mirror of
https://gitee.com/an-tao/drogon.git
synced 2024-12-02 11:47:56 +08:00
254 lines
8.2 KiB
CMake
254 lines
8.2 KiB
CMake
# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
|
|
# file Copyright.txt or https://cmake.org/licensing for details.
|
|
|
|
#[=======================================================================[.rst:
|
|
|
|
FindFilesystem
|
|
##############
|
|
|
|
This module supports the C++17 standard library's filesystem utilities. Use the
|
|
:imp-target:`std::filesystem` imported target to
|
|
|
|
Options
|
|
*******
|
|
|
|
The ``COMPONENTS`` argument to this module supports the following values:
|
|
|
|
.. find-component:: Experimental
|
|
:name: fs.Experimental
|
|
|
|
Allows the module to find the "experimental" Filesystem TS version of the
|
|
Filesystem library. This is the library that should be used with the
|
|
``std::experimental::filesystem`` namespace.
|
|
|
|
.. find-component:: Final
|
|
:name: fs.Final
|
|
|
|
Finds the final C++17 standard version of the filesystem library.
|
|
|
|
If no components are provided, behaves as if the
|
|
:find-component:`fs.Final` component was specified.
|
|
|
|
If both :find-component:`fs.Experimental` and :find-component:`fs.Final` are
|
|
provided, first looks for ``Final``, and falls back to ``Experimental`` in case
|
|
of failure. If ``Final`` is found, :imp-target:`std::filesystem` and all
|
|
:ref:`variables <fs.variables>` will refer to the ``Final`` version.
|
|
|
|
|
|
Imported Targets
|
|
****************
|
|
|
|
.. imp-target:: std::filesystem
|
|
|
|
The ``std::filesystem`` imported target is defined when any requested
|
|
version of the C++ filesystem library has been found, whether it is
|
|
*Experimental* or *Final*.
|
|
|
|
If no version of the filesystem library is available, this target will not
|
|
be defined.
|
|
|
|
.. note::
|
|
This target has ``cxx_std_17`` as an ``INTERFACE``
|
|
:ref:`compile language standard feature <req-lang-standards>`. Linking
|
|
to this target will automatically enable C++17 if no later standard
|
|
version is already required on the linking target.
|
|
|
|
|
|
.. _fs.variables:
|
|
|
|
Variables
|
|
*********
|
|
|
|
.. variable:: CXX_FILESYSTEM_IS_EXPERIMENTAL
|
|
|
|
Set to ``TRUE`` when the :find-component:`fs.Experimental` version of C++
|
|
filesystem library was found, otherwise ``FALSE``.
|
|
|
|
.. variable:: CXX_FILESYSTEM_HAVE_FS
|
|
|
|
Set to ``TRUE`` when a filesystem header was found.
|
|
|
|
.. variable:: CXX_FILESYSTEM_HEADER
|
|
|
|
Set to either ``filesystem`` or ``experimental/filesystem`` depending on
|
|
whether :find-component:`fs.Final` or :find-component:`fs.Experimental` was
|
|
found.
|
|
|
|
.. variable:: CXX_FILESYSTEM_NAMESPACE
|
|
|
|
Set to either ``std::filesystem`` or ``std::experimental::filesystem``
|
|
depending on whether :find-component:`fs.Final` or
|
|
:find-component:`fs.Experimental` was found.
|
|
|
|
|
|
Examples
|
|
********
|
|
|
|
Using `find_package(Filesystem)` with no component arguments:
|
|
|
|
.. code-block:: cmake
|
|
|
|
find_package(Filesystem REQUIRED)
|
|
|
|
add_executable(my-program main.cpp)
|
|
target_link_libraries(my-program PRIVATE std::filesystem)
|
|
|
|
|
|
#]=======================================================================]
|
|
|
|
|
|
if(TARGET std::filesystem)
|
|
# This module has already been processed. Don't do it again.
|
|
return()
|
|
endif()
|
|
|
|
cmake_minimum_required(VERSION 3.10)
|
|
|
|
include(CMakePushCheckState)
|
|
include(CheckIncludeFileCXX)
