From e5b83bd995b711f80485b28b6202c0722fdda0c5 Mon Sep 17 00:00:00 2001
From: S David <2100425+s-daveb@users.noreply.github.com>
Date: Wed, 27 Mar 2024 12:53:57 -0400
Subject: [PATCH] Switch to the CPM package manager and add some macros for
 readability

---
 CMakeLists.txt              | 118 +++++++++++++++++-------------------
 cmake/BuildProperties.cmake |  31 ++++++++++
 cmake/CPM.cmake             |  24 ++++++++
 tests/CMakeLists.txt        |   2 +-
 4 files changed, 112 insertions(+), 63 deletions(-)
 create mode 100644 cmake/BuildProperties.cmake
 create mode 100644 cmake/CPM.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c7ea882..9273ac9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,27 +1,18 @@
 cmake_minimum_required(VERSION 3.26)
 
-# Prevent in-source builds
-if (CMAKE_BINARY_DIR STREQUAL CMAKE_SOURCE_DIR)
-    message(FATAL_ERROR "Source and build directories cannot be the same.")
-endif()
+# Additional paths to search for custom and third-party CMake modules
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
 
-if (CMAKE_VERSION VERSION_GREATER_EQUAL "3.24.0")
-	cmake_policy(SET CMP0135 NEW)
-endif()
+include(BuildProperties)
+
+prevent_in_source_build()
+disable_deprecated_features()
 
 # When this package is included as a subproject, there's no need to
-# build and run the unit-tests. Setting -DENABLE_TESTS to false could
-# speed up build time for pacakge maintainers
-if (NOT DEFINED PROJECT_NAME)
-	option(ENABLE_TESTS "Build and run unit tests" ON)
-else()
-	option(ENABLE_TESTS "Build and run unit tests" OFF)
-endif()
-
-option(USE_SYSTEM_CATCH2
-	"Do not download & compile catch2 library for unit tests"
-	ON
-)
+# build and run the unit-tests.
+# Sets -DENABLE_TESTS to false by default if this is a third-party lib build
+# This check must appear before project()
+disable_tests_if_subproject()
 
 project(<APPLICATION-NAME>
 	VERSION 0.1
@@ -29,6 +20,17 @@ project(<APPLICATION-NAME>
 	# HOMEPAGE_URL <URL>
 	DESCRIPTION "Description"
 )
+include(CPM)
+
+option(USE_SYSTEM_CATCH2
+	"Do not download & compile catch2 library for unit tests"
+	ON
+)
+option(USE_CCACHE
+	[=[Use ccache compiler cache to speed up builds.
+Enabled by default if ccache is found]=]
+ON
+)
 
 IF( NOT CMAKE_BUILD_TYPE )
   SET( CMAKE_BUILD_TYPE Debug )
@@ -43,23 +45,20 @@ set(CMAKE_CXX_EXTENSIONS OFF)
 
 # Search for the code caching compiler wrapper, ccache and enable it
 # if found. This will speed up repeated builds.
-find_program(CCACHE_PATH ccache)
-if(CCACHE_PATH)
-    set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE ${CCACHE_PATH})
-    set_property(GLOBAL PROPERTY RULE_LAUNCH_LINK ${CCACHE_PATH})
-endif(CCACHE_PATH)
+if (USE_CCACHE)
+	message(CHECK_START "Detecting cacche")
 
-if (USE_SYSTEM_CATCH2)
-	message(CHECK_START "Detecting System Catch2 ")
-	find_package(Catch2 3 QUIET)
-
-	if(TARGET Catch2::Catch2)
-		message(CHECK_PASS "found target Catch2::Catch2")
-	else()
-		message(CHECK_FAIL "not found")
-		set(USE_SYSTEM_CATCH2 OFF)
-		message(STATUS "USE_SYSTEM_CATCH2=OFF")
+	find_program(CCACHE_PATH ccache)
+	if(DEFINED CCACHE_PATH)
+  	  message(CHECK_PASS("found"))
+  	  set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE ${CCACHE_PATH})
+  	  set_property(GLOBAL PROPERTY RULE_LAUNCH_LINK ${CCACHE_PATH})
 	endif()
+
+	list(APPEND CMAKE_MESSAGE_INDENT " ")
+  	message(STATUS "(set -DUSE_CCACHE=Off to disable)")
+	list(POP_BACK CMAKE_MESSAGE_INDENT)
+
 endif()
 
