1 files changed, 78 insertions, 0 deletions
diff --git a/cmake/module/AddBoostIfNeeded.cmake b/cmake/module/AddBoostIfNeeded.cmake
new file mode 100644
index 0000000000..ecd0d6f2ab
--- /dev/null
+++ b/cmake/module/AddBoostIfNeeded.cmake
@@ -0,0 +1,78 @@
+# Copyright (c) 2023-present The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or https://opensource.org/license/mit/.
+
+function(add_boost_if_needed)
+  #[=[
+  TODO: Not all targets, which will be added in the future, require
+        Boost. Therefore, a proper check will be appropriate here.
+
+  Implementation notes:
+  Although only Boost headers are used to build Bitcoin Core,
+  we still leverage a standard CMake's approach to handle
+  dependencies, i.e., the Boost::headers "library".
+  A command target_link_libraries(target PRIVATE Boost::headers)
+  will propagate Boost::headers usage requirements to the target.
+  For Boost::headers such usage requirements is an include
+  directory and other added INTERFACE properties.
+  ]=]
+
+  # We cannot rely on find_package(Boost ...) to work properly without
+  # Boost_NO_BOOST_CMAKE set until we require a more recent Boost because
+  # upstream did not ship proper CMake files until 1.82.0.
+  # Until then, we rely on CMake's FindBoost module.
+  # See: https://cmake.org/cmake/help/latest/policy/CMP0167.html
+  if(POLICY CMP0167)
+    cmake_policy(SET CMP0167 OLD)
+  endif()
+  set(Boost_NO_BOOST_CMAKE ON)
+  find_package(Boost 1.73.0 REQUIRED)
+  mark_as_advanced(Boost_INCLUDE_DIR)
+  set_target_properties(Boost::headers PROPERTIES IMPORTED_GLOBAL TRUE)
+  target_compile_definitions(Boost::headers INTERFACE
+    # We don't use multi_index serialization.
+    BOOST_MULTI_INDEX_DISABLE_SERIALIZATION
+  )
+  if(DEFINED VCPKG_TARGET_TRIPLET)
+    # Workaround for https://github.com/microsoft/vcpkg/issues/36955.
+    target_compile_definitions(Boost::headers INTERFACE
+      BOOST_NO_USER_CONFIG
+    )
+  endif()
+
+  # Prevent use of std::unary_function, which was removed in C++17,
+  # and will generate warnings with newer compilers for Boost
+  # older than 1.80.
+  # See: https://github.com/boostorg/config/pull/430.
+  set(CMAKE_REQUIRED_DEFINITIONS -DBOOST_NO_CXX98_FUNCTION_BASE)
+  set(CMAKE_REQUIRED_INCLUDES ${Boost_INCLUDE_DIR})
+  include(CMakePushCheckState)
+  cmake_push_check_state()
+  include(TryAppendCXXFlags)
+  set(CMAKE_REQUIRED_FLAGS ${working_compiler_werror_flag})
+  set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
+  check_cxx_source_compiles("
+    #include <boost/config.hpp>
+    " NO_DIAGNOSTICS_BOOST_NO_CXX98_FUNCTION_BASE
+  )
+  cmake_pop_check_state()
+  if(NO_DIAGNOSTICS_BOOST_NO_CXX98_FUNCTION_BASE)
+    target_compile_definitions(Boost::headers INTERFACE
+      BOOST_NO_CXX98_FUNCTION_BASE
+    )
+  else()
+    set(CMAKE_REQUIRED_DEFINITIONS)
+  endif()
+
+  # Some package managers, such as vcpkg, vendor Boost.Test separately
+  # from the rest of the headers, so we have to check for it individually.
+  if(BUILD_TESTS AND DEFINED VCPKG_TARGET_TRIPLET)
+    list(APPEND CMAKE_REQUIRED_DEFINITIONS -DBOOST_TEST_NO_MAIN)
+    include(CheckIncludeFileCXX)
+    check_include_file_cxx(boost/test/included/unit_test.hpp HAVE_BOOST_INCLUDED_UNIT_TEST_H)
+    if(NOT HAVE_BOOST_INCLUDED_UNIT_TEST_H)
+      message(FATAL_ERROR "Building test_bitcoin executable requested but boost/test/included/unit_test.hpp header not available.")
+    endif()
+  endif()
+
+endfunction()