|
|
|
|
# If we're not cross-compiling, try to run test executables.
|
|
# Otherwise, assume that compile + link is a sufficient check.
|
|
if(CMAKE_CROSSCOMPILING)
|
|
include(CheckCXXSourceCompiles)
|
|
macro(_cmcm_check_cxx_source code var)
|
|
check_cxx_source_compiles("${code}" ${var})
|
|
endmacro()
|
|
else()
|
|
include(CheckCXXSourceRuns)
|
|
macro(_cmcm_check_cxx_source code var)
|
|
check_cxx_source_runs("${code}" ${var})
|
|
endmacro()
|
|
endif()
|
|
|
|
cmake_push_check_state()
|
|
|
|
set(CMAKE_REQUIRED_QUIET ${Filesystem_FIND_QUIETLY})
|
|
|
|
# All of our tests required C++17 or later
|
|
set(CMAKE_CXX_STANDARD 17)
|
|
|
|
# Normalize and check the component list we were given
|
|
set(want_components ${Filesystem_FIND_COMPONENTS})
|
|
if(Filesystem_FIND_COMPONENTS STREQUAL "")
|
|
set(want_components Final)
|
|
endif()
|
|
|
|
# Warn on any unrecognized components
|
|
set(extra_components ${want_components})
|
|
list(REMOVE_ITEM extra_components Final Experimental)
|
|
foreach(component IN LISTS extra_components)
|
|
message(WARNING "Extraneous find_package component for Filesystem: ${component}")
|
|
endforeach()
|
|
|
|
# Detect which of Experimental and Final we should look for
|
|
set(find_experimental TRUE)
|
|
set(find_final TRUE)
|
|
if(NOT "Final" IN_LIST want_components)
|
|
set(find_final FALSE)
|
|
endif()
|
|
if(NOT "Experimental" IN_LIST want_components)
|
|
set(find_experimental FALSE)
|
|
endif()
|
|
|
|
if(find_final)
|
|
check_include_file_cxx("filesystem" _CXX_FILESYSTEM_HAVE_HEADER)
|
|
mark_as_advanced(_CXX_FILESYSTEM_HAVE_HEADER)
|
|
if(_CXX_FILESYSTEM_HAVE_HEADER)
|
|
# We found the non-experimental header. Don't bother looking for the
|
|
# experimental one.
|
|
set(find_experimental FALSE)
|
|
endif()
|
|
else()
|
|
set(_CXX_FILESYSTEM_HAVE_HEADER FALSE)
|
|
endif()
|
|
|
|
if(find_experimental)
|
|
check_include_file_cxx("experimental/filesystem" _CXX_FILESYSTEM_HAVE_EXPERIMENTAL_HEADER)
|
|
mark_as_advanced(_CXX_FILESYSTEM_HAVE_EXPERIMENTAL_HEADER)
|
|
else()
|
|
set(_CXX_FILESYSTEM_HAVE_EXPERIMENTAL_HEADER FALSE)
|
|
endif()
|
|
|
|
if(_CXX_FILESYSTEM_HAVE_HEADER)
|
|
set(_have_fs TRUE)
|
|
set(_fs_header filesystem)
|
|
set(_fs_namespace std::filesystem)
|
|
set(_is_experimental FALSE)
|
|
elseif(_CXX_FILESYSTEM_HAVE_EXPERIMENTAL_HEADER)
|
|
set(_have_fs TRUE)
|
|
set(_fs_header experimental/filesystem)
|
|
set(_fs_namespace std::experimental::filesystem)
|
|
set(_is_experimental TRUE)
|
|
else()
|
|
set(_have_fs FALSE)
|
|
endif()
|
|
|
|
set(CXX_FILESYSTEM_HAVE_FS ${_have_fs} CACHE BOOL "TRUE if we have the C++ filesystem headers")
|
|
