c++ - 在旧版本的 boost 中使用 recursive_directory_iterator？

Question

我需要递归地遍历一个目录；我从这里的另一个线程得到了一个非常好的功能；为了我的目的对它进行了一点点调整，它在带有 boost 1.62 和 clang 的 Mac 上完美运行。

但是，我们使用的是 SemaphoreCI(基于 ubuntu 14.04 LTS 和 boost 1.54)，我无法在这些条件下进行编译。

#include <boost/algorithm/string/replace.hpp>
#include <boost/filesystem.hpp>
#include <boost/range.hpp>
void copyDirectoryRecursively(const fs::path& sourceDir, const fs::path& destinationDir)
{
    if (!fs::exists(sourceDir) || !fs::is_directory(sourceDir))
    {
        throw std::runtime_error("Source directory " + sourceDir.string() + " does not exist or is not a directory");
    }
    if (!fs::create_directory(destinationDir) && !fs::exists(destinationDir))
    {
        throw std::runtime_error("Cannot create destination directory " + destinationDir.string());
    }

    for (const auto& dirEnt : fs::recursive_directory_iterator{sourceDir})
    {
        const auto& path = dirEnt.path();
        auto relativePathStr = path.string();
        boost::algorithm::replace_first(relativePathStr, sourceDir.string(), "");
        try { 
        if (!fs::is_directory(path)) { fs::copy_file(path, destinationDir / relativePathStr); }
        else { fs::copy_directory(path, destinationDir / relativePathStr); }
        }
        catch (...) {
        throw std::runtime_error("Cannot copy file " + path.string() + ", because it already exists in the destination folder.");
        }
    }
}

这是我遇到的错误，

海湾合作委员会:

