_dbus_string_tolower_ascii() was [Commits to core *must* have reviewers]

[Thiago Macieira]

Em Quarta-feira 24 Fevereiro 2010, às 10:04:37, Ralf Habacker escreveu:
> Colin Walters schrieb:
> > Hi Ralf,
> > 
> > On Mon, Feb 22, 2010 at 5:24 AM, Ralf Habacker <ralf.habacker at freenet.de> 
wrote:
> >> Appended is an updated patch.
> > 
> > Thanks!  There are still some issues.
> > 
> > First, and this is really important, it's wrong to use
> > DBUS_CONST_STRING_PREAMBLE here, because we're actually modifying the
> > string.  DBusString has this useful feature where you can say
> > 
> > DBusString foo;
> > 
> > _dbus_string_init_const (&foo, "this string is not copied");
> > 
> > And not have to handle OOM.  This state is reflected in the ->constant
> > member.  If we later call
> > 
> > _dbus_string_tolower_ascii (&foo, 0, 5);
> > 
> > We'd actually be overwriting static memory, which is not good.  We
> > either need to use _DBUS_STRING_PREAMBLE which asserts
> > !string->constant, i.e. make it an error to use with constant data, or
> > we could check ->constant, and if so duplicate the string (this
> > implies we need OOM handling, so the function should return a
> > boolean).  If it's not constant, modify in place.
> 
> thanks for this pointer.
> 
> > The second thing is that it's still using islower/toupper, which is
> > wrong.  It's more correct since we know the string is ASCII to just
> > say:  Otherwise the function is going to have variable behavior for
> > say the session bus when someone logs in in a non-ASCII locale.
> > 
> > if (*s >= 'A' && *s <= 'Z')
> > 
> >   *s += 32;
> 
> or probably better
>        *s += 'a' - 'A';
> 

Or:
	*s |= 0x20;

-- 
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
  Senior Product Manager - Nokia, Qt Development Frameworks
      PGP/GPG: 0x6EF45358; fingerprint:
      E067 918B B660 DBD1 105C  966C 33F5 F005 6EF4 5358
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