Make to_char()'s localized month/day names depend on LC_TIME, not LC_MESSAGES.

Euler Taveira de Oliveira

doc/src/sgml/config.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.178 2008/05/15 00:17:39 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.179 2008/05/19 18:08:15 tgl Exp $ -->
 
 <chapter Id="runtime-config">
   <title>Server Configuration</title>
@@ -4184,9 +4184,9 @@ SET XML OPTION { DOCUMENT | CONTENT };
       </indexterm>
       <listitem>
        <para>
-        Sets the locale to use for formatting date and time values.
-        (Currently, this setting does nothing, but it might in the
-        future.)  Acceptable values are system-dependent; see <xref
+        Sets the locale to use for formatting dates and times, for example
+        with the <function>to_char</function> family of
+        functions. Acceptable values are system-dependent; see <xref
         linkend="locale"> for more information.  If this variable is
         set to the empty string (which is the default) then the value
         is inherited from the execution environment of the server in a

doc/src/sgml/func.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.436 2008/05/04 23:19:23 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.437 2008/05/19 18:08:15 tgl Exp $ -->
 
  <chapter id="functions">
   <title>Functions and Operators</title>
@@ -5079,7 +5079,8 @@ SELECT SUBSTRING('XY1234Z', 'Y*?([0-9]{1,3})');
        </row>   
        <row>
         <entry><literal>TM</literal> prefix</entry>
-        <entry>translation mode (print localized day and month names based on <varname>lc_messages</>)</entry>
+        <entry>translation mode (print localized day and month names based on
+         <xref linkend="guc-lc-time">)</entry>
         <entry><literal>TMMonth</literal></entry>
        </row>       
        <row>

src/backend/utils/adt/oracle_compat.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	$PostgreSQL: pgsql/src/backend/utils/adt/oracle_compat.c,v 1.78 2008/03/25 22:42:44 tgl Exp $
+ *	$PostgreSQL: pgsql/src/backend/utils/adt/oracle_compat.c,v 1.79 2008/05/19 18:08:16 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -48,6 +48,8 @@
 #define USE_WIDE_UPPER_LOWER
 char	   *wstring_lower(char *str);
 char	   *wstring_upper(char *str);
+wchar_t	   *texttowcs(const text *txt);
+text	   *wcstotext(const wchar_t *str, int ncodes);
 #endif
 
 static text *dotrim(const char *string, int stringlen,
@@ -60,7 +62,7 @@ static text *dotrim(const char *string, int stringlen,
 /*
  * Convert a TEXT value into a palloc'd wchar string.
  */
-static wchar_t *
+wchar_t *
 texttowcs(const text *txt)
 {
 	int			nbytes = VARSIZE_ANY_EXHDR(txt);
@@ -112,7 +114,7 @@ texttowcs(const text *txt)
  * must be zero-terminated, but we also require the caller to pass the string
  * length, since it will know it anyway in current uses.
  */
-static text *
+text *
 wcstotext(const wchar_t *str, int ncodes)
 {
 	text	   *result;

src/backend/utils/adt/pg_locale.c

@@ -4,7 +4,7 @@
  *
  * Portions Copyright (c) 2002-2008, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/backend/utils/adt/pg_locale.c,v 1.40 2008/01/01 19:45:52 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/pg_locale.c,v 1.41 2008/05/19 18:08:16 tgl Exp $
  *
  *-----------------------------------------------------------------------
  */
@@ -48,20 +48,31 @@
 #include "postgres.h"
 
 #include <locale.h>
+#include <time.h>
 
 #include "catalog/pg_control.h"
+#include "utils/memutils.h"
 #include "utils/pg_locale.h"
 
 
-/* GUC storage area */
+#define		MAX_L10N_DATA		80
 
+
+/* GUC settings */
 char	   *locale_messages;
 char	   *locale_monetary;
 char	   *locale_numeric;
 char	   *locale_time;
 
+/* lc_time localization cache */
+char	   *localized_abbrev_days[7];
+char	   *localized_full_days[7];
+char	   *localized_abbrev_months[12];
+char	   *localized_full_months[12];
+
 /* indicates whether locale information cache is valid */
 static bool CurrentLocaleConvValid = false;
+static bool CurrentLCTimeValid = false;
 
 /* Environment variable storage area */
 
@@ -209,7 +220,10 @@ locale_xxx_assign(int category, const char *value, bool doit, GucSource source)
 
