CMake自动按目录结构编译Protobuf代码

在使用CMake构建C++项目时，如果有使用Protobuf，CMake提供了一个FindProtobuf.cmake模块来处理PB，其使用方法如下：

find_package(Protobuf REQUIRED)
protobuf_generate_cpp(GENERATED_SRC GENERATED_HEADER "pb/t.proto" "pb.proto")

add_executable(${PROJECT_NAME} main.cpp ${GENERATED_SRC})
target_link_libraries(${PROJECT_NAME} PRIVATE Protobuf)

在构建项目时，会自动生成编译proto为相应的C++代码，包括头文件。

但是CMake自带的FindProtobuf.cmake模块会把所有生成的C++文件放在${CMAKE_CURRENT_BINARY_DIR}目录下，会导致项目中所有proto文件名不能重复，否则会出问题。同时，该模块也只能将Proto编译成C++以及Python，如果想要编译其它的则不支持。

笔者经过一番研究，把它改成可以根据Proto的目录结构生成到${CMAKE_CURRENT_BINARY_DIR}目录下对应的目录中。

只需要修改一下protobuf_generate函数即可。即根据每个proto文件的路径获取相对路径，在${CMAKE_CURRENT_BINARY_DIR}目录下创建好目录，在使用protoc时指定工作目录为该目录。

可以看一下对比：
在这里插入图片描述

为了让protobuf_generate函数支持生成C代码（使用protoc-c插件生成），做如下修改：

在这里插入图片描述

if(NOT protobuf_generate_GENERATE_EXTENSIONS)
    if(protobuf_generate_LANGUAGE STREQUAL cpp)
      set(protobuf_generate_GENERATE_EXTENSIONS .pb.h .pb.cc)
    elseif(protobuf_generate_LANGUAGE STREQUAL c)
      set(protobuf_generate_GENERATE_EXTENSIONS .pb-c.h .pb-c.c)
    elseif(protobuf_generate_LANGUAGE STREQUAL python)
      set(protobuf_generate_GENERATE_EXTENSIONS _pb2.py)
    else()
      message(SEND_ERROR "Error: protobuf_generate given unknown Language ${LANGUAGE}, please provide a value for GENERATE_EXTENSIONS")
      return()
    endif()
  endif()

添加PROTOBUF_GENERATE_C 函数：

function(PROTOBUF_GENERATE_C SRCS HDRS)
  cmake_parse_arguments(protobuf_generate_c "" "EXPORT_MACRO;DESCRIPTORS" "" ${ARGN})

  set(_proto_files "${protobuf_generate_c_UNPARSED_ARGUMENTS}")
  if(NOT _proto_files)
    message(SEND_ERROR "Error: PROTOBUF_GENERATE_C() called without any proto files")
    return()
  endif()

  if(PROTOBUF_GENERATE_CPP_APPEND_PATH)
    set(_append_arg APPEND_PATH)
  endif()

  if(protobuf_generate_c_DESCRIPTORS)
    set(_descriptors DESCRIPTORS)
  endif()

  if(DEFINED PROTOBUF_IMPORT_DIRS AND NOT DEFINED Protobuf_IMPORT_DIRS)
    set(Protobuf_IMPORT_DIRS "${PROTOBUF_IMPORT_DIRS}")
  endif()

  if(DEFINED Protobuf_IMPORT_DIRS)
    set(_import_arg IMPORT_DIRS ${Protobuf_IMPORT_DIRS})
  endif()

  set(_outvar)
  protobuf_generate(${_append_arg} ${_descriptors} LANGUAGE c EXPORT_MACRO ${protobuf_generate_c_EXPORT_MACRO} OUT_VAR _outvar ${_import_arg} PROTOS ${_proto_files})

  set(${SRCS})
  set(${HDRS})
  if(protobuf_generate_c_DESCRIPTORS)
    set(${protobuf_generate_c_DESCRIPTORS})
  endif()

  foreach(_file ${_outvar})
    if(_file MATCHES "c$")
      list(APPEND ${SRCS} ${_file})
    elseif(_file MATCHES "desc$")
      list(APPEND ${protobuf_generate_c_DESCRIPTORS} ${_file})
    else()
      list(APPEND ${HDRS} ${_file})
    endif()
  endforeach()
  set(${SRCS} ${${SRCS}} PARENT_SCOPE)
  set(${HDRS} ${${HDRS}} PARENT_SCOPE)
  if(protobuf_generate_c_DESCRIPTORS)
    set(${protobuf_generate_c_DESCRIPTORS} "${${protobuf_generate_c_DESCRIPTORS}}" PARENT_SCOPE)
  endif()
endfunction()

