hstore_plpython.c

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#include "postgres.h"
#include "fmgr.h"
#include "plpython.h"
#include "plpy_typeio.h"
#include "hstore.h"

PG_MODULE_MAGIC;


PG_FUNCTION_INFO_V1(hstore_to_plpython);

Datum
hstore_to_plpython(PG_FUNCTION_ARGS)
{
    HStore     *in = PG_GETARG_HS(0);
    int         i;
    int         count = HS_COUNT(in);
    char       *base = STRPTR(in);
    HEntry     *entries = ARRPTR(in);
    PyObject   *dict;

    dict = PyDict_New();

    for (i = 0; i < count; i++)
    {
        PyObject   *key;

        key = PyString_FromStringAndSize(HSTORE_KEY(entries, base, i),
                                         HSTORE_KEYLEN(entries, i));
        if (HSTORE_VALISNULL(entries, i))
            PyDict_SetItem(dict, key, Py_None);
        else
        {
            PyObject   *value;

            value = PyString_FromStringAndSize(HSTORE_VAL(entries, base, i),
                                               HSTORE_VALLEN(entries, i));
            PyDict_SetItem(dict, key, value);
            Py_XDECREF(value);
        }
        Py_XDECREF(key);
    }

    return PointerGetDatum(dict);
}


PG_FUNCTION_INFO_V1(plpython_to_hstore);

Datum
plpython_to_hstore(PG_FUNCTION_ARGS)
{
    PyObject   *dict;
    volatile PyObject *items_v = NULL;
    int32       pcount;
    HStore     *out;

    dict = (PyObject *) PG_GETARG_POINTER(0);
    if (!PyMapping_Check(dict))
        ereport(ERROR,
                (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                 errmsg("not a Python mapping")));

    pcount = PyMapping_Size(dict);
    items_v = PyMapping_Items(dict);

    PG_TRY();
    {
        int32       buflen;
        int32       i;
        Pairs      *pairs;
        PyObject   *items = (PyObject *) items_v;

        pairs = palloc(pcount * sizeof(*pairs));

        for (i = 0; i < pcount; i++)
        {
            PyObject   *tuple;
            PyObject   *key;
            PyObject   *value;

            tuple = PyList_GetItem(items, i);
            key = PyTuple_GetItem(tuple, 0);
            value = PyTuple_GetItem(tuple, 1);

            pairs[i].key = PLyObject_AsString(key);
            pairs[i].keylen = hstoreCheckKeyLen(strlen(pairs[i].key));
            pairs[i].needfree = true;

            if (value == Py_None)
            {
                pairs[i].val = NULL;
                pairs[i].vallen = 0;
                pairs[i].isnull = true;
            }
            else
            {
                pairs[i].val = PLyObject_AsString(value);
                pairs[i].vallen = hstoreCheckValLen(strlen(pairs[i].val));
                pairs[i].isnull = false;
            }
        }
        Py_DECREF(items_v);

        pcount = hstoreUniquePairs(pairs, pcount, &buflen);
        out = hstorePairs(pairs, pcount, buflen);
    }
    PG_CATCH();
    {
        Py_DECREF(items_v);
        PG_RE_THROW();
    }
    PG_END_TRY();

    PG_RETURN_POINTER(out);
}