[PATCH] PR21482: long paths on Windows

[Robinson, Paul]

Thanks! r221841.
--paulr

> -----Original Message-----
> From: Michael Spencer [mailto:bigcheesegs at gmail.com]
> Sent: Wednesday, November 12, 2014 3:14 PM
> To: Robinson, Paul
> Cc: llvm-commits at cs.uiuc.edu; Aaron Ballman
> Subject: Re: [PATCH] PR21482: long paths on Windows
> 
> On Tue, Nov 11, 2014 at 8:52 PM, Robinson, Paul
> <Paul_Robinson at playstation.sony.com> wrote:
> > New patch attached.  Threw together . and .. elimination for Michael.
> > Extra test for Rafael, although I had to #include <windows.h> in the
> > unittest to make the necessary Windows APIs available. (Testing a
> relative
> > path requires setting the current directory to a known writeable place,
> > which means calling Windows APIs because path/fs don't have them.)  If
> it's
> > going overboard to do that, let me know and I can take the relative-path
> > test back out; but actually I think it's useful to have it.
> > --paulr
> 
> LGTM. Thanks for fixing this.
> 
> - Michael Spencer
> 
> >
> >> -----Original Message-----
> >> From: llvm-commits-bounces at cs.uiuc.edu [mailto:llvm-commits-
> >> bounces at cs.uiuc.edu] On Behalf Of Robinson, Paul
> >> Sent: Tuesday, November 11, 2014 2:13 PM
> >> To: Michael Spencer
> >> Cc: llvm-commits at cs.uiuc.edu; Aaron Ballman
> >> Subject: RE: [PATCH] PR21482: long paths on Windows
> >>
> >> > -----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
> >> > >> >> >>
> >> > >> >> >>
> >> > >> >> >> _______________________________________________
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> >> > >> >> >>
> >> > >> >
> >> > >> > _______________________________________________
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> >>
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