build: refactor CMake scripts to use functions for variable scope (#87)

* build: refactor CMake scripts to use functions for variable scope

Wrap multiple CMake scripts in functions to restrict variable scope and prevent unintended resets. This ensures better modularity and maintainability in the build process while adhering to modern CMake best practices.

* refactor: simplify opentelemetry fetch logic

Streamline the handling of OpenTelemetry dependencies by removing unnecessary function wrappers and directly implementing the fetching logic. This improves readability and maintainability while ensuring that relevant variables are correctly set within the proper scope.

* refactor: encapsulate OpenTelemetry configuration in a function

Wrap the OpenTelemetry setup in a function to limit variable scope, improving code organization and maintainability.

CMakeLists.txt

@@ -5,6 +5,11 @@ cmake_minimum_required(VERSION 3.24)
 
 project(aimrt LANGUAGES C CXX)
 
+# Prevent variables from being reset by option
+# This setting allows predefined variables to take precedence for FetchContent_MakeAvailable()
+# see: https://cmake.org/cmake/help/latest/policy/CMP0077.html
+set(CMAKE_POLICY_DEFAULT_CMP0077 NEW)
+
 # Set cmake path
 list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake)
 

cmake/GetAsio.cmake

@@ -22,6 +22,8 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_asio)
   FetchContent_GetProperties(asio)
   if(NOT asio_POPULATED)
     FetchContent_Populate(asio)
@@ -77,6 +79,9 @@ if(NOT asio_POPULATED)
 
     install(EXPORT asio-config DESTINATION lib/cmake/asio)
   endif()
+endfunction()
+
+get_asio()
 
 # import targets：
 # asio::asio

cmake/GetBoost.cmake

@@ -22,13 +22,16 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_boost)
   FetchContent_GetProperties(boost)
   if(NOT boost_POPULATED)
     set(BOOST_INCLUDE_LIBRARIES asio beast)
 
-  set(Boost_USE_STATIC_LIBS
+    set(Boost_USE_STATIC_LIBS ON)
-      ON
-      CACHE BOOL "")
 
     FetchContent_MakeAvailable(boost)
   endif()
+endfunction()
+
+get_boost()

cmake/GetCppToml.cmake

@@ -23,6 +23,8 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_cpptoml)
   FetchContent_GetProperties(cpptoml)
   if(NOT cpptoml_POPULATED)
     FetchContent_Populate(cpptoml)
@@ -47,3 +49,6 @@ if(NOT cpptoml_POPULATED)
     add_subdirectory(${cpptoml_SOURCE_DIR} ${cpptoml_BINARY_DIR})
 
   endif()
+endfunction()
+
+get_cpptoml()

cmake/GetFmt.cmake

@@ -22,17 +22,19 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_fmt)
   FetchContent_GetProperties(fmt)
   if(NOT fmt_POPULATED)
-  set(FMT_MASTER_PROJECT
+    set(FMT_MASTER_PROJECT OFF)
-      OFF
+
-      CACHE BOOL "")
+    set(FMT_INSTALL ON)
-  set(FMT_INSTALL
-      ${AIMRT_INSTALL}
-      CACHE BOOL "")
 
     FetchContent_MakeAvailable(fmt)
   endif()
+endfunction()
+
+get_fmt()
 
 # import targets：
 # fmt::fmt

cmake/GetGFlags.cmake

@@ -22,13 +22,13 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_gflags)
   FetchContent_GetProperties(gflags)
   if(NOT gflags_POPULATED)
     FetchContent_Populate(gflags)
 
-  set(BUILD_TESTING
+    set(BUILD_TESTING OFF)
-      OFF
-      CACHE BOOL "")
 
     file(READ ${gflags_SOURCE_DIR}/CMakeLists.txt TMP_VAR)
     string(REPLACE "  set (PKGCONFIG_INSTALL_DIR " "# set (PKGCONFIG_INSTALL_DIR " TMP_VAR "${TMP_VAR}")
@@ -37,6 +37,9 @@ if(NOT gflags_POPULATED)
     add_subdirectory(${gflags_SOURCE_DIR} ${gflags_BINARY_DIR})
 
   endif()
+endfunction()
+
+get_gflags()
 
