/Modules/gdbmmodule.c
C | 548 lines | 483 code | 60 blank | 5 comment | 64 complexity | 8ced0d5a433d43052d3ec098a7965f6b MD5 | raw file
1 2/* DBM module using dictionary interface */ 3/* Author: Anthony Baxter, after dbmmodule.c */ 4/* Doc strings: Mitch Chapman */ 5 6 7#include "Python.h" 8 9#include <sys/types.h> 10#include <sys/stat.h> 11#include <fcntl.h> 12#include "gdbm.h" 13 14#if defined(WIN32) && !defined(__CYGWIN__) 15#include "gdbmerrno.h" 16extern const char * gdbm_strerror(gdbm_error); 17#endif 18 19PyDoc_STRVAR(gdbmmodule__doc__, 20"This module provides an interface to the GNU DBM (GDBM) library.\n\ 21\n\ 22This module is quite similar to the dbm module, but uses GDBM instead to\n\ 23provide some additional functionality. Please note that the file formats\n\ 24created by GDBM and dbm are incompatible. \n\ 25\n\ 26GDBM objects behave like mappings (dictionaries), except that keys and\n\ 27values are always strings. Printing a GDBM object doesn't print the\n\ 28keys and values, and the items() and values() methods are not\n\ 29supported."); 30 31typedef struct { 32 PyObject_HEAD 33 int di_size; /* -1 means recompute */ 34 GDBM_FILE di_dbm; 35} dbmobject; 36 37static PyTypeObject Dbmtype; 38 39#define is_dbmobject(v) (Py_TYPE(v) == &Dbmtype) 40#define check_dbmobject_open(v) if ((v)->di_dbm == NULL) \ 41 { PyErr_SetString(DbmError, "GDBM object has already been closed"); \ 42 return NULL; } 43 44 45 46static PyObject *DbmError; 47 48PyDoc_STRVAR(gdbm_object__doc__, 49"This object represents a GDBM database.\n\ 50GDBM objects behave like mappings (dictionaries), except that keys and\n\ 51values are always strings. Printing a GDBM object doesn't print the\n\ 52keys and values, and the items() and values() methods are not\n\ 53supported.\n\ 54\n\ 55GDBM objects also support additional operations such as firstkey,\n\ 56nextkey, reorganize, and sync."); 57 58static PyObject * 59newdbmobject(char *file, int flags, int mode) 60{ 61 dbmobject *dp; 62 63 dp = PyObject_New(dbmobject, &Dbmtype); 64 if (dp == NULL) 65 return NULL; 66 dp->di_size = -1; 67 errno = 0; 68 if ((dp->di_dbm = gdbm_open(file, 0, flags, mode, NULL)) == 0) { 69 if (errno != 0) 70 PyErr_SetFromErrno(DbmError); 71 else 72 PyErr_SetString(DbmError, gdbm_strerror(gdbm_errno)); 73 Py_DECREF(dp); 74 return NULL; 75 } 76 return (PyObject *)dp; 77} 78 79/* Methods */ 80 81static void 82dbm_dealloc(register dbmobject *dp) 83{ 84 if (dp->di_dbm) 85 gdbm_close(dp->di_dbm); 86 PyObject_Del(dp); 87} 88 89static Py_ssize_t 90dbm_length(dbmobject *dp) 91{ 92 if (dp->di_dbm == NULL) { 93 PyErr_SetString(DbmError, "GDBM object has already been closed"); 94 return -1; 95 } 96 if (dp->di_size < 0) { 97 datum key,okey; 98 int size; 99 okey.dsize=0; 100 okey.dptr=NULL; 101 102 size = 0; 103 for (key=gdbm_firstkey(dp->di_dbm); key.dptr; 104 key = gdbm_nextkey(dp->di_dbm,okey)) { 105 size++; 106 if(okey.dsize) free(okey.dptr); 107 okey=key; 108 } 109 