)
 180 {
 181         register PyObject *v, *item;
 182         datum key;
 183         int err;
 184
 185         if (!PyArg_ParseTuple(args, ":keys"))
 186                 return NULL;
 187         check_dbmobject_open(dp);
 188         v = PyList_New(0);
 189         if (v == NULL)
 190                 return NULL;
 191         for (key = dbm_firstkey(dp->di_dbm); key.dptr;
 192              key = dbm_nextkey(dp->di_dbm)) {
 193                 item = PyString_FromStringAndSize(key.dptr, key.dsize);
 194                 if (item == NULL) {
 195                         Py_DECREF(v);
 196                         return NULL;
 197                 }
 198                 err = PyList_Append(v, item);
 199                 Py_DECREF(item);
 200                 if (err != 0) {
 201                         Py_DECREF(v);
 202                         return NULL;
 203                 }
 204         }
 205         return v;
 206 }
 207
 208 static PyObject *
 209 dbm_has_key(register dbmobject *dp, PyObject *args)
 210 {
 211         datum key, val;
 212         int tmp_size;
 213
 214         if (!PyArg_ParseTuple(args, "s#:has_key", &key.dptr, &tmp_size))
 215                 return NULL;
 216         key.dsize = tmp_size;
 217         check_dbmobject_open(dp);
 218         val = dbm_fetch(dp->di_dbm, key);
 219         return PyInt_FromLong(val.dptr != NULL);
 220 }
 221
 222 static PyObject *
 223 dbm_get(register dbmobject *dp, PyObject *args)
 224 {
 225         datum key, val;
 226         PyObject *defvalue = Py_None;
 227         int tmp_size;
 228
 229         if (!PyArg_ParseTuple(args, "s#|O:get",
 230                               &key.dptr, &tmp_size, &defvalue))
 231                 return NULL;
 232         key.dsize = tmp_size;
 233         check_dbmobject_open(dp);
 234         val = dbm_fetch(dp->di_dbm, key);
 235         if (val.dptr != NULL)
 236                 return PyString_FromStringAndSize(val.dptr, val.dsize);
 237         else {
 238                 Py_INCREF(defvalue);
 239                 return defvalue;
 240         }
 241 }
 242
 243 static PyObject *
 244 dbm_setdefault(register dbmobject *dp, PyObject *args)
 245 {
 246         datum key, val;
 247         PyObject *defvalue = NULL;
 248         int tmp_size;
 249
 250         if (!PyArg_ParseTuple(args, "s#|S:setdefault",
 251                               &key.dptr, &tmp_size, &defvalue))
 252                 return NULL;
 253         key.dsize = tmp_size;
 254         check_dbmobject_open(dp);
 255         val = dbm_fetch(dp->di_dbm, key);
 256         if (val.dptr != NULL)
 257                 return PyString_FromStringAndSize(val.dptr, val.dsize);
 258         if (defvalue == NULL) {
 259                 defvalue = PyString_FromStringAndSize(NULL, 0);
 260                 if (defvalue == NULL)
 261                         return NULL;
 262         }
 263         else
 264                 Py_INCREF(defvalue);
 265         val.dptr = PyString_AS_STRING(defvalue);
 266         val.dsize = PyString_GET_SIZE(defvalue);
 267         if (dbm_store(dp->di_dbm, key, val, DBM_INSERT) < 0) {
 268                 dbm_clearerr(dp->di_dbm);
 269                 PyErr_SetString(DbmError, "cannot add item to database");
 270                 return NULL;
 271         }
 272         return defvalue;
 273 }
 274
 275 static PyMethodDef dbm_methods[] = {
 276         {"close",       (PyCFunction)dbm__close,        METH_VARARGS,
 277          "close()\nClose the database."},
 278         {"keys",        (PyCFunction)dbm_keys,          METH_VARARGS,
