- exported targets go to separate generated file and package config …

…file generated from template to use automatic package resolving and resolution logic

 CMake  provides helpers to generate config file. Generated config file has usefull macro check_required_components() to set necessary variables like PackageName_FOUND if requirements has been satisfied. An absence of dedicated config file confuses user project as necessary variables are not set.

CMakeLists.txt

@@ -177,11 +177,13 @@ if(JSONCPP_WITH_CMAKE_PACKAGE)
     include(CMakePackageConfigHelpers)
     install(EXPORT jsoncpp
         DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/jsoncpp
-        FILE        jsoncppConfig.cmake)
+        FILE        jsoncpp-targets.cmake)
+    configure_package_config_file(jsoncppConfig.cmake.in ${CMAKE_CURRENT_BINARY_DIR}/jsoncppConfig.cmake INSTALL_DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/jsoncpp)
+
     write_basic_package_version_file("${CMAKE_CURRENT_BINARY_DIR}/jsoncppConfigVersion.cmake"
         VERSION ${PROJECT_VERSION}
         COMPATIBILITY SameMajorVersion)
-    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/jsoncppConfigVersion.cmake
+    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/jsoncppConfigVersion.cmake ${CMAKE_CURRENT_BINARY_DIR}/jsoncppConfig.cmake
         DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/jsoncpp)
 endif()
 

jsoncppConfig.cmake.in

@@ -0,0 +1,10 @@
+cmake_policy(PUSH)
+cmake_policy(VERSION 3.0)
+
+@PACKAGE_INIT@
+
+include ( "${CMAKE_CURRENT_LIST_DIR}/jsoncpp-targets.cmake" )
+
+check_required_components(JsonCpp)
+
+cmake_policy(POP)