option(ENABLE_GRPC_REFLECTION "Link to gRPC Reflection library" OFF)
# FIXME(kirillbobyrev): Check if gRPC and Protobuf headers can be included at
# configure time.
find_package(Threads REQUIRED)
if (GRPC_INSTALL_PATH)
# This setup requires gRPC to be built from sources using CMake and installed
# to ${GRPC_INSTALL_PATH} via -DCMAKE_INSTALL_PREFIX=${GRPC_INSTALL_PATH}.
# Libraries will be linked according to gRPC build policy which generates
# static libraries when BUILD_SHARED_LIBS is Off and dynamic libraries when
# it's On (NOTE: This is a variable passed to gRPC CMake build invocation,
# LLVM's BUILD_SHARED_LIBS has no effect).
set(protobuf_MODULE_COMPATIBLE TRUE)
find_package(Protobuf CONFIG REQUIRED HINTS ${GRPC_INSTALL_PATH})
message(STATUS "Using protobuf ${Protobuf_VERSION}")
find_package(gRPC CONFIG REQUIRED HINTS ${GRPC_INSTALL_PATH})
message(STATUS "Using gRPC ${gRPC_VERSION}")
include_directories(${Protobuf_INCLUDE_DIRS})
# gRPC CMake CONFIG gives the libraries slightly odd names, make them match
# the conventional system-installed names.
set_target_properties(protobuf::libprotobuf PROPERTIES IMPORTED_GLOBAL TRUE)
add_library(protobuf ALIAS protobuf::libprotobuf)
set_target_properties(gRPC::grpc++ PROPERTIES IMPORTED_GLOBAL TRUE)
add_library(grpc++ ALIAS gRPC::grpc++)
if (ENABLE_GRPC_REFLECTION)
set_target_properties(gRPC::grpc++_reflection PROPERTIES IMPORTED_GLOBAL TRUE)
add_library(grpc++_reflection ALIAS gRPC::grpc++_reflection)
endif()
set(GRPC_CPP_PLUGIN $<TARGET_FILE:gRPC::grpc_cpp_plugin>)
set(PROTOC ${Protobuf_PROTOC_EXECUTABLE})
else()
# This setup requires system-installed gRPC and Protobuf.
# We always link dynamically in this mode. While the static libraries are
# usually installed, the CMake files telling us *which* static libraries to
# link are not.
if (NOT BUILD_SHARED_LIBS)
message(NOTICE "gRPC and Protobuf will be linked dynamically. If you want static linking, build gRPC from sources with -DBUILD_SHARED_LIBS=Off.")
endif()
find_program(GRPC_CPP_PLUGIN grpc_cpp_plugin)
find_program(PROTOC protoc)
if (NOT GRPC_CPP_PLUGIN OR NOT PROTOC)
message(FATAL_ERROR "gRPC C++ Plugin and Protoc must be on $PATH for gRPC-enabled build.")
endif()
# On macOS the libraries are typically installed via Homebrew and are not on
# the system path.
set(GRPC_OPTS "")
set(PROTOBUF_OPTS "")
set(GRPC_INCLUDE_PATHS "")
if (${APPLE})
find_program(HOMEBREW brew)
# If Homebrew is not found, the user might have installed libraries
# manually. Fall back to the system path.
if (HOMEBREW)
execute_process(COMMAND ${HOMEBREW} --prefix grpc
OUTPUT_VARIABLE GRPC_HOMEBREW_PATH
RESULT_VARIABLE GRPC_HOMEBREW_RETURN_CODE
OUTPUT_STRIP_TRAILING_WHITESPACE)
execute_process(COMMAND ${HOMEBREW} --prefix protobuf
OUTPUT_VARIABLE PROTOBUF_HOMEBREW_PATH
RESULT_VARIABLE PROTOBUF_HOMEBREW_RETURN_CODE
OUTPUT_STRIP_TRAILING_WHITESPACE)
execute_process(COMMAND ${HOMEBREW} --prefix abseil
OUTPUT_VARIABLE ABSL_HOMEBREW_PATH
RESULT_VARIABLE ABSL_HOMEBREW_RETURN_CODE
OUTPUT_STRIP_TRAILING_WHITESPACE)