/home/runner/performous/game/fs.cc: In function ‘void copyDirectoryRecursively(const boost::filesystem::path&, const boost::filesystem::path&)’:
/home/runner/performous/game/fs.cc:74:73: error: no matching function for call to ‘begin(boost::filesystem::recursive_directory_iterator&)’
     for (const auto& dirEnt : fs::recursive_directory_iterator{sourceDir})
                                                                         ^
/home/runner/performous/game/fs.cc:74:73: note: candidates are:
In file included from /usr/include/c++/4.8/string:51:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/boost/variant/variant.hpp:31,
                 from /home/runner/performous/game/configuration.hh:3,
                 from /home/runner/performous/game/fs.cc:2:
/usr/include/c++/4.8/bits/range_access.h:87:5: note: template<class _Tp, long unsigned int _Nm> _Tp* std::begin(_Tp (&)[_Nm])
     ^
/usr/include/c++/4.8/bits/range_access.h:87:5: note:   template argument deduction/substitution failed:
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
     for (const auto& dirEnt : fs::recursive_directory_iterator{sourceDir})
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/boost/variant/detail/move.hpp:22,
                 from /usr/include/c++/4.8/iterator:64,
                 from /usr/include/boost/variant/detail/initializer.hpp:23,
                 from /usr/include/c++/4.8/iterator:64,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/boost/variant.hpp:17,
     begin(_Tp (&__arr)[_Nm])
                 from /usr/include/boost/variant/detail/move.hpp:22,
                 from /usr/include/boost/variant/detail/initializer.hpp:23,
                 from /usr/include/boost/variant/variant.hpp:31,
/home/runner/performous/game/fs.cc:74:73: note:   mismatched types ‘_Tp [_Nm]’ and ‘boost::filesystem::recursive_directory_iterator’
                 from /usr/include/boost/variant.hpp:17,
                                                                         ^
In file included from /usr/include/c++/4.8/string:51:0,
                 from /home/runner/performous/game/configuration.hh:3,
                 from /home/runner/performous/game/fs.cc:2:
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
     begin(const _Container& __cont) -> decltype(__cont.begin())
/usr/include/c++/4.8/bits/range_access.h:58:5: note: template<class _Container> decltype (__cont.begin()) std::begin(const _Container&)
/usr/include/c++/4.8/bits/range_access.h: In substitution of ‘template<class _Container> decltype (__cont.begin()) std::begin(const _Container&) [with _Container = boost::filesystem::recursive_directory_iterator]’:
/usr/include/c++/4.8/bits/range_access.h:58:5: note:   template argument deduction/substitution failed:
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
/home/runner/performous/game/fs.cc:74:73:   required from here
/usr/include/c++/4.8/bits/range_access.h:58:5: error: ‘const class boost::filesystem::recursive_directory_iterator’ has no member named ‘begin’
                 from /usr/include/c++/4.8/ios:42,
/usr/include/c++/4.8/bits/range_access.h:48:5: note: template<class _Container> decltype (__cont.begin()) std::begin(_Container&)
     begin(_Container& __cont) -> decltype(__cont.begin())
     ^
/usr/include/c++/4.8/bits/range_access.h: In substitution of ‘template<class _Container> decltype (__cont.begin()) std::begin(_Container&) [with _Container = boost::filesystem::recursive_directory_iterator]’:
/usr/include/c++/4.8/bits/range_access.h:48:5: error: ‘class boost::filesystem::recursive_directory_iterator’ has no member named ‘begin’
/home/runner/performous/game/fs.cc:74:73:   required from here
                 from /usr/include/boost/config/no_tr1/utility.hpp:21,
In file included from /usr/include/c++/4.8/utility:74:0,
                 from /usr/include/boost/config/select_stdlib_config.hpp:37,
                 from /usr/include/boost/config.hpp:40,
     ^
                 from /usr/include/boost/variant/detail/config.hpp:16,
                 from /usr/include/boost/variant/variant.hpp:23,
                 from /usr/include/boost/variant.hpp:17,
                 from /home/runner/performous/game/configuration.hh:3,
/usr/include/c++/4.8/initializer_list:89:5: note: template<class _Tp> constexpr const _Tp* std::begin(std::initializer_list<_Tp>)
                 from /home/runner/performous/game/fs.cc:2:
     begin(initializer_list<_Tp> __ils) noexcept
     ^
/usr/include/c++/4.8/bits/range_access.h:48:5: note:   template argument deduction/substitution failed:
/usr/include/c++/4.8/initializer_list:89:5: note:   template argument deduction/substitution failed:
/home/runner/performous/game/fs.cc:74:73: note:   ‘boost::filesystem::recursive_directory_iterator’ is not derived from ‘std::initializer_list<_Tp>’
     for (const auto& dirEnt : fs::recursive_directory_iterator{sourceDir})
/home/runner/performous/game/fs.cc:74:73: error: no matching function for call to ‘end(boost::filesystem::recursive_directory_iterator&)’
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
In file included from /usr/include/c++/4.8/string:51:0,
/home/runner/performous/game/fs.cc:74:73: note: candidates are:
                 from /usr/include/c++/4.8/iterator:64,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                                                                         ^
                 from /usr/include/boost/variant/detail/move.hpp:22,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/boost/variant/detail/initializer.hpp:23,
                 from /usr/include/boost/variant.hpp:17,
                 from /home/runner/performous/game/configuration.hh:3,
                 from /usr/include/boost/variant/variant.hpp:31,
/usr/include/c++/4.8/bits/range_access.h:97:5: note: template<class _Tp, long unsigned int _Nm> _Tp* std::end(_Tp (&)[_Nm])
                 from /home/runner/performous/game/fs.cc:2:
/usr/include/c++/4.8/bits/range_access.h:97:5: note:   template argument deduction/substitution failed:
     ^
     end(_Tp (&__arr)[_Nm])
/home/runner/performous/game/fs.cc:74:73: note:   mismatched types ‘_Tp [_Nm]’ and ‘boost::filesystem::recursive_directory_iterator’
     for (const auto& dirEnt : fs::recursive_directory_iterator{sourceDir})
                                                                         ^
In file included from /usr/include/c++/4.8/string:51:0,
                 from /usr/include/c++/4.8/bits/locale_classes.h:40,
                 from /usr/include/c++/4.8/bits/ios_base.h:41,
                 from /usr/include/c++/4.8/ios:42,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iterator:64,
                 from /usr/include/boost/variant/detail/move.hpp:22,
                 from /usr/include/boost/variant.hpp:17,
                 from /usr/include/boost/variant/variant.hpp:31,
                 from /usr/include/boost/variant/detail/initializer.hpp:23,
                 from /home/runner/performous/game/configuration.hh:3,
                 from /home/runner/performous/game/fs.cc:2:
     ^
     end(const _Container& __cont) -> decltype(__cont.end())
/usr/include/c++/4.8/bits/range_access.h:78:5: note: template<class _Container> decltype (__cont.end()) std::end(const _Container&)
/usr/include/c++/4.8/bits/range_access.h: In substitution of ‘template<class _Container> decltype (__cont.end()) std::end(const _Container&) [with _Container = boost::filesystem::recursive_directory_iterator]’:
/usr/include/c++/4.8/bits/range_access.h:78:5: note:   template argument deduction/substitution failed:
/home/runner/performous/game/fs.cc:74:73:   required from here
/usr/include/c++/4.8/bits/range_access.h:78:5: error: ‘const class boost::filesystem::recursive_directory_iterator’ has no member named ‘end’
     end(_Container& __cont) -> decltype(__cont.end())
/usr/include/c++/4.8/bits/range_access.h:68:5: note: template<class _Container> decltype (__cont.end()) std::end(_Container&)
/usr/include/c++/4.8/bits/range_access.h:68:5: note:   template argument deduction/substitution failed:

