jsonb_plperl.c

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#include "postgres.h"

#include <math.h>

#include "fmgr.h"
#include "plperl.h"
#include "plperl_helpers.h"
#include "utils/fmgrprotos.h"
#include "utils/jsonb.h"

PG_MODULE_MAGIC;

static SV  *Jsonb_to_SV(JsonbContainer *jsonb);
static JsonbValue *SV_to_JsonbValue(SV *obj, JsonbParseState **ps, bool is_elem);


static SV  *
JsonbValue_to_SV(JsonbValue *jbv)
{
    dTHX;

    switch (jbv->type)
    {
        case jbvBinary:
            return Jsonb_to_SV(jbv->val.binary.data);

        case jbvNumeric:
            {
                char       *str = DatumGetCString(DirectFunctionCall1(numeric_out,
                                                                      NumericGetDatum(jbv->val.numeric)));
                SV         *result = newSVnv(SvNV(cstr2sv(str)));

                pfree(str);
                return result;
            }

        case jbvString:
            {
                char       *str = pnstrdup(jbv->val.string.val,
                                           jbv->val.string.len);
                SV         *result = cstr2sv(str);

                pfree(str);
                return result;
            }

        case jbvBool:
            return newSVnv(SvNV(jbv->val.boolean ? &PL_sv_yes : &PL_sv_no));

        case jbvNull:
            return newSV(0);

        default:
            elog(ERROR, "unexpected jsonb value type: %d", jbv->type);
            return NULL;
    }
}

static SV  *
Jsonb_to_SV(JsonbContainer *jsonb)
{
    dTHX;
    JsonbValue  v;
    JsonbIterator *it;
    JsonbIteratorToken r;

    it = JsonbIteratorInit(jsonb);
    r = JsonbIteratorNext(&it, &v, true);

    switch (r)
    {
        case WJB_BEGIN_ARRAY:
            if (v.val.array.rawScalar)
            {
                JsonbValue  tmp;

                if ((r = JsonbIteratorNext(&it, &v, true)) != WJB_ELEM ||
                    (r = JsonbIteratorNext(&it, &tmp, true)) != WJB_END_ARRAY ||
                    (r = JsonbIteratorNext(&it, &tmp, true)) != WJB_DONE)
                    elog(ERROR, "unexpected jsonb token: %d", r);

                return JsonbValue_to_SV(&v);
            }
            else
            {
                AV         *av = newAV();

                while ((r = JsonbIteratorNext(&it, &v, true)) != WJB_DONE)
                {
                    if (r == WJB_ELEM)
                        av_push(av, JsonbValue_to_SV(&v));
                }

                return newRV((SV *) av);
            }

        case WJB_BEGIN_OBJECT:
            {
                HV         *hv = newHV();

                while ((r = JsonbIteratorNext(&it, &v, true)) != WJB_DONE)
                {
                    if (r == WJB_KEY)
                    {
                        /* json key in v, json value in val */
                        JsonbValue  val;

                        if (JsonbIteratorNext(&it, &val, true) == WJB_VALUE)
                        {
                            SV         *value = JsonbValue_to_SV(&val);

                            (void) hv_store(hv,
                                            v.val.string.val, v.val.string.len,
                                            value, 0);
                        }
                    }
                }

                return newRV((SV *) hv);
            }

        default:
            elog(ERROR, "unexpected jsonb token: %d", r);
            return NULL;
    }
}

static JsonbValue *
AV_to_JsonbValue(AV *in, JsonbParseState **jsonb_state)
{
    dTHX;
    SSize_t     pcount = av_len(in) + 1;
    SSize_t     i;

    pushJsonbValue(jsonb_state, WJB_BEGIN_ARRAY, NULL);

    for (i = 0; i < pcount; i++)
    {
        SV        **value = av_fetch(in, i, FALSE);

        if (value)
            (void) SV_to_JsonbValue(*value, jsonb_state, true);
    }

    return pushJsonbValue(jsonb_state, WJB_END_ARRAY, NULL);
}

static JsonbValue *
HV_to_JsonbValue(HV *obj, JsonbParseState **jsonb_state)
{
    dTHX;
    JsonbValue  key;
    SV         *val;
    char       *kstr;
    I32         klen;

    key.type = jbvString;

    pushJsonbValue(jsonb_state, WJB_BEGIN_OBJECT, NULL);

