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cpython/Modules/_dbmmodule.c
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/* DBM module using dictionary interface */
// clinic/_dbmmodule.c.h uses internal pycore_modsupport.h API
#ifndef Py_BUILD_CORE_BUILTIN
# define Py_BUILD_CORE_MODULE 1
#endif
#include "Python.h"
#include "pycore_object.h" // _PyObject_VisitType()
#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(USE_GDBM_COMPAT)
#ifdef HAVE_GDBM_NDBM_H
#include <gdbm/ndbm.h>
#elif HAVE_GDBM_DASH_NDBM_H
#include <gdbm-ndbm.h>
#else
#error "No gdbm/ndbm.h or gdbm-ndbm.h available"
#endif
static const char which_dbm[] = "GNU gdbm";
#elif defined(USE_NDBM)
#include <ndbm.h>
#ifdef _GDBM_H_
/* ndbm.h is the GDBM compatibility interface. */
static const char which_dbm[] = "GNU gdbm";
#else
static const char which_dbm[] = "ndbm";
#endif
#elif defined(USE_BERKDB)
#ifndef DB_DBM_HSEARCH
#define DB_DBM_HSEARCH 1
#endif
#include <db.h>
static const char which_dbm[] = "Berkeley DB";
#else
#error "No ndbm.h available!"
#endif
typedef struct {
PyTypeObject *dbm_type;
PyObject *dbm_error;
} _dbm_state;
static inline _dbm_state*
get_dbm_state(PyObject *module)
{
void *state = PyModule_GetState(module);
assert(state != NULL);
return (_dbm_state *)state;
}
/*[clinic input]
module _dbm
class _dbm.dbm "dbmobject *" "&Dbmtype"
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=9b1aa8756d16150e]*/
typedef struct {
PyObject_HEAD
int flags;
int di_size; /* -1 means recompute */
DBM *di_dbm;
} dbmobject;
#define dbmobject_CAST(op) ((dbmobject *)(op))
#include "clinic/_dbmmodule.c.h"
#define check_dbmobject_open(v, err) \
_Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED((v)) \
if ((v)->di_dbm == NULL) { \
PyErr_SetString(err, "DBM object has already been closed"); \
return NULL; \
}
static PyObject *
newdbmobject(_dbm_state *state, const char *file, int flags, int mode)
{
dbmobject *dp = PyObject_GC_New(dbmobject, state->dbm_type);
if (dp == NULL) {
return NULL;
}
dp->di_size = -1;
dp->flags = flags;
PyObject_GC_Track(dp);
/* See issue #19296 */
if ( (dp->di_dbm = dbm_open((char *)file, flags, mode)) == 0 ) {
PyErr_SetFromErrnoWithFilename(state->dbm_error, file);
Py_DECREF(dp);
return NULL;
}
return (PyObject *)dp;
}
/* Methods */
static void
dbm_dealloc(PyObject *self)
{
dbmobject *dp = dbmobject_CAST(self);
PyObject_GC_UnTrack(dp);
if (dp->di_dbm) {
dbm_close(dp->di_dbm);
}
PyTypeObject *tp = Py_TYPE(dp);
tp->tp_free(dp);
Py_DECREF(tp);
}
/*[clinic input]
@critical_section
_dbm.dbm.__len__ as dbm_length
[clinic start generated code]*/
static Py_ssize_t
dbm_length_impl(dbmobject *self)
/*[clinic end generated code: output=d7ea9510562e5f86 input=f912d65e9b06fef5]*/
{
dbmobject *dp = self;
_dbm_state *state = PyType_GetModuleState(Py_TYPE(dp));
assert(state != NULL);
if (dp->di_dbm == NULL) {
PyErr_SetString(state->dbm_error, "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;
}
/*[clinic input]
@critical_section
_dbm.dbm.__bool__ as dbm_bool
[clinic start generated code]*/
static int
dbm_bool_impl(dbmobject *self)
/*[clinic end generated code: output=b550ce1ae52d6ad1 input=212af765b6e60719]*/
{
dbmobject *dp = self;
_dbm_state *state = PyType_GetModuleState(Py_TYPE(dp));
assert(state != NULL);
if (dp->di_dbm == NULL) {
PyErr_SetString(state->dbm_error, "DBM object has already been closed");
return -1;
}
if (dp->di_size > 0) {
/* Known non-zero size. */
return 1;
}
if (dp->di_size == 0) {
/* Known zero size. */
return 0;
}
/* Unknown size. Ensure DBM object has an entry. */
datum key = dbm_firstkey(dp->di_dbm);
if (key.dptr == NULL) {
/* Empty. Cache this fact. */
dp->di_size = 0;
return 0;
}
/* Non-empty. Don't cache the length since we don't know. */
return 1;
}
/*[clinic input]
@critical_section
_dbm.dbm.__getitem__ as dbm_subscript
key: object
/