MinGW下需要安装protobuf和protobuf-c插件：

pacman -S mingw-w64-x86_64-protobuf
pacman -S mingw-w64-x86_64-protobuf-c

测试效果：

在这里插入图片描述

为了不修改原来的FindProtobuf.cmake文件，建议重新保存一份到项目中，比如命名为proto.cmake，为此还需要修改一下里面使用的include的路径：

在这里插入图片描述

即将${CMAKE_CURRENT_LIST_DIR}替换为${CMAKE_ROOT}/Modules。

项目中使用示例：

include(proto.cmake)
protobuf_generate_c(GENERATED_CPP_SRC GENERATED_CPP_HEADER "src/pb/t.proto" "src/pb/x.proto" "a.proto")
protobuf_generate_cpp(GENERATED_C_SRC GENERATED_C_HEADER "src/pb/t.proto" "src/pb/x.proto" "a.proto")

add_executable(${PROJECT_NAME} main.c ${GENERATED_CPP_SRC} ${GENERATED_C_SRC})

附上修改后的FindProtobuf.cmake源码：

# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.

#[=======================================================================[.rst:
FindProtobuf
------------

Locate and configure the Google Protocol Buffers library.

.. versionadded:: 3.6
  Support for :command:`find_package` version checks.

.. versionchanged:: 3.6
  All input and output variables use the ``Protobuf_`` prefix.
  Variables with ``PROTOBUF_`` prefix are still supported for compatibility.

The following variables can be set and are optional:

``Protobuf_SRC_ROOT_FOLDER``
  When compiling with MSVC, if this cache variable is set
  the protobuf-default VS project build locations
  (vsprojects/Debug and vsprojects/Release
  or vsprojects/x64/Debug and vsprojects/x64/Release)
  will be searched for libraries and binaries.
``Protobuf_IMPORT_DIRS``
  List of additional directories to be searched for
  imported .proto files.
``Protobuf_DEBUG``
  .. versionadded:: 3.6

  Show debug messages.
``Protobuf_USE_STATIC_LIBS``
  .. versionadded:: 3.9

  Set to ON to force the use of the static libraries.
  Default is OFF.

Defines the following variables:

``Protobuf_FOUND``
  Found the Google Protocol Buffers library
  (libprotobuf & header files)
``Protobuf_VERSION``
  .. versionadded:: 3.6

  Version of package found.
``Protobuf_INCLUDE_DIRS``
  Include directories for Google Protocol Buffers
``Protobuf_LIBRARIES``
  The protobuf libraries
``Protobuf_PROTOC_LIBRARIES``
  The protoc libraries
``Protobuf_LITE_LIBRARIES``
  The protobuf-lite libraries

.. versionadded:: 3.9
  The following :prop_tgt:`IMPORTED` targets are also defined:

``protobuf::libprotobuf``
  The protobuf library.
``protobuf::libprotobuf-lite``
  The protobuf lite library.
``protobuf::libprotoc``
  The protoc library.
``protobuf::protoc``
  .. versionadded:: 3.10
    The protoc compiler.

The following cache variables are also available to set or use:

``Protobuf_LIBRARY``
  The protobuf library
``Protobuf_PROTOC_LIBRARY``
  The protoc library
``Protobuf_INCLUDE_DIR``
  The include directory for protocol buffers
``Protobuf_PROTOC_EXECUTABLE``
  The protoc compiler
``Protobuf_LIBRARY_DEBUG``
  The protobuf library (debug)
``Protobuf_PROTOC_LIBRARY_DEBUG``
  The protoc library (debug)
``Protobuf_LITE_LIBRARY``
  The protobuf lite library
``Protobuf_LITE_LIBRARY_DEBUG``
  The protobuf lite library (debug)

Example:

.. code-block:: cmake

  find_package(Protobuf REQUIRED)
  include_directories(${Protobuf_INCLUDE_DIRS})
  include_directories(${CMAKE_CURRENT_BINARY_DIR})
  protobuf_generate_cpp(PROTO_SRCS PROTO_HDRS foo.proto)
  protobuf_generate_cpp(PROTO_SRCS PROTO_HDRS EXPORT_MACRO DLL_EXPORT foo.proto)
  protobuf_generate_cpp(PROTO_SRCS PROTO_HDRS DESCRIPTORS PROTO_DESCS foo.proto)
  protobuf_generate_python(PROTO_PY foo.proto)
  add_executable(bar bar.cc ${PROTO_SRCS} ${PROTO_HDRS})
  target_link_libraries(bar ${Protobuf_LIBRARIES})

.. note::
  The ``protobuf_generate_cpp`` and ``protobuf_generate_python``
  functions and :command:`add_executable` or :command:`add_library`
  calls only work properly within the same directory.

