summaryrefslogtreecommitdiffstats
path: root/Modules/_gdbmmodule.c
blob: 12d973b5cee3f2f92672e4c296e17f16a87f2dc9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660

/* DBM module using dictionary interface */
/* Author: Anthony Baxter, after dbmmodule.c */
/* Doc strings: Mitch Chapman */


#include "Python.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "gdbm.h"

#if defined(WIN32) && !defined(__CYGWIN__)
#include "gdbmerrno.h"
extern const char * gdbm_strerror(gdbm_error);
#endif

/*[clinic input]
module _gdbm
class _gdbm.gdbm "dbmobject *" "&Dbmtype"
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=113927c6170729b2]*/

PyDoc_STRVAR(gdbmmodule__doc__,
"This module provides an interface to the GNU DBM (GDBM) library.\n\
\n\
This module is quite similar to the dbm module, but uses GDBM instead to\n\
provide some additional functionality.  Please note that the file formats\n\
created by GDBM and dbm are incompatible.\n\
\n\
GDBM objects behave like mappings (dictionaries), except that keys and\n\
values are always immutable bytes-like objects or strings.  Printing\n\
a GDBM object doesn't print the keys and values, and the items() and\n\
values() methods are not supported.");

typedef struct {
    PyObject_HEAD
    int di_size;        /* -1 means recompute */
    GDBM_FILE di_dbm;
} dbmobject;

static PyTypeObject Dbmtype;

#include "clinic/_gdbmmodule.c.h"

#define is_dbmobject(v) (Py_TYPE(v) == &Dbmtype)
#define check_dbmobject_open(v) if ((v)->di_dbm == NULL) \
    { PyErr_SetString(DbmError, "GDBM object has already been closed"); \
      return NULL; }



static PyObject *DbmError;

PyDoc_STRVAR(gdbm_object__doc__,
"This object represents a GDBM database.\n\
GDBM objects behave like mappings (dictionaries), except that keys and\n\
values are always immutable bytes-like objects or strings.  Printing\n\
a GDBM object doesn't print the keys and values, and the items() and\n\
values() methods are not supported.\n\
\n\
GDBM objects also support additional operations such as firstkey,\n\
nextkey, reorganize, and sync.");

static PyObject *
newdbmobject(const char *file, int flags, int mode)
{
    dbmobject *dp;

    dp = PyObject_New(dbmobject, &Dbmtype);
    if (dp == NULL)
        return NULL;
    dp->di_size = -1;
    errno = 0;
    if ((dp->di_dbm = gdbm_open((char *)file, 0, flags, mode, NULL)) == 0) {
        if (errno != 0)
            PyErr_SetFromErrno(DbmError);
        else
            PyErr_SetString(DbmError, gdbm_strerror(gdbm_errno));
        Py_DECREF(dp);
        return NULL;
    }
    return (PyObject *)dp;
}

/* Methods */

static void
dbm_dealloc(dbmobject *dp)
{
    if (dp->di_dbm)
        gdbm_close(dp->di_dbm);
    PyObject_Del(dp);
}

static Py_ssize_t
dbm_length(dbmobject *dp)
{
    if (dp->di_dbm == NULL) {
        PyErr_SetString(DbmError, "GDBM object has already been closed");
        return -1;
    }
    if (dp->di_size < 0) {
        datum key,okey;
        int size;
        okey.dsize=0;
        okey.dptr=NULL;

        size = 0;
        for (key=gdbm_firstkey(dp->di_dbm); key.dptr;
             key = gdbm_nextkey(dp->di_dbm,okey)) {
            size++;
            if(okey.dsize) free(okey.dptr);
            okey=key;
        }
        dp->di_size = size;
    }
    return dp->di_size;
}

static PyObject *
dbm_subscript(dbmobject *dp, PyObject *key)
{
    PyObject *v;
    datum drec, krec;

    if (!PyArg_Parse(key, "s#", &krec.dptr, &krec.dsize) )
        return NULL;

    if (dp->di_dbm == NULL) {
        PyErr_SetString(DbmError,
                        "GDBM object has already been closed");
        return NULL;
    }
    drec = gdbm_fetch(dp->di_dbm, krec);
    if (drec.dptr == 0) {
        PyErr_SetObject(PyExc_KeyError, key);
        return NULL;
    }
    v = PyBytes_FromStringAndSize(drec.dptr, drec.dsize);
    free(drec.dptr);
    return v;
}

