Fix build error resulting from assigning boost::uuids::random_generator

[argent0]

Hi, I had trouble building rhubarb on linux using boost 1.67.0

[ 71%] Building CXX object CMakeFiles/rhubarb-tools.dir/src/tools/platformTools.cpp.o                                        
/home/rhubarb_user/Docs/...../rhubarb-lip-sync/rhubarb/src/tools/platformTools.cpp: In function ‘boost::filesyst
em::path getTempFilePath()’:                                                                                                 
/home/rhubarb_user/Docs/...../rhubarb-lip-sync/rhubarb/src/tools/platformTools.cpp:60:60: error: use of deleted 
function ‘boost::uuids::random_generator_pure::random_generator_pure(boost::uuids::random_generator_pure&&)’                 
  static auto generateUuid = boost::uuids::random_generator();                                                               
                                                            ^                                                                
In file included from /usr/include/boost/uuid/uuid_generators.hpp:17,                                                        
                 from /home/rhubarb_user/Docs/...../rhubarb-lip-sync/rhubarb/src/tools/platformTools.cpp:5:     
/usr/include/boost/uuid/random_generator.hpp:149:7: note: ‘boost::uuids::random_generator_pure::random_generator_pure(boost::
uuids::random_generator_pure&&)’ is implicitly deleted because the default definition would be ill-formed:                   
 class random_generator_pure                                                                                                 
       ^~~~~~~~~~~~~~~~~~~~~                                                                                                 
/usr/include/boost/uuid/random_generator.hpp:149:7: error: use of deleted function ‘boost::uuids::detail::random_provider::ra
ndom_provider(boost::uuids::detail::random_provider&&)’                                                                      
In file included from /usr/include/boost/uuid/random_generator.hpp:20,                                                       
                 from /usr/include/boost/uuid/uuid_generators.hpp:17,                                            
                 from /home/rhubarb_user/Docs/...../rhubarb-lip-sync/rhubarb/src/tools/platformTools.cpp:5:
/usr/include/boost/uuid/detail/random_provider.hpp:41:7: note: ‘boost::uuids::detail::random_provider::random_provider(boost$
:uuids::detail::random_provider&&)’ is implicitly deleted because the default definition would be ill-formed:               
 class random_provider                                                                                                      
       ^~~~~~~~~~~~~~~                                                                                          
/usr/include/boost/uuid/detail/random_provider.hpp:41:7: error: use of deleted function ‘boost::noncopyable_::noncopyable::n$ncopyable(const boost::noncopyable_::noncopyable&)’                                                             
In file included from /usr/include/boost/noncopyable.hpp:15,                                                                
                 from /usr/include/boost/system/error_code.hpp:18,                                                         
                 from /usr/include/boost/filesystem/path_traits.hpp:23,                                                    
                 from /usr/include/boost/filesystem/path.hpp:25,                                                            
                 from /usr/include/boost/filesystem/operations.hpp:25,                                             
                 from /home/rhubarb_user/Docs/...../rhubarb-lip-sync/rhubarb/src/tools/platformTools.cpp:1:
/usr/include/boost/core/noncopyable.hpp:34:7: note: declared here                                                
       noncopyable( const noncopyable& ) = delete;                                                                          
       ^~~~~~~~~~~                                                                                             
make[2]: *** [CMakeFiles/rhubarb-tools.dir/build.make:89: CMakeFiles/rhubarb-tools.dir/src/tools/platformTools.cpp.o] Error $
make[1]: *** [CMakeFiles/Makefile2:651: CMakeFiles/rhubarb-tools.dir/all] Error 2                                        
make: *** [Makefile:130: all] Error 2

This fixes the issue for me. What do you think?

[sh-dave]

Your changes will create a new generator every time the function is called, which might affect performance depending on how often temporary files are created. Maybe try this instead?

static boost::uuids::random_generator generateUuid;
string fileName = to_string(generateUuid());

[DanielSWolf]

@argent0 Thanks for pointing me to this code. The line I originally wrote certainly doesn't make sense. It creates a new boost::uuids::random_generator, then assigns it to a new variable. This certainly isn't idiomatic C++. As @sh-dave noted, a simple variable declaration should work fine. Plus, it avoids the overhead of creating a new random generator for each random number.

My guess is that depending on the compiler, my original code may or may not invoke the move constructor, which seems to be missing at least from your version of Boost, leading to your compile error.

Could you change your pull request to use @sh-dave's approach instead, then tell me whether it still works for you?

[argent0]

Hi, I applied @sh-dave suggestions and got it to compile and work.

Thanks for writing rhubarb.

PS: The Travis build was canceled. Maybe because I sent two commits in rapid succession.

[DanielSWolf]

Thanks for the PR! Travis is happy now, too. ;-)