/* 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;

	int 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_SetString(PyExc_KeyError,

				PyString_AS_STRING((PyStringObject *)key));

		return NULL;

	}

	if ( dbm_error(dp->di_dbm) ) {

		dbm_clearerr(dp->di_dbm);

		PyErr_SetString(DbmError, "");

		return NULL;

	}

	return PyString_FromStringAndSize(drec.dptr, drec.dsize);

}

static int

dbm_ass_sub(dbmobject *dp, PyObject *v, PyObject *w)

{

        datum krec, drec;

	int tmp_size;

        if ( !PyArg_Parse(v, "s#", &krec.dptr, &tmp_size) ) {

		PyErr_SetString(PyExc_TypeError,

				"dbm mappings have string indices 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_SetString(PyExc_KeyError,

				      PyString_AS_STRING((PyStringObject *)v));

			return -1;

		}

	} else {

		if ( !PyArg_Parse(w, "s#", &drec.dptr, &tmp_size) ) {

			PyErr_SetString(PyExc_TypeError,

				     "dbm mappings have 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 int

dbm_contains(register dbmobject *dp, PyObject *v)

{

	datum key, val;

	if (PyString_AsStringAndSize(v, (char **)&key.dptr,

	                             (Py_ssize_t *)&key.dsize)) {

		return -1;

	}

	/* Expand check_dbmobject_open to return -1 */

	if (dp->di_dbm == NULL) {

		PyErr_SetString(DbmError, "DBM object has already been closed");

		return -1;

	}

	val = dbm_fetch(dp->di_dbm, key);

	return val.dptr != NULL;

}

static PySequenceMethods dbm_as_sequence = {

    (lenfunc)dbm_length,        /*_length*/

    0,                          /*sq_concat*/

    0,                          /*sq_repeat*/

    0,                          /*sq_item*/

    0,                          /*sq_slice*/

    0,                          /*sq_ass_item*/

    0,                          /*sq_ass_slice*/

    (objobjproc)dbm_contains,   /*sq_contains*/

    0,                          /*sq_inplace_concat*/

    0                           /*sq_inplace_repeat*/

};

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 = PyString_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 PyObject *

dbm_has_key(register dbmobject *dp, PyObject *args)

{

	char *tmp_ptr;

	datum key, val;

	int tmp_size;

	if (!PyArg_ParseTuple(args, "s#:has_key", &tmp_ptr, &tmp_size))

		return NULL;

	key.dptr = tmp_ptr;

	key.dsize = tmp_size;

        check_dbmobject_open(dp);

	val = dbm_fetch(dp->di_dbm, key);

	return PyInt_FromLong(val.dptr != NULL);

}

static PyObject *

dbm_get(register dbmobject *dp, PyObject *args)

{

	datum key, val;

	PyObject *defvalue = Py_None;

	char *tmp_ptr;

	int 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 PyString_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;

	int tmp_size;

	if (!PyArg_ParseTuple(args, "s#|S: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 PyString_FromStringAndSize(val.dptr, val.dsize);

	if (defvalue == NULL) {

		defvalue = PyString_FromStringAndSize(NULL, 0);

		if (defvalue == NULL)

			return NULL;

	}

	else

		Py_INCREF(defvalue);

	val.dptr = PyString_AS_STRING(defvalue);

	val.dsize = PyString_GET_SIZE(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");

		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."},

	{"has_key",	(PyCFunction)dbm_has_key,	METH_VARARGS,

	 "has_key(key} -> boolean\nReturn true iff key is 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 PyObject *

dbm_getattr(dbmobject *dp, char *name)

{

	return Py_FindMethod(dbm_methods, (PyObject *)dp, name);

}

static PyTypeObject Dbmtype = {

	PyVarObject_HEAD_INIT(NULL, 0)

	"dbm.dbm",

	sizeof(dbmobject),

	0,

	(destructor)dbm_dealloc,  /*tp_dealloc*/

	0,			  /*tp_print*/

	(getattrfunc)dbm_getattr, /*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_xxx4*/

};

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

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 },

};

PyMODINIT_FUNC

initdbm(void) {

	PyObject *m, *d, *s;

	Dbmtype.ob_type = &PyType_Type;

	m = Py_InitModule("dbm", dbmmodule_methods);

	if (m == NULL)

		return;

	d = PyModule_GetDict(m);

	if (DbmError == NULL)

		DbmError = PyErr_NewException("dbm.error", NULL, NULL);

	s = PyString_FromString(which_dbm);

	if (s != NULL) {

		PyDict_SetItemString(d, "library", s);

		Py_DECREF(s);

	}

	if (DbmError != NULL)

		PyDict_SetItemString(d, "error", DbmError);

}