/*[clinic input]
_gdbm.gdbm.get

    key: object
    default: object = None
    /

Get the value for key, or default if not present.
[clinic start generated code]*/

static PyObject *
_gdbm_gdbm_get_impl(dbmobject *self, PyObject *key, PyObject *default_value)
/*[clinic end generated code: output=19b7c585ad4f554a input=a9c20423f34c17b6]*/
{
    PyObject *res;

    res = dbm_subscript(self, key);
    if (res == NULL && PyErr_ExceptionMatches(PyExc_KeyError)) {
        PyErr_Clear();
        Py_INCREF(default_value);
        return default_value;
    }
    return res;
}

static int
dbm_ass_sub(dbmobject *dp, PyObject *v, PyObject *w)
{
    datum krec, drec;

    if (!PyArg_Parse(v, "s#", &krec.dptr, &krec.dsize) ) {
        PyErr_SetString(PyExc_TypeError,
                        "gdbm mappings have bytes or string indices only");
        return -1;
    }
    if (dp->di_dbm == NULL) {
        PyErr_SetString(DbmError,
                        "GDBM object has already been closed");
        return -1;
    }
    dp->di_size = -1;
    if (w == NULL) {
        if (gdbm_delete(dp->di_dbm, krec) < 0) {
            PyErr_SetObject(PyExc_KeyError, v);
            return -1;
        }
    }
    else {
        if (!PyArg_Parse(w, "s#", &drec.dptr, &drec.dsize)) {
            PyErr_SetString(PyExc_TypeError,
                            "gdbm mappings have byte or string elements only");
            return -1;
        }
        errno = 0;
        if (gdbm_store(dp->di_dbm, krec, drec, GDBM_REPLACE) < 0) {
            if (errno != 0)
                PyErr_SetFromErrno(DbmError);
            else
                PyErr_SetString(DbmError,
                                gdbm_strerror(gdbm_errno));
            return -1;
        }
    }
    return 0;
}

/*[clinic input]
_gdbm.gdbm.setdefault

    key: object
    default: object = None
    /

Get value for key, or set it to default and return default if not present.
[clinic start generated code]*/

static PyObject *
_gdbm_gdbm_setdefault_impl(dbmobject *self, PyObject *key,
                           PyObject *default_value)
/*[clinic end generated code: output=88760ee520329012 input=0db46b69e9680171]*/
{
    PyObject *res;

    res = dbm_subscript(self, key);
    if (res == NULL && PyErr_ExceptionMatches(PyExc_KeyError)) {
        PyErr_Clear();
        if (dbm_ass_sub(self, key, default_value) < 0)
            return NULL;
        return dbm_subscript(self, key);
    }
    return res;
}

static PyMappingMethods dbm_as_mapping = {
    (lenfunc)dbm_length,                /*mp_length*/
    (binaryfunc)dbm_subscript,          /*mp_subscript*/
    (objobjargproc)dbm_ass_sub,         /*mp_ass_subscript*/
};

/*[clinic input]
_gdbm.gdbm.close

Close the database.
[clinic start generated code]*/

static PyObject *
_gdbm_gdbm_close_impl(dbmobject *self)
/*[clinic end generated code: output=23512a594598b563 input=0a203447379b45fd]*/
{
    if (self->di_dbm)
        gdbm_close(self->di_dbm);
    self->di_dbm = NULL;
    Py_RETURN_NONE;
}

