Add support for empty 2D geometries - it's a prototype, need more tes…

…ting

postgis/brin_2d.c

@@ -11,14 +11,23 @@
  * FunctionCallInvoke machinery for each heap tuple.
  */
 
+static FmgrInfo *inclusion_get_procinfo(BrinDesc *bdesc, uint16 attno,
+uint16 procnum);
+
+static bool isempty(Datum the_datum);
+
 PG_FUNCTION_INFO_V1(geom2d_brin_inclusion_add_value);
 Datum
 geom2d_brin_inclusion_add_value(PG_FUNCTION_ARGS)
 {
+        BrinDesc   *bdesc = (BrinDesc *) PG_GETARG_POINTER(0);
 	BrinValues *column = (BrinValues *) PG_GETARG_POINTER(1);
-	Datum newval = PG_GETARG_DATUM(2);
-	bool		isnull = PG_GETARG_BOOL(3);
-	BOX2DF box_geom, *box_key;
+	Datum      newval = PG_GETARG_DATUM(2);
+	bool	   isnull = PG_GETARG_BOOL(3);
+        Oid        colloid = PG_GET_COLLATION();
+        FmgrInfo   *finfo;
+        AttrNumber attno;
+	BOX2DF     box_geom, *box_key;
 
 	/*
 	 * If the new value is null, we record that we saw it if it's the first
@@ -33,8 +42,32 @@ geom2d_brin_inclusion_add_value(PG_FUNCTION_ARGS)
 		PG_RETURN_BOOL(true);
 	}
 
-	if (gserialized_datum_get_box2df_p(newval, &box_geom) == LW_FAILURE)
-		elog(ERROR, "Error while extracting the box2df from the geom");
+
+        /*
+         * If the opclass supports the concept of empty values, test the passed
+         * new value for emptiness; if it returns true, we need to set the
+         * "contains empty" flag in the element (unless already set).
+         */
+        if (gserialized_datum_get_box2df_p(newval, &box_geom) == LW_FAILURE) {
+             if (isempty(newval)) {
+                  attno = column->bv_attno;
+
+                  finfo = inclusion_get_procinfo(bdesc, attno, PROCNUM_EMPTY);
+                  if (finfo != NULL && DatumGetBool(FunctionCall1Coll(finfo, colloid, newval)))
+                  {
+                          if (!DatumGetBool(column->bv_values[INCLUSION_CONTAINS_EMPTY]))
+                          {
+                                 column->bv_values[INCLUSION_CONTAINS_EMPTY] = BoolGetDatum(true);
+                                 PG_RETURN_BOOL(true);
+                          }
+
+                          PG_RETURN_BOOL(false);
+                  }
+             } else {
+                  /* check other cases where it is not possible to retrieve a box*/
+                  elog(ERROR, "Error while extracting the box2df from the geom");
+             }
+        }
 
 	/* if the recorded value is null, we just need to store the box2df */
 	if (column->bv_allnulls)
@@ -61,3 +94,58 @@ geom2d_brin_inclusion_add_value(PG_FUNCTION_ARGS)
 
 	PG_RETURN_BOOL(false);
 }
+
+/*
+ * Cache and return inclusion opclass support procedure
+ *
+ * Return the procedure corresponding to the given function support number
+ * or null if it is not exists.
+ */
+static FmgrInfo *
+inclusion_get_procinfo(BrinDesc *bdesc, uint16 attno, uint16 procnum)
+{
+        InclusionOpaque *opaque;
+        uint16          basenum = procnum - PROCNUM_BASE;
+
+        /*
+         * We cache these in the opaque struct, to avoid repetitive syscache
+         * lookups.
+         */
+        opaque = (InclusionOpaque *) bdesc->bd_info[attno - 1]->oi_opaque;
+
+        /*
+         * If we already searched for this proc and didn't find it, don't bother
+         * searching again.
+         */
+        if (opaque->extra_proc_missing[basenum])
+                return NULL;
+
+        if (opaque->extra_procinfos[basenum].fn_oid == InvalidOid)
+        {
+                if (RegProcedureIsValid(index_getprocid(bdesc->bd_index, attno,
+                                                                                                procnum)))
+                {
+                        fmgr_info_copy(&opaque->extra_procinfos[basenum],
+                                                   index_getprocinfo(bdesc->bd_index, attno, procnum),
+                                                   bdesc->bd_context);
+                }
+                else
+                {
+                        opaque->extra_proc_missing[basenum] = true;
+                        return NULL;
+                }
+        }
+
+        return &opaque->extra_procinfos[basenum];
+}
+
+static bool
+isempty(Datum the_datum)
+{
+        GSERIALIZED *geom = (GSERIALIZED*)PG_DETOAST_DATUM(the_datum);
+        LWGEOM *lwgeom = lwgeom_from_gserialized(geom);
+        bool empty = lwgeom_is_empty(lwgeom);
+
+        lwgeom_free(lwgeom);
+        return empty;
+}

postgis/postgis.sql.in

@@ -5768,6 +5768,7 @@ CREATE OPERATOR CLASS brin_geometry_inclusion_ops_2d
     FUNCTION      2        geom2d_brin_inclusion_add_value(internal, internal, internal, internal) ,
     FUNCTION      3        brin_inclusion_consistent(internal, internal, internal) ,
     FUNCTION      4        brin_inclusion_union(internal, internal, internal) ,
+    FUNCTION     14        st_isempty(geometry) ,
   STORAGE box2df;
 
 ALTER OPERATOR FAMILY brin_geometry_inclusion_family_2d USING brin ADD

postgis/postgis_brin.h

@@ -12,11 +12,24 @@
 #include <math.h>
 #include <float.h>
 #include <string.h>
+#include "access/genam.h"
+#include "access/stratnum.h"
 #include "access/brin_tuple.h"
 #include "utils/datum.h"
 #include "gserialized_gist.h"
 
-#define INCLUSION_UNION				0
+#define	INCLUSION_MAX_PROCNUMS	        4	/* maximum support procs we need */
+#define	PROCNUM_BASE	               11
+
+#define INCLUSION_UNION			0
 #define INCLUSION_UNMERGEABLE		1
 #define INCLUSION_CONTAINS_EMPTY	2
+#define PROCNUM_EMPTY                  14      /* optional support function to manage empty elements */
 
+typedef struct InclusionOpaque
+{
+	FmgrInfo	extra_procinfos[INCLUSION_MAX_PROCNUMS];
+	bool		extra_proc_missing[INCLUSION_MAX_PROCNUMS];
+	Oid		cached_subtype;
+	FmgrInfo	strategy_procinfos[RTMaxStrategyNumber];
+} InclusionOpaque;