.. command:: protobuf_generate_cpp

  Add custom commands to process ``.proto`` files to C++::

    protobuf_generate_cpp (<SRCS> <HDRS>
        [DESCRIPTORS <DESC>] [EXPORT_MACRO <MACRO>] [<ARGN>...])

  ``SRCS``
    Variable to define with autogenerated source files
  ``HDRS``
    Variable to define with autogenerated header files
  ``DESCRIPTORS``
    .. versionadded:: 3.10
      Variable to define with autogenerated descriptor files, if requested.
  ``EXPORT_MACRO``
    is a macro which should expand to ``__declspec(dllexport)`` or
    ``__declspec(dllimport)`` depending on what is being compiled.
  ``ARGN``
    ``.proto`` files

.. command:: protobuf_generate_python

  .. versionadded:: 3.4

  Add custom commands to process ``.proto`` files to Python::

    protobuf_generate_python (<PY> [<ARGN>...])

  ``PY``
    Variable to define with autogenerated Python files
  ``ARGN``
    ``.proto`` files
#]=======================================================================]

function(protobuf_generate)
  set(_options APPEND_PATH DESCRIPTORS)
  set(_singleargs LANGUAGE OUT_VAR EXPORT_MACRO PROTOC_OUT_DIR PLUGIN)
  if(COMMAND target_sources)
    list(APPEND _singleargs TARGET)
  endif()
  set(_multiargs PROTOS IMPORT_DIRS GENERATE_EXTENSIONS)

  cmake_parse_arguments(protobuf_generate "${_options}" "${_singleargs}" "${_multiargs}" "${ARGN}")

  if(NOT protobuf_generate_PROTOS AND NOT protobuf_generate_TARGET)
    message(SEND_ERROR "Error: protobuf_generate called without any targets or source files")
    return()
  endif()

  if(NOT protobuf_generate_OUT_VAR AND NOT protobuf_generate_TARGET)
    message(SEND_ERROR "Error: protobuf_generate called without a target or output variable")
    return()
  endif()

  if(NOT protobuf_generate_LANGUAGE)
    set(protobuf_generate_LANGUAGE cpp)
  endif()
  string(TOLOWER ${protobuf_generate_LANGUAGE} protobuf_generate_LANGUAGE)

  if(NOT protobuf_generate_PROTOC_OUT_DIR)
    set(protobuf_generate_PROTOC_OUT_DIR ${CMAKE_CURRENT_BINARY_DIR})
  endif()

  if(protobuf_generate_EXPORT_MACRO AND protobuf_generate_LANGUAGE STREQUAL cpp)
    set(_dll_export_decl "dllexport_decl=${protobuf_generate_EXPORT_MACRO}:")
  endif()

  if(protobuf_generate_PLUGIN)
    set(_plugin "--plugin=${protobuf_generate_PLUGIN}")
  endif()

  if(NOT protobuf_generate_GENERATE_EXTENSIONS)
    if(protobuf_generate_LANGUAGE STREQUAL cpp)
      set(protobuf_generate_GENERATE_EXTENSIONS .pb.h .pb.cc)
    elseif(protobuf_generate_LANGUAGE STREQUAL c)
      set(protobuf_generate_GENERATE_EXTENSIONS .pb-c.h .pb-c.c)
    elseif(protobuf_generate_LANGUAGE STREQUAL python)
      set(protobuf_generate_GENERATE_EXTENSIONS _pb2.py)
    else()
      message(SEND_ERROR "Error: protobuf_generate given unknown Language ${LANGUAGE}, please provide a value for GENERATE_EXTENSIONS")
      return()
    endif()
  endif()

  if(protobuf_generate_TARGET)
    get_target_property(_source_list ${protobuf_generate_TARGET} SOURCES)
    foreach(_file ${_source_list})
      if(_file MATCHES "proto$")
        list(APPEND protobuf_generate_PROTOS ${_file})
      endif()
    endforeach()
  endif()

  if(NOT protobuf_generate_PROTOS)
    message(SEND_ERROR "Error: protobuf_generate could not find any .proto files")
    return()
  endif()

  if(protobuf_generate_APPEND_PATH)
    # Create an include path for each file specified
    foreach(_file ${protobuf_generate_PROTOS})
      get_filename_component(_abs_file ${_file} ABSOLUTE)
      get_filename_component(_abs_path ${_abs_file} 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()

  foreach(DIR ${protobuf_generate_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()

  set(_generated_srcs_all)
  foreach(_proto ${protobuf_generate_PROTOS})
    get_filename_component(_abs_file ${_proto} ABSOLUTE)
    get_filename_component(_abs_dir ${_abs_file} DIRECTORY)
    get_filename_component(_basename ${_proto} NAME_WLE)
    file(RELATIVE_PATH _rel_dir ${CMAKE_CURRENT_SOURCE_DIR} ${_abs_dir})