/* XXX Should return a set or a set view */
/*[clinic input]
_gdbm.gdbm.keys

Get a list of all keys in the database.
[clinic start generated code]*/

static PyObject *
_gdbm_gdbm_keys_impl(dbmobject *self)
/*[clinic end generated code: output=cb4b1776c3645dcc input=1832ee0a3132cfaf]*/
{
    PyObject *v, *item;
    datum key, nextkey;
    int err;

    if (self == NULL || !is_dbmobject(self)) {
        PyErr_BadInternalCall();
        return NULL;
    }
    check_dbmobject_open(self);

    v = PyList_New(0);
    if (v == NULL)
        return NULL;

    key = gdbm_firstkey(self->di_dbm);
    while (key.dptr) {
        item = PyBytes_FromStringAndSize(key.dptr, key.dsize);
        if (item == NULL) {
            free(key.dptr);
            Py_DECREF(v);
            return NULL;
        }
        err = PyList_Append(v, item);
        Py_DECREF(item);
        if (err != 0) {
            free(key.dptr);
            Py_DECREF(v);
            return NULL;
        }
        nextkey = gdbm_nextkey(self->di_dbm, key);
        free(key.dptr);
        key = nextkey;
    }
    return v;
}

static int
dbm_contains(PyObject *self, PyObject *arg)
{
    dbmobject *dp = (dbmobject *)self;
    datum key;
    Py_ssize_t size;

    if ((dp)->di_dbm == NULL) {
        PyErr_SetString(DbmError,
                        "GDBM object has already been closed");
        return -1;
    }
    if (PyUnicode_Check(arg)) {
        key.dptr = (char *)PyUnicode_AsUTF8AndSize(arg, &size);
        key.dsize = size;
        if (key.dptr == NULL)
            return -1;
    }
    else if (!PyBytes_Check(arg)) {
        PyErr_Format(PyExc_TypeError,
                     "gdbm key must be bytes or string, not %.100s",
                     arg->ob_type->tp_name);
        return -1;
    }
    else {
        key.dptr = PyBytes_AS_STRING(arg);
        key.dsize = PyBytes_GET_SIZE(arg);
    }
    return gdbm_exists(dp->di_dbm, key);
}

static PySequenceMethods dbm_as_sequence = {
        0,                      /* sq_length */
        0,                      /* sq_concat */
        0,                      /* sq_repeat */
        0,                      /* sq_item */
        0,                      /* sq_slice */
        0,                      /* sq_ass_item */
        0,                      /* sq_ass_slice */
        dbm_contains,           /* sq_contains */
        0,                      /* sq_inplace_concat */
        0,                      /* sq_inplace_repeat */
};

/*[clinic input]
_gdbm.gdbm.firstkey

Return the starting key for the traversal.

It's possible to loop over every key in the database using this method
and the nextkey() method.  The traversal is ordered by GDBM's internal
hash values, and won't be sorted by the key values.
[clinic start generated code]*/

static PyObject *
_gdbm_gdbm_firstkey_impl(dbmobject *self)
/*[clinic end generated code: output=9ff85628d84b65d2 input=0dbd6a335d69bba0]*/
{
    PyObject *v;
    datum key;

    check_dbmobject_open(self);
    key = gdbm_firstkey(self->di_dbm);
    if (key.dptr) {
        v = PyBytes_FromStringAndSize(key.dptr, key.dsize);
        free(key.dptr);
        return v;
    }
    else {
        Py_RETURN_NONE;
    }
}

/*[clinic input]
_gdbm.gdbm.nextkey

    key: str(accept={str, robuffer}, zeroes=True)
    /

Returns the key that follows key in the traversal.

The following code prints every key in the database db, without having
to create a list in memory that contains them all:

      k = db.firstkey()
      while k != None:
          print(k)
          k = db.nextkey(k)
[clinic start generated code]*/

static PyObject *
_gdbm_gdbm_nextkey_impl(dbmobject *self, const char *key,
                        Py_ssize_clean_t key_length)
/*[clinic end generated code: output=192ab892de6eb2f6 input=1f1606943614e36f]*/
{
    PyObject *v;
    datum dbm_key, nextkey;

    dbm_key.dptr = (char *)key;
    dbm_key.dsize = key_length;
    check_dbmobject_open(self);
    nextkey = gdbm_nextkey(self->di_dbm, dbm_key);
    if (nextkey.dptr) {
        v = PyBytes_FromStringAndSize(nextkey.dptr, nextkey.dsize);
        free(nextkey.dptr);
        return v;
    }
    else {
        Py_RETURN_NONE;
    }
}

/*[clinic input]
_gdbm.gdbm.reorganize

Reorganize the database.

