@@ -324,3 +324,191 @@ function(install_rust_static_library TARGET)
324324 DESTINATION ${ARG_INSTALL_DIR}
325325 )
326326endfunction ()
327+
328+ # This function creates C++ bindings using the [cxx] crate.
329+ #
330+ # Original function found here: https://github.com/corrosion-rs/corrosion/blob/master/cmake/Corrosion.cmake#L1390
331+ # Simplified for use as part of RustStaticLibrary module. License below.
332+ #
333+ # MIT License
334+ #
335+ # Copyright (c) 2018 Andrew Gaspar
336+ #
337+ # Permission is hereby granted, free of charge, to any person obtaining a copy
338+ # of this software and associated documentation files (the "Software"), to deal
339+ # in the Software without restriction, including without limitation the rights
340+ # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
341+ # copies of the Software, and to permit persons to whom the Software is
342+ # furnished to do so, subject to the following conditions:
343+ #
344+ # The above copyright notice and this permission notice shall be included in all
345+ # copies or substantial portions of the Software.
346+ #
347+ # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
348+ # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
349+ # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
350+ # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
351+ # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
352+ # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
353+ # SOFTWARE.
354+ #
355+ # The rules approximately do the following:
356+ # - Check which version of `cxx` the Rust crate depends on.
357+ # - Check if the exact same version of `cxxbridge-cmd` is installed
358+ # - If not, create a rule to build the exact same version of `cxxbridge-cmd`.
359+ # - Create rules to run `cxxbridge` and generate
360+ # - The `rust/cxx.h` header
361+ # - A header and source file for the specified CXX_BRIDGE_FILE.
362+ # - The generated sources (and header include directories) are added to the
363+ # `${TARGET}` CMake library target.
364+ #
365+ # ```cmake
366+ # rust_cxx_bridge(<TARGET> <CXX_BRIDGE_FILE> [CRATE <CRATE_NAME>])
367+ # ```
368+ #
369+ # Parameters:
370+ # - TARGET:
371+ # Name of the target name. The target that the bridge will be included with.
372+ # - CXX_BRIDGE_FILE:
373+ # Name of the file that include the cxxbridge (e.g., "src/ffi.rs").
374+ # - CRATE_NAME:
375+ # Name of the crate. This parameter is optional. If unspecified, it will
376+ # fallback to `${TARGET}`.
377+ #
378+ function (rust_cxx_bridge TARGET CXX_BRIDGE_FILE )
379+ fb_cmake_parse_args (ARG "" "CRATE" "" "${ARGN} " )
380+
381+ if (DEFINED ARG_CRATE)
382+ set (crate_name "${ARG_CRATE} " )
383+ else ()
384+ set (crate_name "${TARGET} " )
385+ endif ()
386+
387+ execute_process (COMMAND
388+ ${CARGO_COMMAND} tree -i cxx --depth=0
389+ WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
390+ RESULT_VARIABLE cxx_version_result
391+ OUTPUT_VARIABLE cxx_version_output
392+ )
393+
394+ if (NOT "${cxx_version_result} " EQUAL "0" )
395+ message (FATAL_ERROR "Crate ${crate_name} does not depend on cxx." )
396+ endif ()
397+ if (cxx_version_output MATCHES "cxx v([0-9]+.[0-9]+.[0-9]+)" )
398+ set (cxx_required_version "${CMAKE_MATCH_1} " )
399+ else ()
400+ message (
401+ FATAL_ERROR
402+ "Failed to parse cxx version from cargo tree output: `cxx_version_output`" )
403+ endif ()
404+
405+ # First check if a suitable version of cxxbridge is installed
406+ find_program (INSTALLED_CXXBRIDGE cxxbridge PATHS "$ENV{HOME} /.cargo/bin/" )
407+ mark_as_advanced (INSTALLED_CXXBRIDGE )
408+ if (INSTALLED_CXXBRIDGE)
409+ execute_process (
410+ COMMAND ${INSTALLED_CXXBRIDGE}
411+ --version OUTPUT_VARIABLE cxxbridge_version_output )
412+ if (cxxbridge_version_output MATCHES "cxxbridge ([0-9]+.[0-9]+.[0-9]+)" )
413+ set (cxxbridge_version "${CMAKE_MATCH_1} " )
414+ else ()
415+ set (cxxbridge_version "" )
416+ endif ()
417+ endif ()
418+
419+ set (cxxbridge "" )
420+ if (cxxbridge_version)
421+ if (cxxbridge_version VERSION_EQUAL cxx_required_version)
422+ set (cxxbridge "${INSTALLED_CXXBRIDGE} " )
423+ if (NOT TARGET "cxxbridge_v${cxx_required_version} " )
424+ # Add an empty target.
