/* DBM module using dictionary interface */


#define PY_SSIZE_T_CLEAN
#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>
static const char which_dbm[] = "GNU gdbm"; /* EMX port of GDBM */
#elif defined(HAVE_GDBM_NDBM_H)
#include <gdbm/ndbm.h>
static const char which_dbm[] = "GNU gdbm";
#elif defined(HAVE_GDBM_DASH_NDBM_H)
#include <gdbm-ndbm.h>
static const char which_dbm[] = "GNU gdbm";
#elif defined(HAVE_BERKDB_H)
#include <db.h>
static const char which_dbm[] = "Berkeley DB";
#else
#error "No ndbm.h available!"
#endif

/*[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;

#include "clinic/_dbmmodule.c.h"

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

 dp = PyObject_New(dbmobject, &Dbmtype);
 if (dp == NULL)
 return NULL;
 dp->di_size = -1;
 dp->flags = flags;
 /* See issue #19296 */
 if ( (dp->di_dbm = dbm_open((char *)file, flags, mode)) == 0 ) {
 PyErr_SetFromErrnoWithFilename(DbmError, file);
 Py_DECREF(dp);
 return NULL;
 }
 return (PyObject *)dp;
}

/* Methods */

static void
dbm_dealloc(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, 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);
 /* 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(DbmError, "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(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*/
};

/*[clinic input]
_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=046db72377d51be8]*/
{
 if (self->di_dbm)
 dbm_close(self->di_dbm);
 self->di_dbm = NULL;
 Py_RETURN_NONE;
}

/*[clinic input]
_dbm.dbm.keys

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

static PyObject *
_dbm_dbm_keys_impl(dbmobject *self)
/*[clinic end generated code: output=434549f7c121b33c input=d210ba778cd9c68a]*/
{
 PyObject *v, *item;
 datum key;
 int err;

 check_dbmobject_open(self);
 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;
}

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

 if ((dp)->di_dbm == NULL) {
 PyErr_SetString(DbmError,
 "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",
 arg->ob_type->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;
}

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]
_dbm.dbm.get

 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, const char *key,
 Py_ssize_clean_t key_length, PyObject *default_value)
/*[clinic end generated code: output=b44f95eba8203d93 input=b788eba0ffad2e91]*/
/*[clinic end generated code: output=4f5c0e523eaf1251 input=9402c0af8582dc69]*/
{
 datum dbm_key, val;

 dbm_key.dptr = (char *)key;
 dbm_key.dsize = key_length;
 check_dbmobject_open(self);
 val = dbm_fetch(self->di_dbm, dbm_key);
 if (val.dptr != NULL)
 return PyBytes_FromStringAndSize(val.dptr, val.dsize);

 Py_INCREF(default_value);
 return default_value;
}

/*[clinic input]
_dbm.dbm.setdefault
 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, const char *key,
 Py_ssize_clean_t key_length,
 PyObject *default_value)
/*[clinic end generated code: output=52545886cf272161 input=bf40c48edaca01d6]*/
{
 datum dbm_key, val;
 Py_ssize_t tmp_size;

 dbm_key.dptr = (char *)key;
 dbm_key.dsize = key_length;
 check_dbmobject_open(self);
 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 = PyBytes_FromStringAndSize(NULL, 0);
 if (default_value == NULL)
 return NULL;
 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(DbmError, "cannot add item to database");
 Py_DECREF(default_value);
 return NULL;
 }
 return default_value;
}

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[] = {
 _DBM_DBM_CLOSE_METHODDEF
 _DBM_DBM_KEYS_METHODDEF
 _DBM_DBM_GET_METHODDEF
 _DBM_DBM_SETDEFAULT_METHODDEF
 {"__enter__", dbm__enter__, METH_NOARGS, NULL},
 {"__exit__", dbm__exit__, METH_VARARGS, NULL},
 {NULL, NULL} /* sentinel */
};

static PyTypeObject Dbmtype = {
 PyVarObject_HEAD_INIT(NULL, 0)
 "_dbm.dbm",
 sizeof(dbmobject),
 0,
 (destructor)dbm_dealloc, /*tp_dealloc*/
 0, /*tp_vectorcall_offset*/
 0, /*tp_getattr*/
 0, /*tp_setattr*/
 0, /*tp_as_async*/
 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*/
};

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

/*[clinic input]

_dbm.open as dbmopen

 filename: unicode
 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=376a9d903a50df59]*/
{
 int iflags;

 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;
 }

 PyObject *filenamebytes = PyUnicode_EncodeFSDefault(filename);
 if (filenamebytes == NULL) {
 return NULL;
 }
 const char *name = PyBytes_AS_STRING(filenamebytes);
 if (strlen(name) != (size_t)PyBytes_GET_SIZE(filenamebytes)) {
 Py_DECREF(filenamebytes);
 PyErr_SetString(PyExc_ValueError, "embedded null character");
 return NULL;
 }
 PyObject *self = newdbmobject(name, iflags, mode);
 Py_DECREF(filenamebytes);
 return self;
}

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