dp->di_size = size; 110 } 111 return dp->di_size; 112} 113 114static PyObject * 115dbm_subscript(dbmobject *dp, register PyObject *key) 116{ 117 PyObject *v; 118 datum drec, krec; 119 120 if (!PyArg_Parse(key, "s#", &krec.dptr, &krec.dsize) ) 121 return NULL; 122 123 if (dp->di_dbm == NULL) { 124 PyErr_SetString(DbmError, 125 "GDBM object has already been closed"); 126 return NULL; 127 } 128 drec = gdbm_fetch(dp->di_dbm, krec); 129 if (drec.dptr == 0) { 130 PyErr_SetString(PyExc_KeyError, 131 PyString_AS_STRING((PyStringObject *)key)); 132 return NULL; 133 } 134 v = PyString_FromStringAndSize(drec.dptr, drec.dsize); 135 free(drec.dptr); 136 return v; 137} 138 139static int 140dbm_ass_sub(dbmobject *dp, PyObject *v, PyObject *w) 141{ 142 datum krec, drec; 143 144 if (!PyArg_Parse(v, "s#", &krec.dptr, &krec.dsize) ) { 145 PyErr_SetString(PyExc_TypeError, 146 "gdbm mappings have string indices only"); 147 return -1; 148 } 149 if (dp->di_dbm == NULL) { 150 PyErr_SetString(DbmError, 151 "GDBM object has already been closed"); 152 return -1; 153 } 154 dp->di_size = -1; 155 if (w == NULL) { 156 if (gdbm_delete(dp->di_dbm, krec) < 0) { 157 PyErr_SetString(PyExc_KeyError, 158 PyString_AS_STRING((PyStringObject *)v)); 159 return -1; 160 } 161 } 162 else { 163 if (!PyArg_Parse(w, "s#", &drec.dptr, &drec.dsize)) { 164 PyErr_SetString(PyExc_TypeError, 165 "gdbm mappings have string elements only"); 166 return -1; 167 } 168 errno = 0; 169 if (gdbm_store(dp->di_dbm, krec, drec, GDBM_REPLACE) < 0) { 170 if (errno != 0) 171 PyErr_SetFromErrno(DbmError); 172 else 173 PyErr_SetString(DbmError, 174 gdbm_strerror(gdbm_errno)); 175 return -1; 176 } 177 } 178 return 0; 179} 180 181static int 182dbm_contains(register dbmobject *dp, PyObject *arg) 183{ 184 datum key; 185 186 if ((dp)->di_dbm == NULL) { 187 PyErr_SetString(DbmError, 188 "GDBM object has already been closed"); 189 return -1; 190 } 191 if (!PyString_Check(arg)) { 192 PyErr_Format(PyExc_TypeError, 193 "gdbm key must be string, not %.100s", 194 arg->ob_type->tp_name); 195 return -1; 196 } 197 key.dptr = PyString_AS_STRING(arg); 198 key.dsize = PyString_GET_SIZE(arg); 199 return gdbm_exists(dp->di_dbm, key); 200} 201 202static PySequenceMethods dbm_as_sequence = { 203 (lenfunc)dbm_length, /*_length*/ 204 0, /*sq_concat*/ 205 0, /*sq_repeat*/ 206 0, /*sq_item*/ 207 0, /*sq_slice*/ 208 0, /*sq_ass_item*/ 209 0, /*sq_ass_slice*/ 210 (objobjproc)dbm_contains, /*sq_contains*/ 211 0, /*sq_inplace_concat*/ 212 0 /*sq_inplace_repeat*/ 213}; 214 215static PyMappingMethods dbm_as_mapping = { 216 (lenfunc)dbm_length, /*mp_length*/ 217 (binaryfunc)dbm_subscript, /*mp_subscript*/ 218 (objobjargproc)dbm_ass_sub, /*mp_ass_subscript*/ 219}; 220 221PyDoc_STRVAR(dbm_close__doc__, 222"close() -> None\n\ 223Closes the database."); 224 225static PyObject * 226dbm_close(register dbmobject *dp, PyObject *unused) 227{ 228 if (dp->di_dbm) 229 gdbm_close(dp->di_dbm); 230 dp->di_dbm = NULL; 231 