[clinic start generated code]*/
static PyObject *
dbm_subscript_impl(dbmobject *self, PyObject *key)
/*[clinic end generated code: output=6278465f3ff37eaa input=e748b684a0870527]*/
{
datum drec, krec;
Py_ssize_t tmp_size;
dbmobject *dp = self;
_dbm_state *state = PyType_GetModuleState(Py_TYPE(dp));
assert(state != NULL);
if (!PyArg_Parse(key, "s#", &krec.dptr, &tmp_size)) {
return NULL;
}
krec.dsize = tmp_size;
check_dbmobject_open(dp, state->dbm_error);
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(state->dbm_error, "");
return NULL;
}
return PyBytes_FromStringAndSize(drec.dptr, drec.dsize);
}
/*[clinic input]
@critical_section
_dbm.dbm.__setitem__ as dbm_ass_sub
v: object
w: object
/
[clinic start generated code]*/
static int
dbm_ass_sub_impl(dbmobject *self, PyObject *v, PyObject *w)
/*[clinic end generated code: output=33e861810d1fd44a input=4f10cc93a02142ee]*/
{
datum krec, drec;
Py_ssize_t tmp_size;
dbmobject *dp = self;
if ( !PyArg_Parse(v, "s#", &krec.dptr, &tmp_size) ) {
PyErr_SetString(PyExc_TypeError,
"dbm mappings have bytes or string keys only");
return -1;
}
_dbm_state *state = PyType_GetModuleState(Py_TYPE(dp));
assert(state != NULL);
krec.dsize = tmp_size;
if (dp->di_dbm == NULL) {
PyErr_SetString(state->dbm_error, "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);
/* we might get a failure for reasons like file corrupted,
but we are not able to distinguish it */
if (dp->flags & O_RDWR) {
PyErr_SetObject(PyExc_KeyError, v);
}
else {
PyErr_SetString(state->dbm_error, "cannot delete item from database");
}
return -1;
}
} else {
if ( !PyArg_Parse(w, "s#", &drec.dptr, &tmp_size) ) {
PyErr_SetString(PyExc_TypeError,
"dbm mappings have bytes 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(state->dbm_error,
"cannot add item to database");
return -1;
}
}
if ( dbm_error(dp->di_dbm) ) {
dbm_clearerr(dp->di_dbm);
PyErr_SetString(state->dbm_error, "");
return -1;
}
return 0;
}
/*[clinic input]
@critical_section
_dbm.dbm.close
Close the database.
[clinic start generated code]*/
static PyObject *
_dbm_dbm_close_impl(dbmobject *self)
/*[clinic end generated code: output=c8dc5b6709600b86 input=4a94f79facbc28ca]*/
{
if (self->di_dbm) {
dbm_close(self->di_dbm);
}
self->di_dbm = NULL;
Py_RETURN_NONE;
}
/*[clinic input]
@critical_section
_dbm.dbm.keys
cls: defining_class
Return a list of all keys in the database.
[clinic start generated code]*/
static PyObject *
_dbm_dbm_keys_impl(dbmobject *self, PyTypeObject *cls)
/*[clinic end generated code: output=f2a593b3038e5996 input=6ddefeadf2a80156]*/
{
PyObject *v, *item;
datum key;
int err;
_dbm_state *state = PyType_GetModuleState(cls);
assert(state != NULL);
check_dbmobject_open(self, state->dbm_error);
v = PyList_New(0);
if (v == NULL) {
return NULL;
}
for (key = dbm_firstkey(self->di_dbm); key.dptr;
key = dbm_nextkey(self->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;
}
/*[clinic input]
@critical_section
_dbm.dbm.__contains__ as dbm_contains
arg: object
/
[clinic start generated code]*/
static int
dbm_contains_impl(dbmobject *self, PyObject *arg)
/*[clinic end generated code: output=6c42b797ada528bc input=94134e7abf3eeb6e]*/
{
dbmobject *dp = self;
datum key, val;
Py_ssize_t size;
_dbm_state *state = PyType_GetModuleState(Py_TYPE(dp));
assert(state != NULL);
if ((dp)->di_dbm == NULL) {
PyErr_SetString(state->dbm_error,
"DBM 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,
"dbm key must be bytes or string, not %.100s",
Py_TYPE(arg)->tp_name);
return -1;
}
else {
key.dptr = PyBytes_AS_STRING(arg);
key.dsize = PyBytes_GET_SIZE(arg);
}
val = dbm_fetch(dp->di_dbm, key);
return val.dptr != NULL;
}
/*[clinic input]
@critical_section
_dbm.dbm.get
cls: defining_class
key: str(accept={str, robuffer}, zeroes=True)
default: object = None
/
Return the value for key if present, otherwise default.
