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63 lines
2.4 KiB

if(TARGET ghc::filesystem)
return()
endif()
message(STATUS "Third-party: creating target 'ghc::filesystem'")
include(FetchContent)
FetchContent_Declare(
filesystem
GIT_REPOSITORY https://github.com/gulrak/filesystem.git
GIT_TAG v1.5.8
GIT_SHALLOW TRUE
)
FetchContent_MakeAvailable(filesystem)
add_library(ghc::filesystem ALIAS ghc_filesystem)
# Check if we need to link against any special libraries (e.g., stdc++fs for GCC < 9)
set(SAVED_CMAKE_REQUIRED_INCLUDES ${CMAKE_REQUIRED_INCLUDES})
set(SAVED_CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
set(GHC_FILESYSTEM_TEST_CODE [[
#include <ghc/fs_std.hpp>
int main() {
auto cwd = fs::current_path();
return static_cast<int>(cwd.string().size());
}
]])
# Try to compile a simple filesystem program without any linker flags
list(APPEND CMAKE_REQUIRED_INCLUDES "${filesystem_SOURCE_DIR}/include")
check_cxx_source_compiles("${GHC_FILESYSTEM_TEST_CODE}" GHC_FILESYSTEM_NO_LINK_NEEDED)
if(NOT GHC_FILESYSTEM_NO_LINK_NEEDED)
# Add the libstdc++ flag
set(CMAKE_REQUIRED_LIBRARIES ${SAVED_CMAKE_REQUIRED_LIBRARIES} -lstdc++fs)
check_cxx_source_compiles("${GHC_FILESYSTEM_TEST_CODE}" GHC_FILESYSTEM_STDCPPFS_NEEDED)
if(NOT GHC_FILESYSTEM_STDCPPFS_NEEDED)
# Try the libc++ flag
set(CMAKE_REQUIRED_LIBRARIES ${SAVED_CMAKE_REQUIRED_LIBRARIES} -lc++fs)
check_cxx_source_compiles("${GHC_FILESYSTEM_TEST_CODE}" GHC_FILESYSTEM_CPPFS_NEEDED)
endif()
endif()
if(GHC_FILESYSTEM_NO_LINK_NEEDED)
# on certain linux distros we have a version of libstdc++ which has the final code for c++17 fs in the
# libstdc++.so.*. BUT when compiling with g++ < 9, we MUST still link with libstdc++fs.a
# libc++ should not suffer from this issue, so, in theory we should be fine with only checking for
# GCC's libstdc++
if((CMAKE_CXX_COMPILER_ID MATCHES "GNU") AND (CMAKE_CXX_COMPILER_VERSION VERSION_LESS "9.0.0"))
target_link_libraries(ghc_filesystem INTERFACE -lstdc++fs)
endif()
elseif(GHC_FILESYSTEM_STDCPPFS_NEEDED)
target_link_libraries(ghc_filesystem INTERFACE -lstdc++fs)
elseif(GHC_FILESYSTEM_CPPFS_NEEDED)
target_link_libraries(ghc_filesystem INTERFACE -lc++fs)
else()
message(FATAL_ERROR "Unable to determine correct linking options to compile GHC filesystem!")
endif()
set(CMAKE_REQUIRED_INCLUDES ${SAVED_CMAKE_REQUIRED_INCLUDES})
set(CMAKE_REQUIRED_LIBRARIES ${SAVED_CMAKE_REQUIRED_LIBRARIES})