    set(_possible_rel_dir)
    if (NOT protobuf_generate_APPEND_PATH)
        set(_possible_rel_dir ${_rel_dir}/)
    endif()

    set(RelDir)
    if (NOT ${_rel_dir} STREQUAL "")
      set(RelDir /${_rel_dir})
      file(MAKE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}${RelDir})
    endif()

    set(_generated_srcs)
    if (protobuf_generate_APPEND_PATH)
      foreach(_ext ${protobuf_generate_GENERATE_EXTENSIONS})
        list(APPEND _generated_srcs "${protobuf_generate_PROTOC_OUT_DIR}${RelDir}/${_basename}${_ext}")
      endforeach()
    else()
      foreach(_ext ${protobuf_generate_GENERATE_EXTENSIONS})
        list(APPEND _generated_srcs "${protobuf_generate_PROTOC_OUT_DIR}/${_possible_rel_dir}${_basename}${_ext}")
      endforeach()
    endif()

    if(protobuf_generate_DESCRIPTORS AND protobuf_generate_LANGUAGE STREQUAL cpp)
      set(_descriptor_file "${CMAKE_CURRENT_BINARY_DIR}/${_basename}.desc")
      set(_dll_desc_out "--descriptor_set_out=${_descriptor_file}")
      list(APPEND _generated_srcs ${_descriptor_file})
    endif()
    list(APPEND _generated_srcs_all ${_generated_srcs})

    add_custom_command(
      OUTPUT ${_generated_srcs}
      COMMAND  protobuf::protoc
      ARGS --${protobuf_generate_LANGUAGE}_out ${_dll_export_decl}${protobuf_generate_PROTOC_OUT_DIR}${RelDir} ${_plugin} ${_dll_desc_out} ${_protobuf_include_path} ${_abs_file}
      DEPENDS ${_abs_file} protobuf::protoc
      WORKING_DIRECTORY ${protobuf_generate_PROTOC_OUT_DIR}${RelDir}
      COMMENT "Running ${protobuf_generate_LANGUAGE} protocol buffer compiler on ${_proto}"
      VERBATIM )
  endforeach()

  set_source_files_properties(${_generated_srcs_all} PROPERTIES GENERATED TRUE)
  if(protobuf_generate_OUT_VAR)
    set(${protobuf_generate_OUT_VAR} ${_generated_srcs_all} PARENT_SCOPE)
  endif()
  if(protobuf_generate_TARGET)
    target_sources(${protobuf_generate_TARGET} PRIVATE ${_generated_srcs_all})
  endif()
endfunction()

function(PROTOBUF_GENERATE_C SRCS HDRS)
  cmake_parse_arguments(protobuf_generate_c "" "EXPORT_MACRO;DESCRIPTORS" "" ${ARGN})

  set(_proto_files "${protobuf_generate_c_UNPARSED_ARGUMENTS}")
  if(NOT _proto_files)
    message(SEND_ERROR "Error: PROTOBUF_GENERATE_C() called without any proto files")
    return()
  endif()

  if(PROTOBUF_GENERATE_CPP_APPEND_PATH)
    set(_append_arg APPEND_PATH)
  endif()

  if(protobuf_generate_c_DESCRIPTORS)
    set(_descriptors DESCRIPTORS)
  endif()

  if(DEFINED PROTOBUF_IMPORT_DIRS AND NOT DEFINED Protobuf_IMPORT_DIRS)
    set(Protobuf_IMPORT_DIRS "${PROTOBUF_IMPORT_DIRS}")
  endif()

  if(DEFINED Protobuf_IMPORT_DIRS)
    set(_import_arg IMPORT_DIRS ${Protobuf_IMPORT_DIRS})
  endif()

  set(_outvar)
  protobuf_generate(${_append_arg} ${_descriptors} LANGUAGE c EXPORT_MACRO ${protobuf_generate_c_EXPORT_MACRO} OUT_VAR _outvar ${_import_arg} PROTOS ${_proto_files})

  set(${SRCS})
  set(${HDRS})
  if(protobuf_generate_c_DESCRIPTORS)
    set(${protobuf_generate_c_DESCRIPTORS})
  endif()