set(CXX_FILESYSTEM_HEADER ${_fs_header} CACHE STRING "The header that should be included to obtain the filesystem APIs")
|
|
set(CXX_FILESYSTEM_NAMESPACE ${_fs_namespace} CACHE STRING "The C++ namespace that contains the filesystem APIs")
|
|
set(CXX_FILESYSTEM_IS_EXPERIMENTAL ${_is_experimental} CACHE BOOL "TRUE if the C++ filesystem library is the experimental version")
|
|
|
|
set(_found FALSE)
|
|
|
|
if(CXX_FILESYSTEM_HAVE_FS)
|
|
# We have some filesystem library available. Do link checks
|
|
string(CONFIGURE [[
|
|
#include <cstdio>
|
|
#include <@CXX_FILESYSTEM_HEADER@>
|
|
|
|
int main() {
|
|
auto cwd = @CXX_FILESYSTEM_NAMESPACE@::current_path();
|
|
printf("%s", cwd.generic_string().c_str());
|
|
return EXIT_SUCCESS;
|
|
}
|
|
]] code @ONLY)
|
|
|
|
# HACK: Needed to compile correctly on Yocto Linux
|
|
if(CMAKE_CXX_COMPILER_ID STREQUAL "GCC" OR CMAKE_CXX_COMPILER_ID STREQUAL "Clang"
|
|
OR CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
|
|
set(CMAKE_REQUIRED_FLAGS ${prev_req_flags} -std=c++17)
|
|
endif ()
|
|
# Check a simple filesystem program without any linker flags
|
|
_cmcm_check_cxx_source("${code}" CXX_FILESYSTEM_NO_LINK_NEEDED)
|
|
|
|
set(can_link ${CXX_FILESYSTEM_NO_LINK_NEEDED})
|
|
|
|
if(NOT CXX_FILESYSTEM_NO_LINK_NEEDED)
|
|
set(prev_libraries ${CMAKE_REQUIRED_LIBRARIES})
|
|
# Add the libstdc++ flag
|
|
set(CMAKE_REQUIRED_LIBRARIES ${prev_libraries} -lstdc++fs)
|
|
_cmcm_check_cxx_source("${code}" CXX_FILESYSTEM_STDCPPFS_NEEDED)
|
|
set(can_link ${CXX_FILESYSTEM_STDCPPFS_NEEDED})
|
|
if(NOT CXX_FILESYSTEM_STDCPPFS_NEEDED)
|
|
# Try the libc++ flag
|
|
set(CMAKE_REQUIRED_LIBRARIES ${prev_libraries} -lc++fs)
|
|
_cmcm_check_cxx_source("${code}" CXX_FILESYSTEM_CPPFS_NEEDED)
|
|
set(can_link ${CXX_FILESYSTEM_CPPFS_NEEDED})
|
|
endif()
|
|
endif()
|
|
|
|
if(can_link)
|
|
add_library(std::filesystem INTERFACE IMPORTED)
|
|
set_property(TARGET std::filesystem APPEND PROPERTY INTERFACE_COMPILE_FEATURES cxx_std_17)
|
|
set(_found TRUE)
|
|
|
|
if(CXX_FILESYSTEM_NO_LINK_NEEDED)
|
|
# Nothing to add...
|
|
elseif(CXX_FILESYSTEM_STDCPPFS_NEEDED)
|
|
set_property(TARGET std::filesystem APPEND PROPERTY INTERFACE_LINK_LIBRARIES -lstdc++fs)
|
|
elseif(CXX_FILESYSTEM_CPPFS_NEEDED)
|
|
set_property(TARGET std::filesystem APPEND PROPERTY INTERFACE_LINK_LIBRARIES -lc++fs)
|
|
endif()
|
|
endif()
|
|
endif()
|
|
|
|
cmake_pop_check_state()
|
|
|
|
set(Filesystem_FOUND ${_found} CACHE BOOL "TRUE if we can run a program using std::filesystem" FORCE)
|
|
|
|
if(Filesystem_FIND_REQUIRED AND NOT Filesystem_FOUND)
|
|
message(FATAL_ERROR "Cannot run simple program using std::filesystem")
|
|
endif()
|
|
|