[clinic start generated code]*/
static PyObject *
_dbm_dbm_get_impl(dbmobject *self, PyTypeObject *cls, const char *key,
Py_ssize_t key_length, PyObject *default_value)
/*[clinic end generated code: output=b4e55f8b6d482bc4 input=1d88a22bb5e55202]*/
{
datum dbm_key, val;
_dbm_state *state = PyType_GetModuleState(cls);
assert(state != NULL);
dbm_key.dptr = (char *)key;
dbm_key.dsize = key_length;
check_dbmobject_open(self, state->dbm_error);
val = dbm_fetch(self->di_dbm, dbm_key);
if (val.dptr != NULL) {
return PyBytes_FromStringAndSize(val.dptr, val.dsize);
}
return Py_NewRef(default_value);
}
/*[clinic input]
@critical_section
_dbm.dbm.setdefault
cls: defining_class
key: str(accept={str, robuffer}, zeroes=True)
default: object(c_default="NULL") = b''
/
Return the value for key if present, otherwise default.
If key is not in the database, it is inserted with default as the
value.
[clinic start generated code]*/
static PyObject *
_dbm_dbm_setdefault_impl(dbmobject *self, PyTypeObject *cls, const char *key,
Py_ssize_t key_length, PyObject *default_value)
/*[clinic end generated code: output=9c2f6ea6d0fb576c input=81224965c110f830]*/
{
datum dbm_key, val;
Py_ssize_t tmp_size;
_dbm_state *state = PyType_GetModuleState(cls);
assert(state != NULL);
dbm_key.dptr = (char *)key;
dbm_key.dsize = key_length;
check_dbmobject_open(self, state->dbm_error);
val = dbm_fetch(self->di_dbm, dbm_key);
if (val.dptr != NULL) {
return PyBytes_FromStringAndSize(val.dptr, val.dsize);
}
if (default_value == NULL) {
default_value = Py_GetConstant(Py_CONSTANT_EMPTY_BYTES);
val.dptr = NULL;
val.dsize = 0;
}
else {
if ( !PyArg_Parse(default_value, "s#", &val.dptr, &tmp_size) ) {
PyErr_SetString(PyExc_TypeError,
"dbm mappings have bytes or string elements only");
return NULL;
}
val.dsize = tmp_size;
Py_INCREF(default_value);
}
if (dbm_store(self->di_dbm, dbm_key, val, DBM_INSERT) < 0) {
dbm_clearerr(self->di_dbm);
PyErr_SetString(state->dbm_error, "cannot add item to database");
Py_DECREF(default_value);
return NULL;
}
return default_value;
}
/*[clinic input]
@critical_section
_dbm.dbm.clear
cls: defining_class
/
Remove all items from the database.
[clinic start generated code]*/
static PyObject *
_dbm_dbm_clear_impl(dbmobject *self, PyTypeObject *cls)
/*[clinic end generated code: output=8d126b9e1d01a434 input=a1aa5d99adfb9656]*/
{
_dbm_state *state = PyType_GetModuleState(cls);
assert(state != NULL);
check_dbmobject_open(self, state->dbm_error);
datum key;
// Invalidate cache
self->di_size = -1;
while (1) {
key = dbm_firstkey(self->di_dbm);
if (key.dptr == NULL) {
break;
}
if (dbm_delete(self->di_dbm, key) < 0) {
dbm_clearerr(self->di_dbm);
PyErr_SetString(state->dbm_error, "cannot delete item from database");
return NULL;
}
}
Py_RETURN_NONE;
}
static PyObject *
dbm__enter__(PyObject *self, PyObject *Py_UNUSED(dummy))
{
return Py_NewRef(self);
}
/*[clinic input]
@critical_section
_dbm.dbm.__exit__
*exc_info: array
Close the database.
