llvm dev - Sep 2011 - [LLVMdev] [cfe-dev] Unicode path handling on Windows

On Tue, Sep 20, 2011 at 4:15 PM, Nikola Smiljanic <popizdeh at gmail.com>
wrote:
> OK since this approach makes sense I'll shoot with my questions :)
> 1. Where should get_utf8_argv go and is the name of this function OK? Right
> now the function is inside llvm::sys::fs namespace because I need access to
> Windows.h, should I leave it there.
I don't think it belongs there as it has nothing to do with the file
system.  However, I'm not familiar enough to know of a better place
for it either.  Hopefully someone else can chime in with an idea.
> 2. get_utf8_argv allocates new char** representing utf8 argv, should I
> deallocate this inside driver.cpp, use std::vector<std::string>
instead or
> ignore the allocation completely?
Perhaps some SmallVectors would make sense here?  An inner one to hold
the arg data, and an outer one to hold the list of inner vectors.
Then you can do the cleanup within the call.
> 3. There is an #ifdef inside driver.cpp right now that I don't like.
> get_utf8_argv works for windows only, but I could change the function to
> accept argv and return it as vector of utf8 strings. It would convert char*
> to std::string on unix and use GetCommandLine + utf8 conversion on windows.
I have no concrete opinion one way or the other on this.
> 4. Should I wrap functions like ::fstat and ::close for consistency even
> though they don't work with paths?
I don't believe so.
> I'll fix everything that is formatting related. You're right,
current patch
> has Open only for windows but I'll add the other one as well.
Thanks for the help!

~Aaron

Here's a new patch that fixes all the issues mentioned before. Note that
this isn't final, I didn't want to replace all calls to ::stat so that
it's
easier to review.

I have only one more questions:

1. _wopen accepts _stat64i32 instead of stat structure. These two are
exactly the same, the only difference is that stat uses time_t
and _stat64i32 uses __time64_t (time_t is a typedef for __time64_t but this
depends on one more macro). I check to see that size of these two structures
is the same, but is there something more that I could do? I'd also like to
use some kind of static assert instead of runtime assert.

I've also noticed that function LowercaseString (the same applies to
UppercaseString) doesn't work with UTF8 input. It's calling isupper and
tolower and these functions can't handle UTF8. This should get a new issue
probably?

On Wed, Sep 21, 2011 at 1:41 AM, Aaron Ballman <aaron at
aaronballman.com>wrote:
> On Tue, Sep 20, 2011 at 4:15 PM, Nikola Smiljanic <popizdeh at
gmail.com>
> wrote:
> > OK since this approach makes sense I'll shoot with my questions :)
> > 1. Where should get_utf8_argv go and is the name of this function OK?
> Right
> > now the function is inside llvm::sys::fs namespace because I need
access
> to
> > Windows.h, should I leave it there.
>
> I don't think it belongs there as it has nothing to do with the file
> system.  However, I'm not familiar enough to know of a better place
> for it either.  Hopefully someone else can chime in with an idea.
>
> > 2. get_utf8_argv allocates new char** representing utf8 argv, should I
> > deallocate this inside driver.cpp, use std::vector<std::string>
instead
> or
> > ignore the allocation completely?
>
> Perhaps some SmallVectors would make sense here?  An inner one to hold
> the arg data, and an outer one to hold the list of inner vectors.
> Then you can do the cleanup within the call.
>
> > 3. There is an #ifdef inside driver.cpp right now that I don't
like.
> > get_utf8_argv works for windows only, but I could change the function
to
> > accept argv and return it as vector of utf8 strings. It would convert
> char*
> > to std::string on unix and use GetCommandLine + utf8 conversion on
> windows.
>
> I have no concrete opinion one way or the other on this.
>
> > 4. Should I wrap functions like ::fstat and ::close for consistency
even
> > though they don't work with paths?
>
> I don't believe so.
>
> > I'll fix everything that is formatting related. You're right,
current
> patch
> > has Open only for windows but I'll add the other one as well.
>
> Thanks for the help!
>
> ~Aaron
>
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I think the assert you have for _stat64i32 is fine. It is a constant expression
so should compile to nothing, and the chance of the definition changing is
pretty much zero.

LowercaseString appears to be used by ASM printers where the output is expected
to be ASCII, and then some WIN32-conditioned code in FileManager.cpp. I hate to
say it but you'll probably need to convert the UTF-8 paths to wide char,
lower case it using CharLowerBuffW (since it needs to match the casing rules
used by NTFS), and then convert back to UTF-8.

If you need to be pedantic about recognizing whether two paths are the same on
Windows you also need to call GetFullPathName in order to expand any 8.3 path
components, but this is an expensive function so I wouldn't do it unless
absolutely necessary.

There is also a call to _fullpath in there that needs to be changed to
_wfullpath.

The rest of the patch looks good.

On Sep 23, 2011, at 9:57 AM, Nikola Smiljanic wrote:
> Here's a new patch that fixes all the issues mentioned before. Note
that this isn't final, I didn't want to replace all calls to ::stat so
that it's easier to review.
> 
> I have only one more questions:
> 
> 1. _wopen accepts _stat64i32 instead of stat structure. These two are
exactly the same, the only difference is that stat uses time_t and _stat64i32
uses __time64_t (time_t is a typedef for __time64_t but this depends on one more
macro). I check to see that size of these two structures is the same, but is
there something more that I could do? I'd also like to use some kind of
static assert instead of runtime assert.
> 
> I've also noticed that function LowercaseString (the same applies to
UppercaseString) doesn't work with UTF8 input. It's calling isupper and
tolower and these functions can't handle UTF8. This should get a new issue
probably?
> 
> On Wed, Sep 21, 2011 at 1:41 AM, Aaron Ballman <aaron at
aaronballman.com> wrote:
> On Tue, Sep 20, 2011 at 4:15 PM, Nikola Smiljanic <popizdeh at
gmail.com> wrote:
> > OK since this approach makes sense I'll shoot with my questions :)
> > 1. Where should get_utf8_argv go and is the name of this function OK?
Right
> > now the function is inside llvm::sys::fs namespace because I need
access to
> > Windows.h, should I leave it there.
> 
> I don't think it belongs there as it has nothing to do with the file
> system.  However, I'm not familiar enough to know of a better place
> for it either.  Hopefully someone else can chime in with an idea.
> 
> > 2. get_utf8_argv allocates new char** representing utf8 argv, should I
> > deallocate this inside driver.cpp, use std::vector<std::string>
instead or
> > ignore the allocation completely?
> 
> Perhaps some SmallVectors would make sense here?  An inner one to hold
> the arg data, and an outer one to hold the list of inner vectors.
> Then you can do the cleanup within the call.
> 
> > 3. There is an #ifdef inside driver.cpp right now that I don't
like.
> > get_utf8_argv works for windows only, but I could change the function
to
> > accept argv and return it as vector of utf8 strings. It would convert
char*
> > to std::string on unix and use GetCommandLine + utf8 conversion on
windows.
> 
> I have no concrete opinion one way or the other on this.
> 
> > 4. Should I wrap functions like ::fstat and ::close for consistency
even
> > though they don't work with paths?
> 
> I don't believe so.
> 
> > I'll fix everything that is formatting related. You're right,
current patch
> > has Open only for windows but I'll add the other one as well.
> 
> Thanks for the help!
> 
> ~Aaron
> 
> <clang.patch><llvm.patch>
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