Wrap ICU ucol_open().

Hide details of supporting older ICU versions in a wrapper
function. The current code only needs to handle
icu_set_collation_attributes(), but a subsequent commit will add
additional version-specific code.

Discussion: https://postgr.es/m/7ee414ad-deb5-1144-8a0e-b34ae3b71cd5@enterprisedb.com
Reviewed-by: Peter Eisentraut

diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index c3ede994be54f13774a45de4563b6135074c446a..dd0786dff52186ffcbbe23fec030def06d2613f8 100644 (file)
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -140,6 +140,7 @@ static char *IsoLocaleName(const char *);
  */
 static UConverter *icu_converter = NULL;
 
+static UCollator *pg_ucol_open(const char *loc_str);
 static void init_icu_converter(void);
 static size_t uchar_length(UConverter *converter,
                           const char *str, int32_t len);
@@ -1430,17 +1431,8 @@ make_icu_collator(const char *iculocstr,
 {
 #ifdef USE_ICU
    UCollator  *collator;
-   UErrorCode  status;
 
-   status = U_ZERO_ERROR;
-   collator = ucol_open(iculocstr, &status);
-   if (U_FAILURE(status))
-       ereport(ERROR,
-               (errmsg("could not open collator for locale \"%s\": %s",
-                       iculocstr, u_errorName(status))));
-
-   if (U_ICU_VERSION_MAJOR_NUM < 54)
-       icu_set_collation_attributes(collator, iculocstr);
+   collator = pg_ucol_open(iculocstr);
 
    /*
     * If rules are specified, we extract the rules of the standard collation,
@@ -1451,6 +1443,7 @@ make_icu_collator(const char *iculocstr,
        const UChar *default_rules;
        UChar      *agg_rules;
        UChar      *my_rules;
+       UErrorCode  status;
        int32_t     length;
 
        default_rules = ucol_getRules(collator, &length);
@@ -1722,16 +1715,11 @@ get_collation_actual_version(char collprovider, const char *collcollate)
    if (collprovider == COLLPROVIDER_ICU)
    {
        UCollator  *collator;
-       UErrorCode  status;
        UVersionInfo versioninfo;
        char        buf[U_MAX_VERSION_STRING_LENGTH];
 
-       status = U_ZERO_ERROR;
-       collator = ucol_open(collcollate, &status);
-       if (U_FAILURE(status))
-           ereport(ERROR,
-                   (errmsg("could not open collator for locale \"%s\": %s",
-                           collcollate, u_errorName(status))));
+       collator = pg_ucol_open(collcollate);
+
        ucol_getVersion(collator, versioninfo);
        ucol_close(collator);
 
@@ -2505,6 +2493,43 @@ pg_strnxfrm_prefix(char *dest, size_t destsize, const char *src,
 }
 
 #ifdef USE_ICU
+
+/*
+ * Wrapper around ucol_open() to handle API differences for older ICU
+ * versions.
+ */
+static UCollator *
+pg_ucol_open(const char *loc_str)
+{
+   UCollator  *collator;
+   UErrorCode  status;
+
+   /*
+    * Must never open default collator, because it depends on the environment
+    * and may change at any time.
+    *
+    * NB: the default collator is not the same as the collator for the root
+    * locale. The root locale may be specified as the empty string, "und", or
+    * "root". The default collator is opened by passing NULL to ucol_open().
+    */
+   if (loc_str == NULL)
+       ereport(ERROR,
+               (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+                errmsg("opening default collator is not supported")));
+
+   status = U_ZERO_ERROR;
+   collator = ucol_open(loc_str, &status);
+   if (U_FAILURE(status))
+       ereport(ERROR,
+               (errmsg("could not open collator for locale \"%s\": %s",
+                       loc_str, u_errorName(status))));
+
+   if (U_ICU_VERSION_MAJOR_NUM < 54)
+       icu_set_collation_attributes(collator, loc_str);
+
+   return collator;
+}
+
 static void
 init_icu_converter(void)
 {
@@ -2771,17 +2796,8 @@ check_icu_locale(const char *icu_locale)
 {
 #ifdef USE_ICU
    UCollator  *collator;
-   UErrorCode  status;
-
-   status = U_ZERO_ERROR;
-   collator = ucol_open(icu_locale, &status);
-   if (U_FAILURE(status))
-       ereport(ERROR,
-               (errmsg("could not open collator for locale \"%s\": %s",
-                       icu_locale, u_errorName(status))));
 
-   if (U_ICU_VERSION_MAJOR_NUM < 54)
-       icu_set_collation_attributes(collator, icu_locale);
+   collator = pg_ucol_open(icu_locale);
    ucol_close(collator);
 #else
    ereport(ERROR,