 # enable compile_commands.json generation for clangd
@@ -88,43 +87,39 @@ include(FetchContent)
 #)
 
 if (ENABLE_TESTS)
-	if (NOT USE_SYSTEM_CATCH2)
-		FetchContent_Declare(
-    	  Catch2
-	    	URL https://github.com/catchorg/Catch2/archive/refs/tags/v3.4.0.zip
-	    	URL_HASH MD5=c426e77d4ee0055410bc930182959ae5
-		)
-		FetchContent_MakeAvailable(Catch2)
-	else()
-		include_directories(${CATCH2_INCLUDE_DIRS})
-		link_directories(${CATCH2_LIBRARY_DIRS})
-	endif()
-	FetchContent_Declare(
-		FakeIt
-		URL https://github.com/eranpeer/FakeIt/archive/refs/tags/2.4.0.zip
-		URL_HASH MD5=72e4ce7f1c0de97074d2d5b517753286
-		FIND_PACKAGE_ARGS
+	CPMFindPackage(NAME Catch2
+		GITHUB_REPOSITORY catchorg/Catch2
+		VERSION 3.4.0
+		OPTIONS
+			"CATCH_DEVELOPMENT_BUILD OFF"
+			"CATCH_BUILD_TESTING OFF"
+	)
+	CPMFindPackage(NAME FakeIt
+		GITHUB_REPOSITORY eranpeer/FakeIt
+		GIT_TAG 2.4.0
+		OPTIONS
+ 	   		"ENABLE_TESTING OFF"
 	)
-	FetchContent_MakeAvailable(FakeIt)
 
 	if (TARGET Catch2)
 		set_target_properties(Catch2 PROPERTIES
 			CXX_STANDARD 20
 		)
-	endif()
-
-	if (TARGET Catch2WithMain)
+	elseif (TARGET Catch2WithMain)
 		set_target_properties(Catch2WithMain PROPERTIES
- 		       	CXX_STANDARD 20
+ 		    	CXX_STANDARD 20
 		)
 	endif()
-	list(APPEND cmake_module_path ${Catch2_source_dir}/extras)
+	if (Catch2_ADDED STREQUAL "YES")
+		list(APPEND CMAKE_MODULE_PATH ${Catch2_SOURCE_DIR}/extras)
+	endif()
 endif()
 
 # Set output directories for build targets
-set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/build/lib)
-set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/build/lib)
-set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/build/bin)
+set(ARTIFACT_DIR "${CMAKE_BINARY_DIR}/out")
+set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${ARTIFACT_DIR}/lib)
+set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${ARTIFACT_DIR}/lib)
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${ARTIFACT_DIR}/bin)
 
 # Include directories
 include_directories(${CMAKE_SOURCE_DIR}/src)
@@ -134,7 +129,7 @@ include_directories(${CMAKE_SOURCE_DIR}/include)
 #add_custom_target(copy_assets
 #COMMAND ${CMAKE_COMMAND} -E copy_directory ${CMAKE_CURRENT_LIST_DIR}/data ${CMAKE_BINARY_DIR}/artifacts/share/data
 #	COMMAND ${CMAKE_COMMAND} -E copy_directory ${CMAKE_CURRENT_LIST_DIR}/data ${CMAKE_BINARY_DIR}/tests/data
-	#)
+#)
 
