Findnlohmann_json.cmake

cmake/Findnlohmann_json.cmake

@@ -0,0 +1,28 @@
+#
+# Input variables:
+# - `JSON_INCLUDE_DIR`
+# If input variables are not specified, try to find nlohmann_json config.
+# Input variables could also be provided as environment variables.
+#
+# Output targets:
+# - `nlohmann_json::nlohmann_json`
+
+UNIFY_ENVVARS_AND_CACHE(JSON_INCLUDE_DIR)
+
+if(NOT JSON_INCLUDE_DIR)
+    find_package(nlohmann_json CONFIG)
+    if(nlohmann_json_DIR)
+        return()
+    endif()
+endif()
+
+find_path(json_header_path "nlohmann/json.hpp" HINTS "${JSON_INCLUDE_DIR}")
+
+if(json_header_path)
+    message(STATUS "JSON for Modern C++ header file found in '${json_header_path}'.")
+    add_library(nlohmann_json::nlohmann_json INTERFACE IMPORTED)
+    target_include_directories(nlohmann_json::nlohmann_json INTERFACE ${json_header_path})
+    return()
+endif()
+
+message(FATAL_ERROR "Unable to find JSON for Modern C++ header file / package, aborting")