  foreach(_file ${_outvar})
    if(_file MATCHES "c$")
      list(APPEND ${SRCS} ${_file})
    elseif(_file MATCHES "desc$")
      list(APPEND ${protobuf_generate_c_DESCRIPTORS} ${_file})
    else()
      list(APPEND ${HDRS} ${_file})
    endif()
  endforeach()
  set(${SRCS} ${${SRCS}} PARENT_SCOPE)
  set(${HDRS} ${${HDRS}} PARENT_SCOPE)
  if(protobuf_generate_c_DESCRIPTORS)
    set(${protobuf_generate_c_DESCRIPTORS} "${${protobuf_generate_c_DESCRIPTORS}}" PARENT_SCOPE)
  endif()
endfunction()

function(PROTOBUF_GENERATE_CPP SRCS HDRS)
  cmake_parse_arguments(protobuf_generate_cpp "" "EXPORT_MACRO;DESCRIPTORS" "" ${ARGN})

  set(_proto_files "${protobuf_generate_cpp_UNPARSED_ARGUMENTS}")
  if(NOT _proto_files)
    message(SEND_ERROR "Error: PROTOBUF_GENERATE_CPP() called without any proto files")
    return()
  endif()

  if(PROTOBUF_GENERATE_CPP_APPEND_PATH)
    set(_append_arg APPEND_PATH)
  endif()

  if(protobuf_generate_cpp_DESCRIPTORS)
    set(_descriptors DESCRIPTORS)
  endif()

  if(DEFINED PROTOBUF_IMPORT_DIRS AND NOT DEFINED Protobuf_IMPORT_DIRS)
    set(Protobuf_IMPORT_DIRS "${PROTOBUF_IMPORT_DIRS}")
  endif()

  if(DEFINED Protobuf_IMPORT_DIRS)
    set(_import_arg IMPORT_DIRS ${Protobuf_IMPORT_DIRS})
  endif()

  set(_outvar)
  protobuf_generate(${_append_arg} ${_descriptors} LANGUAGE cpp EXPORT_MACRO ${protobuf_generate_cpp_EXPORT_MACRO} OUT_VAR _outvar ${_import_arg} PROTOS ${_proto_files})

  set(${SRCS})
  set(${HDRS})
  if(protobuf_generate_cpp_DESCRIPTORS)
    set(${protobuf_generate_cpp_DESCRIPTORS})
  endif()

  foreach(_file ${_outvar})
    if(_file MATCHES "cc$")
      list(APPEND ${SRCS} ${_file})
    elseif(_file MATCHES "desc$")
      list(APPEND ${protobuf_generate_cpp_DESCRIPTORS} ${_file})
    else()
      list(APPEND ${HDRS} ${_file})
    endif()
  endforeach()
  set(${SRCS} ${${SRCS}} PARENT_SCOPE)
  set(${HDRS} ${${HDRS}} PARENT_SCOPE)
  if(protobuf_generate_cpp_DESCRIPTORS)
    set(${protobuf_generate_cpp_DESCRIPTORS} "${${protobuf_generate_cpp_DESCRIPTORS}}" PARENT_SCOPE)
  endif()
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)
    set(_append_arg APPEND_PATH)
  endif()

  if(DEFINED PROTOBUF_IMPORT_DIRS AND NOT DEFINED Protobuf_IMPORT_DIRS)
    set(Protobuf_IMPORT_DIRS "${PROTOBUF_IMPORT_DIRS}")
  endif()

  if(DEFINED Protobuf_IMPORT_DIRS)
    set(_import_arg IMPORT_DIRS ${Protobuf_IMPORT_DIRS})
  endif()

  set(_outvar)
  protobuf_generate(${_append_arg} LANGUAGE python OUT_VAR _outvar ${_import_arg} PROTOS ${ARGN})
  set(${SRCS} ${_outvar} PARENT_SCOPE)
endfunction()


if(Protobuf_DEBUG)
  # Output some of their choices
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                 "Protobuf_USE_STATIC_LIBS = ${Protobuf_USE_STATIC_LIBS}")
endif()


# 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(CMAKE_SIZEOF_VOID_P EQUAL 8)
  set(_PROTOBUF_ARCH_DIR x64/)
endif()


# Support preference of static libs by adjusting CMAKE_FIND_LIBRARY_SUFFIXES
if( Protobuf_USE_STATIC_LIBS )
  set( _protobuf_ORIG_CMAKE_FIND_LIBRARY_SUFFIXES ${CMAKE_FIND_LIBRARY_SUFFIXES})
  if(WIN32)
    set(CMAKE_FIND_LIBRARY_SUFFIXES .lib .a ${CMAKE_FIND_LIBRARY_SUFFIXES})
  else()
    set(CMAKE_FIND_LIBRARY_SUFFIXES .a )
  endif()
endif()

include(${CMAKE_ROOT}/Modules/SelectLibraryConfigurations.cmake)