 # Add subdirectories
 add_subdirectory(src)
@@ -144,5 +139,4 @@ if(ENABLE_TESTS)
 	add_subdirectory(tests)
 endif()
 
-
-# vim: ts=2 sw=2 noet foldmethod=indent :
+# vim: ts=4 sw=4 noet foldmethod=indent :
diff --git a/cmake/BuildProperties.cmake b/cmake/BuildProperties.cmake
new file mode 100644
index 0000000..46b67ad
--- /dev/null
+++ b/cmake/BuildProperties.cmake
@@ -0,0 +1,31 @@
+# BuildProperties.cmake
+# Copyright (c) 2024 Saul D Beniquez
+# License: MIT
+#
+# This module defines a function prevent_in_source_build() that prevents in-source builds
+# and sets a policy for CMake version 3.24.0 and above.
+
+function(prevent_in_source_build)
+	# Prevent in-source builds
+	if (CMAKE_BINARY_DIR STREQUAL CMAKE_SOURCE_DIR)
+		message(FATAL_ERROR "Source and build directories cannot be the same.")
+	endif()
+endfunction()
+
+function(disable_deprecated_features)
+	# Use new timestamp behavior when extracting files archives
+	if (CMAKE_VERSION VERSION_GREATER_EQUAL "3.24.0")
+		cmake_policy(SET CMP0135 NEW)
+	endif()
+endfunction()
+
+function(disable_tests_if_subproject)
+if (NOT DEFINED PROJECT_NAME)
+	option(ENABLE_TESTS "Build and run unit tests" ON)
+else()
+	option(ENABLE_TESTS "Build and run unit tests" OFF)
+endif()
+endfunction()
+
+
+# vim: ts=4 sts=4 sw=4 noet :
diff --git a/cmake/CPM.cmake b/cmake/CPM.cmake
new file mode 100644
index 0000000..cc25ec2
--- /dev/null
+++ b/cmake/CPM.cmake
@@ -0,0 +1,24 @@
+# SPDX-License-Identifier: MIT
+#
+# SPDX-FileCopyrightText: Copyright (c) 2019-2023 Lars Melchior and contributors
+
+set(CPM_DOWNLOAD_VERSION 0.38.7)
+set(CPM_HASH_SUM "83e5eb71b2bbb8b1f2ad38f1950287a057624e385c238f6087f94cdfc44af9c5")
+
+if(CPM_SOURCE_CACHE)
+  set(CPM_DOWNLOAD_LOCATION "${CPM_SOURCE_CACHE}/cpm/CPM_${CPM_DOWNLOAD_VERSION}.cmake")
+elseif(DEFINED ENV{CPM_SOURCE_CACHE})
+  set(CPM_DOWNLOAD_LOCATION "$ENV{CPM_SOURCE_CACHE}/cpm/CPM_${CPM_DOWNLOAD_VERSION}.cmake")
+else()
+  set(CPM_DOWNLOAD_LOCATION "${CMAKE_BINARY_DIR}/cmake/CPM_${CPM_DOWNLOAD_VERSION}.cmake")
+endif()
+
+# Expand relative path. This is important if the provided path contains a tilde (~)
+get_filename_component(CPM_DOWNLOAD_LOCATION ${CPM_DOWNLOAD_LOCATION} ABSOLUTE)
+
+file(DOWNLOAD
+     https://github.com/cpm-cmake/CPM.cmake/releases/download/v${CPM_DOWNLOAD_VERSION}/CPM.cmake
+     ${CPM_DOWNLOAD_LOCATION} EXPECTED_HASH SHA256=${CPM_HASH_SUM}
+)
+
+include(${CPM_DOWNLOAD_LOCATION})
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 7d5db25..dd0766a 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -19,7 +19,7 @@ set_target_properties(test-runner PROPERTIES
 # add catch2's ctest cmake module and register the tests defined by mdml-tests
 # using catch_discover_tests
 include(ctest)
-include(catch)
+include(Catch)
 catch_discover_tests(test-runner)
 
 # bonus: add a custom ctest target to the build system, to run tests in the