postgresql/contrib/hstore_plpython/hstore_plpython.c
Peter Eisentraut cac7658205 Add transforms feature
This provides a mechanism for specifying conversions between SQL data
types and procedural languages.  As examples, there are transforms
for hstore and ltree for PL/Perl and PL/Python.

reviews by Pavel Stěhule and Andres Freund
2015-04-26 10:33:14 -04:00

117 lines
2.3 KiB
C

#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);
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(HS_KEY(entries, base, i), HS_KEYLEN(entries, i));
if (HS_VALISNULL(entries, i))
PyDict_SetItem(dict, key, Py_None);
else
{
PyObject *value;
value = PyString_FromStringAndSize(HS_VAL(entries, base,i), HS_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);
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);
}