 # import targets:
 # gflags::gflags

cmake/GetGTest.cmake

@@ -22,19 +22,20 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_googletest)
   FetchContent_GetProperties(googletest)
   if(NOT googletest_POPULATED)
     if(WIN32)
-    set(gtest_force_shared_crt
+      set(gtest_force_shared_crt ON)
-        ON
-        CACHE BOOL "")
     endif()
-  set(INSTALL_GTEST
+    set(INSTALL_GTEST OFF)
-      OFF
-      CACHE BOOL "")
 
     FetchContent_MakeAvailable(googletest)
   endif()
+endfunction()
+
+get_googletest()
 
 # import targets:
 # GTest::gtest

cmake/GetIceoryx.cmake

@@ -25,6 +25,8 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_iceoryx)
   FetchContent_GetProperties(iceoryx)
   if(NOT iceoryx_POPULATED)
 
@@ -34,3 +36,6 @@ if(NOT iceoryx_POPULATED)
     add_subdirectory(${iceoryx_SOURCE_DIR}/iceoryx_meta ${iceoryx_BINARY_DIR})
 
   endif()
+endfunction()
+
+get_iceoryx()

cmake/GetJsonCpp.cmake

@@ -22,33 +22,22 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_jsoncpp)
   FetchContent_GetProperties(jsoncpp)
   if(NOT jsoncpp_POPULATED)
-  set(JSONCPP_WITH_TESTS
+    set(JSONCPP_WITH_TESTS OFF)
-      OFF
-      CACHE BOOL "")
-  set(JSONCPP_WITH_POST_BUILD_UNITTEST
-      OFF
-      CACHE BOOL "")
 
-  set(BUILD_OBJECT_LIBS
+    set(JSONCPP_WITH_POST_BUILD_UNITTEST OFF)
-      OFF
+
-      CACHE BOOL "")
+    set(BUILD_OBJECT_LIBS OFF)
 
     if(BUILD_SHARED_LIBS)
-    set(BUILD_SHARED_LIBS
+      set(BUILD_SHARED_LIBS ON)
-        ON
+      set(BUILD_STATIC_LIBS OFF)
-        CACHE BOOL "")
-    set(BUILD_STATIC_LIBS
-        OFF
-        CACHE BOOL "")
     else()
-    set(BUILD_SHARED_LIBS
+      set(BUILD_SHARED_LIBS OFF)
-        OFF
+      set(BUILD_STATIC_LIBS ON)
-        CACHE BOOL "")
-    set(BUILD_STATIC_LIBS
-        ON
-        CACHE BOOL "")
     endif()
 
     FetchContent_MakeAvailable(jsoncpp)
@@ -59,6 +48,9 @@ if(NOT jsoncpp_POPULATED)
       add_library(jsoncpp::jsoncpp ALIAS jsoncpp_lib)
     endif()
   endif()
+endfunction()
+
+get_jsoncpp()
 
 # import targets:
 # jsoncpp::jsoncpp

cmake/GetLibUnifex.cmake

@@ -22,11 +22,11 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_libunifex)
   FetchContent_GetProperties(libunifex)
   if(NOT libunifex_POPULATED)
-  set(UNIFEX_BUILD_EXAMPLES
+    set(UNIFEX_BUILD_EXAMPLES OFF)
-      OFF
-      CACHE BOOL "")
 
     FetchContent_MakeAvailable(libunifex)
 
@@ -36,6 +36,9 @@ if(NOT libunifex_POPULATED)
 
     add_library(unifex::unifex ALIAS unifex)
   endif()
+endfunction()
+
+get_libunifex()
 
 # import targets:
 # unifex::unifex

cmake/GetNghttp2.cmake

@@ -22,6 +22,8 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_nghttp2)
   FetchContent_GetProperties(nghttp2)
   if(NOT nghttp2_POPULATED)
     FetchContent_Populate(nghttp2)
@@ -38,6 +40,9 @@ if(NOT nghttp2_POPULATED)
 
     add_subdirectory(${nghttp2_SOURCE_DIR} ${nghttp2_BINARY_DIR} EXCLUDE_FROM_ALL)
   endif()
+endfunction()
+
+get_nghttp2()
 
 # import targets:
 # nghttp2::nghttp2

cmake/GetNlohmannJson.cmake

@@ -22,10 +22,15 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_nlohmann_json)
   FetchContent_GetProperties(nlohmann_json)
   if(NOT nlohmann_json_POPULATED)
     FetchContent_MakeAvailable(nlohmann_json)
   endif()
+endfunction()
+
+get_nlohmann_json()
 