If you have carried out a lot of deletions and would like to shrink
the space used by the GDBM file, this routine will reorganize the
database.  GDBM will not shorten the length of a database file except
by using this reorganization; otherwise, deleted file space will be
kept and reused as new (key,value) pairs are added.
[clinic start generated code]*/

static PyObject *
_gdbm_gdbm_reorganize_impl(dbmobject *self)
/*[clinic end generated code: output=38d9624df92e961d input=f6bea85bcfd40dd2]*/
{
    check_dbmobject_open(self);
    errno = 0;
    if (gdbm_reorganize(self->di_dbm) < 0) {
        if (errno != 0)
            PyErr_SetFromErrno(DbmError);
        else
            PyErr_SetString(DbmError, gdbm_strerror(gdbm_errno));
        return NULL;
    }
    Py_RETURN_NONE;
}

/*[clinic input]
_gdbm.gdbm.sync

Flush the database to the disk file.

When the database has been opened in fast mode, this method forces
any unwritten data to be written to the disk.
[clinic start generated code]*/

static PyObject *
_gdbm_gdbm_sync_impl(dbmobject *self)
/*[clinic end generated code: output=488b15f47028f125 input=2a47d2c9e153ab8a]*/
{
    check_dbmobject_open(self);
    gdbm_sync(self->di_dbm);
    Py_RETURN_NONE;
}

static PyObject *
dbm__enter__(PyObject *self, PyObject *args)
{
    Py_INCREF(self);
    return self;
}

static PyObject *
dbm__exit__(PyObject *self, PyObject *args)
{
    _Py_IDENTIFIER(close);
    return _PyObject_CallMethodId(self, &PyId_close, NULL);
}

static PyMethodDef dbm_methods[] = {
    _GDBM_GDBM_CLOSE_METHODDEF
    _GDBM_GDBM_KEYS_METHODDEF
    _GDBM_GDBM_FIRSTKEY_METHODDEF
    _GDBM_GDBM_NEXTKEY_METHODDEF
    _GDBM_GDBM_REORGANIZE_METHODDEF
    _GDBM_GDBM_SYNC_METHODDEF
    _GDBM_GDBM_GET_METHODDEF
    _GDBM_GDBM_GET_METHODDEF
    _GDBM_GDBM_SETDEFAULT_METHODDEF
    {"__enter__", dbm__enter__, METH_NOARGS, NULL},
    {"__exit__",  dbm__exit__, METH_VARARGS, NULL},
    {NULL,              NULL}           /* sentinel */
};

static PyTypeObject Dbmtype = {
    PyVarObject_HEAD_INIT(0, 0)
    "_gdbm.gdbm",
    sizeof(dbmobject),
    0,
    (destructor)dbm_dealloc,            /*tp_dealloc*/
    0,                                  /*tp_print*/
    0,                                  /*tp_getattr*/
    0,                                  /*tp_setattr*/
    0,                                  /*tp_reserved*/
    0,                                  /*tp_repr*/
    0,                                  /*tp_as_number*/
    &dbm_as_sequence,                   /*tp_as_sequence*/
    &dbm_as_mapping,                    /*tp_as_mapping*/
    0,                                  /*tp_hash*/
    0,                                  /*tp_call*/
    0,                                  /*tp_str*/
    0,                                  /*tp_getattro*/
    0,                                  /*tp_setattro*/
    0,                                  /*tp_as_buffer*/
    Py_TPFLAGS_DEFAULT,                 /*tp_xxx4*/
    gdbm_object__doc__,                 /*tp_doc*/
    0,                                  /*tp_traverse*/
    0,                                  /*tp_clear*/
    0,                                  /*tp_richcompare*/
    0,                                  /*tp_weaklistoffset*/
    0,                                  /*tp_iter*/
    0,                                  /*tp_iternext*/
    dbm_methods,                        /*tp_methods*/
};

/* ----------------------------------------------------------------- */

/*[clinic input]
_gdbm.open as dbmopen
    filename as name: str
    flags: str="r"
    mode: int(py_default="0o666") = 0o666
    /

Open a dbm database and return a dbm object.