Py_INCREF(Py_None); 232 return Py_None; 233} 234 235PyDoc_STRVAR(dbm_keys__doc__, 236"keys() -> list_of_keys\n\ 237Get a list of all keys in the database."); 238 239static PyObject * 240dbm_keys(register dbmobject *dp, PyObject *unused) 241{ 242 register PyObject *v, *item; 243 datum key, nextkey; 244 int err; 245 246 if (dp == NULL || !is_dbmobject(dp)) { 247 PyErr_BadInternalCall(); 248 return NULL; 249 } 250 check_dbmobject_open(dp); 251 252 v = PyList_New(0); 253 if (v == NULL) 254 return NULL; 255 256 key = gdbm_firstkey(dp->di_dbm); 257 while (key.dptr) { 258 item = PyString_FromStringAndSize(key.dptr, key.dsize); 259 if (item == NULL) { 260 free(key.dptr); 261 Py_DECREF(v); 262 return NULL; 263 } 264 err = PyList_Append(v, item); 265 Py_DECREF(item); 266 if (err != 0) { 267 free(key.dptr); 268 Py_DECREF(v); 269 return NULL; 270 } 271 nextkey = gdbm_nextkey(dp->di_dbm, key); 272 free(key.dptr); 273 key = nextkey; 274 } 275 return v; 276} 277 278PyDoc_STRVAR(dbm_has_key__doc__, 279"has_key(key) -> boolean\n\ 280Find out whether or not the database contains a given key."); 281 282static PyObject * 283dbm_has_key(register dbmobject *dp, PyObject *args) 284{ 285 datum key; 286 287 if (!PyArg_ParseTuple(args, "s#:has_key", &key.dptr, &key.dsize)) 288 return NULL; 289 check_dbmobject_open(dp); 290 return PyInt_FromLong((long) gdbm_exists(dp->di_dbm, key)); 291} 292 293PyDoc_STRVAR(dbm_firstkey__doc__, 294"firstkey() -> key\n\ 295It's possible to loop over every key in the database using this method\n\ 296and the nextkey() method. The traversal is ordered by GDBM's internal\n\ 297hash values, and won't be sorted by the key values. This method\n\ 298returns the starting key."); 299 300static PyObject * 301dbm_firstkey(register dbmobject *dp, PyObject *unused) 302{ 303 register PyObject *v; 304 datum key; 305 306 check_dbmobject_open(dp); 307 key = gdbm_firstkey(dp->di_dbm); 308 if (key.dptr) { 309 v = PyString_FromStringAndSize(key.dptr, key.dsize); 310 free(key.dptr); 311 return v; 312 } 313 else { 314 Py_INCREF(Py_None); 315 return Py_None; 316 } 317} 318 319PyDoc_STRVAR(dbm_nextkey__doc__, 320"nextkey(key) -> next_key\n\ 321Returns the key that follows key in the traversal.\n\ 322The following code prints every key in the database db, without having\n\ 323to create a list in memory that contains them all:\n\ 324\n\ 325 k = db.firstkey()\n\ 326 while k != None:\n\ 327 print k\n\ 328 k = db.nextkey(k)"); 329 330static PyObject * 331dbm_nextkey(register dbmobject *dp, PyObject *args) 332{ 333 register PyObject *v; 334 datum key, nextkey; 335 336 if (!PyArg_ParseTuple(args, "s#:nextkey", &key.dptr, &key.dsize)) 337 return NULL; 338 check_dbmobject_open(dp); 339 nextkey = gdbm_nextkey(dp->di_dbm, key); 340 if (nextkey.dptr) { 341 v = PyString_FromStringAndSize(nextkey.dptr, nextkey.dsize); 342 free(nextkey.dptr); 343 return v; 344 } 345 else { 346 Py_INCREF(Py_None); 347 return Py_None; 348 } 349} 350 