Use bundled generate_protobuf() function

cpp/CMakeLists.txt

@@ -221,25 +221,18 @@ endif ()
 set (RESOURCES_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../resources")
 
 set (
-  PROTOBUF_SOURCES "${RESOURCES_DIR}/phonemetadata.proto"
-                   "${RESOURCES_DIR}/phonenumber.proto"
+  PROTO_FILES "${RESOURCES_DIR}/phonemetadata.proto"
+              "${RESOURCES_DIR}/phonenumber.proto"
 )
 
-set (
-  PROTOBUF_OUTPUT "${CMAKE_CURRENT_SOURCE_DIR}/src/phonenumbers/phonemetadata.pb.cc"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/src/phonenumbers/phonemetadata.pb.h"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/src/phonenumbers/phonenumber.pb.cc"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/src/phonenumbers/phonenumber.pb.h"
-)
-
-add_custom_command (
-  COMMAND protobuf::protoc
-  ARGS --cpp_out=${CMAKE_CURRENT_SOURCE_DIR}/src/phonenumbers/ --proto_path=${RESOURCES_DIR} ${PROTOBUF_SOURCES}
-  VERBATIM
-
-  OUTPUT ${PROTOBUF_OUTPUT}
-  DEPENDS ${PROTOBUF_SOURCES}
-)
+add_library(proto-objects OBJECT ${PROTO_FILES})
+target_link_libraries(proto-objects PUBLIC protobuf::libprotobuf)
+set(PROTO_BINARY_DIR "${CMAKE_CURRENT_SOURCE_DIR}/src")
+target_include_directories(proto-objects PUBLIC "$<BUILD_INTERFACE:${PROTO_BINARY_DIR}>")
+protobuf_generate(
+    TARGET proto-objects
+    IMPORT_DIRS "${RESOURCES_DIR}"
+    PROTOC_OUT_DIR "${PROTO_BINARY_DIR}/phonenumbers")
 
 if (BUILD_GEOCODER)
   # Geocoding data cpp file generation
@@ -269,9 +262,7 @@ set (
   "src/phonenumbers/base/strings/string_piece.cc"
   "src/phonenumbers/default_logger.cc"
   "src/phonenumbers/logger.cc"
-  "src/phonenumbers/phonemetadata.pb.cc" # Generated by Protocol Buffers.
   "src/phonenumbers/phonenumber.cc"
-  "src/phonenumbers/phonenumber.pb.cc"   # Generated by Protocol Buffers.
   "src/phonenumbers/phonenumberutil.cc"
   "src/phonenumbers/regex_based_matcher.cc"
   "src/phonenumbers/regexp_cache.cc"
@@ -292,7 +283,6 @@ if (BUILD_GEOCODER)
     "src/phonenumbers/geocoding/geocoding_data.cc"
     "src/phonenumbers/geocoding/mapping_file_provider.cc"
     "src/phonenumbers/geocoding/phonenumber_offline_geocoder.cc"
-    "src/phonenumbers/phonenumber.pb.h"  # Forces proto buffer generation.
   )
 endif ()
 
@@ -452,6 +442,8 @@ if (APPLE)
   list (APPEND LIBRARY_DEPS ${COREFOUNDATION_LIB} ${FOUNDATION_LIB})
 endif ()
 
+list (APPEND LIBRARY_DEPS proto-objects)
+
 #----------------------------------------------------------------
 # Build libraries
 #----------------------------------------------------------------
@@ -603,7 +595,7 @@ endif()
 # Install built libraries
 #----------------------------------------------------------------
 
-set (BUILT_LIBS)
+set (BUILT_LIBS proto-objects)
 set(targets_export_name "${PROJECT_NAME}-targets")
 
 if (BUILD_STATIC_LIB)