# 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(${name}_LIBRARIES)
    # Use result recorded by a previous call.
    return()
  elseif(${name}_LIBRARY)
    # Honor cache entry used by CMake 3.5 and lower.
    set(${name}_LIBRARIES "${${name}_LIBRARY}" PARENT_SCOPE)
  else()
    find_library(${name}_LIBRARY_RELEASE
      NAMES ${filename}
      NAMES_PER_DIR
      PATHS ${Protobuf_SRC_ROOT_FOLDER}/vsprojects/${_PROTOBUF_ARCH_DIR}Release)
    mark_as_advanced(${name}_LIBRARY_RELEASE)

    find_library(${name}_LIBRARY_DEBUG
      NAMES ${filename}d ${filename}
      NAMES_PER_DIR
      PATHS ${Protobuf_SRC_ROOT_FOLDER}/vsprojects/${_PROTOBUF_ARCH_DIR}Debug)
    mark_as_advanced(${name}_LIBRARY_DEBUG)

    select_library_configurations(${name})

    if(UNIX AND Threads_FOUND AND ${name}_LIBRARY)
      list(APPEND ${name}_LIBRARIES ${CMAKE_THREAD_LIBS_INIT})
    endif()

    set(${name}_LIBRARY "${${name}_LIBRARY}" PARENT_SCOPE)
    set(${name}_LIBRARIES "${${name}_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()


# Google's provided vcproj files generate libraries with a "lib"
# prefix on Windows
if(MSVC)
    set(Protobuf_ORIG_FIND_LIBRARY_PREFIXES "${CMAKE_FIND_LIBRARY_PREFIXES}")
    set(CMAKE_FIND_LIBRARY_PREFIXES "lib" "")

    find_path(Protobuf_SRC_ROOT_FOLDER protobuf.pc.in)
endif()

if(UNIX)
  # Protobuf headers may depend on threading.
  find_package(Threads QUIET)
endif()

# The Protobuf library
_protobuf_find_libraries(Protobuf protobuf)
#DOC "The Google Protocol Buffers RELEASE Library"

_protobuf_find_libraries(Protobuf_LITE protobuf-lite)

# The Protobuf Protoc Library
_protobuf_find_libraries(Protobuf_PROTOC protoc)

# Restore original find library prefixes
if(MSVC)
    set(CMAKE_FIND_LIBRARY_PREFIXES "${Protobuf_ORIG_FIND_LIBRARY_PREFIXES}")
endif()

# Find the include directory
find_path(Protobuf_INCLUDE_DIR
    google/protobuf/service.h
    PATHS ${Protobuf_SRC_ROOT_FOLDER}/src
)
mark_as_advanced(Protobuf_INCLUDE_DIR)

# Find the protoc Executable
find_program(Protobuf_PROTOC_EXECUTABLE
    NAMES protoc
    DOC "The Google Protocol Buffers Compiler"
    PATHS
    ${Protobuf_SRC_ROOT_FOLDER}/vsprojects/${_PROTOBUF_ARCH_DIR}Release
    ${Protobuf_SRC_ROOT_FOLDER}/vsprojects/${_PROTOBUF_ARCH_DIR}Debug
)
mark_as_advanced(Protobuf_PROTOC_EXECUTABLE)

if(Protobuf_DEBUG)
    message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
        "requested version of Google Protobuf is ${Protobuf_FIND_VERSION}")
endif()

if(Protobuf_INCLUDE_DIR)
  set(_PROTOBUF_COMMON_HEADER ${Protobuf_INCLUDE_DIR}/google/protobuf/stubs/common.h)

  if(Protobuf_DEBUG)
    message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                   "location of common.h: ${_PROTOBUF_COMMON_HEADER}")
  endif()

  set(Protobuf_VERSION "")
  set(Protobuf_LIB_VERSION "")
  file(STRINGS ${_PROTOBUF_COMMON_HEADER} _PROTOBUF_COMMON_H_CONTENTS REGEX "#define[ \t]+GOOGLE_PROTOBUF_VERSION[ \t]+")
  if(_PROTOBUF_COMMON_H_CONTENTS MATCHES "#define[ \t]+GOOGLE_PROTOBUF_VERSION[ \t]+([0-9]+)")
      set(Protobuf_LIB_VERSION "${CMAKE_MATCH_1}")
  endif()
  unset(_PROTOBUF_COMMON_H_CONTENTS)

  math(EXPR _PROTOBUF_MAJOR_VERSION "${Protobuf_LIB_VERSION} / 1000000")
  math(EXPR _PROTOBUF_MINOR_VERSION "${Protobuf_LIB_VERSION} / 1000 % 1000")
  math(EXPR _PROTOBUF_SUBMINOR_VERSION "${Protobuf_LIB_VERSION} % 1000")
  set(Protobuf_VERSION "${_PROTOBUF_MAJOR_VERSION}.${_PROTOBUF_MINOR_VERSION}.${_PROTOBUF_SUBMINOR_VERSION}")

