Add CMake package file generation support

Author: dreifachstein

CMakeLists.txt

@@ -6,6 +6,7 @@ OPTION(JSONCPP_WITH_TESTS "Compile and run JsonCpp test executables" ON)
 OPTION(JSONCPP_WITH_POST_BUILD_UNITTEST "Automatically run unit-tests as a post build step" ON)
 OPTION(JSONCPP_WITH_WARNING_AS_ERROR "Force compilation to fail if a warning occurs" OFF)
 OPTION(JSONCPP_WITH_PKGCONFIG_SUPPORT "Generate and install .pc files" ON)
+OPTION(JSONCPP_WITH_CMAKE_PACKAGE "Generate and install cmake package files" OFF)
 
 # Ensures that CMAKE_BUILD_TYPE is visible in cmake-gui on Unix
 IF(NOT WIN32)
@@ -24,7 +25,9 @@ SET(LIBRARY_INSTALL_DIR lib
     CACHE PATH "Install dir for shared libraries")
 SET(INCLUDE_INSTALL_DIR include
     CACHE PATH "Install dir for headers")
-MARK_AS_ADVANCED( RUNTIME_INSTALL_DIR ARCHIVE_INSTALL_DIR INCLUDE_INSTALL_DIR )
+SET(PACKAGE_INSTALL_DIR lib/cmake
+    CACHE PATH "Install dir for cmake package config files")
+MARK_AS_ADVANCED( RUNTIME_INSTALL_DIR ARCHIVE_INSTALL_DIR INCLUDE_INSTALL_DIR PACKAGE_INSTALL_DIR )
 
 # This ensures shared DLL are in the same dir as executable on Windows.
 # Put all executables / libraries are in a project global directory.
@@ -101,6 +104,12 @@ IF(JSONCPP_WITH_PKGCONFIG_SUPPORT)
 		DESTINATION "${CMAKE_INSTALL_PREFIX}/lib/pkgconfig")
 ENDIF(JSONCPP_WITH_PKGCONFIG_SUPPORT)
 
+IF(JSONCPP_WITH_CMAKE_PACKAGE)
+        INSTALL(EXPORT jsoncpp
+                DESTINATION ${PACKAGE_INSTALL_DIR}/jsoncpp
+                FILE        jsoncppConfig.cmake)
+ENDIF(JSONCPP_WITH_CMAKE_PACKAGE)
+
 # Build the different applications
 ADD_SUBDIRECTORY( src )
 

src/lib_json/CMakeLists.txt

@@ -40,7 +40,17 @@ SET_TARGET_PROPERTIES( jsoncpp_lib PROPERTIES OUTPUT_NAME jsoncpp )
 SET_TARGET_PROPERTIES( jsoncpp_lib PROPERTIES VERSION ${JSONCPP_VERSION} SOVERSION ${JSONCPP_VERSION_MAJOR} )
 
 # Install instructions for this target
-INSTALL( TARGETS jsoncpp_lib
+IF(JSONCPP_WITH_CMAKE_PACKAGE)
+    TARGET_INCLUDE_DIRECTORIES( jsoncpp_lib
+                                PUBLIC $<INSTALL_INTERFACE:${INCLUDE_INSTALL_DIR}>
+                                       $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/${JSON_INCLUDE_DIR}>
+                                )
+    SET(INSTALL_EXPORT EXPORT jsoncpp)
+ELSE(JSONCPP_WITH_CMAKE_PACKAGE)
+    SET(INSTALL_EXPORT)
+ENDIF(JSONCPP_WITH_CMAKE_PACKAGE)
+
+INSTALL( TARGETS jsoncpp_lib ${INSTALL_EXPORT}
          RUNTIME DESTINATION ${RUNTIME_INSTALL_DIR}
          LIBRARY DESTINATION ${LIBRARY_INSTALL_DIR}
          ARCHIVE DESTINATION ${ARCHIVE_INSTALL_DIR}