protobuf/cmake/protobuf-module.cmake.in

# Functions

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

  if(PROTOBUF_GENERATE_CPP_APPEND_PATH)
    # 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}.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} ${_protobuf_include_path} ${ABS_FIL}
      DEPENDS ${ABS_FIL} ${Protobuf_PROTOC_EXECUTABLE}
      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()

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

  if(PROTOBUF_GENERATE_CPP_APPEND_PATH)
    # 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})
  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}/${FIL_WE}_pb2.py")
    add_custom_command(
      OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${FIL_WE}_pb2.py"
      COMMAND  ${Protobuf_PROTOC_EXECUTABLE} --python_out ${CMAKE_CURRENT_BINARY_DIR} ${_protobuf_include_path} ${ABS_FIL}
      DEPENDS ${ABS_FIL} ${Protobuf_PROTOC_EXECUTABLE}
      COMMENT "Running Python protocol buffer compiler on ${FIL}"
      VERBATIM )
  endforeach()

  set(${SRCS} ${${SRCS}} PARENT_SCOPE)
endfunction()

# Environment

# Backwards compatibility
# Define camel case versions of input variables
foreach(UPPER
    PROTOBUF_SRC_ROOT_FOLDER
    PROTOBUF_IMPORT_DIRS
    PROTOBUF_DEBUG
    PROTOBUF_LIBRARY
    PROTOBUF_PROTOC_LIBRARY
    PROTOBUF_INCLUDE_DIR
    PROTOBUF_PROTOC_EXECUTABLE
    PROTOBUF_LIBRARY_DEBUG
    PROTOBUF_PROTOC_LIBRARY_DEBUG
    PROTOBUF_LITE_LIBRARY
    PROTOBUF_LITE_LIBRARY_DEBUG
    )
    if (DEFINED ${UPPER})
        string(REPLACE "PROTOBUF_" "Protobuf_" Camel ${UPPER})
        if (NOT DEFINED ${Camel})
            set(${Camel} ${${UPPER}})
        endif()
    endif()
endforeach()

if(DEFINED Protobuf_SRC_ROOT_FOLDER)
  message(AUTHOR_WARNING "Variable Protobuf_SRC_ROOT_FOLDER defined, but not"
    " used in CONFIG mode")
endif()

include(SelectLibraryConfigurations)

# Internal function: search for normal library as well as a debug one
#    if the debug one is specified also include debug/optimized keywords
#    in *_LIBRARIES variable
function(_protobuf_find_libraries name filename)
  if(${name}_LIBRARIES)
    # Use result recorded by a previous call.
  elseif(${name}_LIBRARY)
    # Honor cache entry used by CMake 3.5 and lower.
    set(${name}_LIBRARIES "${${name}_LIBRARY}" PARENT_SCOPE)
  else()
    get_target_property(${name}_LIBRARY_RELEASE protobuf::lib${filename}
      LOCATION_RELEASE)
    get_target_property(${name}_LIBRARY_DEBUG protobuf::lib${filename}
      LOCATION_DEBUG)

    select_library_configurations(${name})
    set(${name}_LIBRARY ${${name}_LIBRARY} PARENT_SCOPE)
    set(${name}_LIBRARIES ${${name}_LIBRARIES} PARENT_SCOPE)
  endif()
endfunction()

# Internal function: find threads library
function(_protobuf_find_threads)
    set(CMAKE_THREAD_PREFER_PTHREAD TRUE)
    find_package(Threads)
    if(Threads_FOUND)
        list(APPEND PROTOBUF_LIBRARIES ${CMAKE_THREAD_LIBS_INIT})
        set(PROTOBUF_LIBRARIES "${PROTOBUF_LIBRARIES}" PARENT_SCOPE)
    endif()
endfunction()

#
# Main.
#

# By default have PROTOBUF_GENERATE_CPP macro pass -I to protoc
# for each directory where a proto file is referenced.
if(NOT DEFINED PROTOBUF_GENERATE_CPP_APPEND_PATH)
  set(PROTOBUF_GENERATE_CPP_APPEND_PATH TRUE)
endif()

# The Protobuf library
_protobuf_find_libraries(Protobuf protobuf)

# The Protobuf Lite library
_protobuf_find_libraries(Protobuf_LITE protobuf-lite)

# The Protobuf Protoc Library
_protobuf_find_libraries(Protobuf_PROTOC protoc)

if(UNIX)
  _protobuf_find_threads()
endif()

# Set the include directory
get_target_property(Protobuf_INCLUDE_DIRS protobuf::libprotobuf
  INTERFACE_INCLUDE_DIRECTORIES)

# Set the protoc Executable
get_target_property(Protobuf_PROTOC_EXECUTABLE protobuf::protoc
  IMPORTED_LOCATION_RELEASE)
if(NOT EXISTS "${Protobuf_PROTOC_EXECUTABLE}")
  get_target_property(Protobuf_PROTOC_EXECUTABLE protobuf::protoc
    IMPORTED_LOCATION_DEBUG)
endif()

# Version info variable
set(Protobuf_VERSION "@protobuf_VERSION@")

include(FindPackageHandleStandardArgs)
FIND_PACKAGE_HANDLE_STANDARD_ARGS(Protobuf
    REQUIRED_VARS Protobuf_PROTOC_EXECUTABLE Protobuf_LIBRARIES Protobuf_INCLUDE_DIRS
    VERSION_VAR Protobuf_VERSION
)

# Backwards compatibility
# Define upper case versions of output variables
foreach(Camel
    Protobuf_VERSION
    Protobuf_SRC_ROOT_FOLDER
    Protobuf_IMPORT_DIRS
    Protobuf_DEBUG
    Protobuf_INCLUDE_DIRS
    Protobuf_LIBRARIES
    Protobuf_PROTOC_LIBRARIES
    Protobuf_LITE_LIBRARIES
    Protobuf_LIBRARY
    Protobuf_PROTOC_LIBRARY
    Protobuf_INCLUDE_DIR
    Protobuf_PROTOC_EXECUTABLE
    Protobuf_LIBRARY_DEBUG
    Protobuf_PROTOC_LIBRARY_DEBUG
    Protobuf_LITE_LIBRARY
    Protobuf_LITE_LIBRARY_DEBUG
    )
    string(TOUPPER ${Camel} UPPER)
    set(${UPPER} ${${Camel}})
endforeach()