Keep the usage of temporary EbmlDocVersion instances to init global semantic classes

[robUx4]

This will need an update on the libmatroska side before this is merged. After this MR it won't be possible to used temporary EbmlDocVersion anymore.
=> #228

We now have the EbmlId static+constepr and the Semantic and SemanticContext constexpr.

A test has been added to test the various issues found with EbmlDocVersion usage.

[mbunkus]

Thanks. Unfortunately I cannot really test it without a corresponding PR to libMatroska.

[robUx4]

Thanks. Unfortunately I cannot really test it without a corresponding PR to libMatroska.

It builds fine with Matroska-Org/libmatroska#168 for me

[mbunkus]

Ah right, I was only looking for a similar branch name. Sorry. Will test.

[mbunkus]

After pushing the latest merges this branch doesn't merge anymore. Can you please rebase? Thanks.

[robUx4]

Rebased this and Matroska-Org/libmatroska#168

[neheb]

@robUx4

../src/EbmlHead.cpp:33:65: error: invalid escape sequence '\0' in an unevaluated string literal [clang-diagnostic-error]
   33 | DEFINE_EBML_MASTER_ORPHAN(EbmlHead, 0x1A45DFA3, false, "EBMLHead\0ratamapaga", AllEbmlVersions)

[neheb]

yeah.

[1/3] Compiling C++ object libebml.so.6.0.0.p/src_EbmlHead.cpp.o
FAILED: libebml.so.6.0.0.p/src_EbmlHead.cpp.o 
clang++ -Ilibebml.so.6.0.0.p -I. -I.. -fvisibility=hidden -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -std=c++20 -O0 -g -fPIC '-DEBML_DLL_API=__attribute__((visibility("default")))' -MD -MQ libebml.so.6.0.0.p/src_EbmlHead.cpp.o -MF libebml.so.6.0.0.p/src_EbmlHead.cpp.o.d -o libebml.so.6.0.0.p/src_EbmlHead.cpp.o -c ../src/EbmlHead.cpp
../src/EbmlHead.cpp:33:65: error: invalid escape sequence '\0' in an unevaluated string literal
   33 | DEFINE_EBML_MASTER_ORPHAN(EbmlHead, 0x1A45DFA3, false, "EBMLHead\0ratamapaga", AllEbmlVersions)
      |                                                                 ^~
../ebml/EbmlElement.h:142:104: note: expanded from macro 'DEFINE_EBML_MASTER_ORPHAN'
  142 | #define DEFINE_EBML_MASTER_ORPHAN(x,id,infinite,name,versions)  DEFINE_xxx_MASTER_ORPHAN(x,id,infinite,name,versions,GetEbmlGlobal_Context)
      |                                                                                                        ^~~~
../ebml/EbmlElement.h:72:138: note: expanded from macro 'DEFINE_xxx_MASTER_ORPHAN'
   72 |     static constexpr const libebml::EbmlId Id_##x    {id}; static_assert(libebml::EbmlId::IsValid(Id_##x .GetValue()), "invalid id for " name ); \
      |                                                                                                                                          ^~~~
1 error generated.
[2/3] Compiling C++ object libebml.so.6.0.0.p/src_EbmlCrc32.cpp.o
FAILED: libebml.so.6.0.0.p/src_EbmlCrc32.cpp.o 
clang++ -Ilibebml.so.6.0.0.p -I. -I.. -fvisibility=hidden -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -std=c++20 -O0 -g -fPIC '-DEBML_DLL_API=__attribute__((visibility("default")))' -MD -MQ libebml.so.6.0.0.p/src_EbmlCrc32.cpp.o -MF libebml.so.6.0.0.p/src_EbmlCrc32.cpp.o.d -o libebml.so.6.0.0.p/src_EbmlCrc32.cpp.o -c ../src/EbmlCrc32.cpp
../src/EbmlCrc32.cpp:31:53: error: invalid escape sequence '\0' in an unevaluated string literal
   31 | DEFINE_EBML_CLASS_ORPHAN(EbmlCrc32, 0xBF, "EBMLCrc32\0ratamadabapa", AllEbmlVersions)
      |                                                     ^~
../ebml/EbmlElement.h:143:94: note: expanded from macro 'DEFINE_EBML_CLASS_ORPHAN'
  143 | #define DEFINE_EBML_CLASS_ORPHAN(x,id,name,versions)            DEFINE_xxx_CLASS_ORPHAN(x,id,name,versions,GetEbmlGlobal_Context)
      |                                                                                              ^~~~
../ebml/EbmlElement.h:135:138: note: expanded from macro 'DEFINE_xxx_CLASS_ORPHAN'
  135 |     static constexpr const libebml::EbmlId Id_##x    {id}; static_assert(libebml::EbmlId::IsValid(Id_##x .GetValue()), "invalid id for " name ); \
      |                                                                                                                                          ^~~~
1 error generated.
ninja: build stopped: subcommand failed

Need clang++ CI to catch this.

[robUx4]

We do build with clang on the macOS CI. And I don't think a \0 in a literal string is invalid in C++. It's not in C.

For the record this is used to detect usage of the source code in proprietary programs 😉

[robUx4]

Ah it's the concatenation with a \0 the leads to a problem. Still, it builds fine with AppleClang 14 or gcc 13. It's odd that all of a sudden this becomes an error and not just a warning.

[neheb]

To be fair, I ran into this error on Fedora 38.