plpy_util.c

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/*
 * utility functions
 *
 * src/pl/plpython/plpy_util.c
 */

#include "postgres.h"

#include "mb/pg_wchar.h"
#include "utils/memutils.h"
#include "utils/palloc.h"

#include "plpython.h"

#include "plpy_util.h"

#include "plpy_elog.h"


void *
PLy_malloc(size_t bytes)
{
    /* We need our allocations to be long-lived, so use TopMemoryContext */
    return MemoryContextAlloc(TopMemoryContext, bytes);
}

void *
PLy_malloc0(size_t bytes)
{
    void       *ptr = PLy_malloc(bytes);

    MemSet(ptr, 0, bytes);
    return ptr;
}

char *
PLy_strdup(const char *str)
{
    char       *result;
    size_t      len;

    len = strlen(str) + 1;
    result = PLy_malloc(len);
    memcpy(result, str, len);

    return result;
}

/* define this away */
void
PLy_free(void *ptr)
{
    pfree(ptr);
}

/*
 * Convert a Python unicode object to a Python string/bytes object in
 * PostgreSQL server encoding.  Reference ownership is passed to the
 * caller.
 */
PyObject *
PLyUnicode_Bytes(PyObject *unicode)
{
    PyObject    *bytes, *rv;
    char        *utf8string, *encoded;

    /* First encode the Python unicode object with UTF-8. */
    bytes = PyUnicode_AsUTF8String(unicode);
    if (bytes == NULL)
        PLy_elog(ERROR, "could not convert Python Unicode object to bytes");

    utf8string = PyBytes_AsString(bytes);
    if (utf8string == NULL) {
        Py_DECREF(bytes);
        PLy_elog(ERROR, "could not extract bytes from encoded string");
    }

    /*
     * Then convert to server encoding if necessary.
     *
     * PyUnicode_AsEncodedString could be used to encode the object directly
     * in the server encoding, but Python doesn't support all the encodings
     * that PostgreSQL does (EUC_TW and MULE_INTERNAL). UTF-8 is used as an
     * intermediary in PLyUnicode_FromString as well.
     */
    if (GetDatabaseEncoding() != PG_UTF8)
    {
        PG_TRY();
        {
            encoded = (char *) pg_do_encoding_conversion(
                (unsigned char *) utf8string,
                strlen(utf8string),
                PG_UTF8,
                GetDatabaseEncoding());
        }
        PG_CATCH();
        {
            Py_DECREF(bytes);
            PG_RE_THROW();
        }
        PG_END_TRY();
    }
    else
        encoded = utf8string;

    /* finally, build a bytes object in the server encoding */
    rv = PyBytes_FromStringAndSize(encoded, strlen(encoded));

    /* if pg_do_encoding_conversion allocated memory, free it now */
    if (utf8string != encoded)
        pfree(encoded);

    Py_DECREF(bytes);
    return rv;
}

/*
 * Convert a Python unicode object to a C string in PostgreSQL server
 * encoding.  No Python object reference is passed out of this
 * function.  The result is palloc'ed.
 *
 * Note that this function is disguised as PyString_AsString() when
 * using Python 3.  That function retuns a pointer into the internal
 * memory of the argument, which isn't exactly the interface of this
 * function.  But in either case you get a rather short-lived
 * reference that you ought to better leave alone.
 */
char *
PLyUnicode_AsString(PyObject *unicode)
{
    PyObject   *o = PLyUnicode_Bytes(unicode);
    char       *rv = pstrdup(PyBytes_AsString(o));

    Py_XDECREF(o);
    return rv;
}

#if PY_MAJOR_VERSION >= 3
/*
 * Convert a C string in the PostgreSQL server encoding to a Python
 * unicode object.  Reference ownership is passed to the caller.
 */
PyObject *
PLyUnicode_FromString(const char *s)
{
    char       *utf8string;
    PyObject   *o;

    utf8string = (char *) pg_do_encoding_conversion((unsigned char *) s,
                                                    strlen(s),
                                                    GetDatabaseEncoding(),
                                                    PG_UTF8);

    o = PyUnicode_FromString(utf8string);

    if (utf8string != s)
        pfree(utf8string);

    return o;
}

#endif   /* PY_MAJOR_VERSION >= 3 */