Make cast function from circle to polygon error safe

Previously, the function casting type circle to type polygon could not
be made error safe, because it is an SQL language function.

This refactors it as a C/internal function, by sharing code with the
C/internal function that the SQL function previously wrapped, and soft
error support is added.

Author: jian he <jian.universality@gmail.com>
Reviewed-by: Amul Sul <sulamul@gmail.com>
Reviewed-by: Corey Huinker <corey.huinker@gmail.com>
Discussion: Discussion: https://www.postgresql.org/message-id/flat/CADkLM%3Dfv1JfY4Ufa-jcwwNbjQixNViskQ8jZu3Tz_p656i_4hQ%40mail.gmail.com

diff --git a/src/backend/catalog/system_functions.sql b/src/backend/catalog/system_functions.sql
index 1c5b6d6df05dff4406450777a74d84938567ba43..c3c0a6e84ed7c3c87921d2047ee994d7063f0425 100644 (file)
--- a/src/backend/catalog/system_functions.sql
+++ b/src/backend/catalog/system_functions.sql
@@ -99,12 +99,6 @@ CREATE OR REPLACE FUNCTION path_contain_pt(path, point)
  IMMUTABLE PARALLEL SAFE STRICT COST 1
 RETURN on_ppath($2, $1);
 
-CREATE OR REPLACE FUNCTION polygon(circle)
- RETURNS polygon
- LANGUAGE sql
- IMMUTABLE PARALLEL SAFE STRICT COST 1
-RETURN polygon(12, $1);
-
 CREATE OR REPLACE FUNCTION age(timestamptz)
  RETURNS interval
  LANGUAGE sql

diff --git a/src/backend/utils/adt/geo_ops.c b/src/backend/utils/adt/geo_ops.c
index cbc4621e9b20d397f7beadeda999bcf7a1a22df9..cc5ce013d0f0741aa0abff5cf34fdf685f898d2c 100644 (file)
--- a/src/backend/utils/adt/geo_ops.c
+++ b/src/backend/utils/adt/geo_ops.c
@@ -125,6 +125,7 @@ static float8 circle_ar(CIRCLE *circle);
 
 /* Routines for polygons */
 static void make_bound_box(POLYGON *poly);
+static POLYGON *circle_poly_internal(int32 npts, const CIRCLE *circle, FunctionCallInfo fcinfo);
 static void poly_to_circle(CIRCLE *result, POLYGON *poly, Node *escontext);
 static bool lseg_inside_poly(Point *a, Point *b, POLYGON *poly, int start);
 static bool poly_contain_poly(POLYGON *contains_poly, POLYGON *contained_poly);
@@ -5317,11 +5318,9 @@ fail:
 }
 
 
-Datum
-circle_poly(PG_FUNCTION_ARGS)
+static POLYGON *
+circle_poly_internal(int32 npts, const CIRCLE *circle, FunctionCallInfo fcinfo)
 {
-       int32           npts = PG_GETARG_INT32(0);
-       CIRCLE     *circle = PG_GETARG_CIRCLE_P(1);
        POLYGON    *poly;
        int                     base_size,
                                size;
@@ -5330,12 +5329,12 @@ circle_poly(PG_FUNCTION_ARGS)
        float8          anglestep;
 
        if (FPzero(circle->radius))
-               ereport(ERROR,
+               ereturn(fcinfo->context, NULL,
                                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                                 errmsg("cannot convert circle with radius zero to polygon")));
 
        if (npts < 2)
-               ereport(ERROR,
+               ereturn(fcinfo->context, NULL,
                                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                                 errmsg("must request at least 2 points")));
 
@@ -5344,7 +5343,7 @@ circle_poly(PG_FUNCTION_ARGS)
 
        /* Check for integer overflow */
        if (base_size / npts != sizeof(poly->p[0]) || size <= base_size)
-               ereport(ERROR,
+               ereturn(fcinfo->context, NULL,
                                (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
                                 errmsg("too many points requested")));
 
@@ -5356,17 +5355,51 @@ circle_poly(PG_FUNCTION_ARGS)
 
        for (i = 0; i < npts; i++)
        {
-               angle = float8_mul(anglestep, i);
+               float8          temp;
 
-               poly->p[i].x = float8_mi(circle->center.x,
-                                                                float8_mul(circle->radius, cos(angle)));
-               poly->p[i].y = float8_pl(circle->center.y,
-                                                                float8_mul(circle->radius, sin(angle)));
+               angle = float8_mul_safe(anglestep, i, fcinfo->context);
+               if (SOFT_ERROR_OCCURRED(fcinfo->context))
+                       return NULL;
+
+               temp = float8_mul_safe(circle->radius, cos(angle), fcinfo->context);
+               if (SOFT_ERROR_OCCURRED(fcinfo->context))
+                       return NULL;
+
+               poly->p[i].x = float8_mi_safe(circle->center.x, temp, fcinfo->context);
+               if (SOFT_ERROR_OCCURRED(fcinfo->context))
+                       return NULL;
+
+               temp = float8_mul_safe(circle->radius, sin(angle), fcinfo->context);
+               if (SOFT_ERROR_OCCURRED(fcinfo->context))
+                       return NULL;
+
+               poly->p[i].y = float8_pl_safe(circle->center.y, temp, fcinfo->context);
+               if (SOFT_ERROR_OCCURRED(fcinfo->context))
+                       return NULL;
        }
 
        make_bound_box(poly);
 
-       PG_RETURN_POLYGON_P(poly);
+       return poly;
+}
+
+Datum
+circle_poly(PG_FUNCTION_ARGS)
+{
+       int32           npts = PG_GETARG_INT32(0);
+       CIRCLE     *circle = PG_GETARG_CIRCLE_P(1);
+
+       PG_RETURN_POLYGON_P(circle_poly_internal(npts, circle, fcinfo));
+}
+
+/* convert circle to 12-vertex polygon */
+Datum
+circle_to_poly(PG_FUNCTION_ARGS)
+{
+       int32           npts = 12;
+       CIRCLE     *circle = PG_GETARG_CIRCLE_P(0);
+
+       PG_RETURN_POLYGON_P(circle_poly_internal(npts, circle, fcinfo));
 }
 
 /*

diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 4d9ccc5789c4d2825bdd0062d2e19b483c628a91..81b2bf39b3f80b1a54f6419948e0f811dd3b5847 100644 (file)
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -57,6 +57,6 @@
  */
 
 /*                                                     yyyymmddN */
-#define CATALOG_VERSION_NO     202603241
+#define CATALOG_VERSION_NO     202603301
 
 #endif

diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 0118e970ddafebfdccb6edec10666c9181206996..3579cec5744cba63b140ba4af80c331c4df2ffd1 100644 (file)
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -3390,8 +3390,8 @@
   proname => 'center', prorettype => 'point', proargtypes => 'circle',
   prosrc => 'circle_center' },
 { oid => '1544', descr => 'convert circle to 12-vertex polygon',
-  proname => 'polygon', prolang => 'sql', prorettype => 'polygon',
-  proargtypes => 'circle', prosrc => 'see system_functions.sql' },
+  proname => 'polygon', prorettype => 'polygon',
+  proargtypes => 'circle', prosrc => 'circle_to_poly' },
 { oid => '1545', descr => 'number of points',
   proname => 'npoints', prorettype => 'int4', proargtypes => 'path',
   prosrc => 'path_npoints' },