Update CPM.cmake to version 0.42.0

Author: jhasse

cmake/CPM.cmake

@@ -42,7 +42,11 @@ if(NOT COMMAND cpm_message)
   endfunction()
 endif()
 
-set(CURRENT_CPM_VERSION 0.40.2)
+if(DEFINED EXTRACTED_CPM_VERSION)
+  set(CURRENT_CPM_VERSION "${EXTRACTED_CPM_VERSION}${CPM_DEVELOPMENT}")
+else()
+  set(CURRENT_CPM_VERSION 0.42.0)
+endif()
 
 get_filename_component(CPM_CURRENT_DIRECTORY "${CMAKE_CURRENT_LIST_DIR}" REALPATH)
 if(CPM_DIRECTORY)
@@ -162,7 +166,7 @@ set(CPM_SOURCE_CACHE
     CACHE PATH "Directory to download CPM dependencies"
 )
 
-if(NOT CPM_DONT_UPDATE_MODULE_PATH)
+if(NOT CPM_DONT_UPDATE_MODULE_PATH AND NOT DEFINED CMAKE_FIND_PACKAGE_REDIRECTS_DIR)
   set(CPM_MODULE_PATH
       "${CMAKE_BINARY_DIR}/CPM_modules"
       CACHE INTERNAL ""
@@ -198,6 +202,60 @@ function(cpm_package_name_from_git_uri URI RESULT)
   endif()
 endfunction()
 
+# Find the shortest hash that can be used eg, if origin_hash is
+# cccb77ae9609d2768ed80dd42cec54f77b1f1455 the following files will be checked, until one is found
+# that is either empty (allowing us to assign origin_hash), or whose contents matches ${origin_hash}
+#
+# * .../cccb.hash
+# * .../cccb77ae.hash
+# * .../cccb77ae9609.hash
+# * .../cccb77ae9609d276.hash
+# * etc
+#
+# We will be able to use a shorter path with very high probability, but in the (rare) event that the
+# first couple characters collide, we will check longer and longer substrings.
+function(cpm_get_shortest_hash source_cache_dir origin_hash short_hash_output_var)
+  # for compatibility with caches populated by a previous version of CPM, check if a directory using
+  # the full hash already exists
+  if(EXISTS "${source_cache_dir}/${origin_hash}")
+    set(${short_hash_output_var}
+        "${origin_hash}"
+        PARENT_SCOPE
+    )
+    return()
+  endif()
+
+  foreach(len RANGE 4 40 4)
+    string(SUBSTRING "${origin_hash}" 0 ${len} short_hash)
+    set(hash_lock ${source_cache_dir}/${short_hash}.lock)
+    set(hash_fp ${source_cache_dir}/${short_hash}.hash)
+    # Take a lock, so we don't have a race condition with another instance of cmake. We will release
+    # this lock when we can, however, if there is an error, we want to ensure it gets released on
+    # it's own on exit from the function.
+    file(LOCK ${hash_lock} GUARD FUNCTION)
+
+    # Load the contents of .../${short_hash}.hash
+    file(TOUCH ${hash_fp})
+    file(READ ${hash_fp} hash_fp_contents)
+
+    if(hash_fp_contents STREQUAL "")
+      # Write the origin hash
+      file(WRITE ${hash_fp} ${origin_hash})
+      file(LOCK ${hash_lock} RELEASE)
+      break()
+    elseif(hash_fp_contents STREQUAL origin_hash)
+      file(LOCK ${hash_lock} RELEASE)
+      break()
+    else()
+      file(LOCK ${hash_lock} RELEASE)
+    endif()
+  endforeach()
+  set(${short_hash_output_var}
+      "${short_hash}"
+      PARENT_SCOPE
+  )
+endfunction()
+
 # Try to infer package name and version from a url
 function(cpm_package_name_and_ver_from_url url outName outVer)
   if(url MATCHES "[/\\?]([a-zA-Z0-9_\\.-]+)\\.(tar|tar\\.gz|tar\\.bz2|zip|ZIP)(\\?|/|$)")
@@ -269,10 +327,25 @@ endfunction()
 # finding the system library
 function(cpm_create_module_file Name)
   if(NOT CPM_DONT_UPDATE_MODULE_PATH)
-    # erase any previous modules
-    file(WRITE ${CPM_MODULE_PATH}/Find${Name}.cmake
-         "include(\"${CPM_FILE}\")\n${ARGN}\nset(${Name}_FOUND TRUE)"
-    )
+    if(DEFINED CMAKE_FIND_PACKAGE_REDIRECTS_DIR)
+      # Redirect find_package calls to the CPM package. This is what FetchContent does when you set
+      # OVERRIDE_FIND_PACKAGE. The CMAKE_FIND_PACKAGE_REDIRECTS_DIR works for find_package in CONFIG
+      # mode, unlike the Find${Name}.cmake fallback. CMAKE_FIND_PACKAGE_REDIRECTS_DIR is not defined
+      # in script mode, or in CMake < 3.24.
+      # https://cmake.org/cmake/help/latest/module/FetchContent.html#fetchcontent-find-package-integration-examples
+      string(TOLOWER ${Name} NameLower)
+      file(WRITE ${CMAKE_FIND_PACKAGE_REDIRECTS_DIR}/${NameLower}-config.cmake
+           "include(\"\${CMAKE_CURRENT_LIST_DIR}/${NameLower}-extra.cmake\" OPTIONAL)\n"
+           "include(\"\${CMAKE_CURRENT_LIST_DIR}/${Name}Extra.cmake\" OPTIONAL)\n"
+      )
+      file(WRITE ${CMAKE_FIND_PACKAGE_REDIRECTS_DIR}/${NameLower}-config-version.cmake
+           "set(PACKAGE_VERSION_COMPATIBLE TRUE)\n" "set(PACKAGE_VERSION_EXACT TRUE)\n"
+      )
+    else()
+      file(WRITE ${CPM_MODULE_PATH}/Find${Name}.cmake
+           "include(\"${CPM_FILE}\")\n${ARGN}\nset(${Name}_FOUND TRUE)"
+      )
+    endif()
   endif()
 endfunction()
 