 # import targets:
 # nlohmann_json::nlohmann_json

cmake/GetOpenTelemetryCpp.cmake

@@ -18,35 +18,23 @@ else()
     DOWNLOAD_EXTRACT_TIMESTAMP TRUE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_opentelemetry_cpp)
   FetchContent_GetProperties(opentelemetry_cpp)
   if(NOT opentelemetry_cpp_POPULATED)
-  set(BUILD_TESTING
+    set(BUILD_TESTING OFF)
-      OFF
-      CACHE BOOL "")
 
-  set(WITH_BENCHMARK
+    set(WITH_BENCHMARK OFF)
-      OFF
-      CACHE BOOL "")
 
-  set(WITH_EXAMPLES
+    set(WITH_EXAMPLES OFF)
-      OFF
-      CACHE BOOL "")
 
-  set(WITH_FUNC_TESTS
+    set(WITH_FUNC_TESTS OFF)
-      OFF
-      CACHE BOOL "")
 
-  set(WITH_NO_DEPRECATED_CODE
+    set(WITH_NO_DEPRECATED_CODE ON)
-      ON
-      CACHE BOOL "")
 
-  set(WITH_DEPRECATED_SDK_FACTORY
+    set(WITH_DEPRECATED_SDK_FACTORY OFF)
-      OFF
-      CACHE BOOL "")
 
-  set(WITH_OTLP_HTTP
+    set(WITH_OTLP_HTTP ON)
-      ON
-      CACHE BOOL "")
 
     set(WITH_STL
         "CXX20"
@@ -56,13 +44,9 @@ if(NOT opentelemetry_cpp_POPULATED)
         ${opentelemetry_proto_SOURCE_DIR}
         CACHE PATH "")
 
-  set(PROTOBUF_PROTOC_EXECUTABLE
+    set(PROTOBUF_PROTOC_EXECUTABLE ${Protobuf_PROTOC_EXECUTABLE})
-      ${Protobuf_PROTOC_EXECUTABLE}
-      CACHE STRING "")
 
-  set(BUILD_SHARED_LIBS
+    set(BUILD_SHARED_LIBS OFF)
-      OFF
-      CACHE BOOL "")
 
     FetchContent_MakeAvailable(opentelemetry_cpp)
 
@@ -135,6 +119,9 @@ if(NOT opentelemetry_cpp_POPULATED)
     endif()
 
   endif()
+endfunction()
+
+get_opentelemetry_cpp()
 
 # import targets:
 # opentelemetry-cpp::api

cmake/GetProtobuf.cmake

@@ -22,35 +22,29 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_protobuf)
   FetchContent_GetProperties(protobuf)
   if(NOT protobuf_POPULATED)
-  set(protobuf_BUILD_TESTS
+    set(protobuf_BUILD_TESTS OFF)
-      OFF
+
-      CACHE BOOL "")
+    set(protobuf_BUILD_CONFORMANCE OFF)
-  set(protobuf_BUILD_CONFORMANCE
+
-      OFF
+    set(protobuf_DISABLE_RTTI OFF)
-      CACHE BOOL "")
+
-  set(protobuf_BUILD_EXAMPLES
+    set(protobuf_WITH_ZLIB OFF)
-      OFF
+
-      CACHE BOOL "")
+    set(protobuf_MSVC_STATIC_RUNTIME OFF)
-  set(protobuf_DISABLE_RTTI
+
-      OFF
+    set(protobuf_INSTALL ${AIMRT_INSTALL})
-      CACHE BOOL "")
+
-  set(protobuf_WITH_ZLIB
+    set(protobuf_VERBOSE ON)
-      OFF
-      CACHE BOOL "")
-  set(protobuf_MSVC_STATIC_RUNTIME
-      OFF
-      CACHE BOOL "")
-  set(protobuf_INSTALL
-      ${AIMRT_INSTALL}
-      CACHE BOOL "")
-  set(protobuf_VERBOSE
-      ON
-      CACHE BOOL "")
 
     FetchContent_MakeAvailable(protobuf)
   endif()
+endfunction()
+
+get_protobuf()
 
