Modules/dbmmodule.c

   1 /***********************************************************
   2 Copyright (c) 2000, BeOpen.com.
   3 Copyright (c) 1995-2000, Corporation for National Research Initiatives.
   4 Copyright (c) 1990-1995, Stichting Mathematisch Centrum.
   5 All rights reserved.
   6
   7 See the file "Misc/COPYRIGHT" for information on usage and
   8 redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES.
   9 ******************************************************************/
  10
  11 /* DBM module using dictionary interface */
  12
  13
  14 #include "Python.h"
  15
  16 #include <sys/types.h>
  17 #include <sys/stat.h>
  18 #include <fcntl.h>
  19 #include <ndbm.h>
  20
  21 typedef struct {
  22         PyObject_HEAD
  23         int di_size;    /* -1 means recompute */
  24         DBM *di_dbm;
  25 } dbmobject;
  26
  27 staticforward PyTypeObject Dbmtype;
  28
  29 #define is_dbmobject(v) ((v)->ob_type == &Dbmtype)
  30 #define check_dbmobject_open(v) if ((v)->di_dbm == NULL) \
  31                { PyErr_SetString(DbmError, "DBM object has already been closed"); \
  32                  return NULL; }
  33
  34 static PyObject *DbmError;
  35
  36 static PyObject *
  37 newdbmobject(char *file, int flags, int mode)
  38 {
  39         dbmobject *dp;
  40
  41         dp = PyObject_New(dbmobject, &Dbmtype);
  42         if (dp == NULL)
  43                 return NULL;
  44         dp->di_size = -1;
  45         if ( (dp->di_dbm = dbm_open(file, flags, mode)) == 0 ) {
  46                 PyErr_SetFromErrno(DbmError);
  47                 Py_DECREF(dp);
  48                 return NULL;
  49         }
  50         return (PyObject *)dp;
  51 }
  52
  53 /* Methods */
  54
  55 static void
  56 dbm_dealloc(register dbmobject *dp)
  57 {
  58         if ( dp->di_dbm )
  59                 dbm_close(dp->di_dbm);
  60         PyObject_Del(dp);
  61 }
  62
  63 static int
  64 dbm_length(dbmobject *dp)
  65 {
  66         if (dp->di_dbm == NULL) {
  67                  PyErr_SetString(DbmError, "DBM object has already been closed");
  68                  return -1;
  69         }
  70         if ( dp->di_size < 0 ) {
  71                 datum key;
  72                 int size;
  73
  74                 size = 0;
  75                 for ( key=dbm_firstkey(dp->di_dbm); key.dptr;
  76                       key = dbm_nextkey(dp->di_dbm))
  77                         size++;
  78                 dp->di_size = size;
  79         }
  80         return dp->di_size;
  81 }
  82
  83 static PyObject *
  84 dbm_subscript(dbmobject *dp, register PyObject *key)
  85 {
  86         datum drec, krec;
  87
  88         if (!PyArg_Parse(key, "s#", &krec.dptr, &krec.dsize) )
  89                 return NULL;
  90
  91         check_dbmobject_open(dp);
  92         drec = dbm_fetch(dp->di_dbm, krec);
  93         if ( drec.dptr == 0 ) {
  94                 PyErr_SetString(PyExc_KeyError,
  95                                 PyString_AS_STRING((PyStringObject *)key));
  96                 return NULL;
  97         }
  98         if ( dbm_error(dp->di_dbm) ) {
  99                 dbm_clearerr(dp->di_dbm);
 100                 PyErr_SetString(DbmError, "");
 101                 return NULL;
 102         }
 103         return PyString_FromStringAndSize(drec.dptr, drec.dsize);
 104 }
 105
 106 static int
 107 dbm_ass_sub(dbmobject *dp, PyObject *v, PyObject *w)
 108 {
 109         datum krec, drec;
 110
 111         if ( !PyArg_Parse(v, "s#", &krec.dptr, &krec.dsize) ) {
 112                 PyErr_SetString(PyExc_TypeError,
 113                                 "dbm mappings have string indices only");
 114                 return -1;
 115         }
 116         if (dp->di_dbm == NULL) {
 117                  PyErr_SetString(DbmError, "DBM object has already been closed");
 118                  return -1;
 119         }
 120         dp->di_size = -1;
 121         if (w == NULL) {
 122                 if ( dbm_delete(dp->di_dbm, krec) < 0 ) {
 123                         dbm_clearerr(dp->di_dbm);
 124                         PyErr_SetString(PyExc_KeyError,
 125                                       PyString_AS_STRING((PyStringObject *)v));
 126                         return -1;
 127                 }
 128         } else {
 129                 if ( !PyArg_Parse(w, "s#", &drec.dptr, &drec.dsize) ) {
 130                         PyErr_SetString(PyExc_TypeError,
 131                                      "dbm mappings have string elements only");
 132                         return -1;
 133                 }
 134                 if ( dbm_store(dp->di_dbm, krec, drec, DBM_REPLACE) < 0 ) {
 135                         dbm_clearerr(dp->di_dbm);
 136                         PyErr_SetString(DbmError,
 137                                         "Cannot add item to database");
 138                         return -1;
 139                 }
