1option(ENABLE_GRPC_REFLECTION "Link clangd-index-server to gRPC Reflection library" OFF)
2
3# FIXME(kirillbobyrev): Check if gRPC and Protobuf headers can be included at
4# configure time.
5find_package(Threads REQUIRED)
6if (GRPC_INSTALL_PATH)
7  # This setup requires gRPC to be built from sources using CMake and installed
8  # to ${GRPC_INSTALL_PATH} via -DCMAKE_INSTALL_PREFIX=${GRPC_INSTALL_PATH}.
9  # Libraries will be linked according to gRPC build policy which generates
10  # static libraries when BUILD_SHARED_LIBS is Off and dynamic libraries when
11  # it's On (NOTE: This is a variable passed to gRPC CMake build invocation,
12  # LLVM's BUILD_SHARED_LIBS has no effect).
13  set(protobuf_MODULE_COMPATIBLE TRUE)
14  find_package(Protobuf CONFIG REQUIRED HINTS ${GRPC_INSTALL_PATH})
15  message(STATUS "Using protobuf ${protobuf_VERSION}")
16  find_package(gRPC CONFIG REQUIRED HINTS ${GRPC_INSTALL_PATH})
17  message(STATUS "Using gRPC ${gRPC_VERSION}")
18
19  include_directories(${Protobuf_INCLUDE_DIRS})
20
21  # gRPC CMake CONFIG gives the libraries slightly odd names, make them match
22  # the conventional system-installed names.
23  set_target_properties(protobuf::libprotobuf PROPERTIES IMPORTED_GLOBAL TRUE)
24  add_library(protobuf ALIAS protobuf::libprotobuf)
25  set_target_properties(gRPC::grpc++ PROPERTIES IMPORTED_GLOBAL TRUE)
26  add_library(grpc++ ALIAS gRPC::grpc++)
27  if (ENABLE_GRPC_REFLECTION)
28    set_target_properties(gRPC::grpc++_reflection PROPERTIES IMPORTED_GLOBAL TRUE)
29    add_library(grpc++_reflection ALIAS gRPC::grpc++_reflection)
30  endif()
31
32  set(GRPC_CPP_PLUGIN $<TARGET_FILE:gRPC::grpc_cpp_plugin>)
33  set(PROTOC ${Protobuf_PROTOC_EXECUTABLE})
34else()
35  # This setup requires system-installed gRPC and Protobuf.
36  # We always link dynamically in this mode. While the static libraries are
37  # usually installed, the CMake files telling us *which* static libraries to
38  # link are not.
39  if (NOT BUILD_SHARED_LIBS)
40    message(NOTICE "gRPC and Protobuf will be linked dynamically. If you want static linking, build gRPC from sources with -DBUILD_SHARED_LIBS=Off.")
41  endif()
42  find_program(GRPC_CPP_PLUGIN grpc_cpp_plugin)
43  find_program(PROTOC protoc)
44  if (NOT GRPC_CPP_PLUGIN OR NOT PROTOC)
45    message(FATAL_ERROR "gRPC C++ Plugin and Protoc must be on $PATH for Clangd remote index build.")
46  endif()
47  # On macOS the libraries are typically installed via Homebrew and are not on
48  # the system path.
49  set(GRPC_OPTS "")
50  set(PROTOBUF_OPTS "")
51  if (${APPLE})
52    find_program(HOMEBREW brew)
53    # If Homebrew is not found, the user might have installed libraries
54    # manually. Fall back to the system path.
55    if (HOMEBREW)
56      execute_process(COMMAND ${HOMEBREW} --prefix grpc
57        OUTPUT_VARIABLE GRPC_HOMEBREW_PATH
58        RESULT_VARIABLE GRPC_HOMEBREW_RETURN_CODE
59        OUTPUT_STRIP_TRAILING_WHITESPACE)
60      execute_process(COMMAND ${HOMEBREW} --prefix protobuf
61        OUTPUT_VARIABLE PROTOBUF_HOMEBREW_PATH
62        RESULT_VARIABLE PROTOBUF_HOMEBREW_RETURN_CODE
63        OUTPUT_STRIP_TRAILING_WHITESPACE)
64      # If either library is not installed via Homebrew, fall back to the
65      # system path.