  if(Protobuf_DEBUG)
    message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
        "${_PROTOBUF_COMMON_HEADER} reveals protobuf ${Protobuf_VERSION}")
  endif()

  if(Protobuf_PROTOC_EXECUTABLE)
    # Check Protobuf compiler version to be aligned with libraries version
    execute_process(COMMAND ${Protobuf_PROTOC_EXECUTABLE} --version
                    OUTPUT_VARIABLE _PROTOBUF_PROTOC_EXECUTABLE_VERSION)

    if("${_PROTOBUF_PROTOC_EXECUTABLE_VERSION}" MATCHES "libprotoc ([0-9.]+)")
      set(_PROTOBUF_PROTOC_EXECUTABLE_VERSION "${CMAKE_MATCH_1}")
    endif()

    if(Protobuf_DEBUG)
      message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
          "${Protobuf_PROTOC_EXECUTABLE} reveals version ${_PROTOBUF_PROTOC_EXECUTABLE_VERSION}")
    endif()

    if(NOT "${_PROTOBUF_PROTOC_EXECUTABLE_VERSION}" VERSION_EQUAL "${Protobuf_VERSION}")
      message(WARNING "Protobuf compiler version ${_PROTOBUF_PROTOC_EXECUTABLE_VERSION}"
        " doesn't match library version ${Protobuf_VERSION}")
    endif()
  endif()

  if(Protobuf_LIBRARY)
      if(NOT TARGET protobuf::libprotobuf)
          add_library(protobuf::libprotobuf UNKNOWN IMPORTED)
          set_target_properties(protobuf::libprotobuf PROPERTIES
            INTERFACE_INCLUDE_DIRECTORIES "${Protobuf_INCLUDE_DIR}")
          if(EXISTS "${Protobuf_LIBRARY}")
            set_target_properties(protobuf::libprotobuf PROPERTIES
              IMPORTED_LOCATION "${Protobuf_LIBRARY}")
          endif()
          if(EXISTS "${Protobuf_LIBRARY_RELEASE}")
            set_property(TARGET protobuf::libprotobuf APPEND PROPERTY
              IMPORTED_CONFIGURATIONS RELEASE)
            set_target_properties(protobuf::libprotobuf PROPERTIES
              IMPORTED_LOCATION_RELEASE "${Protobuf_LIBRARY_RELEASE}")
          endif()
          if(EXISTS "${Protobuf_LIBRARY_DEBUG}")
            set_property(TARGET protobuf::libprotobuf APPEND PROPERTY
              IMPORTED_CONFIGURATIONS DEBUG)
            set_target_properties(protobuf::libprotobuf PROPERTIES
              IMPORTED_LOCATION_DEBUG "${Protobuf_LIBRARY_DEBUG}")
          endif()
          if (Protobuf_VERSION VERSION_GREATER_EQUAL "3.6")
            set_property(TARGET protobuf::libprotobuf APPEND PROPERTY
              INTERFACE_COMPILE_FEATURES cxx_std_11
            )
          endif()
          if (MSVC AND NOT Protobuf_USE_STATIC_LIBS)
            set_property(TARGET protobuf::libprotobuf APPEND PROPERTY
              INTERFACE_COMPILE_DEFINITIONS "PROTOBUF_USE_DLLS"
            )
          endif()
          if(UNIX AND TARGET Threads::Threads)
            set_property(TARGET protobuf::libprotobuf APPEND PROPERTY
                INTERFACE_LINK_LIBRARIES Threads::Threads)
          endif()
      endif()
  endif()