351PyDoc_STRVAR(dbm_reorganize__doc__, 352"reorganize() -> None\n\ 353If you have carried out a lot of deletions and would like to shrink\n\ 354the space used by the GDBM file, this routine will reorganize the\n\ 355database. GDBM will not shorten the length of a database file except\n\ 356by using this reorganization; otherwise, deleted file space will be\n\ 357kept and reused as new (key,value) pairs are added."); 358 359static PyObject * 360dbm_reorganize(register dbmobject *dp, PyObject *unused) 361{ 362 check_dbmobject_open(dp); 363 errno = 0; 364 if (gdbm_reorganize(dp->di_dbm) < 0) { 365 if (errno != 0) 366 PyErr_SetFromErrno(DbmError); 367 else 368 PyErr_SetString(DbmError, gdbm_strerror(gdbm_errno)); 369 return NULL; 370 } 371 Py_INCREF(Py_None); 372 return Py_None; 373} 374 375PyDoc_STRVAR(dbm_sync__doc__, 376"sync() -> None\n\ 377When the database has been opened in fast mode, this method forces\n\ 378any unwritten data to be written to the disk."); 379 380static PyObject * 381dbm_sync(register dbmobject *dp, PyObject *unused) 382{ 383 check_dbmobject_open(dp); 384 gdbm_sync(dp->di_dbm); 385 Py_INCREF(Py_None); 386 return Py_None; 387} 388 389static PyMethodDef dbm_methods[] = { 390 {"close", (PyCFunction)dbm_close, METH_NOARGS, dbm_close__doc__}, 391 {"keys", (PyCFunction)dbm_keys, METH_NOARGS, dbm_keys__doc__}, 392 {"has_key", (PyCFunction)dbm_has_key, METH_VARARGS, dbm_has_key__doc__}, 393 {"firstkey", (PyCFunction)dbm_firstkey,METH_NOARGS, dbm_firstkey__doc__}, 394 {"nextkey", (PyCFunction)dbm_nextkey, METH_VARARGS, dbm_nextkey__doc__}, 395 {"reorganize",(PyCFunction)dbm_reorganize,METH_NOARGS, dbm_reorganize__doc__}, 396 {"sync", (PyCFunction)dbm_sync, METH_NOARGS, dbm_sync__doc__}, 397 {NULL, NULL} /* sentinel */ 398}; 399 400static PyObject * 401dbm_getattr(dbmobject *dp, char *name) 402{ 403 return Py_FindMethod(dbm_methods, (PyObject *)dp, name); 404} 405 406static PyTypeObject Dbmtype = { 407 PyVarObject_HEAD_INIT(0, 0) 408 "gdbm.gdbm", 409 sizeof(dbmobject), 410 0, 411 (destructor)dbm_dealloc, /*tp_dealloc*/ 412 0, /*tp_print*/ 413 (getattrfunc)dbm_getattr, /*tp_getattr*/ 414 0, /*tp_setattr*/ 415 0, /*tp_compare*/ 416 0, /*tp_repr*/ 417 0, /*tp_as_number*/ 418 &dbm_as_sequence, /*tp_as_sequence*/ 419 &dbm_as_mapping, /*tp_as_mapping*/ 420 0, /*tp_hash*/ 421 0, /*tp_call*/ 422 0, /*tp_str*/ 423 0, /*tp_getattro*/ 424 0, /*tp_setattro*/ 425 0, /*tp_as_buffer*/ 426 Py_TPFLAGS_DEFAULT, /*tp_xxx4*/ 427 gdbm_object__doc__, /*tp_doc*/ 428}; 429 430/* ----------------------------------------------------------------- */ 431 432PyDoc_STRVAR(dbmopen__doc__, 433"open(filename, [flags, [mode]]) -> dbm_object\n\ 434Open a dbm database and return a dbm object. The filename argument is\n\ 435the name of the database file.\n\ 436\n\ 437The optional flags argument can be 'r' (to open an existing database\n\ 438for reading only -- default), 'w' (to open an existing database for\n\ 439reading and writing), 'c' (which creates the database if it doesn't\n\ 440exist), or 'n' (which always creates a new empty database).