[PATCH] PR21482: long paths on Windows

[Michael Spencer]

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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