如何使用 CMake 编译 .proto 文件以生成 .grpc.pb.cc 和 .grpc.pb.h 文件？

Question

我正在尝试使用 C++ 中的 gRPC 创建服务器和客户端设置。 我在 CMake 中生成.grpc.pb.h和.grpc.pb.cc文件时.grpc.pb.h问题。 以下是我的项目设置。

gRPCStarter
  |__build
  |__proto
  |    |__ file.proto
  |    |__ CMakeLists.txt
  |__main.cpp
  |__CMakeLists.txt

以下是我当前的 CMakeLists.txt 文件

在proto目录中：

INCLUDE(FindProtobuf)
FIND_PACKAGE(Protobuf REQUIRED)
INCLUDE_DIRECTORIES(${PROTOBUF_INCLUDE_DIR})
PROTOBUF_GENERATE_CPP(PROTO_SRC PROTO_HEADER file.proto)
ADD_LIBRARY(proto ${PROTO_HEADER} ${PROTO_SRC})

内部source目录（遵循此建议）：

cmake_minimum_required(VERSION 3.16)
project(gRPCStarter)

set(CMAKE_CXX_STANDARD 14)

include(FetchContent)
FetchContent_Declare(
        gRPC
        GIT_REPOSITORY https://github.com/grpc/grpc
        GIT_TAG        v1.27.1
)
FetchContent_MakeAvailable(gRPC)

add_subdirectory(proto)

include_directories($(CMAKE_CURRENT_BINARY_DIR))

find_program(GRPC_CPP_PLUGIN grpc_cpp_plugin) # Get full path to plugin

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

    if(PROTOBUF_GENERATE_CPP_APPEND_PATH) # This variable is common for all types of output.
        # Create an include path for each file specified
        foreach(FIL ${ARGN})
            get_filename_component(ABS_FIL ${FIL} ABSOLUTE)
            get_filename_component(ABS_PATH ${ABS_FIL} PATH)
            list(FIND _protobuf_include_path ${ABS_PATH} _contains_already)
            if(${_contains_already} EQUAL -1)
                list(APPEND _protobuf_include_path -I ${ABS_PATH})
            endif()
        endforeach()
    else()
        set(_protobuf_include_path -I ${CMAKE_CURRENT_SOURCE_DIR})
    endif()

    if(DEFINED PROTOBUF_IMPORT_DIRS)
        foreach(DIR ${Protobuf_IMPORT_DIRS})
            get_filename_component(ABS_PATH ${DIR} ABSOLUTE)
            list(FIND _protobuf_include_path ${ABS_PATH} _contains_already)
            if(${_contains_already} EQUAL -1)
                list(APPEND _protobuf_include_path -I ${ABS_PATH})
            endif()
        endforeach()
    endif()

    set(${SRCS})
    set(${HDRS})
    foreach(FIL ${ARGN})
        get_filename_component(ABS_FIL ${FIL} ABSOLUTE)
        get_filename_component(FIL_WE ${FIL} NAME_WE)

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

        add_custom_command(
                OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${FIL_WE}.grpc.pb.cc"
                "${CMAKE_CURRENT_BINARY_DIR}/${FIL_WE}.grpc.pb.h"
                COMMAND  ${Protobuf_PROTOC_EXECUTABLE}
                ARGS --grpc_out=${CMAKE_CURRENT_BINARY_DIR}
                --plugin=protoc-gen-grpc=${GRPC_CPP_PLUGIN}
                ${_protobuf_include_path} ${ABS_FIL}
                DEPENDS ${ABS_FIL} ${Protobuf_PROTOC_EXECUTABLE}
                COMMENT "Running gRPC 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()

file(GLOB ProtoFiles "${CMAKE_CURRENT_SOURCE_DIR}/proto/*.proto")
PROTOBUF_GENERATE_GRPC_CPP(ProtoGRPCSources ProtoGRPCHeaders ${ProtoFiles})

add_executable(main main.cpp)
target_link_libraries(main proto ${PROTOBUF_LIBRARY} grpc++)

当我执行以下操作时，我没有得到任何.gpc.pb.h或.grpc.pb.cc文件：

cd build
cmake .. && make -j4

这是我的CMakeOutput.log

Answer 1

我通过遵循这个 CMake 架构解决了这个问题。