/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)
 17static char *which_dbm = "ndbm";
 18#else
 19static char *which_dbm = "GNU gdbm";  /* EMX port of GDBM */
 20#endif
 21#elif defined(HAVE_GDBM_NDBM_H)
 22#include <gdbm/ndbm.h>
 23static char *which_dbm = "GNU gdbm";
 24#elif defined(HAVE_GDBM_DASH_NDBM_H)
 25#include <gdbm-ndbm.h>
 26static char *which_dbm = "GNU gdbm";
 27#elif defined(HAVE_BERKDB_H)
 28#include <db.h>
 29static char *which_dbm = "Berkeley DB";
 30#else
 31#error "No ndbm.h available!"
 32#endif
 33
 34typedef struct {
 35	PyObject_HEAD
 36	int di_size;	/* -1 means recompute */
 37	DBM *di_dbm;
 38} dbmobject;
 39
 40static 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
 47static PyObject *DbmError;
 48
 49static PyObject *
 50newdbmobject(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
 68static void
 69dbm_dealloc(register dbmobject *dp)
 70{
 71        if ( dp->di_dbm )
 72		dbm_close(dp->di_dbm);
 73	PyObject_Del(dp);
 74}
 75
 76static Py_ssize_t
 77dbm_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
 96static PyObject *
 97dbm_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
121static int
122dbm_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
167static int
168dbm_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
186static 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
199static 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
205static PyObject *
206dbm__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
215static PyObject *
216dbm_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
243static PyObject *
244dbm_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
259static PyObject *
260dbm_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
282static PyObject *
283dbm_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
316static 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
333static PyObject *
334dbm_getattr(dbmobject *dp, char *name)
335{
336	return Py_FindMethod(dbm_methods, (PyObject *)dp, name);
337}
338
339static 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
364static PyObject *
365dbmopen(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
392static 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
399PyMODINIT_FUNC
400initdbm(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}