66      if (GRPC_HOMEBREW_RETURN_CODE EQUAL "0")
67        include_directories(${GRPC_HOMEBREW_PATH}/include)
68        list(APPEND GRPC_OPTS PATHS ${GRPC_HOMEBREW_PATH}/lib NO_DEFAULT_PATH)
69      endif()
70      if (PROTOBUF_HOMEBREW_RETURN_CODE EQUAL "0")
71        include_directories(${PROTOBUF_HOMEBREW_PATH}/include)
72        list(APPEND PROTOBUF_OPTS PATHS ${PROTOBUF_HOMEBREW_PATH}/lib NO_DEFAULT_PATH)
73      endif()
74    endif()
75  endif()
76  find_library(GRPC_LIBRARY grpc++ $GRPC_OPTS REQUIRED)
77  add_library(grpc++ UNKNOWN IMPORTED GLOBAL)
78  message(STATUS "Using grpc++: " ${GRPC_LIBRARY})
79  set_target_properties(grpc++ PROPERTIES IMPORTED_LOCATION ${GRPC_LIBRARY})
80  if (ENABLE_GRPC_REFLECTION)
81    find_library(GRPC_REFLECTION_LIBRARY grpc++_reflection $GRPC_OPTS REQUIRED)
82    add_library(grpc++_reflection UNKNOWN IMPORTED GLOBAL)
83    set_target_properties(grpc++_reflection PROPERTIES IMPORTED_LOCATION ${GRPC_REFLECTION_LIBRARY})
84  endif()
85  find_library(PROTOBUF_LIBRARY protobuf $PROTOBUF_OPTS REQUIRED)
86  message(STATUS "Using protobuf: " ${PROTOBUF_LIBRARY})
87  add_library(protobuf UNKNOWN IMPORTED GLOBAL)
88  set_target_properties(protobuf PROPERTIES IMPORTED_LOCATION ${PROTOBUF_LIBRARY})
89endif()
90
91if (ENABLE_GRPC_REFLECTION)
92  set(REFLECTION_LIBRARY grpc++_reflection)
93endif()
94
95# Proto headers are generated in ${CMAKE_CURRENT_BINARY_DIR}.
96# Libraries that use these headers should adjust the include path.
97# If the "GRPC" argument is given, services are also generated.
98# The DEPENDS list should name *.proto source files that are imported.
99# They may be relative to the source dir or absolute (for generated protos).
100function(generate_protos LibraryName ProtoFile)
101  cmake_parse_arguments(PARSE_ARGV 2 PROTO "GRPC" "" "DEPENDS")
102  get_filename_component(ProtoSourceAbsolutePath "${CMAKE_CURRENT_SOURCE_DIR}/${ProtoFile}" ABSOLUTE)
103  get_filename_component(ProtoSourcePath ${ProtoSourceAbsolutePath} PATH)
104  get_filename_component(Basename ${ProtoSourceAbsolutePath} NAME_WLE)
105
106  set(GeneratedProtoSource "${CMAKE_CURRENT_BINARY_DIR}/${Basename}.pb.cc")
107  set(GeneratedProtoHeader "${CMAKE_CURRENT_BINARY_DIR}/${Basename}.pb.h")
108  set(Flags
109    --cpp_out="${CMAKE_CURRENT_BINARY_DIR}"
110    --proto_path="${ProtoSourcePath}")
111  if (PROTO_GRPC)
112    list(APPEND Flags
113      --grpc_out="${CMAKE_CURRENT_BINARY_DIR}"
114      --plugin=protoc-gen-grpc="${GRPC_CPP_PLUGIN}")
115    list(APPEND GeneratedProtoSource "${CMAKE_CURRENT_BINARY_DIR}/${Basename}.grpc.pb.cc")
116    list(APPEND GeneratedProtoHeader "${CMAKE_CURRENT_BINARY_DIR}/${Basename}.grpc.pb.h")
117  endif()
118  add_custom_command(
119        OUTPUT ${GeneratedProtoSource} ${GeneratedProtoHeader}
120        COMMAND ${PROTOC}
121        ARGS ${Flags} "${ProtoSourceAbsolutePath}"
122        DEPENDS "${ProtoSourceAbsolutePath}")
123
124  add_clang_library(${LibraryName} ${GeneratedProtoSource}
125    PARTIAL_SOURCES_INTENDED
126    LINK_LIBS PUBLIC grpc++ protobuf)
127
128  # Ensure dependency headers are generated before dependent protos are built.
129  # DEPENDS arg is a list of "Foo.proto". While they're logically relative to
130  # the source dir, the generated headers we need are in the binary dir.
131  foreach(ImportedProto IN LISTS PROTO_DEPENDS)
132    # Foo.proto -> Foo.pb.h
133    STRING(REGEX REPLACE "\\.proto$" ".pb.h" ImportedHeader "${ImportedProto}")
134    # Foo.pb.h -> ${CMAKE_CURRENT_BINARY_DIR}/Foo.pb.h
135    get_filename_component(ImportedHeader "${ImportedHeader}"
136      ABSOLUTE
137      BASE_DIR "${CMAKE_CURRENT_BINARY_DIR}")
138    # Compilation of each generated source depends on ${BINARY}/Foo.pb.h.
139    foreach(Generated IN LISTS GeneratedProtoSource)
140      # FIXME: CMake docs suggest OBJECT_DEPENDS isn't needed, but I can't get
141      #        the recommended add_dependencies() approach to work.
142      set_source_files_properties("${Generated}"
143        PROPERTIES OBJECT_DEPENDS "${ImportedHeader}")
144    endforeach(Generated)
145  endforeach(ImportedProto)
146endfunction()
147