@@ -324,3 +324,203 @@ 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+ if (USE_CARGO_VENDOR)
388+ set (extra_cargo_env "CARGO_HOME=${RUST_CARGO_HOME} " )
389+ endif ()
390+
391+ execute_process (
392+ COMMAND
393+ "${CMAKE_COMMAND} " -E env
394+ ${extra_cargo_env}
395+ "${CARGO_COMMAND} " tree -i cxx --depth=0
396+ WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
397+ RESULT_VARIABLE cxx_version_result
398+ OUTPUT_VARIABLE cxx_version_output
399+ )
400+
401+ if (NOT "${cxx_version_result} " EQUAL "0" )
402+ message (FATAL_ERROR "Crate ${crate_name} does not depend on cxx." )
403+ endif ()
404+ if (cxx_version_output MATCHES "cxx v([0-9]+.[0-9]+.[0-9]+)" )
405+ set (cxx_required_version "${CMAKE_MATCH_1} " )
406+ else ()
407+ message (
408+ FATAL_ERROR
409+ "Failed to parse cxx version from cargo tree output: `cxx_version_output`" )
410+ endif ()
411+
412+ # First check if a suitable version of cxxbridge is installed
413+ find_program (INSTALLED_CXXBRIDGE cxxbridge PATHS "$ENV{HOME} /.cargo/bin/" )
414+ mark_as_advanced (INSTALLED_CXXBRIDGE)
415+ if (INSTALLED_CXXBRIDGE)
416+ execute_process (
417+ COMMAND "${INSTALLED_CXXBRIDGE} " --version
418+ OUTPUT_VARIABLE cxxbridge_version_output
419+ )
420+ if (cxxbridge_version_output MATCHES "cxxbridge ([0-9]+.[0-9]+.[0-9]+)" )
421+ set (cxxbridge_version "${CMAKE_MATCH_1} " )
422+ else ()
423+ set (cxxbridge_version "" )
424+ endif ()
425+ endif ()
426+
427+ set (cxxbridge "" )
428+ if (cxxbridge_version)
429+ if (cxxbridge_version VERSION_EQUAL cxx_required_version)
430+ set (cxxbridge "${INSTALLED_CXXBRIDGE} " )
431+ if (NOT TARGET "cxxbridge_v${cxx_required_version} " )
432+ # Add an empty target.
433+ add_custom_target ("cxxbridge_v${cxx_required_version} " )
434+ endif ()
435+ endif ()
436+ endif ()
437+
438+ # No suitable version of cxxbridge was installed,
439+ # so use custom target to install correct version.
440+ if (NOT cxxbridge)
441+ if (NOT TARGET "cxxbridge_v${cxx_required_version} " )
442+ add_custom_command (
443+ OUTPUT
444+ "${CMAKE_BINARY_DIR} /cxxbridge_v${cxx_required_version} /bin/cxxbridge"
445+ COMMAND
446+ "${CMAKE_COMMAND} " -E make_directory
447+ "${CMAKE_BINARY_DIR} /cxxbridge_v${cxx_required_version} "
448+ COMMAND
449+ "${CMAKE_COMMAND} " -E remove -f "${CMAKE_CURRENT_SOURCE_DIR} /Cargo.lock"
450+ COMMAND
451+ "${CMAKE_COMMAND} " -E env
452+ ${extra_cargo_env}
453+ "${CARGO_COMMAND} " install cxxbridge-cmd
454+ --version "${cxx_required_version} "
455+ --root "${CMAKE_BINARY_DIR} /cxxbridge_v${cxx_required_version} "
456+ --quiet
457+ COMMAND
458+ "${CMAKE_COMMAND} " -E remove -f "${CMAKE_CURRENT_SOURCE_DIR} /Cargo.lock"
459+ COMMENT "Installing cxxbridge (version ${cxx_required_version} )"
460+ )
461+ add_custom_target (
462+ "cxxbridge_v${cxx_required_version} "
463+ DEPENDS "${CMAKE_BINARY_DIR} /cxxbridge_v${cxx_required_version} /bin/cxxbridge"
464+ )
465+ endif ()
466+ set (
467+ cxxbridge
468+ "${CMAKE_BINARY_DIR} /cxxbridge_v${cxx_required_version} /bin/cxxbridge"
469+ )
470+ endif ()
471+
472+ add_library (${crate_name} STATIC )
473+ target_include_directories (
474+ ${crate_name}
475+ PUBLIC
476+ $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR} >
477+ $<INSTALL_INTERFACE:include >
478+ )
479+
480+ file (MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR} /rust" )
481+ add_custom_command (
482+ OUTPUT "${CMAKE_CURRENT_BINARY_DIR} /rust/cxx.h"
483+ COMMAND
484+ "${cxxbridge} " --header --output "${CMAKE_CURRENT_BINARY_DIR} /rust/cxx.h"
485+ DEPENDS "cxxbridge_v${cxx_required_version} "
486+ COMMENT "Generating rust/cxx.h header"
487+ )
488+
489+ get_filename_component (filename_component ${CXX_BRIDGE_FILE} NAME )
490+ get_filename_component (directory_component ${CXX_BRIDGE_FILE} DIRECTORY )
491+ set (directory "" )
492+ if (directory_component)
493+ set (directory "${directory_component} " )
494+ endif ()
495+
496+ set (cxx_header ${directory} /${filename_component} .h)
497+ set (cxx_source ${directory} /${filename_component} .cc)
498+ set (rust_source_path "${CMAKE_CURRENT_SOURCE_DIR} /${CXX_BRIDGE_FILE} " )
499+
500+ file (
501+ MAKE_DIRECTORY
502+ "${CMAKE_CURRENT_BINARY_DIR} /${directory_component} "
503+ )
504+
505+ add_custom_command (
506+ OUTPUT
507+ "${CMAKE_CURRENT_BINARY_DIR} /${cxx_header} "
508+ "${CMAKE_CURRENT_BINARY_DIR} /${cxx_source} "
509+ COMMAND
510+ ${cxxbridge} ${rust_source_path}
511+ --header --output "${CMAKE_CURRENT_BINARY_DIR} /${cxx_header} "
512+ COMMAND
513+ ${cxxbridge} ${rust_source_path}
514+ --output "${CMAKE_CURRENT_BINARY_DIR} /${cxx_source} "
515+ --include "${cxx_header} "
516+ DEPENDS "cxxbridge_v${cxx_required_version} " "${rust_source_path} "
517+ COMMENT "Generating cxx bindings for crate ${crate_name} "
518+ )
519+
520+ target_sources (${crate_name}
521+ PRIVATE
522+ "${CMAKE_CURRENT_BINARY_DIR} /${cxx_header} "
523+ "${CMAKE_CURRENT_BINARY_DIR} /rust/cxx.h"
524+ "${CMAKE_CURRENT_BINARY_DIR} /${cxx_source} "
525+ )
526+ endfunction ()
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