Using cmake to create protobuf / grpc cc files

Question

If I want to recreate the following protoc command in cmake:

protoc -I ../proto/ --cpp_out=. service.proto

I use the following lines in cmake:

file(GLOB ProtoFiles "${CMAKE_CURRENT_SOURCE_DIR}/*.proto")
PROTOBUF_GENERATE_CPP(ProtoSources ProtoHeaders ${ProtoFiles})

If instead I want to recreate the protoc command below:

protoc -I ../proto/ --grpc_out=. --plugin=protoc-gen-grpc=`which grpc_cpp_plugin` service.proto

In the above example, I cannot determine how to modify the cmake file, please help!

Question: how can I turn to:

--plugin=EXECUTABLE           Specifies a plugin executable to use.
                              Normally, protoc searches the PATH for
                              plugins, but you may specify additional
                              executables not in the path using this flag.
                              Additionally, EXECUTABLE may be of the form
                              NAME=PATH, in which case the given plugin name
                              is mapped to the given executable even if
                              the executable own name differs.

I read the PROTOBUF_GENERATE_CPP documentation but could not find an answer!

Answer 1

findProtobuf.cmake - protoc: PROTOBUF_GENERATE_CPP - --cpp_out PROTOBUF_GENERATE_PYTHON - --py_out. . PROTOBUF_GENERATE_CPP.

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()

, PROTOBUF_GENERATE_CPP:

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