[clinic start generated code]*/
static PyObject *
_dbm_dbm___exit___impl(dbmobject *self, PyObject * const *exc_info,
Py_ssize_t exc_info_length)
/*[clinic end generated code: output=f9549bf513b3285d input=340d8190b6fb0f15]*/
{
return _dbm_dbm_close_impl(self);
}
static PyMethodDef dbm_methods[] = {
_DBM_DBM_CLOSE_METHODDEF
_DBM_DBM_KEYS_METHODDEF
_DBM_DBM_GET_METHODDEF
_DBM_DBM_SETDEFAULT_METHODDEF
_DBM_DBM_CLEAR_METHODDEF
{"__enter__", dbm__enter__, METH_NOARGS, NULL},
_DBM_DBM___EXIT___METHODDEF
{NULL, NULL} /* sentinel */
};
static PyType_Slot dbmtype_spec_slots[] = {
{Py_tp_dealloc, dbm_dealloc},
{Py_tp_traverse, _PyObject_VisitType},
{Py_tp_methods, dbm_methods},
{Py_sq_contains, dbm_contains},
{Py_mp_length, dbm_length},
{Py_mp_subscript, dbm_subscript},
{Py_mp_ass_subscript, dbm_ass_sub},
{Py_nb_bool, dbm_bool},
{0, 0}
};
static PyType_Spec dbmtype_spec = {
.name = "_dbm.dbm",
.basicsize = sizeof(dbmobject),
// Calling PyType_GetModuleState() on a subclass is not safe.
// dbmtype_spec does not have Py_TPFLAGS_BASETYPE flag
// which prevents to create a subclass.
// So calling PyType_GetModuleState() in this file is always safe.
.flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_DISALLOW_INSTANTIATION |
Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_IMMUTABLETYPE),
.slots = dbmtype_spec_slots,
};
/* ----------------------------------------------------------------- */
/*[clinic input]
_dbm.open as dbmopen
filename: object
The filename to open.
flags: str="r"
How to open the file. "r" for reading, "w" for writing, etc.
mode: int(py_default="0o666") = 0o666
If creating a new file, the mode bits for the new file
(e.g. os.O_RDWR).
/
Return a database object.
[clinic start generated code]*/
static PyObject *
dbmopen_impl(PyObject *module, PyObject *filename, const char *flags,
int mode)
/*[clinic end generated code: output=9527750f5df90764 input=d8cf50a9f81218c8]*/
{
int iflags;
_dbm_state *state = get_dbm_state(module);
assert(state != NULL);
if (strcmp(flags, "r") == 0) {
iflags = O_RDONLY;
}
else if (strcmp(flags, "w") == 0) {
iflags = O_RDWR;
}
else if (strcmp(flags, "rw") == 0) {
/* Backward compatibility */
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(state->dbm_error,
"arg 2 to open should be 'r', 'w', 'c', or 'n'");
return NULL;
}
PyObject *filenamebytes;
if (!PyUnicode_FSConverter(filename, &filenamebytes)) {
return NULL;
}
const char *name = PyBytes_AS_STRING(filenamebytes);
PyObject *self = newdbmobject(state, name, iflags, mode);
Py_DECREF(filenamebytes);
return self;
}
static PyMethodDef dbmmodule_methods[] = {
DBMOPEN_METHODDEF
{ 0, 0 },
};
#if defined(GDBM_VERSION_MAJOR) || defined(DB_VERSION_MAJOR)
static PyStructSequence_Field version_info_fields[] = {
{"major", "Major release number"},
{"minor", "Minor release number"},
{"patch", "Patch release number"},
{0}
};
static PyObject *
make_version_info(PyTypeObject *type, int major, int minor, int patch)
{
PyObject *version;
int pos = 0;
version = PyStructSequence_New(type);
if (version == NULL) {
return NULL;
}
#define SetItem(VALUE) \
PyStructSequence_SET_ITEM(version, pos++, VALUE); \
if (PyErr_Occurred()) { \
Py_DECREF(version); \
return NULL; \
}
SetItem(PyLong_FromLong(major))
SetItem(PyLong_FromLong(minor))
SetItem(PyLong_FromLong(patch))
#undef SetItem
return version;
}
#endif
#if defined(GDBM_VERSION_MAJOR)
PyDoc_STRVAR(gdbm_version_info__doc__,
"_dbm.gdbm_version_info\n\
\n\
GDBM version information as a named tuple.");
static PyStructSequence_Desc gdbm_version_info_desc = {
"_dbm.gdbm_version_info", /* name */
