From 464f37b114addd757c6260850d7c4e0ec65c850a Mon Sep 17 00:00:00 2001
From: ClausKlein <claus.klein@arcormail.de>
Date: Mon, 25 Nov 2024 09:41:38 +0100
Subject: [PATCH] Install cmake config package

Add find-package-test

Prevent undefined cmake values
---
 CMakeLists.txt                            | 38 +++++++++++++++++++++--
 cmake/config.cmake.in                     |  7 +++++
 examples/CMakeLists.txt                   | 14 +++++++--
 tests/beman/inplace_vector/CMakeLists.txt | 26 +++++++++++++++-
 4 files changed, 79 insertions(+), 6 deletions(-)
 create mode 100644 cmake/config.cmake.in

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 52b19f5..b4ead02 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -37,6 +37,7 @@ set(CPACK_GENERATOR TGZ)
 
 # includes
 include(GNUInstallDirs)
+include(CMakePackageConfigHelpers)
 include(CPack)
 
 add_library(beman.inplace_vector INTERFACE)
@@ -63,9 +64,14 @@ target_compile_features(
         "$<$<NOT:$<COMPILE_FEATURES:cxx_std_23>>:cxx_std_20>"
 )
 
-set(TARGET_PACKAGE_NAME ${PROJECT_NAME}-config)
-set(TARGETS_EXPORT_NAME ${PROJECT_NAME}-targets)
-set(INSTALL_CONFIGDIR ${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME})
+# export cmake config package
+set(TARGET_NAME inplace_vector)
+set(TARGET_NAMESPACE beman)
+set(TARGET_ALIAS ${TARGET_NAMESPACE}::${TARGET_NAME})
+set(TARGET_PREFIX ${TARGET_NAMESPACE}.${TARGET_NAME}) # -> PROJECT_NAME?
+set(TARGET_PACKAGE_NAME ${TARGET_NAME}-config)
+set(TARGETS_EXPORT_NAME ${TARGET_NAME}-targets)
+set(INSTALL_CONFIGDIR ${CMAKE_INSTALL_LIBDIR}/cmake/${TARGET_NAME})
 
 # Install the InplaceVector library to the appropriate destination
 install(
@@ -74,6 +80,32 @@ install(
     FILE_SET inplace_vector_public_headers
 )
 
+write_basic_package_version_file(
+    ${CMAKE_CURRENT_BINARY_DIR}/${TARGET_PACKAGE_NAME}-version.cmake
+    VERSION ${PROJECT_VERSION}
+    COMPATIBILITY AnyNewerVersion
+)
+
+configure_package_config_file(
+    cmake/config.cmake.in
+    ${CMAKE_CURRENT_BINARY_DIR}/${TARGET_PACKAGE_NAME}.cmake
+    INSTALL_DESTINATION ${INSTALL_CONFIGDIR}
+)
+
+install(
+    FILES
+        ${CMAKE_CURRENT_BINARY_DIR}/${TARGET_PACKAGE_NAME}.cmake
+        ${CMAKE_CURRENT_BINARY_DIR}/${TARGET_PACKAGE_NAME}-version.cmake
+    DESTINATION ${INSTALL_CONFIGDIR}
+)
+
+install(
+    EXPORT ${TARGETS_EXPORT_NAME}
+    FILE ${TARGETS_EXPORT_NAME}.cmake
+    DESTINATION "${INSTALL_CONFIGDIR}"
+    NAMESPACE ${TARGET_NAMESPACE}::
+)
+
 if(BEMAN_INPLACE_VECTOR_BUILD_TESTS)
     enable_testing()
     add_subdirectory(tests/beman/inplace_vector)
diff --git a/cmake/config.cmake.in b/cmake/config.cmake.in
new file mode 100644
index 0000000..e6ed3e2
--- /dev/null
+++ b/cmake/config.cmake.in
@@ -0,0 +1,7 @@
+# cmake/Config.cmake.in -*-makefile-*-
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+@PACKAGE_INIT@
+
+include("${CMAKE_CURRENT_LIST_DIR}/@TARGETS_EXPORT_NAME@.cmake")
+check_required_components("@TARGET_NAME@")
diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index 496bc08..353eaee 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -1,8 +1,17 @@
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
+cmake_minimum_required(VERSION 3.25...3.31)
+
+project(beman_inplace_vector_example LANGUAGES CXX)
+
+if(PROJECT_IS_TOP_LEVEL)
+    find_package(inplace_vector 1.0.0 EXACT REQUIRED)
+    enable_testing()
+endif()
+
 set(ALL_EXAMPLES fibonacci)
 
-message("Examples to be built: ${ALL_EXAMPLES}")
+message(STATUS "Examples to be built: ${ALL_EXAMPLES}")
 
 foreach(example ${ALL_EXAMPLES})
     add_executable(beman.inplace_vector.examples.${example})
@@ -12,6 +21,7 @@ foreach(example ${ALL_EXAMPLES})
     )
     target_link_libraries(
         beman.inplace_vector.examples.${example}
-        beman.inplace_vector
+        beman::inplace_vector
     )
+    add_test(NAME ${example} COMMAND beman.inplace_vector.examples.${example})
 endforeach()
diff --git a/tests/beman/inplace_vector/CMakeLists.txt b/tests/beman/inplace_vector/CMakeLists.txt
index 0dc7351..25eb05a 100644
--- a/tests/beman/inplace_vector/CMakeLists.txt
+++ b/tests/beman/inplace_vector/CMakeLists.txt
@@ -6,6 +6,30 @@
 # Tests
 add_executable(beman.inplace_vector.test inplace_vector.test.cpp)
 
-target_link_libraries(beman.inplace_vector.test PRIVATE beman.inplace_vector)
+target_link_libraries(beman.inplace_vector.test PRIVATE beman::inplace_vector)
 
 add_test(NAME beman.inplace_vector.test COMMAND beman.inplace_vector.test)
+
+# test if the targets are findable from the build directory
+# NOTE: For an INTERFACE library and multi config generators, we may always use
+# the -C Debug config type instead of  $<CONFIG> to prevent problems! CK
+if(CMAKE_BUILD_TYPE STREQUAL Debug)
+    if(NOT DEFINED CMAKE_CXX_STANDARD)
+        set(CMAKE_CXX_STANDARD 20)
+    endif()
+    if(NOT DEFINED CMAKE_PREFIX_PATH)
+        set(CMAKE_PREFIX_PATH ${CMAKE_INSTALL_PREFIX})
+    endif()
+    add_test(
+        NAME find-package-test
+        COMMAND
+            ${CMAKE_CTEST_COMMAND} --verbose --output-on-failure -C Debug
+            --build-and-test "${PROJECT_SOURCE_DIR}/examples"
+            "${CMAKE_CURRENT_BINARY_DIR}/find-package-test" --build-generator
+            ${CMAKE_GENERATOR} --build-makeprogram ${CMAKE_MAKE_PROGRAM}
+            --build-options "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
+            "-DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}"
+            "-DCMAKE_BUILD_TYPE=Debug"
+            "-DCMAKE_PREFIX_PATH=${CMAKE_PREFIX_PATH}"
+    )
+endif()