 279          "keys() -> list\nReturn a list of all keys in the database."},
 280         {"has_key",     (PyCFunction)dbm_has_key,       METH_VARARGS,
 281          "has_key(key} -> boolean\nReturn true iff key is in the database."},
 282         {"get",         (PyCFunction)dbm_get,           METH_VARARGS,
 283          "get(key[, default]) -> value\n"
 284          "Return the value for key if present, otherwise default."},
 285         {"setdefault",  (PyCFunction)dbm_setdefault,    METH_VARARGS,
 286          "setdefault(key[, default]) -> value\n"
 287          "Return the value for key if present, otherwise default.  If key\n"
 288          "is not in the database, it is inserted with default as the value."},
 289         {NULL,          NULL}           /* sentinel */
 290 };
 291
 292 static PyObject *
 293 dbm_getattr(dbmobject *dp, char *name)
 294 {
 295         return Py_FindMethod(dbm_methods, (PyObject *)dp, name);
 296 }
 297
 298 static PyTypeObject Dbmtype = {
 299         PyObject_HEAD_INIT(NULL)
 300         0,
 301         "dbm.dbm",
 302         sizeof(dbmobject),
 303         0,
 304         (destructor)dbm_dealloc,  /*tp_dealloc*/
 305         0,                        /*tp_print*/
 306         (getattrfunc)dbm_getattr, /*tp_getattr*/
 307         0,                        /*tp_setattr*/
 308         0,                        /*tp_compare*/
 309         0,                        /*tp_repr*/
 310         0,                        /*tp_as_number*/
 311         0,                        /*tp_as_sequence*/
 312         &dbm_as_mapping,          /*tp_as_mapping*/
 313 };
 314
 315 /* ----------------------------------------------------------------- */
 316
 317 static PyObject *
 318 dbmopen(PyObject *self, PyObject *args)
 319 {
 320         char *name;
 321         char *flags = "r";
 322         int iflags;
 323         int mode = 0666;
 324
 325         if ( !PyArg_ParseTuple(args, "s|si:open", &name, &flags, &mode) )
 326                 return NULL;
 327         if ( strcmp(flags, "r") == 0 )
 328                 iflags = O_RDONLY;
 329         else if ( strcmp(flags, "w") == 0 )
 330                 iflags = O_RDWR;
 331         else if ( strcmp(flags, "rw") == 0 ) /* B/W compat */
 332                 iflags = O_RDWR|O_CREAT;
 333         else if ( strcmp(flags, "c") == 0 )
 334                 iflags = O_RDWR|O_CREAT;
 335         else if ( strcmp(flags, "n") == 0 )
 336                 iflags = O_RDWR|O_CREAT|O_TRUNC;
 337         else {
 338                 PyErr_SetString(DbmError,
 339                                 "arg 2 to open should be 'r', 'w', 'c', or 'n'");
 340                 return NULL;
 341         }
 342         return newdbmobject(name, iflags, mode);
 343 }
 344
 345 static PyMethodDef dbmmodule_methods[] = {
 346         { "open", (PyCFunction)dbmopen, METH_VARARGS,
 347           "open(path[, flag[, mode]]) -> mapping\n"
 348           "Return a database object."},
 349         { 0, 0 },
 350 };
 351
 352 DL_EXPORT(void)
 353 initdbm(void) {
 354         PyObject *m, *d, *s;
 355
 356         Dbmtype.ob_type = &PyType_Type;
 357         m = Py_InitModule("dbm", dbmmodule_methods);
 358         d = PyModule_GetDict(m);
 359         if (DbmError == NULL)
 360                 DbmError = PyErr_NewException("dbm.error", NULL, NULL);
 361         s = PyString_FromString(which_dbm);
 362         if (s != NULL) {
 363                 PyDict_SetItemString(d, "library", s);
 364                 Py_DECREF(s);
 365         }
 366         if (DbmError != NULL)
 367                 PyDict_SetItemString(d, "error", DbmError);
 368 }