gdbm_version_info__doc__, /* doc */
version_info_fields, /* fields */
3
};
static int
add_version_constants(PyObject *module)
{
if (PyModule_AddStringConstant(module, "gdbm_version", gdbm_version) < 0) {
return -1;
}
PyTypeObject *version_type;
version_type = PyStructSequence_NewType(&gdbm_version_info_desc);
if (version_type == NULL) {
return -1;
}
if (PyModule_Add(module, "GDBM_VERSION_INFO",
make_version_info(version_type, GDBM_VERSION_MAJOR,
GDBM_VERSION_MINOR, GDBM_VERSION_PATCH)) < 0)
{
Py_DECREF(version_type);
return -1;
}
if (PyModule_Add(module, "gdbm_version_info",
make_version_info(version_type, gdbm_version_number[0],
gdbm_version_number[1],
gdbm_version_number[2])) < 0)
{
Py_DECREF(version_type);
return -1;
}
Py_DECREF(version_type);
return 0;
}
#elif defined(DB_VERSION_MAJOR)
PyDoc_STRVAR(bdb_version_info__doc__,
"_dbm.bdb_version_info\n\
\n\
Berkeley DB version information as a named tuple.");
static PyStructSequence_Desc bdb_version_info_desc = {
"_dbm.bdb_version_info", /* name */
bdb_version_info__doc__, /* doc */
version_info_fields, /* fields */
3
};
static int
add_version_constants(PyObject *module)
{
int major, minor, patch;
const char *version = db_version(&major, &minor, &patch);
if (PyModule_AddStringConstant(module, "BDB_VERSION", DB_VERSION_STRING) < 0) {
return -1;
}
if (PyModule_AddStringConstant(module, "bdb_version", version) < 0) {
return -1;
}
PyTypeObject *version_type;
version_type = PyStructSequence_NewType(&bdb_version_info_desc);
if (version_type == NULL) {
return -1;
}
if (PyModule_Add(module, "BDB_VERSION_INFO",
make_version_info(version_type, DB_VERSION_MAJOR,
DB_VERSION_MINOR, DB_VERSION_PATCH)) < 0)
{
Py_DECREF(version_type);
return -1;
}
if (PyModule_Add(module, "bdb_version_info",
make_version_info(version_type, major, minor, patch)) < 0)
{
Py_DECREF(version_type);
return -1;
}
Py_DECREF(version_type);
return 0;
}
#else
static int
add_version_constants(PyObject *module)
{
return 0;
}
#endif
static int
_dbm_exec(PyObject *module)
{
_dbm_state *state = get_dbm_state(module);
state->dbm_type = (PyTypeObject *)PyType_FromModuleAndSpec(module,
&dbmtype_spec, NULL);
if (state->dbm_type == NULL) {
return -1;
}
state->dbm_error = PyErr_NewException("_dbm.error", PyExc_OSError, NULL);
if (state->dbm_error == NULL) {
return -1;
}
if (PyModule_AddStringConstant(module, "library", which_dbm) < 0) {
return -1;
}
if (add_version_constants(module) < 0) {
return -1;
}
if (PyModule_AddType(module, (PyTypeObject *)state->dbm_error) < 0) {
return -1;
}
return 0;
}
static int
_dbm_module_traverse(PyObject *module, visitproc visit, void *arg)
{
_dbm_state *state = get_dbm_state(module);
Py_VISIT(state->dbm_error);
Py_VISIT(state->dbm_type);
return 0;
}
static int
_dbm_module_clear(PyObject *module)
{
_dbm_state *state = get_dbm_state(module);
Py_CLEAR(state->dbm_error);
Py_CLEAR(state->dbm_type);
return 0;
}
static void
_dbm_module_free(void *module)
{
(void)_dbm_module_clear((PyObject *)module);
}
static PyModuleDef_Slot _dbmmodule_slots[] = {
_Py_ABI_SLOT,
{Py_mod_exec, _dbm_exec},
{Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
{Py_mod_gil, Py_MOD_GIL_NOT_USED},
{0, NULL}
};
static struct PyModuleDef _dbmmodule = {
PyModuleDef_HEAD_INIT,
.m_name = "_dbm",
.m_size = sizeof(_dbm_state),
.m_methods = dbmmodule_methods,
.m_slots = _dbmmodule_slots,
.m_traverse = _dbm_module_traverse,
.m_clear = _dbm_module_clear,
.m_free = _dbm_module_free,
};
PyMODINIT_FUNC
PyInit__dbm(void)
{
return PyModuleDef_Init(&_dbmmodule);
}
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