From c47190f2f1bb7e23ae7da76ca659235862a74d70 Mon Sep 17 00:00:00 2001
From: Daniel Lemire <daniel@lemire.me>
Date: Sat, 28 Oct 2023 16:47:22 -0400
Subject: [PATCH] Switching to CPM

---
 CMakeLists.txt                 |  2 +-
 cmake/CPM.cmake                | 24 ++++++++++++++++
 cmake/import.cmake             | 52 ----------------------------------
 microbenchmarks/CMakeLists.txt | 11 +++++--
 tools/cmake/FindCTargets.cmake |  7 +++--
 5 files changed, 39 insertions(+), 57 deletions(-)
 create mode 100644 cmake/CPM.cmake
 delete mode 100644 cmake/import.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index bde4727cd..9bdd478bd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -52,7 +52,7 @@ set(CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/tools/cmake")
 find_package(CTargets)
 find_package(Options)
 find_package(LTO)
-include(Import)
+include(cmake/CPM.cmake)
 
 configure_file("${CMAKE_CURRENT_SOURCE_DIR}/roaring.pc.in"
                "${CMAKE_CURRENT_BINARY_DIR}/roaring.pc" @ONLY)
diff --git a/cmake/CPM.cmake b/cmake/CPM.cmake
new file mode 100644
index 000000000..ad6b74a8b
--- /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 0.38.6)
+set(CPM_HASH_SUM "11c3fa5f1ba14f15d31c2fb63dbc8628ee133d81c8d764caad9a8db9e0bacb07")
+
+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(${CPM_DOWNLOAD_LOCATION})
diff --git a/cmake/import.cmake b/cmake/import.cmake
deleted file mode 100644
index a9b6ffe5d..000000000
--- a/cmake/import.cmake
+++ /dev/null
@@ -1,52 +0,0 @@
-set(dep_root "${PROJEC_SOURCE_DIR}/dependencies/.cache")
-if(DEFINED ENV{roaring_DEPENDENCY_CACHE_DIR})
-  set(dep_root "$ENV{roaring_DEPENDENCY_CACHE_DIR}")
-endif()
-
-function(import_dependency NAME GITHUB_REPO COMMIT)
-  message(STATUS "Importing ${NAME} (${GITHUB_REPO}@${COMMIT})")
-  set(target "${dep_root}/${NAME}")
-
-  # If the folder exists in the cache, then we assume that everything is as
-  # should be and do nothing
-  if(EXISTS "${target}")
-    set("${NAME}_SOURCE_DIR" "${target}" PARENT_SCOPE)
-    return()
-  endif()
-
-  set(zip_url "https://github.com/${GITHUB_REPO}/archive/${COMMIT}.zip")
-  set(archive "${dep_root}/archive.zip")
-  set(dest "${dep_root}/_extract")
-
-  file(DOWNLOAD "${zip_url}" "${archive}")
-  file(MAKE_DIRECTORY "${dest}")
-  execute_process(
-          WORKING_DIRECTORY "${dest}"
-          COMMAND "${CMAKE_COMMAND}" -E tar xf "${archive}")
-  file(REMOVE "${archive}")
-
-  # GitHub archives only ever have one folder component at the root, so this
-  # will always match that single folder
-  file(GLOB dir LIST_DIRECTORIES YES "${dest}/*")
-
-  file(RENAME "${dir}" "${target}")
-
-  set("${NAME}_SOURCE_DIR" "${target}" PARENT_SCOPE)
-endfunction()
-
-# Delegates to the dependency
-macro(add_dependency NAME)
-  if(NOT DEFINED "${NAME}_SOURCE_DIR")
-    message(FATAL_ERROR "Missing ${NAME}_SOURCE_DIR variable")
-  endif()
-
-  add_subdirectory("${${NAME}_SOURCE_DIR}" "${PROJECT_BINARY_DIR}/_deps/${NAME}" EXCLUDE_FROM_ALL)
-endmacro()
-
-function(set_off NAME)
-  set("${NAME}" OFF CACHE INTERNAL "")
-endfunction()
-
-function(set_on NAME)
-  set("${NAME}" ON CACHE INTERNAL "")
-endfunction()
\ No newline at end of file
diff --git a/microbenchmarks/CMakeLists.txt b/microbenchmarks/CMakeLists.txt
index 628515bbc..4a7288e70 100644
--- a/microbenchmarks/CMakeLists.txt
+++ b/microbenchmarks/CMakeLists.txt
@@ -7,8 +7,15 @@ set_off(BENCHMARK_ENABLE_TESTING)
 set_off(BENCHMARK_ENABLE_INSTALL)
 set_off(BENCHMARK_ENABLE_WERROR)
 set(BENCHMARK_ENABLE_WERROR OFF)
-import_dependency(google_benchmarks google/benchmark 3441176)
-add_dependency(google_benchmarks)
+ CPMAddPackage(
+     NAME benchmark
+     GITHUB_REPOSITORY google/benchmark
+     GIT_TAG 3441176
+     OPTIONS "BENCHMARK_ENABLE_TESTING OFF"
+             "BENCHMARK_ENABLE_INSTALL OFF"
+             "BENCHMARK_ENABLE_WERROR OFF"
+
+   )
 
 add_executable(bench bench.cpp)
 target_link_libraries(bench PRIVATE roaring)
diff --git a/tools/cmake/FindCTargets.cmake b/tools/cmake/FindCTargets.cmake
index c659bdf55..8eb227e6c 100644
--- a/tools/cmake/FindCTargets.cmake
+++ b/tools/cmake/FindCTargets.cmake
@@ -4,8 +4,11 @@ endif ()
 include(${PROJECT_SOURCE_DIR}/tools/cmake/Import.cmake)
 set(BUILD_STATIC_LIB ON)
 if (ENABLE_ROARING_TESTS)
-  import_dependency(cmocka clibs/cmocka  f5e2cd7)
-  add_dependency(cmocka)
+  CPMAddPackage(
+       NAME cmocka
+       GITHUB_REPOSITORY clibs/cmocka
+       GIT_TAG f5e2cd7
+    )
 endif()
 
 function(add_c_test TEST_NAME)