[PATCH] PR21482: long paths on Windows

[Robinson, Paul]

> -----Original Message-----
> From: Aaron Ballman [mailto:aaron.ballman at gmail.com]
> Sent: Monday, November 10, 2014 2:47 PM
> To: Rafael Espíndola
> Cc: Robinson, Paul; llvm-commits at cs.uiuc.edu
> Subject: Re: [PATCH] PR21482: long paths on Windows
> 
> On Mon, Nov 10, 2014 at 5:43 PM, Rafael Espíndola
> <rafael.espindola at gmail.com> wrote:
> > static std::error_code widen_path(const Twine &Path8,
> >
> > widenPath
> >
> > Using  '\\?\'  also disables using / as a path separator, no? Don't we
> > have to check/assert that there is no / in Path8?

So for paranoia I should translate all / to \ in the widened path?  I don't
see any existing utility to do that, but easy enough to invent one.

> >
> > +  size_t NLevels = ((248 - TmpLen) / 10) + 1;
> > +  const char *OneDir = "\\123456789";
> >
> > Use the size of OneDir instead of hard codding the 10.
> >
> > Aaron, this only uses '\\?\' to create long paths. They can still be
> > accessed by regular tools by changing the current directory, no?
> 
> Yes, relative paths aren't an issue. Just tools using absolute paths
> that don't support the extended path namespace (which can happen if
> the app assumes MAX_PATH is actually the max).
> 
> ~Aaron
> 
> >
> > On 10 November 2014 16:01, Robinson, Paul
> > <Paul_Robinson at playstation.sony.com> wrote:
> >> Support directory names longer than 248 characters on Windows.
> >>
> >> The normal Windows path limit is 260 characters; the limit for
> directory
> >> names is 248, to leave room for an 8.3 filename at the end.  Adding the
> >> '\\?\' prefix greatly expands these limits.  Intercept path names that
> >> we are about to pass to the Windows APIs and add the prefix if
> necessary.
> >>
> >> Also correct the comment about the state of the temporary directory
> used
> >> by the Support unittests.
> >> --paulr
> >>
> >>
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