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cpython/Modules/_dbmmodule.c
Brett Cannon 7317c1ef7a dbm.gnu and dbm.ndbm accept both strings and bytes as keys and values. For the 
former they are converted to bytes before being written to the DB.

Closes issue 3799. Reviewed by Skip Montanaro.
2008-11-25 19:19:17 +00:00

433 lines
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C
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/* DBM module using dictionary interface */
#include "Python.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
/* Some Linux systems install gdbm/ndbm.h, but not ndbm.h. This supports
* whichever configure was able to locate.
*/
#if defined(HAVE_NDBM_H)
#include <ndbm.h>
#if defined(PYOS_OS2) && !defined(PYCC_GCC)
static char *which_dbm = "ndbm";
#else
static char *which_dbm = "GNU gdbm"; /* EMX port of GDBM */
#endif
#elif defined(HAVE_GDBM_NDBM_H)
#include <gdbm/ndbm.h>
static char *which_dbm = "GNU gdbm";
#elif defined(HAVE_BERKDB_H)
#include <db.h>
static char *which_dbm = "Berkeley DB";
#else
#error "No ndbm.h available!"
#endif
typedef struct {
PyObject_HEAD
int di_size; /* -1 means recompute */
DBM *di_dbm;
} dbmobject;
static PyTypeObject Dbmtype;
#define is_dbmobject(v) (Py_TYPE(v) == &Dbmtype)
#define check_dbmobject_open(v) if ((v)->di_dbm == NULL) \
{ PyErr_SetString(DbmError, "DBM object has already been closed"); \
return NULL; }
static PyObject *DbmError;
static PyObject *
newdbmobject(char *file, int flags, int mode)
{
dbmobject *dp;
dp = PyObject_New(dbmobject, &Dbmtype);
if (dp == NULL)
return NULL;
dp->di_size = -1;
if ( (dp->di_dbm = dbm_open(file, flags, mode)) == 0 ) {
PyErr_SetFromErrno(DbmError);
Py_DECREF(dp);
return NULL;
}
return (PyObject *)dp;
}
/* Methods */
static void
dbm_dealloc(register dbmobject *dp)
{
if ( dp->di_dbm )
dbm_close(dp->di_dbm);
PyObject_Del(dp);
}
static Py_ssize_t
dbm_length(dbmobject *dp)
{
if (dp->di_dbm == NULL) {
PyErr_SetString(DbmError, "DBM object has already been closed");
return -1;
}
if ( dp->di_size < 0 ) {
datum key;
int size;
size = 0;
for ( key=dbm_firstkey(dp->di_dbm); key.dptr;
key = dbm_nextkey(dp->di_dbm))
size++;
dp->di_size = size;
}
return dp->di_size;
}
static PyObject *
dbm_subscript(dbmobject *dp, register PyObject *key)
{
datum drec, krec;
Py_ssize_t tmp_size;
if (!PyArg_Parse(key, "s#", &krec.dptr, &tmp_size) )
return NULL;
krec.dsize = tmp_size;
check_dbmobject_open(dp);
drec = dbm_fetch(dp->di_dbm, krec);
if ( drec.dptr == 0 ) {
PyErr_SetObject(PyExc_KeyError, key);
return NULL;
}
if ( dbm_error(dp->di_dbm) ) {
dbm_clearerr(dp->di_dbm);
PyErr_SetString(DbmError, "");
return NULL;
}
return PyBytes_FromStringAndSize(drec.dptr, drec.dsize);
}
static int
dbm_ass_sub(dbmobject *dp, PyObject *v, PyObject *w)
{
datum krec, drec;
Py_ssize_t tmp_size;
if ( !PyArg_Parse(v, "s#", &krec.dptr, &tmp_size) ) {
PyErr_SetString(PyExc_TypeError,
"dbm mappings have bytes or string keys only");
return -1;
}
krec.dsize = tmp_size;
if (dp->di_dbm == NULL) {
PyErr_SetString(DbmError, "DBM object has already been closed");
return -1;