     ^/usr/include/c++/4.8/bits/range_access.h: In substitution of ‘template<class _Container> decltype (__cont.end()) std::end(_Container&) [with _Container = boost::filesystem::recursive_directory_iterator]’:
/home/runner/performous/game/fs.cc:74:73:   required from here
/usr/include/c++/4.8/bits/range_access.h:68:5: error: ‘class boost::filesystem::recursive_directory_iterator’ has no member named ‘end’
In file included from /usr/include/c++/4.8/utility:74:0,
                 from /usr/include/boost/config/no_tr1/utility.hpp:21,
                 from /usr/include/boost/config/select_stdlib_config.hpp:37,
                 from /usr/include/boost/config.hpp:40,
                 from /usr/include/boost/variant/detail/config.hpp:16,
                 from /usr/include/boost/variant/variant.hpp:23,
                 from /usr/include/boost/variant.hpp:17,
                 from /home/runner/performous/game/configuration.hh:3,
                 from /home/runner/performous/game/fs.cc:2:
/usr/include/c++/4.8/initializer_list:99:5: note: template<class _Tp> constexpr const _Tp* std::end(std::initializer_list<_Tp>)
     end(initializer_list<_Tp> __ils) noexcept
     ^
/usr/include/c++/4.8/initializer_list:99:5: note:   template argument deduction/substitution failed:
/home/runner/performous/game/fs.cc:74:73: note:   ‘boost::filesystem::recursive_directory_iterator’ is not derived from ‘std::initializer_list<_Tp>’
     for (const auto& dirEnt : fs::recursive_directory_iterator{sourceDir})
                                                                         ^
make[2]: *** [game/CMakeFiles/performous.dir/fs.cc.o] Error 1
make[1]: *** [game/CMakeFiles/performous.dir/all] Error 2
make: *** [all] Error 2

clang :

/home/runner/performous/game/fs.cc:74:29: error: invalid range expression of
      type 'boost::filesystem::recursive_directory_iterator'; no viable 'begin'
      function available
    for (const auto& dirEnt : fs::recursive_directory_iterator{sourceDir})
                            ^ ~~
1 error generated.
make[2]: *** [game/CMakeFiles/performous.dir/fs.cc.o] Error 1
make[1]: *** [game/CMakeFiles/performous.dir/all] Error 2
make: *** [all] Error 2

Answer 1

那时候，迭代器没有对范围概念建模。所以，只需制作您自己的范围:

for (const auto& dirEnt : boost::make_iterator_range(fs::recursive_directory_iterator{sourceDir}, {})) {

查看 Live On GCC 4.8 and Boost 1.54