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"
16 extern const char * gdbm_strerror(gdbm_error);
17 #endif
18
19 PyDoc_STRVAR(gdbmmodule__doc__,
20 "This module provides an interface to the GNU DBM (GDBM) library.\n\
21 \n\
22 This module is quite similar to the dbm module, but uses GDBM instead to\n\
23 provide some additional functionality. Please note that the file formats\n\
24 created by GDBM and dbm are incompatible. \n\
25 \n\
26 GDBM objects behave like mappings (dictionaries), except that keys and\n\
27 values are always strings. Printing a GDBM object doesn't print the\n\
28 keys and values, and the items() and values() methods are not\n\
29 supported.");
30
31 typedef struct {
32 PyObject_HEAD
33 int di_size; /* -1 means recompute */
34 GDBM_FILE di_dbm;
35 } dbmobject;
36
37 static 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
46 static PyObject *DbmError;
47
48 PyDoc_STRVAR(gdbm_object__doc__,
49 "This object represents a GDBM database.\n\
50 GDBM objects behave like mappings (dictionaries), except that keys and\n\
51 values are always strings. Printing a GDBM object doesn't print the\n\
52 keys and values, and the items() and values() methods are not\n\
53 supported.\n\
54 \n\
55 GDBM objects also support additional operations such as firstkey,\n\
56 nextkey, reorganize, and sync.");
57
58 static PyObject *
newdbmobject(char * file,int flags,int mode)59 newdbmobject(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
81 static void
dbm_dealloc(register dbmobject * dp)82 dbm_dealloc(register dbmobject *dp)
83 {
84 if (dp->di_dbm)
85 gdbm_close(dp->di_dbm);
86 PyObject_Del(dp);
87 }
88
89 static Py_ssize_t
dbm_length(dbmobject * dp)90 dbm_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
114 static PyObject *
dbm_subscript(dbmobject * dp,register PyObject * key)115 dbm_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
139 static int
dbm_ass_sub(dbmobject * dp,PyObject * v,PyObject * w)140 dbm_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
181 static int
dbm_contains(register dbmobject * dp,PyObject * arg)182 dbm_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
202 static 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
215 static 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
221 PyDoc_STRVAR(dbm_close__doc__,
222 "close() -> None\n\
223 Closes the database.");
224
225 static PyObject *
dbm_close(register dbmobject * dp,PyObject * unused)226 dbm_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
235 PyDoc_STRVAR(dbm_keys__doc__,
236 "keys() -> list_of_keys\n\
237 Get a list of all keys in the database.");
238
239 static PyObject *
dbm_keys(register dbmobject * dp,PyObject * unused)240 dbm_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
278 PyDoc_STRVAR(dbm_has_key__doc__,
279 "has_key(key) -> boolean\n\
280 Find out whether or not the database contains a given key.");
281
282 static PyObject *
dbm_has_key(register dbmobject * dp,PyObject * args)283 dbm_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
293 PyDoc_STRVAR(dbm_firstkey__doc__,
294 "firstkey() -> key\n\
295 It's possible to loop over every key in the database using this method\n\
296 and the nextkey() method. The traversal is ordered by GDBM's internal\n\
297 hash values, and won't be sorted by the key values. This method\n\
298 returns the starting key.");
299
300 static PyObject *
dbm_firstkey(register dbmobject * dp,PyObject * unused)301 dbm_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
319 PyDoc_STRVAR(dbm_nextkey__doc__,
320 "nextkey(key) -> next_key\n\
321 Returns the key that follows key in the traversal.\n\
322 The following code prints every key in the database db, without having\n\
323 to 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
330 static PyObject *
dbm_nextkey(register dbmobject * dp,PyObject * args)331 dbm_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
351 PyDoc_STRVAR(dbm_reorganize__doc__,
352 "reorganize() -> None\n\
353 If you have carried out a lot of deletions and would like to shrink\n\
354 the space used by the GDBM file, this routine will reorganize the\n\
355 database. GDBM will not shorten the length of a database file except\n\
356 by using this reorganization; otherwise, deleted file space will be\n\
357 kept and reused as new (key,value) pairs are added.");
358
359 static PyObject *
dbm_reorganize(register dbmobject * dp,PyObject * unused)360 dbm_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
375 PyDoc_STRVAR(dbm_sync__doc__,
376 "sync() -> None\n\
377 When the database has been opened in fast mode, this method forces\n\
378 any unwritten data to be written to the disk.");
379
380 static PyObject *
dbm_sync(register dbmobject * dp,PyObject * unused)381 dbm_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
389 static 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
400 static PyObject *
dbm_getattr(dbmobject * dp,char * name)401 dbm_getattr(dbmobject *dp, char *name)
402 {
403 return Py_FindMethod(dbm_methods, (PyObject *)dp, name);
404 }
405
406 static 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
432 PyDoc_STRVAR(dbmopen__doc__,
433 "open(filename, [flags, [mode]]) -> dbm_object\n\
434 Open a dbm database and return a dbm object. The filename argument is\n\
435 the name of the database file.\n\
436 \n\
437 The optional flags argument can be 'r' (to open an existing database\n\
438 for reading only -- default), 'w' (to open an existing database for\n\
439 reading and writing), 'c' (which creates the database if it doesn't\n\
440 exist), or 'n' (which always creates a new empty database).\n\
441 \n\
442 Some versions of gdbm support additional flags which must be\n\
443 appended 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\
445 opens the database in fast mode; altered data will not automatically\n\
446 be written to the disk after every change. This results in faster\n\
447 writes to the database, but may result in an inconsistent database\n\
448 if the program crashes while the database is still open. Use the\n\
449 sync() method to force any unwritten data to be written to the disk.\n\
450 The 's' flag causes all database operations to be synchronized to\n\
451 disk. The 'u' flag disables locking of the database file.\n\
452 \n\
453 The optional mode argument is the Unix mode of the file, used only\n\
454 when the database has to be created. It defaults to octal 0666. ");
455
456 static PyObject *
dbmopen(PyObject * self,PyObject * args)457 dbmopen(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
513 static 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
525 static PyMethodDef dbmmodule_methods[] = {
526 { "open", (PyCFunction)dbmopen, METH_VARARGS, dbmopen__doc__},
527 { 0, 0 },
528 };
529
530 PyMODINIT_FUNC
initgdbm(void)531 initgdbm(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 }
549