[PATCH] PR21482: long paths on Windows

[Robinson, Paul]

> -----Original Message-----
> From: Michael Spencer [mailto:bigcheesegs at gmail.com]
> Sent: Tuesday, November 11, 2014 12:36 PM
> To: Robinson, Paul
> Cc: Aaron Ballman; Rafael Espíndola; llvm-commits at cs.uiuc.edu
> Subject: Re: [PATCH] PR21482: long paths on Windows
> 
> On Tue, Nov 11, 2014 at 7:27 AM, Robinson, Paul
> <Paul_Robinson at playstation.sony.com> wrote:
> > New patch attached.
> >
> > I ended up not using make_absolute because it caused more string
> copying.
> > If there's some reason to consider it safer than current_path and doing
> > my own pasting, I can do that instead, but only if y'all think it has
> > actual value.
> >
> > This changed the specific error returned by another fs test, which
> > seems reasonable.
> > --paulr
> 
> This patch doesn't seem to be able to handle "..\foo". \\?\ disables
> expansion of . and ..

Feh.

I'm not able to find a pre-Windows8 API that does this canonicalization
on sufficiently long path names.  If anybody else has one I'm all ears.
Otherwise I guess I have to write my own.
--paulr

> 
> Other than that it looks fine.
> 
> - Michael Spencer
> 
> >
> >> -----Original Message-----
> >> From: Michael Spencer [mailto:bigcheesegs at gmail.com]
> >> Sent: Monday, November 10, 2014 4:04 PM
> >> To: Robinson, Paul
> >> Cc: Aaron Ballman; Rafael Espíndola; llvm-commits at cs.uiuc.edu
> >> Subject: Re: [PATCH] PR21482: long paths on Windows
> >>
> >> On Mon, Nov 10, 2014 at 3:05 PM, Robinson, Paul
> >> <Paul_Robinson at playstation.sony.com> wrote:
> >> >> -----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.
> >>
> >> sys::path::native(). in Path.h
> >>
> >> We also have make_absolute in FileSystem.h
> >>
> >> - Michael Spencer
> >>
> >> >
> >> >> >
> >> >> > +  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
> >> >> >>
> >> >> >>
> >> >> >> _______________________________________________
> >> >> >> llvm-commits mailing list
> >> >> >> llvm-commits at cs.uiuc.edu
> >> >> >> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> >> >> >>
> >> >
> >> > _______________________________________________
> >> > llvm-commits mailing list
> >> > llvm-commits at cs.uiuc.edu
> >> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits