kicad-developers team mailing list archive

[Cirilo Bernardo <cirilo.bernardo@xxxxxxxxx>]

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.


>>
>> 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

- 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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