Enable target namespaces and build dir project config

CMake convention is to use a project namespace, i.e. Foo::, for imported targets. When multiple targets are imported from a project, this looks like Foo::Bar1 Foo::Bar2, etc. This adds the nlohmann_json:: namespace to the exported target names. This also allows the generated project config files to be used from the build directory instead of just the install directory.

Enable target namespaces and build dir project config
33a2154f · Chuck Atkins · 031b88d3 · 33a2154f · 33a2154f
Commit 33a2154f authored Apr 09, 2018 by Chuck Atkins
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Showing with 12 additions and 3 deletions

CMakeLists.txt CMakeLists.txt +9 -2

config.cmake.in cmake/config.cmake.in +3 -1

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--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -27,9 +27,10 @@ set(NLOHMANN_JSON_CONFIG_INSTALL_DIR        "lib/cmake/${PROJECT_NAME}"
 set(NLOHMANN_JSON_INCLUDE_INSTALL_DIR       "include")
 set(NLOHMANN_JSON_TARGETS_EXPORT_NAME       "${PROJECT_NAME}Targets")
 set(NLOHMANN_JSON_CMAKE_CONFIG_TEMPLATE     "cmake/config.cmake.in")
-set(NLOHMANN_JSON_CMAKE_CONFIG_DIR          "${CMAKE_CURRENT_BINARY_DIR}/cmake_config")
+set(NLOHMANN_JSON_CMAKE_CONFIG_DIR          "${CMAKE_CURRENT_BINARY_DIR}")
 set(NLOHMANN_JSON_CMAKE_VERSION_CONFIG_FILE "${NLOHMANN_JSON_CMAKE_CONFIG_DIR}/${PROJECT_NAME}ConfigVersion.cmake")
 set(NLOHMANN_JSON_CMAKE_PROJECT_CONFIG_FILE "${NLOHMANN_JSON_CMAKE_CONFIG_DIR}/${PROJECT_NAME}Config.cmake")
+set(NLOHMANN_JSON_CMAKE_PROJECT_TARGETS_FILE "${NLOHMANN_JSON_CMAKE_CONFIG_DIR}/${PROJECT_NAME}Targets.cmake")
 if (JSON_MultipleHeaders)
    set(NLOHMANN_JSON_INCLUDE_BUILD_DIR "${PROJECT_SOURCE_DIR}/include/")
@@ -44,7 +45,7 @@ endif()
 ## create target and add include path
 ##
 add_library(${NLOHMANN_JSON_TARGET_NAME} INTERFACE)
+add_library(${PROJECT_NAME}::${NLOHMANN_JSON_TARGET_NAME} ALIAS ${NLOHMANN_JSON_TARGET_NAME})
 target_compile_features(${NLOHMANN_JSON_TARGET_NAME} INTERFACE cxx_std_11)
 target_include_directories(
@@ -105,6 +106,11 @@ if (NLOHMANN_ADD_NATVIS)
        DESTINATION .
 )
 endif()
+export(
+    TARGETS ${NLOHMANN_JSON_TARGET_NAME}
+    NAMESPACE ${PROJECT_NAME}::
+    FILE ${NLOHMANN_JSON_CMAKE_PROJECT_TARGETS_FILE}
+)
 install(
    TARGETS ${NLOHMANN_JSON_TARGET_NAME}
    EXPORT ${NLOHMANN_JSON_TARGETS_EXPORT_NAME}
@@ -112,5 +118,6 @@ install(
 )
 install(
    EXPORT ${NLOHMANN_JSON_TARGETS_EXPORT_NAME}
+    NAMESPACE ${PROJECT_NAME}::
    DESTINATION ${NLOHMANN_JSON_CONFIG_INSTALL_DIR}
 )
--- a/cmake/config.cmake.in
+++ b/cmake/config.cmake.in
 @PACKAGE_INIT@
-include("${CMAKE_CURRENT_LIST_DIR}/@NLOHMANN_JSON_TARGETS_EXPORT_NAME@.cmake")
+if(NOT TARGET @PROJECT_NAME@::@NLOHMANN_JSON_TARGET_NAME@)
+    include("${CMAKE_CURRENT_LIST_DIR}/@NLOHMANN_JSON_TARGETS_EXPORT_NAME@.cmake")
+endif()
 check_required_components("@PROJECT_NAME@")