RASTER_getGDALDrivers()

Datum RASTER_getGDALDrivers

(

PG_FUNCTION_ARGS

)

Definition at line 339 of file rtpg_gdal.c.

{
        FuncCallContext *funcctx;
        TupleDesc tupdesc;
 
        uint32_t drv_count;
        rt_gdaldriver drv_set;
        rt_gdaldriver drv_set2;
        int call_cntr;
        int max_calls;
 
        /* first call of function */
        if (SRF_IS_FIRSTCALL()) {
                MemoryContext oldcontext;
 
                /* create a function context for cross-call persistence */
                funcctx = SRF_FIRSTCALL_INIT();
 
                /* switch to memory context appropriate for multiple function calls */
                oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
 
                drv_set = rt_raster_gdal_drivers(&drv_count, 0);
                if (NULL == drv_set || !drv_count) {
                        elog(NOTICE, "No GDAL drivers found");
                        MemoryContextSwitchTo(oldcontext);
                        SRF_RETURN_DONE(funcctx);
                }
 
                POSTGIS_RT_DEBUGF(3, "%d drivers returned", (int) drv_count);
 
                /* Store needed information */
                funcctx->user_fctx = drv_set;
 
                /* total number of tuples to be returned */
                funcctx->max_calls = drv_count;
 
                /* Build a tuple descriptor for our result type */
                if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE) {
                        ereport(ERROR, (
                                errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                                errmsg(
                                        "function returning record called in context "
                                        "that cannot accept type record"
                                )
                        ));
                }
 
                BlessTupleDesc(tupdesc);
                funcctx->tuple_desc = tupdesc;
                MemoryContextSwitchTo(oldcontext);
        }
 
        /* stuff done on every call of the function */
        funcctx = SRF_PERCALL_SETUP();
 
        call_cntr = funcctx->call_cntr;
        max_calls = funcctx->max_calls;
        tupdesc = funcctx->tuple_desc;
        drv_set2 = funcctx->user_fctx;
 
        /* do when there is more left to send */
        if (call_cntr < max_calls) {
                Datum values[VALUES_LENGTH];
                bool nulls[VALUES_LENGTH];
                HeapTuple tuple;
                Datum result;
 
                POSTGIS_RT_DEBUGF(3, "Result %d", call_cntr);
 
                memset(nulls, FALSE, sizeof(bool) * VALUES_LENGTH);
 
                values[0] = Int32GetDatum(drv_set2[call_cntr].idx);
                values[1] = CStringGetTextDatum(drv_set2[call_cntr].short_name);
                values[2] = CStringGetTextDatum(drv_set2[call_cntr].long_name);
                values[3] = BoolGetDatum(drv_set2[call_cntr].can_read);
                values[4] = BoolGetDatum(drv_set2[call_cntr].can_write);
                values[5] = CStringGetTextDatum(drv_set2[call_cntr].create_options);
 
                POSTGIS_RT_DEBUGF(4, "Result %d, Index %d", call_cntr, drv_set2[call_cntr].idx);
                POSTGIS_RT_DEBUGF(4, "Result %d, Short Name %s", call_cntr, drv_set2[call_cntr].short_name);
                POSTGIS_RT_DEBUGF(4, "Result %d, Full Name %s", call_cntr, drv_set2[call_cntr].long_name);
                POSTGIS_RT_DEBUGF(4, "Result %d, Can Read %u", call_cntr, drv_set2[call_cntr].can_read);
                POSTGIS_RT_DEBUGF(4, "Result %d, Can Write %u", call_cntr, drv_set2[call_cntr].can_write);
                POSTGIS_RT_DEBUGF(5, "Result %d, Create Options %s", call_cntr, drv_set2[call_cntr].create_options);
 
                /* build a tuple */
                tuple = heap_form_tuple(tupdesc, values, nulls);
 
                /* make the tuple into a datum */
                result = HeapTupleGetDatum(tuple);
 
                /* clean up */
                pfree(drv_set2[call_cntr].short_name);
                pfree(drv_set2[call_cntr].long_name);
                pfree(drv_set2[call_cntr].create_options);
 
                SRF_RETURN_NEXT(funcctx, result);
        }
        /* do when there is no more left */
        else {
                pfree(drv_set2);
                SRF_RETURN_DONE(funcctx);
        }
}

References FALSE, POSTGIS_RT_DEBUGF, rt_raster_gdal_drivers(), and VALUES_LENGTH.

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