[PATCHES] Fix for 8.3 MSVC locale (Was [HACKERS] NLS on MSVC strikes back!)

[Gevik Babakhani]

Hereby a patch that fixes NLS support on PG 8.3 compiled with MSVC.

There problem:

NLS support does not work on PG 8.3 compiled with MSVC. 
I encountered this bug when I was trying to show localized months and days
using TO_CHAR.

The main reason for this problem is because Gettext on Windows does not
respond to LC_MESSAGES environment variable. Changing this variable should
trigger Gettext to load a different messages catalog which unfortunately
does not work on Windows. Gettext uses the locale of the current thread in
execution to determine which message catalog should be loaded.
 
This is all discussed in:
http://archives.postgresql.org/pgsql-hackers/2008-02/msg00485.php

How it is fixed:

Changing the LC_MESSAGES is done in pg_locale.c::pg_perm_setlocale(int
category, const char *locale).
In order to force Gettext to load a messages catalog we have to call
WIN32API::SetThreadLocale(unsigned long locale_id)

(You probably see it coming)
Our input parameter for locale in pg_perm_setlocale is a string and there is
no unified way in Windows to translate a locale string to a locale_id for
SetThreadLocale to use. Therefore we will use a static table of values to
anticipate the locale name:

pg_win32_locale_database::{0x041b,{"sk","sk-SK","sk_SK","Slovak_Slovakia"}} 

Given any of "sk","sk-SK","sk_SK".... the 0x041b is returned for
SetThreadLocale as input parameter.

(We are not quite done yet)
Gettext, internally uses a hack to force itself to reload. This hidden
feature is also explained in GetText docs. By incrementing a Gettext
internal variable (_nl_msg_cat_cntr) we force Gettext to reload on the next
LC_MESSAGES->MSGID query.

Tests:

- Tested on Win XP MSVC (VC++ 8.0)
- Just a routine "make check" test on my Linux box
- MINGW is not tested. (I do not have the installation)

Fix notes:

- Gettext behaves oddly when the env. variable LANGUAGE is set before
starting PG
- The locale names in the static table are case sensitive. 'nl_NL' !=
'NL_NL'
- At this moment I only have included locale names we actually support in PG
installation.
- Where are the JP locale .po and .mo files? These are not in sources!
- Even though there are 20+ locales in PG installation, does not mean those
are complete. Try TMMonth,TMDay on "nl_NL". You will get English names :)
(My fault, hee hee,  I haven't completed nl.po translations yet.)

TODO:

- Provide/complete the day and month names for all supported locales.
- Create docs for supported locale names on Windows. (Values of the static
table)

Regards,
Gevik Babakhani
------------------------------------------------
PostgreSQL NL       http://www.postgresql.nl
TrueSoftware BV     http://www.truesoftware.nl
------------------------------------------------

1.pg_locale.c.patch
Description: Binary data

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Warning: Console code page (437) differs from Windows code page (1252)
         8-bit characters might not work correctly. See psql reference
         page "Notes for Windows users" for details.

Gevik=# set lc_messages to 'sv_SE';
SET
Gevik=# select to_char((current_date + s.a),'TMDay TMMonth YYYY') as dates from 
generate_series(0,6) as s(a);
         dates
-----------------------
 Torsdag Februari 2008
 Fredag Februari 2008
 L÷rdag Februari 2008
 S÷ndag Februari 2008
 Mσndag Februari 2008
 Tisdag Februari 2008
 Onsdag Februari 2008
(7 rows)

Gevik=# set lc_messages to 'de_DE';
SET
Gevik=# select to_char((current_date + s.a),'TMDay TMMonth YYYY') as dates from 
generate_series(0,6) as s(a);
          dates
-------------------------
 Donnerstag Februar 2008
 Freitag Februar 2008
 Samstag Februar 2008
 Sonntag Februar 2008
 Montag Februar 2008
 Dienstag Februar 2008
 Mittwoch Februar 2008
(7 rows)

Gevik=# set lc_messages to 'English_United_States';
SET
Gevik=# select to_char((current_date + s.a),'TMDay TMMonth YYYY') as dates from 
generate_series(0,6) as s(a);
          dates
-------------------------
 Thursday February 2008
 Friday February 2008
 Saturday February 2008
 Sunday February 2008
 Monday February 2008
 Tuesday February 2008
 Wednesday February 2008
(7 rows)

Gevik=# set lc_messages to 'tr-TR';
SET
Gevik=# select to_char((current_date + s.a),'TMDay TMMonth YYYY') as dates from 
generate_series(0,6) as s(a);
        dates
----------------------
 Persembe Subat 2008
 Cuma Subat 2008
 Cumartesi Subat 2008
 Pazar Subat 2008
 Pazartesi Subat 2008
 Sali Subat 2008
 ╟arsamba Subat 2008
(7 rows)

Gevik=# set lc_messages to 'fr';
SET
Gevik=# select to_char((current_date + s.a),'TMDay TMMonth YYYY') as dates from 
generate_series(0,6) as s(a);
         dates
-----------------------
 Jeudi FΘvrier 2008
 Vendredi FΘvrier 2008
 Samedi FΘvrier 2008
 Dimanche FΘvrier 2008
 Lundi FΘvrier 2008
 Mardi FΘvrier 2008
 Mercredi FΘvrier 2008
(7 rows)

Gevik=#




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