Refactor pg_set_regex_collation() for clarity.

Discussion: https://postgr.es/m/63409030-2746-462e-beac-759bd43032ce@proxel.se
Reviewed-by: Andreas Karlsson

diff --git a/src/backend/regex/regc_pg_locale.c b/src/backend/regex/regc_pg_locale.c
index 85f3238eb071a379c33d4efe9e533f756160e554..9d98d10a285098eae05b3054eb83b2cd4e517ad7 100644 (file)
--- a/src/backend/regex/regc_pg_locale.c
+++ b/src/backend/regex/regc_pg_locale.c
@@ -261,29 +261,33 @@ pg_set_regex_collation(Oid collation)
                                        (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                                         errmsg("nondeterministic collations are not supported for regular expressions")));
 
+               if (pg_regex_locale && pg_regex_locale->provider == COLLPROVIDER_BUILTIN)
+               {
+                       Assert(GetDatabaseEncoding() == PG_UTF8);
+                       pg_regex_strategy = PG_REGEX_BUILTIN;
+               }
 #ifdef USE_ICU
-               if (pg_regex_locale && pg_regex_locale->provider == COLLPROVIDER_ICU)
+               else if (pg_regex_locale && pg_regex_locale->provider == COLLPROVIDER_ICU)
+               {
                        pg_regex_strategy = PG_REGEX_LOCALE_ICU;
-               else
+               }
 #endif
-               if (GetDatabaseEncoding() == PG_UTF8)
+               else
                {
-                       if (pg_regex_locale)
+                       if (GetDatabaseEncoding() == PG_UTF8)
                        {
-                               if (pg_regex_locale->provider == COLLPROVIDER_BUILTIN)
-                                       pg_regex_strategy = PG_REGEX_BUILTIN;
-                               else
+                               if (pg_regex_locale)
                                        pg_regex_strategy = PG_REGEX_LOCALE_WIDE_L;
+                               else
+                                       pg_regex_strategy = PG_REGEX_LOCALE_WIDE;
                        }
                        else
-                               pg_regex_strategy = PG_REGEX_LOCALE_WIDE;
-               }
-               else
-               {
-                       if (pg_regex_locale)
-                               pg_regex_strategy = PG_REGEX_LOCALE_1BYTE_L;
-                       else
-                               pg_regex_strategy = PG_REGEX_LOCALE_1BYTE;
+                       {
+                               if (pg_regex_locale)
+                                       pg_regex_strategy = PG_REGEX_LOCALE_1BYTE_L;
+                               else
+                                       pg_regex_strategy = PG_REGEX_LOCALE_1BYTE;
+                       }
                }
 
                pg_regex_collation = collation;