 140         }
 141         if ( dbm_error(dp->di_dbm) ) {
 142                 dbm_clearerr(dp->di_dbm);
 143                 PyErr_SetString(DbmError, "");
 144                 return -1;
 145         }
 146         return 0;
 147 }
 148
 149 static PyMappingMethods dbm_as_mapping = {
 150         (inquiry)dbm_length,            /*mp_length*/
 151         (binaryfunc)dbm_subscript,      /*mp_subscript*/
 152         (objobjargproc)dbm_ass_sub,     /*mp_ass_subscript*/
 153 };
 154
 155 static PyObject *
 156 dbm__close(register dbmobject *dp, PyObject *args)
 157 {
 158         if ( !PyArg_NoArgs(args) )
 159                 return NULL;
 160         if ( dp->di_dbm )
 161                 dbm_close(dp->di_dbm);
 162         dp->di_dbm = NULL;
 163         Py_INCREF(Py_None);
 164         return Py_None;
 165 }
 166
 167 static PyObject *
 168 dbm_keys(register dbmobject *dp, PyObject *args)
 169 {
 170         register PyObject *v, *item;
 171         datum key;
 172         int err;
 173
 174         if (!PyArg_NoArgs(args))
 175                 return NULL;
 176         check_dbmobject_open(dp);
 177         v = PyList_New(0);
 178         if (v == NULL)
 179                 return NULL;
 180         for (key = dbm_firstkey(dp->di_dbm); key.dptr;
 181              key = dbm_nextkey(dp->di_dbm)) {
 182                 item = PyString_FromStringAndSize(key.dptr, key.dsize);
 183                 if (item == NULL) {
 184                         Py_DECREF(v);
 185                         return NULL;
 186                 }
 187                 err = PyList_Append(v, item);
 188                 Py_DECREF(item);
 189                 if (err != 0) {
 190                         Py_DECREF(v);
 191                         return NULL;
 192                 }
 193         }
 194         return v;
 195 }
 196
 197 static PyObject *
 198 dbm_has_key(register dbmobject *dp, PyObject *args)
 199 {
 200         datum key, val;
 201
 202         if (!PyArg_Parse(args, "s#", &key.dptr, &key.dsize))
 203                 return NULL;
 204         check_dbmobject_open(dp);
 205         val = dbm_fetch(dp->di_dbm, key);
 206         return PyInt_FromLong(val.dptr != NULL);
 207 }
 208
 209 static PyMethodDef dbm_methods[] = {
 210         {"close",       (PyCFunction)dbm__close},
 211         {"keys",        (PyCFunction)dbm_keys},
 212         {"has_key",     (PyCFunction)dbm_has_key},
 213         {NULL,          NULL}           /* sentinel */
 214 };
 215
 216 static PyObject *
 217 dbm_getattr(dbmobject *dp, char *name)
 218 {
 219         return Py_FindMethod(dbm_methods, (PyObject *)dp, name);
 220 }
 221
 222 static PyTypeObject Dbmtype = {
 223         PyObject_HEAD_INIT(&PyType_Type)
 224         0,
 225         "dbm",
 226         sizeof(dbmobject),
 227         0,
 228         (destructor)dbm_dealloc,  /*tp_dealloc*/
 229         0,                        /*tp_print*/
 230         (getattrfunc)dbm_getattr, /*tp_getattr*/
 231         0,                        /*tp_setattr*/
 232         0,                        /*tp_compare*/
 233         0,                        /*tp_repr*/
 234         0,                        /*tp_as_number*/
 235         0,                        /*tp_as_sequence*/
 236         &dbm_as_mapping,          /*tp_as_mapping*/
 237 };
 238
 239 /* ----------------------------------------------------------------- */
 240
 241 static PyObject *
 242 dbmopen(PyObject *self, PyObject *args)
 243 {
 244         char *name;
 245         char *flags = "r";
 246         int iflags;
 247         int mode = 0666;
 248
 249         if ( !PyArg_ParseTuple(args, "s|si:open", &name, &flags, &mode) )
 250                 return NULL;
 251         if ( strcmp(flags, "r") == 0 )
 252                 iflags = O_RDONLY;
 253         else if ( strcmp(flags, "w") == 0 )
 254                 iflags = O_RDWR;
 255         else if ( strcmp(flags, "rw") == 0 ) /* B/W compat */
 256                 iflags = O_RDWR|O_CREAT;
 257         else if ( strcmp(flags, "c") == 0 )
 258                 iflags = O_RDWR|O_CREAT;
 259         else if ( strcmp(flags, "n") == 0 )
 260                 iflags = O_RDWR|O_CREAT|O_TRUNC;
 261         else {
 262                 PyErr_SetString(DbmError,
 263                                 "Flags should be one of 'r', 'w', 'c' or 'n'");
 264                 return NULL;
 265         }
 266         return newdbmobject(name, iflags, mode);
 267 }
 268
 269 static PyMethodDef dbmmodule_methods[] = {
 270         { "open", (PyCFunction)dbmopen, 1 },
 271         { 0, 0 },
 272 };
 273
 274 DL_EXPORT(void)
 275 initdbm(void) {
 276         PyObject *m, *d;
 277
 278         m = Py_InitModule("dbm", dbmmodule_methods);
 279         d = PyModule_GetDict(m);
 280         DbmError = PyErr_NewException("dbm.error", NULL, NULL);
 281         if (DbmError != NULL)
 282                 PyDict_SetItemString(d, "error", DbmError);
 283 }