MegEngine/cmake/protobuf.cmake

function(PROTOBUF_GENERATE_CPP_WITH_ROOT SRCS HDRS ROOT_DIR)
  if(NOT ARGN)
    message(
      SEND_ERROR
        "Error: PROTOBUF_GENERATE_CPP_WITH_ROOT() called without any proto files")
    return()
  endif()

  set(${SRCS})
  set(${HDRS})
  foreach(FIL ${ARGN})
    set(ABS_FIL ${ROOT_DIR}/${FIL})
    get_filename_component(FIL_WE ${FIL} NAME_WE)
    get_filename_component(FIL_DIR ${ABS_FIL} PATH)
    file(RELATIVE_PATH REL_DIR ${ROOT_DIR} ${FIL_DIR})

    list(APPEND ${SRCS} "${CMAKE_CURRENT_BINARY_DIR}/${FIL_WE}.pb.cc")
    list(APPEND ${HDRS} "${CMAKE_CURRENT_BINARY_DIR}/${FIL_WE}.pb.h")

    add_custom_command(
      OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${FIL_WE}.pb.cc"
             "${CMAKE_CURRENT_BINARY_DIR}/${FIL_WE}.pb.h"
      COMMAND ${PROTOBUF_PROTOC_EXECUTABLE} ARGS --cpp_out ${CMAKE_CURRENT_BINARY_DIR}
              -I ${FIL_DIR} ${ABS_FIL} -I ${PROTOBUF_INCLUDE_DIRS}
      DEPENDS ${ABS_FIL} libprotobuf
      COMMENT "Running C++ protocol buffer compiler on ${FIL}"
      VERBATIM)
  endforeach()

  set_source_files_properties(${${SRCS}} ${${HDRS}} PROPERTIES GENERATED TRUE)
  set(${SRCS}
      ${${SRCS}}
      PARENT_SCOPE)
  set(${HDRS}
      ${${HDRS}}
      PARENT_SCOPE)
endfunction()

if(MGE_USE_SYSTEM_LIB)
  find_package(Protobuf)
  if(Protobuf_FOUND)
    add_library(libprotobuf INTERFACE)
    target_link_libraries(libprotobuf INTERFACE ${Protobuf_LIBRARIES})
    target_include_directories(libprotobuf INTERFACE ${Protobuf_INCLUDE_DIRS})
    get_filename_component(Protobuf_ROOT ${Protobuf_INCLUDE_DIR} DIRECTORY)
    set(PROTOBUF_ROOT ${Protobuf_ROOT})
    set(PROTOBUF_PROTOC_EXECUTABLE ${Protobuf_PROTOC_EXECUTABLE})
    set(PROTOBUF_INCLUDE_DIRS ${Protobuf_INCLUDE_DIRS})
    return()
  endif()
endif()

include(ExternalProject)
include(GNUInstallDirs)

set(PROTOBUF_DIR
    "${PROJECT_SOURCE_DIR}/third_party/protobuf"
    CACHE STRING "protobuf directory")
set(PROTOBUF_BUILD_DIR ${PROJECT_BINARY_DIR}/third_party/protobuf)

if(${CMAKE_BUILD_TYPE} STREQUAL "Debug")
  set(PROTOBUF_LIB ${PROTOBUF_BUILD_DIR}/${CMAKE_INSTALL_LIBDIR}/libprotobufd.a)
else()
  set(PROTOBUF_LIB ${PROTOBUF_BUILD_DIR}/${CMAKE_INSTALL_LIBDIR}/libprotobuf.a)
endif()
set(PROTOBUF_PROTOC_EXECUTABLE ${PROTOBUF_BUILD_DIR}/bin/protoc)

ExternalProject_Add(
  protobuf
  SOURCE_DIR ${PROTOBUF_DIR}/cmake
  PREFIX ${PROTOBUF_BUILD_DIR}
  CMAKE_ARGS -DCMAKE_C_COMPILER_LAUNCHER=${CMAKE_C_COMPILER_LAUNCHER}
             -DCMAKE_CXX_COMPILER_LAUNCHER=${CMAKE_CXX_COMPILER_LAUNCHER}
             -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
             -DCMAKE_INSTALL_PREFIX=${PROTOBUF_BUILD_DIR}
             -Dprotobuf_BUILD_EXAMPLES=OFF
             -Dprotobuf_BUILD_TESTS=OFF
             -DBUILD_SHARED_LIBS=OFF
             -DCMAKE_POSITION_INDEPENDENT_CODE=ON
  BUILD_BYPRODUCTS ${PROTOBUF_LIB} ${PROTOBUF_PROTOC_EXECUTABLE})

set(PROTOBUF_INC ${PROTOBUF_BUILD_DIR}/include)
file(MAKE_DIRECTORY ${PROTOBUF_INC})

add_library(libprotobuf STATIC IMPORTED GLOBAL)
add_dependencies(libprotobuf protobuf)
set_target_properties(
  libprotobuf PROPERTIES IMPORTED_LOCATION ${PROTOBUF_LIB}
                         INTERFACE_INCLUDE_DIRECTORIES ${PROTOBUF_BUILD_DIR}/include)

add_executable(protoc IMPORTED GLOBAL)
add_dependencies(protoc protobuf)
set_target_properties(protoc PROPERTIES IMPORTED_LOCATION
                                        ${PROTOBUF_BUILD_DIR}/bin/protoc)

set(PROTOBUF_ROOT ${PROTOBUF_BUILD_DIR})
set(PROTOBUF_PROTOC_EXECUTABLE protoc)
set(PROTOBUF_INCLUDE_DIRS ${PROTOBUF_BUILD_DIR}/include)