kicad-developers team mailing list archive

[Wayne Stambaugh <stambaughw@xxxxxxxxx>]

On 2/28/2017 4:08 PM, Cirilo Bernardo wrote:
> On Wed, Mar 1, 2017 at 12:18 AM, Wayne Stambaugh <stambaughw@xxxxxxxxx> wrote:
>> On 2/27/2017 8:57 PM, Cirilo Bernardo wrote:
>>> On Tue, Feb 28, 2017 at 1:07 AM, Wayne Stambaugh <stambaughw@xxxxxxxxx> wrote:
>>>> On 2/26/2017 4:04 PM, Cirilo Bernardo wrote:
>>>>> There is one other way which I found after much digging
>>>>> and it involves a GCC extension. Since we use GCC on
>>>>> Windows this might be acceptable:
>>>>>
>>>>> a. create a derived class of std::ifstream/ofstream. On
>>>>> Windows the derived class will be used while on other
>>>>> OS it will simply be typedef to std::ifstream/ofstream
>>>>
>>>> This seems reasonable to me.
>>>>
>>>
>>>  I had a look at the GCC STL implementation and unfortunately
>>> is is impossible for me to implement (a) since I can't accomplish
>>> what I want by deriving std::ifstream/ofstream due to the access
>>> specifiers on the necessary member variables and the fact that
>>> the open() function is not declared virtual.
>>>
>>>>>
>>>>> b. overload open() to use the gcc extension like this:
>>>>> __gnu_cxx::stdio_filebuf buf( _wopen ( utf8_filename, _O_RDONLY ) );
>>>>> std::istream mystream ( &buf );
>>>>
>>>> If this is portable, than I'm file with this as well but on the surface
>>>> it looks gcc specific.  If that is the case, then I would rather got
>>>> with option a.
>>>>
>>>
>>> Even solution (a), which I now know is not possible, would have been
>>> a gcc-specific hack.
>>>
>>> The solution I'm working on at the moment requires the replacement of
>>>
>>> std::ifstream X;
>>> X.open( filename, ... );
>>> X.close();
>>>
>>> with
>>>
>>> OPEN_ISTREAM( X, filename );
>>> CLOSE_STREAM( X );
>>>
>>> On builds which are not MinGW the helper macros generate exactly
>>> the same code as before. On MinGW builds, the helper macros
>>> create an extra class which creates an i/ostream and cleans up
>>> where required on destruction. The only caveat in MinGW is that
>>> rather than an explicit ifstream/ofstream the object which is actually
>>> created is an istream/ostream, but this is not a difficult thing to handle.
>>> The good thing about preserving the use of std::iostream is that I
>>> can eliminate some of the locale switching code and simply use
>>> imbue() on the open streams to avoid unintended effects on other
>>> code.
>>
>> I'm not sure at this point why you wouldn't just use FILE_LINE_READER or
>> wxFFileInputStream which we know both work with utf8 file names.  It
>> seems a bit like reinventing the wheel.  I realize this doesn't solve
>> the oce issue but for KiCad's file parsing usage, I think it makes more
>> sense.  I'm not saying your solution isn't valid, it just seems like
>> unnecessary work.
>>
> 
> The std::stream objects have modular localization support which we need
> to force "C" locale for VRML and IDF output and of course the '<<' and '>>'
> stream operators. The code which needs to be reworked already uses
> streams, so this gcc-specific hack is the easiest way to fix the UTF8
> issue within KiCad (but of course not for external libs like OCE). This
> change is already a 1600+ lines patch + a few hundred lines for the
> additional files. Changing the modules to use FILE_LINE_READER
> means that we need to perform app-wide locale changes just to input/
> output a file since wx does not implement stream locale settings, plus
> I would need to change the many hundreds (possibly a few thousand)
> lines with streaming ops.

Please fix it this way.  I'm not sure I really like it but it sounds
like you've programmed yourself into a hole.  I try to avoid the stream
<< and >> operators just because of these issues.

> 
> 
>>>
>>> I still need to look into how the issue with OCE can be tackled then
>>> see if the devs are willing to make changes. This UTF8 filename
>>> problem has come up on the MinGW list many times and a number
>>> of users had suggested various changes over the years but this
>>> really seems to be a "won't fix" issue.
>>
>> I spent about an hour the other day looking through the opencascade
>> documentation and the oce source code and I couldn't find the code for
>> the file parsers.  Could you point me to the source file where the base
>> file parser code lives so I can take a look at it.  We can open utf-8
>> file names just fine in mingw.  I don't understand why oce cannot open
>> them on mingw as well.
>>
> 
> The OpenCascade source is easily grepped for FILE, fstream and so on.
> The vast bulk of OpenCascade modules make use of defined classes to
> handle I/O in various 'FSD' files, to to find all relevant files:
> 
> find . -name "*FSD*"
> 
> You can see the use of "_wopen" in those classes to open filestreams;
> this is a Microsoft extension which is available in MSVC but not in
> MinGW since the STL is different.  Other directories of interest are:
> 
> src/STEPControl
> src/IGESControl
> src/STEPCAFControl
> src/IGESCAFControl

Thanks for the info.  I'll take a look at it when I can.