@@ -475,7 +548,7 @@ function(cpm_add_patches)
 
   # Find the patch program.
   find_program(PATCH_EXECUTABLE patch)
-  if(WIN32 AND NOT PATCH_EXECUTABLE)
+  if(CMAKE_HOST_WIN32 AND NOT PATCH_EXECUTABLE)
     # The Windows git executable is distributed with patch.exe. Find the path to the executable, if
     # it exists, then search `../usr/bin` and `../../usr/bin` for patch.exe.
     find_package(Git QUIET)
@@ -575,14 +648,6 @@ endfunction()
 function(CPMAddPackage)
   cpm_set_policies()
 
-  list(LENGTH ARGN argnLength)
-  if(argnLength EQUAL 1)
-    cpm_parse_add_package_single_arg("${ARGN}" ARGN)
-
-    # The shorthand syntax implies EXCLUDE_FROM_ALL and SYSTEM
-    set(ARGN "${ARGN};EXCLUDE_FROM_ALL;YES;SYSTEM;YES;")
-  endif()
-
   set(oneValueArgs
       NAME
       FORCE
@@ -605,10 +670,26 @@ function(CPMAddPackage)
 
   set(multiValueArgs URL OPTIONS DOWNLOAD_COMMAND PATCHES)
 
+  list(LENGTH ARGN argnLength)
+
+  # Parse single shorthand argument
+  if(argnLength EQUAL 1)
+    cpm_parse_add_package_single_arg("${ARGN}" ARGN)
+
+    # The shorthand syntax implies EXCLUDE_FROM_ALL and SYSTEM
+    set(ARGN "${ARGN};EXCLUDE_FROM_ALL;YES;SYSTEM;YES;")
+
+    # Parse URI shorthand argument
+  elseif(argnLength GREATER 1 AND "${ARGV0}" STREQUAL "URI")
+    list(REMOVE_AT ARGN 0 1) # remove "URI gh:<...>@version#tag"
+    cpm_parse_add_package_single_arg("${ARGV1}" ARGV0)
+
+    set(ARGN "${ARGV0};EXCLUDE_FROM_ALL;YES;SYSTEM;YES;${ARGN}")
+  endif()
+
   cmake_parse_arguments(CPM_ARGS "" "${oneValueArgs}" "${multiValueArgs}" "${ARGN}")
 
