gdbmmodule.c

python s60 1.4.5版本的源代码

/* DBM module using dictionary interface */
/* Author: Anthony Baxter, after dbmmodule.c */
/* Doc strings: Mitch Chapman */


#include "Python.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "gdbm.h"

#if defined(WIN32) && !defined(__CYGWIN__)
#include "gdbmerrno.h"
extern const char * gdbm_strerror(gdbm_error);
#endif

static char gdbmmodule__doc__[] = "\
This module provides an interface to the GNU DBM (GDBM) library.\n\
\n\
This module is quite similar to the dbm module, but uses GDBM instead to\n\
provide some additional functionality. Please note that the file formats\n\
created by GDBM and dbm are incompatible. \n\
\n\
GDBM objects behave like mappings (dictionaries), except that keys and\n\
values are always strings. Printing a GDBM object doesn't print the\n\
keys and values, and the items() and values() methods are not\n\
supported.";

typedef struct {
    PyObject_HEAD
    int di_size;	/* -1 means recompute */
    GDBM_FILE di_dbm;
} dbmobject;

staticforward PyTypeObject Dbmtype;

#define is_dbmobject(v) ((v)->ob_type == &Dbmtype)
#define check_dbmobject_open(v) if ((v)->di_dbm == NULL) \
    { PyErr_SetString(DbmError, "GDBM object has already been closed"); \
      return NULL; }



static PyObject *DbmError;

static char gdbm_object__doc__[] = "\
This object represents a GDBM database.\n\
GDBM objects behave like mappings (dictionaries), except that keys and\n\
values are always strings. Printing a GDBM object doesn't print the\n\
keys and values, and the items() and values() methods are not\n\
supported.\n\
\n\
GDBM objects also support additional operations such as firstkey,\n\
nextkey, reorganize, and sync.";

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;
    errno = 0;
    if ((dp->di_dbm = gdbm_open(file, 0, flags, mode, NULL)) == 0) {
        if (errno != 0)
            PyErr_SetFromErrno(DbmError);
        else
            PyErr_SetString(DbmError, gdbm_strerror(gdbm_errno));
        Py_DECREF(dp);
        return NULL;
    }
    return (PyObject *)dp;
}

/* Methods */

static void
dbm_dealloc(register dbmobject *dp)
{
    if (dp->di_dbm)
        gdbm_close(dp->di_dbm);
    PyObject_Del(dp);
}

static int
dbm_length(dbmobject *dp)
{
    if (dp->di_dbm == NULL) {
        PyErr_SetString(DbmError, "GDBM object has already been closed"); 
        return -1; 
    }
    if (dp->di_size < 0) {
        datum key,okey;
        int size;
        okey.dsize=0;

        size = 0;
        for (key=gdbm_firstkey(dp->di_dbm); key.dptr;
             key = gdbm_nextkey(dp->di_dbm,okey)) {
            size++;
            if(okey.dsize) free(okey.dptr);
            okey=key;
        }
        dp->di_size = size;
    }
    return dp->di_size;
}

static PyObject *
dbm_subscript(dbmobject *dp, register PyObject *key)
{
    PyObject *v;
    datum drec, krec;

    if (!PyArg_Parse(key, "s#", &krec.dptr, &krec.dsize) )
        return NULL;

    if (dp->di_dbm == NULL) {
        PyErr_SetString(DbmError,
                        "GDBM object has already been closed");
        return NULL;
    }
    drec = gdbm_fetch(dp->di_dbm, krec);
    if (drec.dptr == 0) {
        PyErr_SetString(PyExc_KeyError,
                        PyString_AS_STRING((PyStringObject *)key));
        return NULL;
    }
    v = PyString_FromStringAndSize(drec.dptr, drec.dsize);
    free(drec.dptr);
    return v;
}

static int
dbm_ass_sub(dbmobject *dp, PyObject *v, PyObject *w)
{
    datum krec, drec;

    if (!PyArg_Parse(v, "s#", &krec.dptr, &krec.dsize) ) {
        PyErr_SetString(PyExc_TypeError,
                        "gdbm mappings have string indices only");
        return -1;
    }
    if (dp->di_dbm == NULL) {
        PyErr_SetString(DbmError,
                        "GDBM object has already been closed"); 
        return -1; 
    }
    dp->di_size = -1;
    if (w == NULL) {
        if (gdbm_delete(dp->di_dbm, krec) < 0) {
            PyErr_SetString(PyExc_KeyError,
                            PyString_AS_STRING((PyStringObject *)v));
            return -1;
        }
    }
    else {
        if (!PyArg_Parse(w, "s#", &drec.dptr, &drec.dsize)) {
            PyErr_SetString(PyExc_TypeError,
                            "gdbm mappings have string elements only");
            return -1;
        }
        errno = 0;
        if (gdbm_store(dp->di_dbm, krec, drec, GDBM_REPLACE) < 0) {
            if (errno != 0)
                PyErr_SetFromErrno(DbmError);
            else
                PyErr_SetString(DbmError,
                                gdbm_strerror(gdbm_errno));
            return -1;
        }
    }
    return 0;
}

static PyMappingMethods dbm_as_mapping = {
    (inquiry)dbm_length,		/*mp_length*/
    (binaryfunc)dbm_subscript,          /*mp_subscript*/
    (objobjargproc)dbm_ass_sub,         /*mp_ass_subscript*/
};

static char dbm_close__doc__[] = "\
close() -> None\n\
Closes the database.";

static PyObject *
dbm_close(register dbmobject *dp, PyObject *args)
{
    if (!PyArg_ParseTuple(args, ":close"))
        return NULL;
    if (dp->di_dbm)
        gdbm_close(dp->di_dbm);
    dp->di_dbm = NULL;
    Py_INCREF(Py_None);
    return Py_None;
}

static char dbm_keys__doc__[] = "\
keys() -> list_of_keys\n\
Get a list of all keys in the database.";

static PyObject *
dbm_keys(register dbmobject *dp, PyObject *args)
{
    register PyObject *v, *item;
    datum key, nextkey;
    int err;

    if (dp == NULL || !is_dbmobject(dp)) {
        PyErr_BadInternalCall();
        return NULL;
    }
    if (!PyArg_ParseTuple(args, ":keys"))
        return NULL;

    check_dbmobject_open(dp);

    v = PyList_New(0);
    if (v == NULL)
        return NULL;

    key = gdbm_firstkey(dp->di_dbm);
    while (key.dptr) {
        item = PyString_FromStringAndSize(key.dptr, key.dsize);
        if (item == NULL) {
            free(key.dptr);
            Py_DECREF(v);
            return NULL;
        }
        err = PyList_Append(v, item);
        Py_DECREF(item);
        if (err != 0) {
            free(key.dptr);
            Py_DECREF(v);
            return NULL;
        }
        nextkey = gdbm_nextkey(dp->di_dbm, key);
        free(key.dptr);
        key = nextkey;
    }
    return v;
}

static char dbm_has_key__doc__[] = "\
has_key(key) -> boolean\n\
Find out whether or not the database contains a given key.";

static PyObject *
dbm_has_key(register dbmobject *dp, PyObject *args)
{
    datum key;

    if (!PyArg_ParseTuple(args, "s#:has_key", &key.dptr, &key.dsize))
        return NULL;
    check_dbmobject_open(dp);
    return PyInt_FromLong((long) gdbm_exists(dp->di_dbm, key));
}