  if(Protobuf_LITE_LIBRARY)
      if(NOT TARGET protobuf::libprotobuf-lite)
          add_library(protobuf::libprotobuf-lite UNKNOWN IMPORTED)
          set_target_properties(protobuf::libprotobuf-lite PROPERTIES
            INTERFACE_INCLUDE_DIRECTORIES "${Protobuf_INCLUDE_DIR}")
          if(EXISTS "${Protobuf_LITE_LIBRARY}")
            set_target_properties(protobuf::libprotobuf-lite PROPERTIES
              IMPORTED_LOCATION "${Protobuf_LITE_LIBRARY}")
          endif()
          if(EXISTS "${Protobuf_LITE_LIBRARY_RELEASE}")
            set_property(TARGET protobuf::libprotobuf-lite APPEND PROPERTY
              IMPORTED_CONFIGURATIONS RELEASE)
            set_target_properties(protobuf::libprotobuf-lite PROPERTIES
              IMPORTED_LOCATION_RELEASE "${Protobuf_LITE_LIBRARY_RELEASE}")
          endif()
          if(EXISTS "${Protobuf_LITE_LIBRARY_DEBUG}")
            set_property(TARGET protobuf::libprotobuf-lite APPEND PROPERTY
              IMPORTED_CONFIGURATIONS DEBUG)
            set_target_properties(protobuf::libprotobuf-lite PROPERTIES
              IMPORTED_LOCATION_DEBUG "${Protobuf_LITE_LIBRARY_DEBUG}")
          endif()
          if (MSVC AND NOT Protobuf_USE_STATIC_LIBS)
            set_property(TARGET protobuf::libprotobuf-lite APPEND PROPERTY
              INTERFACE_COMPILE_DEFINITIONS "PROTOBUF_USE_DLLS"
            )
          endif()
          if(UNIX AND TARGET Threads::Threads)
            set_property(TARGET protobuf::libprotobuf-lite APPEND PROPERTY
                INTERFACE_LINK_LIBRARIES Threads::Threads)
          endif()
      endif()
  endif()

  if(Protobuf_PROTOC_LIBRARY)
      if(NOT TARGET protobuf::libprotoc)
          add_library(protobuf::libprotoc UNKNOWN IMPORTED)
          set_target_properties(protobuf::libprotoc PROPERTIES
            INTERFACE_INCLUDE_DIRECTORIES "${Protobuf_INCLUDE_DIR}")
          if(EXISTS "${Protobuf_PROTOC_LIBRARY}")
            set_target_properties(protobuf::libprotoc PROPERTIES
              IMPORTED_LOCATION "${Protobuf_PROTOC_LIBRARY}")
          endif()
          if(EXISTS "${Protobuf_PROTOC_LIBRARY_RELEASE}")
            set_property(TARGET protobuf::libprotoc APPEND PROPERTY
              IMPORTED_CONFIGURATIONS RELEASE)
            set_target_properties(protobuf::libprotoc PROPERTIES
              IMPORTED_LOCATION_RELEASE "${Protobuf_PROTOC_LIBRARY_RELEASE}")
          endif()
          if(EXISTS "${Protobuf_PROTOC_LIBRARY_DEBUG}")
            set_property(TARGET protobuf::libprotoc APPEND PROPERTY
              IMPORTED_CONFIGURATIONS DEBUG)
            set_target_properties(protobuf::libprotoc PROPERTIES
              IMPORTED_LOCATION_DEBUG "${Protobuf_PROTOC_LIBRARY_DEBUG}")
          endif()
          if (Protobuf_VERSION VERSION_GREATER_EQUAL "3.6")
            set_property(TARGET protobuf::libprotoc APPEND PROPERTY
              INTERFACE_COMPILE_FEATURES cxx_std_11
            )
          endif()
          if (MSVC AND NOT Protobuf_USE_STATIC_LIBS)
            set_property(TARGET protobuf::libprotoc APPEND PROPERTY
              INTERFACE_COMPILE_DEFINITIONS "PROTOBUF_USE_DLLS"
            )
          endif()
          if(UNIX AND TARGET Threads::Threads)
            set_property(TARGET protobuf::libprotoc APPEND PROPERTY
                INTERFACE_LINK_LIBRARIES Threads::Threads)
          endif()
      endif()
  endif()

  if(Protobuf_PROTOC_EXECUTABLE)
      if(NOT TARGET protobuf::protoc)
          add_executable(protobuf::protoc IMPORTED)
          if(EXISTS "${Protobuf_PROTOC_EXECUTABLE}")
            set_target_properties(protobuf::protoc PROPERTIES
              IMPORTED_LOCATION "${Protobuf_PROTOC_EXECUTABLE}")
          endif()
      endif()
  endif()
endif()

include(${CMAKE_ROOT}/Modules/FindPackageHandleStandardArgs.cmake)
FIND_PACKAGE_HANDLE_STANDARD_ARGS(Protobuf
    REQUIRED_VARS Protobuf_LIBRARIES Protobuf_INCLUDE_DIR
    VERSION_VAR Protobuf_VERSION
)

if(Protobuf_FOUND)
    set(Protobuf_INCLUDE_DIRS ${Protobuf_INCLUDE_DIR})
endif()

# Restore the original find library ordering
if( Protobuf_USE_STATIC_LIBS )
  set(CMAKE_FIND_LIBRARY_SUFFIXES ${_protobuf_ORIG_CMAKE_FIND_LIBRARY_SUFFIXES})
endif()

# Backwards compatibility
# Define upper case versions of output variables
foreach(Camel
    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()