}
dp->di_size = -1;
if (w == NULL) {
if ( dbm_delete(dp->di_dbm, krec) < 0 ) {
dbm_clearerr(dp->di_dbm);
PyErr_SetObject(PyExc_KeyError, v);
return -1;
}
} else {
if ( !PyArg_Parse(w, "s#", &drec.dptr, &tmp_size) ) {
PyErr_SetString(PyExc_TypeError,
"dbm mappings have byte or string elements only");
return -1;
}
drec.dsize = tmp_size;
if ( dbm_store(dp->di_dbm, krec, drec, DBM_REPLACE) < 0 ) {
dbm_clearerr(dp->di_dbm);
PyErr_SetString(DbmError,
"cannot add item to database");
return -1;
}
}
if ( dbm_error(dp->di_dbm) ) {
dbm_clearerr(dp->di_dbm);
PyErr_SetString(DbmError, "");
return -1;
}
return 0;
}
static PyMappingMethods dbm_as_mapping = {
(lenfunc)dbm_length, /*mp_length*/
(binaryfunc)dbm_subscript, /*mp_subscript*/
(objobjargproc)dbm_ass_sub, /*mp_ass_subscript*/
};
static PyObject *
dbm__close(register dbmobject *dp, PyObject *unused)
{
if (dp->di_dbm)
dbm_close(dp->di_dbm);
dp->di_dbm = NULL;
Py_INCREF(Py_None);
return Py_None;
}
static PyObject *
dbm_keys(register dbmobject *dp, PyObject *unused)
{
register PyObject *v, *item;
datum key;
int err;
check_dbmobject_open(dp);
v = PyList_New(0);
if (v == NULL)
return NULL;
for (key = dbm_firstkey(dp->di_dbm); key.dptr;
key = dbm_nextkey(dp->di_dbm)) {
item = PyBytes_FromStringAndSize(key.dptr, key.dsize);
if (item == NULL) {
Py_DECREF(v);
return NULL;
}
err = PyList_Append(v, item);
Py_DECREF(item);
if (err != 0) {
Py_DECREF(v);
return NULL;
}
}
return v;
}
static int
dbm_contains(PyObject *self, PyObject *arg)
{
dbmobject *dp = (dbmobject *)self;
datum key, val;
if ((dp)->di_dbm == NULL) {
PyErr_SetString(DbmError,
"DBM object has already been closed");
return -1;
}
if (PyUnicode_Check(arg)) {
arg = _PyUnicode_AsDefaultEncodedString(arg, NULL);
if (arg == NULL)
return -1;
}
if (!PyBytes_Check(arg)) {
PyErr_Format(PyExc_TypeError,
"dbm key must be string, not %.100s",
arg->ob_type->tp_name);
return -1;
}
key.dptr = PyBytes_AS_STRING(arg);
key.dsize = PyBytes_GET_SIZE(arg);
val = dbm_fetch(dp->di_dbm, key);
return val.dptr != NULL;
}
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 */
};
static PyObject *
dbm_get(register dbmobject *dp, PyObject *args)
{
datum key, val;
PyObject *defvalue = Py_None;
char *tmp_ptr;
Py_ssize_t tmp_size;
if (!PyArg_ParseTuple(args, "s#|O:get",
&tmp_ptr, &tmp_size, &defvalue))
return NULL;
key.dptr = tmp_ptr;
key.dsize = tmp_size;
check_dbmobject_open(dp);
val = dbm_fetch(dp->di_dbm, key);
if (val.dptr != NULL)
return PyBytes_FromStringAndSize(val.dptr, val.dsize);
else {
Py_INCREF(defvalue);
return defvalue;
}
}
static PyObject *
dbm_setdefault(register dbmobject *dp, PyObject *args)
{
datum key, val;
PyObject *defvalue = NULL;
char *tmp_ptr;
Py_ssize_t tmp_size;
if (!PyArg_ParseTuple(args, "s#|O:setdefault",
&tmp_ptr, &tmp_size, &defvalue))
return NULL;
key.dptr = tmp_ptr;
key.dsize = tmp_size;
check_dbmobject_open(dp);
val = dbm_fetch(dp->di_dbm, key);
if (val.dptr != NULL)
return PyBytes_FromStringAndSize(val.dptr, val.dsize);
if (defvalue == NULL) {
defvalue = PyBytes_FromStringAndSize(NULL, 0);
if (defvalue == NULL)
return NULL;