 # import targets:
 # protobuf::libprotobuf

cmake/GetPybind11.cmake

@@ -22,7 +22,12 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_pybind11)
   FetchContent_GetProperties(pybind11)
   if(NOT pybind11_POPULATED)
     FetchContent_MakeAvailable(pybind11)
   endif()
+endfunction()
+
+get_pybind11()

cmake/GetSqlite.cmake

@@ -23,6 +23,8 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_sqlite)
   FetchContent_GetProperties(sqlite)
   if(NOT sqlite_POPULATED)
     FetchContent_Populate(sqlite)
@@ -41,6 +43,9 @@ if(NOT sqlite_POPULATED)
       target_link_libraries(libsqlite PUBLIC pthread dl)
     endif()
   endif()
+endfunction()
+
+get_sqlite()
 
 # import targets:
 # sqlite::libsqlite

cmake/GetStdexec.cmake

@@ -22,22 +22,19 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_stdexec)
   FetchContent_GetProperties(stdexec)
   if(NOT stdexec_POPULATED)
-  set(STDEXEC_ENABLE_IO_URING_TESTS
+    set(STDEXEC_ENABLE_IO_URING_TESTS OFF)
-      OFF
+    set(STDEXEC_BUILD_EXAMPLES OFF)
-      CACHE BOOL "")
+    set(STDEXEC_BUILD_TESTS OFF)
-
-  set(STDEXEC_BUILD_EXAMPLES
-      OFF
-      CACHE BOOL "")
-
-  set(STDEXEC_BUILD_TESTS
-      OFF
-      CACHE BOOL "")
 
     FetchContent_MakeAvailable(stdexec)
   endif()
+endfunction()
+
+get_stdexec()
 
 # import targets:
 # STDEXEC::stdexec

cmake/GetTBB.cmake

@@ -22,26 +22,23 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_tbb)
   FetchContent_GetProperties(tbb)
   if(NOT tbb_POPULATED)
-  set(TBB_TEST
+    set(TBB_TEST OFF)
-      OFF
-      CACHE BOOL "")
 
-  set(TBB_DIR
+    set(TBB_DIR "")
-      ""
-      CACHE STRING "" FORCE)
 
-  set(TBB_INSTALL
+    set(TBB_INSTALL ON)
-      ON
-      CACHE BOOL "")
 
-  set(TBB_STRICT
+    set(TBB_STRICT OFF)
-      OFF
-      CACHE BOOL "")
 
     FetchContent_MakeAvailable(tbb)
   endif()
+endfunction()
+
+get_tbb()
 
 # import targets:
 # TBB::tbb

cmake/GetYamlCpp.cmake

@@ -22,28 +22,27 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_yaml_cpp)
   FetchContent_GetProperties(yaml-cpp)
   if(NOT yaml-cpp_POPULATED)
-  set(BUILD_TESTING
+    set(BUILD_TESTING OFF)
-      OFF
+
-      CACHE BOOL "")
+    set(YAML_CPP_BUILD_TESTS OFF)
-  set(YAML_CPP_BUILD_TESTS
+
-      OFF
+    set(YAML_CPP_BUILD_TOOLS OFF)
-      CACHE BOOL "")
+
-  set(YAML_CPP_BUILD_TOOLS
+    set(YAML_CPP_INSTALL ON)
-      OFF
+
-      CACHE BOOL "")
+    set(YAML_CPP_FORMAT_SOURCE OFF)
-  set(YAML_CPP_INSTALL
+
-      ON
+    set(YAML_CPP_BUILD_CONTRIB OFF)
-      CACHE BOOL "")
+
-  set(YAML_CPP_FORMAT_SOURCE
-      OFF
-      CACHE BOOL "")
-  set(YAML_CPP_BUILD_CONTRIB
-      OFF
-      CACHE BOOL "")
     FetchContent_MakeAvailable(yaml-cpp)
   endif()
+endfunction()
+
+get_yaml_cpp()
 
 # import targets:
 # yaml-cpp::yaml-cpp

cmake/GetZenoh.cmake

@@ -23,7 +23,12 @@ else()
     OVERRIDE_FIND_PACKAGE)
 endif()
 
+# Wrap it in a function to restrict the scope of the variables
+function(get_zenohc)
   FetchContent_GetProperties(zenohc)
   if(NOT zenohc_POPULATED)
     FetchContent_MakeAvailable(zenohc)
   endif()
+endfunction()
+
+get_zenohc()