[Notion-devel] 'use_mb': any reason to have this set to 'false' ever?

[Arnout E. <no...@bz...>]

Hello,

The global field 'use_mb' determines whether to use multibyte-aware functions[1].

It seems this field is actually usually set to 'true', except when the locale 
is unless the locale is 'C', 'POSIX', Statefull (whatever that means - anyway 
we don't support it) or erronous.

This interpretation of 'use_mb' seems to be a little too strict: right now 
use_mb is also being used to decide which functions to use when reading 
external strings, like between 'XTextPropertyToStringList' and 
'XmbTextPropertyToTextList' in xwindow_get_text_property. This means 
xwindow_get_text_property will not be able to read UTF-8 text properties
when using the 'C' or 'POSIX' locales, even though XmbTextPropertyToTextList 
can and will convert them to the current locale encoding (stripping any mb
characters).

I think it makes sense to change the meaning of 'use_mb' to mean 'use 
multibyte-aware functions when handling strings that are in the current
locale encoding (such as all our internal strings). For external strings,
we should always use multibyte-aware functions to convert the external strings
to the internal locale-dependent encoding.

As for a specific use case, the current use of use_mb causes the (UTF-8 EWMH)
_NET_WM_NAME property to be ignored when using a 'C' or 'POSIX' locale. This
is especially problematic when there is no useful XA_WM_NAME to fall back on,
which is ugly anyway but is reported to happen sometimes.

Any objections to changing the semantics of 'use_mb' in this way?


Kind regards,

Arnout

[1]: for example for deciding between '!iswprint(str_wchar_at(buf, 32))' and 
'iscntrl(*buf)' or deciding between 'XmbTextListToTextProperty' and 
'XStringListToTextProperty'.