# If either library is not installed via Homebrew, fall back to the
# system path.
if (GRPC_HOMEBREW_RETURN_CODE EQUAL "0")
list(APPEND GRPC_INCLUDE_PATHS ${GRPC_HOMEBREW_PATH}/include)
list(APPEND GRPC_OPTS PATHS ${GRPC_HOMEBREW_PATH}/lib NO_DEFAULT_PATH)
endif()
if (PROTOBUF_HOMEBREW_RETURN_CODE EQUAL "0")
list(APPEND GRPC_INCLUDE_PATHS ${PROTOBUF_HOMEBREW_PATH}/include)
list(APPEND PROTOBUF_OPTS PATHS ${PROTOBUF_HOMEBREW_PATH}/lib NO_DEFAULT_PATH)
endif()
if (ABSL_HOMEBREW_RETURN_CODE EQUAL "0")
list(APPEND GRPC_INCLUDE_PATHS ${ABSL_HOMEBREW_PATH}/include)
endif()
endif()
endif()
if(NOT TARGET grpc++)
find_library(GRPC_LIBRARY grpc++ ${GRPC_OPTS} REQUIRED)
add_library(grpc++ UNKNOWN IMPORTED GLOBAL)
message(STATUS "Using grpc++: " ${GRPC_LIBRARY})
set_target_properties(grpc++ PROPERTIES IMPORTED_LOCATION ${GRPC_LIBRARY})
target_include_directories(grpc++ INTERFACE ${GRPC_INCLUDE_PATHS})
if (ENABLE_GRPC_REFLECTION)
find_library(GRPC_REFLECTION_LIBRARY grpc++_reflection ${GRPC_OPTS} REQUIRED)
add_library(grpc++_reflection UNKNOWN IMPORTED GLOBAL)
set_target_properties(grpc++_reflection PROPERTIES IMPORTED_LOCATION ${GRPC_REFLECTION_LIBRARY})
endif()
find_library(PROTOBUF_LIBRARY protobuf ${PROTOBUF_OPTS} REQUIRED)
message(STATUS "Using protobuf: " ${PROTOBUF_LIBRARY})
add_library(protobuf UNKNOWN IMPORTED GLOBAL)
set_target_properties(protobuf PROPERTIES IMPORTED_LOCATION ${PROTOBUF_LIBRARY})
endif()
endif()
if (ENABLE_GRPC_REFLECTION)
set(REFLECTION_LIBRARY grpc++_reflection)
endif()
# Proto headers are generated in ${CMAKE_CURRENT_BINARY_DIR}.
# Libraries that use these headers should adjust the include path.
# If the "GRPC" argument is given, services are also generated.
# The DEPENDS list should name *.proto source files that are imported.
# They may be relative to the source dir or absolute (for generated protos).
function(generate_proto_sources GeneratedSource ProtoFile)
cmake_parse_arguments(PARSE_ARGV 2 PROTO "GRPC" "" "DEPENDS")
get_filename_component(ProtoSourceAbsolutePath "${CMAKE_CURRENT_SOURCE_DIR}/${ProtoFile}" ABSOLUTE)
get_filename_component(ProtoSourcePath ${ProtoSourceAbsolutePath} PATH)
get_filename_component(Basename ${ProtoSourceAbsolutePath} NAME_WLE)
set(GeneratedProtoSource "${CMAKE_CURRENT_BINARY_DIR}/${Basename}.pb.cc")
set(GeneratedProtoHeader "${CMAKE_CURRENT_BINARY_DIR}/${Basename}.pb.h")
set(Flags
--cpp_out="${CMAKE_CURRENT_BINARY_DIR}"
--proto_path="${ProtoSourcePath}")
if (PROTO_GRPC)
list(APPEND Flags
--grpc_out="${CMAKE_CURRENT_BINARY_DIR}"
--plugin=protoc-gen-grpc="${GRPC_CPP_PLUGIN}")
list(APPEND GeneratedProtoSource "${CMAKE_CURRENT_BINARY_DIR}/${Basename}.grpc.pb.cc")
list(APPEND GeneratedProtoHeader "${CMAKE_CURRENT_BINARY_DIR}/${Basename}.grpc.pb.h")
endif()
add_custom_command(
OUTPUT ${GeneratedProtoSource} ${GeneratedProtoHeader}
COMMAND ${PROTOC}
ARGS ${Flags} "${ProtoSourceAbsolutePath}"
DEPENDS "${ProtoSourceAbsolutePath}")
set(${GeneratedSource} ${GeneratedProtoSource} PARENT_SCOPE)
# Ensure dependency headers are generated before dependent protos are built.
# DEPENDS arg is a list of "Foo.proto". While they're logically relative to
# the source dir, the generated headers we need are in the binary dir.
foreach(ImportedProto IN LISTS PROTO_DEPENDS)
# Foo.proto -> Foo.pb.h
STRING(REGEX REPLACE "\\.proto$" ".pb.h" ImportedHeader "${ImportedProto}")
# Foo.pb.h -> ${CMAKE_CURRENT_BINARY_DIR}/Foo.pb.h
get_filename_component(ImportedHeader "${ImportedHeader}"
ABSOLUTE
BASE_DIR "${CMAKE_CURRENT_BINARY_DIR}")
# Compilation of each generated source depends on ${BINARY}/Foo.pb.h.
foreach(Generated IN LISTS GeneratedProtoSource)
# FIXME: CMake docs suggest OBJECT_DEPENDS isn't needed, but I can't get
# the recommended add_dependencies() approach to work.
set_source_files_properties("${Generated}"
PROPERTIES OBJECT_DEPENDS "${ImportedHeader}")
endforeach(Generated)
endforeach(ImportedProto)
endfunction()