The filename argument is the name of the database file.

The optional flags argument can be 'r' (to open an existing database
for reading only -- default), 'w' (to open an existing database for
reading and writing), 'c' (which creates the database if it doesn't
exist), or 'n' (which always creates a new empty database).

Some versions of gdbm support additional flags which must be
appended to one of the flags described above.  The module constant
'open_flags' is a string of valid additional flags.  The 'f' flag
opens the database in fast mode; altered data will not automatically
be written to the disk after every change.  This results in faster
writes to the database, but may result in an inconsistent database
if the program crashes while the database is still open.  Use the
sync() method to force any unwritten data to be written to the disk.
The 's' flag causes all database operations to be synchronized to
disk.  The 'u' flag disables locking of the database file.

The optional mode argument is the Unix mode of the file, used only
when the database has to be created.  It defaults to octal 0o666.
[clinic start generated code]*/

static PyObject *
dbmopen_impl(PyObject *module, const char *name, const char *flags, int mode)
/*[clinic end generated code: output=31aa1bafdf5da688 input=55563cd60e51984a]*/
{
    int iflags;

    switch (flags[0]) {
    case 'r':
        iflags = GDBM_READER;
        break;
    case 'w':
        iflags = GDBM_WRITER;
        break;
    case 'c':
        iflags = GDBM_WRCREAT;
        break;
    case 'n':
        iflags = GDBM_NEWDB;
        break;
    default:
        PyErr_SetString(DbmError,
                        "First flag must be one of 'r', 'w', 'c' or 'n'");
        return NULL;
    }
    for (flags++; *flags != '\0'; flags++) {
        char buf[40];
        switch (*flags) {
#ifdef GDBM_FAST
            case 'f':
                iflags |= GDBM_FAST;
                break;
#endif
#ifdef GDBM_SYNC
            case 's':
                iflags |= GDBM_SYNC;
                break;
#endif
#ifdef GDBM_NOLOCK
            case 'u':
                iflags |= GDBM_NOLOCK;
                break;
#endif
            default:
                PyOS_snprintf(buf, sizeof(buf), "Flag '%c' is not supported.",
                              *flags);
                PyErr_SetString(DbmError, buf);
                return NULL;
        }
    }

    return newdbmobject(name, iflags, mode);
}

static const char dbmmodule_open_flags[] = "rwcn"
#ifdef GDBM_FAST
                                     "f"
#endif
#ifdef GDBM_SYNC
                                     "s"
#endif
#ifdef GDBM_NOLOCK
                                     "u"
#endif
                                     ;

static PyMethodDef dbmmodule_methods[] = {
    DBMOPEN_METHODDEF
    { 0, 0 },
};


static struct PyModuleDef _gdbmmodule = {
        PyModuleDef_HEAD_INIT,
        "_gdbm",
        gdbmmodule__doc__,
        -1,
        dbmmodule_methods,
        NULL,
        NULL,
        NULL,
        NULL
};

PyMODINIT_FUNC
PyInit__gdbm(void) {
    PyObject *m, *d, *s;

    if (PyType_Ready(&Dbmtype) < 0)
            return NULL;
    m = PyModule_Create(&_gdbmmodule);
    if (m == NULL)
        return NULL;
    d = PyModule_GetDict(m);
    DbmError = PyErr_NewException("_gdbm.error", PyExc_OSError, NULL);
    if (DbmError != NULL) {
        PyDict_SetItemString(d, "error", DbmError);
        s = PyUnicode_FromString(dbmmodule_open_flags);
        PyDict_SetItemString(d, "open_flags", s);
        Py_DECREF(s);
    }
    return m;
}