val.dptr = NULL;
val.dsize = 0;
}
else {
if ( !PyArg_Parse(defvalue, "s#", &val.dptr, &tmp_size) ) {
PyErr_SetString(PyExc_TypeError,
"dbm mappings have byte string elements only");
return NULL;
}
val.dsize = tmp_size;
Py_INCREF(defvalue);
}
if (dbm_store(dp->di_dbm, key, val, DBM_INSERT) < 0) {
dbm_clearerr(dp->di_dbm);
PyErr_SetString(DbmError, "cannot add item to database");
Py_DECREF(defvalue);
return NULL;
}
return defvalue;
}
static PyMethodDef dbm_methods[] = {
{"close", (PyCFunction)dbm__close, METH_NOARGS,
"close()\nClose the database."},
{"keys", (PyCFunction)dbm_keys, METH_NOARGS,
"keys() -> list\nReturn a list of all keys in the database."},
{"get", (PyCFunction)dbm_get, METH_VARARGS,
"get(key[, default]) -> value\n"
"Return the value for key if present, otherwise default."},
{"setdefault", (PyCFunction)dbm_setdefault, METH_VARARGS,
"setdefault(key[, default]) -> value\n"
"Return the value for key if present, otherwise default. If key\n"
"is not in the database, it is inserted with default as the value."},
{NULL, NULL} /* sentinel */
};
static PyTypeObject Dbmtype = {
PyVarObject_HEAD_INIT(NULL, 0)
"_dbm.dbm",
sizeof(dbmobject),
0,
(destructor)dbm_dealloc, /*tp_dealloc*/
0, /*tp_print*/
0, /*tp_getattr*/
0, /*tp_setattr*/
0, /*tp_compare*/
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_flags*/
0, /*tp_doc*/
0, /*tp_traverse*/
0, /*tp_clear*/
0, /*tp_richcompare*/
0, /*tp_weaklistoffset*/
0, /*tp_iter*/
0, /*tp_iternext*/
dbm_methods, /*tp_methods*/
};
/* ----------------------------------------------------------------- */
static PyObject *
dbmopen(PyObject *self, PyObject *args)
{
char *name;
char *flags = "r";
int iflags;
int mode = 0666;
if ( !PyArg_ParseTuple(args, "s|si:open", &name, &flags, &mode) )
return NULL;
if ( strcmp(flags, "r") == 0 )
iflags = O_RDONLY;
else if ( strcmp(flags, "w") == 0 )
iflags = O_RDWR;
else if ( strcmp(flags, "rw") == 0 ) /* B/W compat */
iflags = O_RDWR|O_CREAT;
else if ( strcmp(flags, "c") == 0 )
iflags = O_RDWR|O_CREAT;
else if ( strcmp(flags, "n") == 0 )
iflags = O_RDWR|O_CREAT|O_TRUNC;
else {
PyErr_SetString(DbmError,
"arg 2 to open should be 'r', 'w', 'c', or 'n'");
return NULL;
}
return newdbmobject(name, iflags, mode);
}
static PyMethodDef dbmmodule_methods[] = {
{ "open", (PyCFunction)dbmopen, METH_VARARGS,
"open(path[, flag[, mode]]) -> mapping\n"
"Return a database object."},
{ 0, 0 },
};
static struct PyModuleDef _dbmmodule = {
PyModuleDef_HEAD_INIT,
"_dbm",
NULL,
-1,
dbmmodule_methods,
NULL,
NULL,
NULL,
NULL
};
PyMODINIT_FUNC
PyInit__dbm(void) {
PyObject *m, *d, *s;
if (PyType_Ready(&Dbmtype) < 0)
return NULL;
m = PyModule_Create(&_dbmmodule);
if (m == NULL)
return NULL;
d = PyModule_GetDict(m);
if (DbmError == NULL)
DbmError = PyErr_NewException("_dbm.error",
PyExc_IOError, NULL);
s = PyUnicode_FromString(which_dbm);
if (s != NULL) {
PyDict_SetItemString(d, "library", s);
Py_DECREF(s);
}
if (DbmError != NULL)
PyDict_SetItemString(d, "error", DbmError);
if (PyErr_Occurred()) {
Py_DECREF(m);
m = NULL;
}
return m;
}
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