\n\ 441\n\ 442Some versions of gdbm support additional flags which must be\n\ 443appended to one of the flags described above. The module constant\n\ 444'open_flags' is a string of valid additional flags. The 'f' flag\n\ 445opens the database in fast mode; altered data will not automatically\n\ 446be written to the disk after every change. This results in faster\n\ 447writes to the database, but may result in an inconsistent database\n\ 448if the program crashes while the database is still open. Use the\n\ 449sync() method to force any unwritten data to be written to the disk.\n\ 450The 's' flag causes all database operations to be synchronized to\n\ 451disk. The 'u' flag disables locking of the database file.\n\ 452\n\ 453The optional mode argument is the Unix mode of the file, used only\n\ 454when the database has to be created. It defaults to octal 0666. "); 455 456static PyObject * 457dbmopen(PyObject *self, PyObject *args) 458{ 459 char *name; 460 char *flags = "r"; 461 int iflags; 462 int mode = 0666; 463 464 if (!PyArg_ParseTuple(args, "s|si:open", &name, &flags, &mode)) 465 return NULL; 466 switch (flags[0]) { 467 case 'r': 468 iflags = GDBM_READER; 469 break; 470 case 'w': 471 iflags = GDBM_WRITER; 472 break; 473 case 'c': 474 iflags = GDBM_WRCREAT; 475 break; 476 case 'n': 477 iflags = GDBM_NEWDB; 478 break; 479 default: 480 PyErr_SetString(DbmError, 481 "First flag must be one of 'r', 'w', 'c' or 'n'"); 482 return NULL; 483 } 484 for (flags++; *flags != '\0'; flags++) { 485 char buf[40]; 486 switch (*flags) { 487#ifdef GDBM_FAST 488 case 'f': 489 iflags |= GDBM_FAST; 490 break; 491#endif 492#ifdef GDBM_SYNC 493 case 's': 494 iflags |= GDBM_SYNC; 495 break; 496#endif 497#ifdef GDBM_NOLOCK 498 case 'u': 499 iflags |= GDBM_NOLOCK; 500 break; 501#endif 502 default: 503 PyOS_snprintf(buf, sizeof(buf), "Flag '%c' is not supported.", 504 *flags); 505 PyErr_SetString(DbmError, buf); 506 return NULL; 507 } 508 } 509 510 return newdbmobject(name, iflags, mode); 511} 512 513static char dbmmodule_open_flags[] = "rwcn" 514#ifdef GDBM_FAST 515 "f" 516#endif 517#ifdef GDBM_SYNC 518 "s" 519#endif 520#ifdef GDBM_NOLOCK 521 "u" 522#endif 523 ; 524 525static PyMethodDef dbmmodule_methods[] = { 526 { "open", (PyCFunction)dbmopen, METH_VARARGS, dbmopen__doc__}, 527 { 0, 0 }, 528}; 529 530PyMODINIT_FUNC 531initgdbm(void) { 532 PyObject *m, *d, *s; 533 534 Dbmtype.ob_type = &PyType_Type; 535 m = Py_InitModule4("gdbm", dbmmodule_methods, 536 gdbmmodule__doc__, (PyObject *)NULL, 537 PYTHON_API_VERSION); 538 if (m == NULL) 539 return; 540 d = PyModule_GetDict(m); 541 DbmError = PyErr_NewException("gdbm.error", NULL, NULL); 542 if (DbmError != NULL) { 543 PyDict_SetItemString(d, "error", DbmError); 544 s = PyString_FromString(dbmmodule_open_flags); 545 PyDict_SetItemString(d, "open_flags", s); 546 Py_DECREF(s); 547 } 548}