> 
> - Cirilo
> 
> 
>>>
>>> If we use anything other than gcc on Windows we can tackle the
>>> other issues then.
>>>
>>> - Cirilo
>>>
>>>>>
>>>>> The destructor must contain code to delete buf since
>>>>> the istream will not delete it on destruction.
>>>>>
>>>>> If that would be acceptable I'll make some test
>>>>> programs and work on a patch set. This solution
>>>>> would also work on OCE and I can talk to the OCE
>>>>> patch team to see what they think of it.
>>>>>
>>>>> - Cirilo
>>>>>
>>>>>
>>>>> On Mon, Feb 27, 2017 at 4:54 AM, Wayne Stambaugh <stambaughw@xxxxxxxxx> wrote:
>>>>>> On 2/26/2017 1:50 AM, Cirilo Bernardo wrote:
>>>>>>> Hi folks,
>>>>>>>
>>>>>>>  This whole thing with UTF-8 filenames in Windows is a disaster.
>>>>>>> What I've found so far:
>>>>>>>
>>>>>>> 1. Regarding OCE: Since OCE 0.17 (OpenCascade 6.8) UTF8
>>>>>>> filenames have been supported when built with MSVC but
>>>>>>> obviously not with MinGW.
>>>>>>>
>>>>>>> 2. MinGW does not provide any means of transparently using
>>>>>>> UTF-8 filenames. All filenames within the STL *must* be
>>>>>>> char* and MinGW *will* simply pass these on to OpenFileA()
>>>>>>> on Windows resulting in UTF-8 being interpreted as ASCII-8
>>>>>>> (and who uses ASCII-8 filenames anyway).
>>>>>>>
>>>>>>> So everything hinges on (2). If OCE uses std::stream then
>>>>>>> fixing all issues under Windows is a lost cause. If OCE
>>>>>>> simply plays with FILE* then it can be patched to work
>>>>>>> in MinGW by invoking _wfopen() rather than fopen().
>>>>>>>
>>>>>>> As for kicad itself, std::stream is used in:
>>>>>>> (a) VRML export
>>>>>>> (b) IDF static library
>>>>>>> (c) Scenegraph dynamic library for 3D plugins
>>>>>>>
>>>>>>> 2 paths forward come to mind and both will involve some work:
>>>>>>>
>>>>>>> (1) Move to the MSVC build system on Windows: this makes
>>>>>>> it possible for us to use Microsoft extensions to STL to deal
>>>>>>> with non-ASCII filename issues. There is no need to dig into
>>>>>>> the OCE code since we know it will work correctly when built
>>>>>>> with MSVC.
>>>>>>
>>>>>> This is not an acceptable solution.  It's not portable and would limit
>>>>>> windows builds to using msvc.
>>>>>>
>>>>>>>
>>>>>>> (2) Rework kicad code to play with FILE* (or wxFileStream)
>>>>>>> rather than std::ifstream/ofstream. Although this will fix the
>>>>>>> issues which are confined to kicad's source, it does nothing
>>>>>>> to address the OCE issue. Whether or not OCE in MinGW
>>>>>>> is a lost cause remains to be seen.
>>>>>>
>>>>>> FILE* is how we pretty much do it everywhere else in KiCad with good
>>>>>> results so I don't see any reason not to do it this way with the model
>>>>>> parser code.  At least it's portable across all build platforms.
>>>>>> Doesn't oce have a reader function that takes a FILE *?
>>>>>>
>>>>>>>
>>>>>>> One other possibility (but one which I hadn't looked into)
>>>>>>> is to see if the STL implementation within MinGW uses the
>>>>>>> MinGW-CRT. If it does then it may be possible to fix
>>>>>>> everything by ensuring that the MinGW-CRT converts all
>>>>>>> filenames to UTF16 and opens a file using FileOpenW().
>>>>>>> In all cases this is not a pleasant task.
>>>>>>>
>>>>>>> Any comments/suggestions?
>>>>>>>
>>>>>>> - Cirilo
>>>>>>>
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>>>>>>>
>>>>>>
>>>>>>
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