425+ add_custom_target ("cxxbridge_v${cxx_required_version} " )
426+ endif ()
427+ endif ()
428+ endif ()
429+
430+ # No suitable version of cxxbridge was installed,
431+ # so use custom target to install correct version.
432+ if (NOT cxxbridge)
433+ if (NOT TARGET "cxxbridge_v${cxx_required_version} " )
434+ add_custom_command (
435+ OUTPUT
436+ "${CMAKE_BINARY_DIR} /cxxbridge_v${cxx_required_version} /bin/cxxbridge"
437+ COMMAND
438+ ${CMAKE_COMMAND} -E make_directory
439+ "${CMAKE_BINARY_DIR} /cxxbridge_v${cxx_required_version} "
440+ COMMAND
441+ ${CARGO_COMMAND} install cxxbridge-cmd
442+ --version "${cxx_required_version} "
443+ --root "${CMAKE_BINARY_DIR} /cxxbridge_v${cxx_required_version} "
444+ --quiet
445+ # todo: use --target-dir to potentially reuse artifacts
446+ COMMENT "Installing cxxbridge (version ${cxx_required_version} )"
447+ )
448+ add_custom_target (
449+ "cxxbridge_v${cxx_required_version} "
450+ DEPENDS
451+ "${CMAKE_BINARY_DIR} /cxxbridge_v${cxx_required_version} /bin/cxxbridge"
452+ )
453+ endif ()
454+ set (
455+ cxxbridge
456+ "${CMAKE_BINARY_DIR} /cxxbridge_v${cxx_required_version} /bin/cxxbridge" )
457+ endif ()
458+
459+ add_library (${crate_name} STATIC )
460+ target_include_directories (
461+ ${crate_name}
462+ PUBLIC
463+ $<BUILD_INTERFACE :${CMAKE_CURRENT_BINARY_DIR} >
464+ $<INSTALL_INTERFACE :include >
465+ )
466+
467+ file (MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR} /rust" )
468+ add_custom_command (
469+ OUTPUT "${CMAKE_CURRENT_BINARY_DIR} /rust/cxx.h"
470+ COMMAND
471+ ${cxxbridge}
472+ --header --output "${CMAKE_CURRENT_BINARY_DIR} /rust/cxx.h"
473+ DEPENDS "cxxbridge_v${cxx_required_version} "
474+ COMMENT "Generating rust/cxx.h header"
475+ )
476+
477+ get_filename_component (filename_component ${CXX_BRIDGE_FILE} NAME )
478+ get_filename_component (directory_component ${CXX_BRIDGE_FILE} DIRECTORY )
479+ set (directory "" )
480+ if (directory_component)
481+ set (directory "${directory_component} " )
482+ endif ()
483+
484+ set (cxx_header ${directory} /${filename_component} .h)
485+ set (cxx_source ${directory} /${filename_component} .cc)
486+ set (rust_source_path "${CMAKE_CURRENT_SOURCE_DIR} /${CXX_BRIDGE_FILE} " )
487+
488+ file (
489+ MAKE_DIRECTORY
490+ "${CMAKE_CURRENT_BINARY_DIR} /${directory_component} "
491+ )
492+
493+ add_custom_command (
494+ OUTPUT
495+ "${CMAKE_CURRENT_BINARY_DIR} /${cxx_header} "
496+ "${CMAKE_CURRENT_BINARY_DIR} /${cxx_source} "
497+ COMMAND
498+ ${cxxbridge} ${rust_source_path}
499+ --header --output "${CMAKE_CURRENT_BINARY_DIR} /${cxx_header} "
500+ COMMAND
501+ ${cxxbridge} ${rust_source_path}
502+ --output "${CMAKE_CURRENT_BINARY_DIR} /${cxx_source} "
503+ --include "${cxx_header} "
504+ DEPENDS "cxxbridge_v${cxx_required_version} " "${rust_source_path} "
505+ COMMENT "Generating cxx bindings for crate ${crate_name} "
506+ )
507+
508+ target_sources (${crate_name}
509+ PRIVATE
510+ "${CMAKE_CURRENT_BINARY_DIR} /${cxx_header} "
511+ "${CMAKE_CURRENT_BINARY_DIR} /rust/cxx.h"
512+ "${CMAKE_CURRENT_BINARY_DIR} /${cxx_source} "
513+ )
514+ endfunction ()
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