 	/* need to reload cache next time? */
 	if (doit && value != NULL)
+	{
 		CurrentLocaleConvValid = false;
+		CurrentLCTimeValid = false;
+	}
 
 	return value;
 }
@@ -424,3 +438,78 @@ PGLC_localeconv(void)
 	CurrentLocaleConvValid = true;
 	return &CurrentLocaleConv;
 }
+
+
+/*
+ * Update the lc_time localization cache variables if needed.
+ */
+void
+cache_locale_time(void)
+{
+	char		*save_lc_time;
+	time_t		timenow;
+	struct tm	*timeinfo;
+	char		buf[MAX_L10N_DATA];
+	char	   *ptr;
+	int			i;
+
+	/* did we do this already? */
+	if (CurrentLCTimeValid)
+		return;
+
+	elog(DEBUG3, "cache_locale_time() executed; locale: \"%s\"", locale_time);
+
+	/* set user's value of time locale */
+	save_lc_time = setlocale(LC_TIME, NULL);
+	if (save_lc_time)
+		save_lc_time = pstrdup(save_lc_time);
+
+	setlocale(LC_TIME, locale_time);
+
+	timenow = time(NULL);
+	timeinfo = localtime(&timenow);
+
+	/* localized days */
+	for (i = 0; i < 7; i++)
+	{
+		timeinfo->tm_wday = i;
+		strftime(buf, MAX_L10N_DATA, "%a", timeinfo);
+		ptr = MemoryContextStrdup(TopMemoryContext, buf);
+		if (localized_abbrev_days[i])
+			pfree(localized_abbrev_days[i]);
+		localized_abbrev_days[i] = ptr;
+
+		strftime(buf, MAX_L10N_DATA, "%A", timeinfo);
+		ptr = MemoryContextStrdup(TopMemoryContext, buf);
+		if (localized_full_days[i])
+			pfree(localized_full_days[i]);
+		localized_full_days[i] = ptr;
+	}
+
+	/* localized months */
+	for (i = 0; i < 12; i++)
+	{
+		timeinfo->tm_mon = i;
+		timeinfo->tm_mday = 1;	/* make sure we don't have invalid date */
+		strftime(buf, MAX_L10N_DATA, "%b", timeinfo);
+		ptr = MemoryContextStrdup(TopMemoryContext, buf);
+		if (localized_abbrev_months[i])
+			pfree(localized_abbrev_months[i]);
+		localized_abbrev_months[i] = ptr;
+
+		strftime(buf, MAX_L10N_DATA, "%B", timeinfo);
+		ptr = MemoryContextStrdup(TopMemoryContext, buf);
+		if (localized_full_months[i])
+			pfree(localized_full_months[i]);
+		localized_full_months[i] = ptr;
+	}
+
+	/* try to restore internal settings */
+	if (save_lc_time)
+	{
+		setlocale(LC_TIME, save_lc_time);
+		pfree(save_lc_time);
+	}
+
+	CurrentLCTimeValid = true;
+}

src/include/utils/pg_locale.h

@@ -2,7 +2,7 @@
  *
  * PostgreSQL locale utilities
  *
- * $PostgreSQL: pgsql/src/include/utils/pg_locale.h,v 1.24 2008/01/01 19:45:59 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/utils/pg_locale.h,v 1.25 2008/05/19 18:08:16 tgl Exp $
  *
  * Copyright (c) 2002-2008, PostgreSQL Global Development Group
  *
@@ -17,11 +17,19 @@
 #include "utils/guc.h"
 
 
+/* GUC settings */
 extern char *locale_messages;
 extern char *locale_monetary;
 extern char *locale_numeric;
 extern char *locale_time;
 
+/* lc_time localization cache */
+extern char *localized_abbrev_days[];
+extern char *localized_full_days[];
+extern char *localized_abbrev_months[];
+extern char *localized_full_months[];
+
+
 extern const char *locale_messages_assign(const char *value,
 					   bool doit, GucSource source);
 extern const char *locale_monetary_assign(const char *value,
@@ -42,4 +50,6 @@ extern bool lc_ctype_is_c(void);
  */
 extern struct lconv *PGLC_localeconv(void);
 
+extern void cache_locale_time(void);
+
 #endif   /* _PG_LOCALE_ */