From d30cd9d4d330b1ed431bc66cac4b24d67ce95324 Mon Sep 17 00:00:00 2001
From: Florian Albrechtskirchinger <falbrechtskirchinger@gmail.com>
Date: Thu, 22 Sep 2022 13:47:31 +0200
Subject: [PATCH] Add custom CMake feature summary

---
 CMakeLists.txt           | 20 +---------
 cmake/json_summary.cmake | 82 ++++++++++++++++++++++++++++++++++++++++
 tests/CMakeLists.txt     | 18 ++++-----
 3 files changed, 91 insertions(+), 29 deletions(-)
 create mode 100644 cmake/json_summary.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1d689298b..dbde03798 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -58,26 +58,8 @@ set(NLOHMANN_JSON_PKGCONFIG_INSTALL_DIR     "${CMAKE_INSTALL_DATADIR}/pkgconfig"
 
 if (JSON_MultipleHeaders)
     set(NLOHMANN_JSON_INCLUDE_BUILD_DIR "${PROJECT_SOURCE_DIR}/include/")
-    message(STATUS "Using the multi-header code from ${NLOHMANN_JSON_INCLUDE_BUILD_DIR}")
 else()
     set(NLOHMANN_JSON_INCLUDE_BUILD_DIR "${PROJECT_SOURCE_DIR}/single_include/")
-    message(STATUS "Using the single-header code from ${NLOHMANN_JSON_INCLUDE_BUILD_DIR}")
-endif()
-
-if (NOT JSON_ImplicitConversions)
-    message(STATUS "Implicit conversions are disabled")
-endif()
-
-if (JSON_DisableEnumSerialization)
-    message(STATUS "Enum integer serialization is disabled")
-endif()
-
-if (JSON_LegacyDiscardedValueComparison)
-    message(STATUS "Legacy discarded value comparison enabled")
-endif()
-
-if (JSON_Diagnostics)
-    message(STATUS "Diagnostics enabled")
 endif()
 
 if (JSON_SystemInclude)
@@ -195,3 +177,5 @@ if(JSON_Install)
         DESTINATION ${NLOHMANN_JSON_PKGCONFIG_INSTALL_DIR}
     )
 endif()
+
+include(json_summary)
diff --git a/cmake/json_summary.cmake b/cmake/json_summary.cmake
new file mode 100644
index 000000000..b20210f1b
--- /dev/null
+++ b/cmake/json_summary.cmake
@@ -0,0 +1,82 @@
+# ANSI codes
+set(rst "")
+set(bld "")
+# no color output on Windows or if disabled via CLICOLOR=0/CLICOLOR_FORCE=0
+if(NOT WIN32 AND NOT ("$ENV{CLICOLOR}" STREQUAL "0" OR "$ENV{CLICOLOR_FORCE}" STREQUAL "0"))
+    string(ASCII 27 esc)
+    set(rst "${esc}[0m") # reset
+    set(bld "${esc}[1m") # bold
+endif()
+
+#############################################################################
+# json_feature(
+#     var text
+#     [VALUES <value>...]
+#     [NEGATE])
+#
+# Print feature info using <text> and the boolean value of <var> converted to
+# YES/NO.
+#
+# If additional values are given and <var> matches any of them, <var> is not
+# converted to YES/NO.
+#
+# If NEGATE is specified, the boolean value of <var> is negated.
+#############################################################################
+
+function(json_feature var text)
+    cmake_parse_arguments(args "NEGATE" "" "VALUES" ${ARGN})
+
+    set(state NO)
+    if(args_VALUES)
+        foreach(value ${args_VALUES})
+            if(${var} STREQUAL value)
+                set(state ${value})
+                break()
+            endif()
+        endforeach()
+    elseif(${args_NEGATE} AND NOT ${var} OR ${var})
+        set(state YES)
+    endif()
+
+    message("   ${text} ${bld}${state}${rst}")
+endfunction()
+
+#############################################################################
+# print feature summary
+#############################################################################
+
+message(STATUS "[nohmann_json]: Feature summary:")
+
+json_feature(JSON_BuildTests "Build tests?")
+if(JSON_BuildTests)
+    json_feature(JSON_32bitTest "Build the 32bit unit test?" VALUES AUTO ONLY)
+    json_feature(JSON_FastTests "Skip expensive/slow tests?")
+    json_feature(JSON_Valgrind "Execute test suite with Valgrind?")
+
+    set(test_cxx_standards "")
+    foreach(cxx_standard ${JSON_TEST_CXX_STANDARDS_FEATURE_INFO})
+        if(NOT cxx_standard MATCHES "^[\[].+[\]]$")
+            set(cxx_standard "${bld}${cxx_standard}${rst}")
+        endif()
+        set(test_cxx_standards "${test_cxx_standards} ${cxx_standard}")
+    endforeach()
+
+    if(JSON_TEST_CXX_STANDARDS_FORCED)
+        set(test_cxx_standards "${test_cxx_standards} ${bld}(forced)${rst}")
+    endif()
+    message("   Test C++ standards:${test_cxx_standards}")
+endif()
+
+message("")
+
+json_feature(JSON_Diagnostics "Diagnostics enabled?" NEGATE)
+json_feature(JSON_DisableEnumSerialization "Default integer enum serialization enabled?")
+json_feature(JSON_GlobalUDLs "Define user-defined string literals globally?")
+json_feature(JSON_ImplicitConversions "Implicit conversions enabled?")
+json_feature(JSON_LegacyDiscardedValueComparison "Legacy discarded value comparison enabled?")
+
+message("")
+
+json_feature(JSON_MultipleHeaders "Use the multi-header code?")
+message("   Include directory: ${NLOHMANN_JSON_INCLUDE_BUILD_DIR}")
+json_feature(JSON_SystemInclude "Include as system headers?")
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 99f0d3efd..d85db0451 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -95,27 +95,23 @@ json_test_set_test_options(test-unicode4 TEST_PROPERTIES TIMEOUT 3000)
 
 if("${JSON_TestStandards}" STREQUAL "")
     set(test_cxx_standards 11 14 17 20 23)
-    unset(test_force)
+    set(test_force "")
 else()
     set(test_cxx_standards ${JSON_TestStandards})
     set(test_force FORCE)
 endif()
 
-# Print selected standards marking unavailable ones with brackets
-set(msg_standards "")
+# create list of selected C++ standards for feature summary
+set(info "")
 foreach(cxx_standard ${test_cxx_standards})
     if(compiler_supports_cpp_${cxx_standard})
-        list(APPEND msg_standards ${cxx_standard})
+        list(APPEND info ${cxx_standard})
     else()
-        list(APPEND msg_standards [${cxx_standard}])
+        list(APPEND info [${cxx_standard}])
     endif()
 endforeach()
-string(JOIN " " msg_standards ${msg_standards})
-set(msg "Testing standards: ${msg_standards}")
-if(test_force)
-    string(APPEND msg " (forced)")
-endif()
-message(STATUS "${msg}")
+set(JSON_TEST_CXX_STANDARDS_FEATURE_INFO "${info}" PARENT_SCOPE)
+set(JSON_TEST_CXX_STANDARDS_FORCED ${test_force} PARENT_SCOPE)
 
 # *DO* use json_test_set_test_options() above this line