making |nsWindowAPI| available 'globally'

While trying to fix bug 162361 
(http://bugzilla.mozilla.org/show_bug.cgi?id=162361), I came up with the 
following idea.

Win32 has (rather annoying) two-tiered APIs, 'A' APIs and 'W' APIs. The 
former is available on both Win9x/ME and Win2k/XP while the latter is 
only available on Win2k/XP. The latter is also "emulated" on Win9x/ME by 
MSLU (Microsoft Layer for Unicode). MS's recommended way of building a 
single 'Unicode' binary is to use 'W' APIs (use 'T' APIs that are 
macro-expanded to 'W" API calls at the compile time when 'UNICODE'? is 
defined).

However, we do not use this approach. I guess the decision not to take 
that path was made  because the DLL for MSLU can't be shipped with 
Mozilla. Although it's very likely to be present on 99% of Win9x/ME 
boxes (it comes with MS IE), it would certainly be ironic to make MS IE 
a requirement for Mozilla on Win9x/ME.

Anyway, what Mozilla does is to do what MSLU does on its own [1]. It 
involves detecting the OS and setting function pointers to either 'A' or 
'W' API wrappers (with string parameter conversion between 'A'NSI and 
Unicode) depending on the OS. Most of these is localized in 
widget/src/windows (viewer for test also need), but xpcom/io (for file 
i/o) and intl/locale/src/windows need to behave differently depending on 
the OS. My tentative patch for bug 162361 has some overlap with what's 
done in widget/src/windows. Besides, the OS detection code is duplicated 
in two files intl/locale/src/windows.

To avoid the following pattern as much as possible and to avoid the 
duplication of code,

   if (isNT) { call W API}
   else { call A API }

I guess we have to move a part of |nsIToolkit| implementation (wrapper 
for Win32 APIs) in widget/src/windows/nsToolkit.h Perhaps, we can make a 
'convenience class' |nsWindowsAPI| with static member variables that are 
function pointers to Win32 API wrappers. These member variables have to 
be init'd once at the xpcom startup to either A API wrappers or W API 
wrappers. In addition, we need a member function |IsNT()| to be used for 
a few cases where we can't help using

if (isNT) { call W API}
   else { call A API }


Any thought or opinion is welcome. Incidentally, this will finish up 
Mozilla's transition to 'Unicode' on Win2k/XP and take care of a host of 
bugs (see int'l release notes for 1.4)

Jungshik


  [1]
http://lxr.mozilla.org/seamonkey/source/widget/src/windows/nsWindowAPI.h
http://lxr.mozilla.org/seamonkey/source/widget/src/windows/nsToolkit.cpp
http://lxr.mozilla.org/seamonkey/source/widget/src/windows/nsToolkit.h