    (void) hv_iterinit(obj);

    while ((val = hv_iternextsv(obj, &kstr, &klen)))
    {
        key.val.string.val = pnstrdup(kstr, klen);
        key.val.string.len = klen;
        pushJsonbValue(jsonb_state, WJB_KEY, &key);
        (void) SV_to_JsonbValue(val, jsonb_state, false);
    }

    return pushJsonbValue(jsonb_state, WJB_END_OBJECT, NULL);
}

static JsonbValue *
SV_to_JsonbValue(SV *in, JsonbParseState **jsonb_state, bool is_elem)
{
    dTHX;
    JsonbValue  out;            /* result */

    /* Dereference references recursively. */
    while (SvROK(in))
        in = SvRV(in);

    switch (SvTYPE(in))
    {
        case SVt_PVAV:
            return AV_to_JsonbValue((AV *) in, jsonb_state);

        case SVt_PVHV:
            return HV_to_JsonbValue((HV *) in, jsonb_state);

        default:
            if (!SvOK(in))
            {
                out.type = jbvNull;
            }
            else if (SvUOK(in))
            {
                /*
                 * If UV is >=64 bits, we have no better way to make this
                 * happen than converting to text and back.  Given the low
                 * usage of UV in Perl code, it's not clear it's worth working
                 * hard to provide alternate code paths.
                 */
                const char *strval = SvPV_nolen(in);

                out.type = jbvNumeric;
                out.val.numeric =
                    DatumGetNumeric(DirectFunctionCall3(numeric_in,
                                                        CStringGetDatum(strval),
                                                        ObjectIdGetDatum(InvalidOid),
                                                        Int32GetDatum(-1)));
            }
            else if (SvIOK(in))
            {
                IV          ival = SvIV(in);

                out.type = jbvNumeric;
                out.val.numeric = int64_to_numeric(ival);
            }
            else if (SvNOK(in))
            {
                double      nval = SvNV(in);

                /*
                 * jsonb doesn't allow infinity or NaN (per JSON
                 * specification), but the numeric type that is used for the
                 * storage accepts those, so we have to reject them here
                 * explicitly.
                 */
                if (isinf(nval))
                    ereport(ERROR,
                            (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                             errmsg("cannot convert infinity to jsonb")));
                if (isnan(nval))
                    ereport(ERROR,
                            (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                             errmsg("cannot convert NaN to jsonb")));

                out.type = jbvNumeric;
                out.val.numeric =
                    DatumGetNumeric(DirectFunctionCall1(float8_numeric,
                                                        Float8GetDatum(nval)));
            }
            else if (SvPOK(in))
            {
                out.type = jbvString;
                out.val.string.val = sv2cstr(in);
                out.val.string.len = strlen(out.val.string.val);
            }
            else
            {
                /*
                 * XXX It might be nice if we could include the Perl type in
                 * the error message.
                 */
                ereport(ERROR,
                        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                         errmsg("cannot transform this Perl type to jsonb")));
                return NULL;
            }
    }

    /* Push result into 'jsonb_state' unless it is a raw scalar. */
    return *jsonb_state
        ? pushJsonbValue(jsonb_state, is_elem ? WJB_ELEM : WJB_VALUE, &out)
        : memcpy(palloc(sizeof(JsonbValue)), &out, sizeof(JsonbValue));
}


PG_FUNCTION_INFO_V1(jsonb_to_plperl);

Datum
jsonb_to_plperl(PG_FUNCTION_ARGS)
{
    dTHX;
    Jsonb      *in = PG_GETARG_JSONB_P(0);
    SV         *sv = Jsonb_to_SV(&in->root);

    return PointerGetDatum(sv);
}


PG_FUNCTION_INFO_V1(plperl_to_jsonb);

Datum
plperl_to_jsonb(PG_FUNCTION_ARGS)
{
    dTHX;
    JsonbParseState *jsonb_state = NULL;
    SV         *in = (SV *) PG_GETARG_POINTER(0);
    JsonbValue *out = SV_to_JsonbValue(in, &jsonb_state, true);
    Jsonb      *result = JsonbValueToJsonb(out);

    PG_RETURN_JSONB_P(result);
}