   # Set default values for arguments
-
   if(NOT DEFINED CPM_ARGS_VERSION)
     if(DEFINED CPM_ARGS_GIT_TAG)
       cpm_get_version_from_git_tag("${CPM_ARGS_GIT_TAG}" CPM_ARGS_VERSION)
@@ -779,9 +860,19 @@ function(CPMAddPackage)
       set(download_directory ${CPM_SOURCE_CACHE}/${lower_case_name}/${CPM_ARGS_CUSTOM_CACHE_KEY})
     elseif(CPM_USE_NAMED_CACHE_DIRECTORIES)
       string(SHA1 origin_hash "${origin_parameters};NEW_CACHE_STRUCTURE_TAG")
+      cpm_get_shortest_hash(
+        "${CPM_SOURCE_CACHE}/${lower_case_name}" # source cache directory
+        "${origin_hash}" # Input hash
+        origin_hash # Computed hash
+      )
       set(download_directory ${CPM_SOURCE_CACHE}/${lower_case_name}/${origin_hash}/${CPM_ARGS_NAME})
     else()
       string(SHA1 origin_hash "${origin_parameters}")
+      cpm_get_shortest_hash(
+        "${CPM_SOURCE_CACHE}/${lower_case_name}" # source cache directory
+        "${origin_hash}" # Input hash
+        origin_hash # Computed hash
+      )
       set(download_directory ${CPM_SOURCE_CACHE}/${lower_case_name}/${origin_hash})
     endif()
     # Expand `download_directory` relative path. This is important because EXISTS doesn't work for
@@ -848,7 +939,9 @@ function(CPMAddPackage)
     endif()
   endif()
 
-  cpm_create_module_file(${CPM_ARGS_NAME} "CPMAddPackage(\"${ARGN}\")")
+  if(NOT "${DOWNLOAD_ONLY}")
+    cpm_create_module_file(${CPM_ARGS_NAME} "CPMAddPackage(\"${ARGN}\")")
+  endif()
 
   if(CPM_PACKAGE_LOCK_ENABLED)
     if((CPM_ARGS_VERSION AND NOT CPM_ARGS_SOURCE_DIR) OR CPM_INCLUDE_ALL_IN_PACKAGE_LOCK)
@@ -869,8 +962,9 @@ function(CPMAddPackage)
     # Calling FetchContent_MakeAvailable will then internally forward these options to
     # add_subdirectory. Up until these changes, we had to call FetchContent_Populate and
     # add_subdirectory separately, which is no longer necessary and has been deprecated as of 3.30.
+    # A Bug in CMake prevents us to use the non-deprecated functions until 3.30.3.
     set(fetchContentDeclareExtraArgs "")
-    if(${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.28.0")
+    if(${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.30.3")
       if(${CPM_ARGS_EXCLUDE_FROM_ALL})
         list(APPEND fetchContentDeclareExtraArgs EXCLUDE_FROM_ALL)
       endif()
@@ -896,7 +990,7 @@ function(CPMAddPackage)
     if(CPM_SOURCE_CACHE AND download_directory)
       file(LOCK ${download_directory}/../cmake.lock RELEASE)
     endif()
-    if(${populated} AND ${CMAKE_VERSION} VERSION_LESS "3.28.0")
+    if(${populated} AND ${CMAKE_VERSION} VERSION_LESS "3.30.3")
       cpm_add_subdirectory(
         "${CPM_ARGS_NAME}"
         "${DOWNLOAD_ONLY}"
@@ -1098,7 +1192,7 @@ function(cpm_fetch_package PACKAGE DOWNLOAD_ONLY populated)
   string(TOLOWER "${PACKAGE}" lower_case_name)
 
   if(NOT ${lower_case_name}_POPULATED)
-    if(${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.28.0")
+    if(${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.30.3")
       if(DOWNLOAD_ONLY)
         # MakeAvailable will call add_subdirectory internally which is not what we want when
         # DOWNLOAD_ONLY is set. Populate will only download the dependency without adding it to the