lwgeom_out_mvt.c

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/**********************************************************************
 *
 * PostGIS - Spatial Types for PostgreSQL
 * http://postgis.net
 *
 * PostGIS is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * PostGIS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with PostGIS.  If not, see <http://www.gnu.org/licenses/>.
 *
 **********************************************************************
 *
 * Copyright (C) 2016-2017 Björn Harrtell <bjorn@wololo.org>
 *
 **********************************************************************/

#include "postgres.h"
#include "utils/builtins.h"
#include "executor/spi.h"
#include "../postgis_config.h"
#include "lwgeom_pg.h"
#include "lwgeom_log.h"
#include "liblwgeom.h"
#include "mvt.h"

#ifdef HAVE_LIBPROTOBUF
#include "vector_tile.pb-c.h"
#endif  /* HAVE_LIBPROTOBUF */

PG_FUNCTION_INFO_V1(ST_AsMVTGeom);
Datum ST_AsMVTGeom(PG_FUNCTION_ARGS)
{
#ifndef HAVE_LIBPROTOBUF
        elog(ERROR, "Missing libprotobuf-c");
        PG_RETURN_NULL();
#else
        LWGEOM *lwgeom_in, *lwgeom_out;
        GSERIALIZED *geom_in, *geom_out;
        GBOX *bounds;
        int extent, buffer;
        bool clip_geom;
        if (PG_ARGISNULL(0))
                PG_RETURN_NULL();
        geom_in = PG_GETARG_GSERIALIZED_P(0);
        lwgeom_in = lwgeom_from_gserialized(geom_in);
        if (PG_ARGISNULL(1))
                elog(ERROR, "ST_AsMVTGeom: parameter bounds cannot be null");
        bounds = (GBOX *) PG_GETARG_POINTER(1);
        extent = PG_ARGISNULL(2) ? 4096 : PG_GETARG_INT32(2);
        buffer = PG_ARGISNULL(3) ? 256 : PG_GETARG_INT32(3);
        clip_geom = PG_ARGISNULL(4) ? true : PG_GETARG_BOOL(4);
        lwgeom_out = mvt_geom(lwgeom_in, bounds, extent, buffer, clip_geom);
        lwgeom_free(lwgeom_in);
        if (lwgeom_out == NULL)
                PG_RETURN_NULL();
        geom_out = geometry_serialize(lwgeom_out);
        lwgeom_free(lwgeom_out);
        PG_FREE_IF_COPY(geom_in, 0);
        PG_RETURN_POINTER(geom_out);
#endif
}

PG_FUNCTION_INFO_V1(pgis_asmvt_transfn);
Datum pgis_asmvt_transfn(PG_FUNCTION_ARGS)
{
#ifndef HAVE_LIBPROTOBUF
        elog(ERROR, "Missing libprotobuf-c");
        PG_RETURN_NULL();
#else
        MemoryContext aggcontext;
        struct mvt_agg_context *ctx;

        if (!AggCheckCallContext(fcinfo, &aggcontext))
                elog(ERROR, "pgis_asmvt_transfn: called in non-aggregate context");
        MemoryContextSwitchTo(aggcontext);

        if (PG_ARGISNULL(0)) {
                ctx = palloc(sizeof(*ctx));
                ctx->name = "default";
                if (PG_NARGS() > 2 && !PG_ARGISNULL(2))
                        ctx->name = text_to_cstring(PG_GETARG_TEXT_P(2));
                ctx->extent = 4096;
                if (PG_NARGS() > 3 && !PG_ARGISNULL(3))
                        ctx->extent = PG_GETARG_INT32(3);
                ctx->geom_name = NULL;
                if (PG_NARGS() > 4 && !PG_ARGISNULL(4))
                        ctx->geom_name = text_to_cstring(PG_GETARG_TEXT_P(4));
                mvt_agg_init_context(ctx);
        } else {
                ctx = (struct mvt_agg_context *) PG_GETARG_POINTER(0);
        }

        if (!type_is_rowtype(get_fn_expr_argtype(fcinfo->flinfo, 1)))
                elog(ERROR, "pgis_asmvt_transfn: parameter row cannot be other than a rowtype");
        ctx->row = PG_GETARG_HEAPTUPLEHEADER(1);

        mvt_agg_transfn(ctx);
        PG_FREE_IF_COPY(ctx->row, 1);
        PG_RETURN_POINTER(ctx);
#endif
}

PG_FUNCTION_INFO_V1(pgis_asmvt_finalfn);
Datum pgis_asmvt_finalfn(PG_FUNCTION_ARGS)
{
#ifndef HAVE_LIBPROTOBUF
        elog(ERROR, "Missing libprotobuf-c");
        PG_RETURN_NULL();
#else
        struct mvt_agg_context *ctx;
        uint8_t *buf;
        if (!AggCheckCallContext(fcinfo, NULL))
                elog(ERROR, "pgis_asmvt_finalfn called in non-aggregate context");

        if (PG_ARGISNULL(0))
        {
                bytea *emptybuf = palloc(VARHDRSZ);
                SET_VARSIZE(emptybuf, VARHDRSZ);
                PG_RETURN_BYTEA_P(emptybuf);
        }

        ctx = (struct mvt_agg_context *) PG_GETARG_POINTER(0);
        buf = mvt_agg_finalfn(ctx);
        PG_RETURN_BYTEA_P(buf);
#endif
}