From 5ef2e27e8e0f18cbef015e4943e70abfb4679c1b Mon Sep 17 00:00:00 2001
From: Mathis Logemann <mathisloge@gmail.com>
Date: Wed, 13 Oct 2021 10:16:39 +0200
Subject: [PATCH] [CMake] add boost regex icu check

---
 CMakeLists.txt                 | 11 +++++++++--
 cmake/CheckBoostRegexIcu.cmake | 23 +++++++++++++++++++++++
 2 files changed, 32 insertions(+), 2 deletions(-)
 create mode 100644 cmake/CheckBoostRegexIcu.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index ed5392ba3..47bbaa15d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -129,22 +129,29 @@ set(MAPNIK_OPTIONAL_LIBS_INCLUDE "")
 
 # needs to be before the first call of find_boost.
 if(USE_MULTITHREADED)
-    message(STATUS "multithreaded enabled")
     set(Boost_USE_MULTITHREADED ON)
     list(APPEND MAPNIK_COMPILE_DEFS MAPNIK_THREADSAFE)
 else()
     set(Boost_USE_MULTITHREADED OFF)
-    message(STATUS "multithreaded disabled")
 endif()
 
+
 find_package(PkgConfig)
 mapnik_find_threads()
 mapnik_find_package(ICU REQUIRED COMPONENTS uc i18n data)
+
 mapnik_find_package(Boost ${BOOST_MIN_VERSION} REQUIRED COMPONENTS filesystem system regex)
+list(APPEND MAPNIK_COMPILE_DEFS BOOST_REGEX_HAS_ICU)
 if(USE_BOOST_REGEX_ICU_WORKAROUND)
     message(STATUS "using boost regex workaround")
     set_property(TARGET Boost::regex PROPERTY INTERFACE_LINK_LIBRARIES)
 endif()
+include(CheckBoostRegexIcu)
+check_boost_regex()
+if(BOOST_REGEX_HAS_ICU)
+    message(STATUS "boost regex has icu support")
+    list(APPEND MAPNIK_COMPILE_DEFS BOOST_REGEX_HAS_ICU)
+endif()
 
 mapnik_find_package(Freetype REQUIRED)
 
diff --git a/cmake/CheckBoostRegexIcu.cmake b/cmake/CheckBoostRegexIcu.cmake
new file mode 100644
index 000000000..b2e7b9430
--- /dev/null
+++ b/cmake/CheckBoostRegexIcu.cmake
@@ -0,0 +1,23 @@
+include(CheckCXXSourceRuns)
+
+function(check_boost_regex)
+    set(CMAKE_REQUIRED_LIBRARIES ICU::uc ICU::data ICU::i18n Boost::headers Boost::regex)
+    check_cxx_source_runs([[
+    #include <boost/regex/icu.hpp>
+    #include <unicode/unistr.h>
+    int main()
+    {
+        U_NAMESPACE_QUALIFIER UnicodeString ustr;
+        try {
+            boost::u32regex pattern = boost::make_u32regex(ustr);
+        }
+        // an exception is fine, still indicates support is
+        // likely compiled into regex
+        catch (...) {
+            return 0;
+        }
+        return 0;
+    }
+    ]] BOOST_REGEX_HAS_ICU)
+    set(BOOST_REGEX_HAS_ICU ${BOOST_REGEX_HAS_ICU} PARENT_SCOPE)
+endfunction(check_boost_regex)