ExternalProject: Move inline scripts to separate files

This makes the scripts easier to work on, since the separate files
don't require the extra level of escaping that the inlined code did.
This also means the scripts can be rendered with appropriate
syntax highlighting in IDEs, etc.

Modules/ExternalProject.cmake

@@ -1254,7 +1254,25 @@ define_property(DIRECTORY PROPERTY "EP_UPDATE_DISCONNECTED" INHERITED
   "ExternalProject module."
   )
 
-function(_ep_write_gitclone_script script_filename source_dir git_EXECUTABLE git_repository git_tag git_remote_name init_submodules git_submodules_recurse git_submodules git_shallow git_progress git_config src_name work_dir gitclone_infofile gitclone_stampfile tls_verify)
+function(_ep_write_gitclone_script
+         script_filename
+         source_dir
+         git_EXECUTABLE
+         git_repository
+         git_tag
+         git_remote_name
+         init_submodules
+         git_submodules_recurse
+         git_submodules
+         git_shallow
+         git_progress
+         git_config
+         src_name
+         work_dir
+         gitclone_infofile
+         gitclone_stampfile
+         tls_verify)
+
   if(NOT GIT_VERSION_STRING VERSION_LESS 1.8.5)
     # Use `git checkout <tree-ish> --` to avoid ambiguity with a local path.
     set(git_checkout_explicit-- "--")
@@ -1300,136 +1318,48 @@ function(_ep_write_gitclone_script script_filename source_dir git_EXECUTABLE git
   endif()
   string (REPLACE ";" " " git_options "${git_options}")
 
-  file(WRITE ${script_filename}
-"
-if(EXISTS \"${gitclone_stampfile}\" AND EXISTS \"${gitclone_infofile}\" AND
-  \"${gitclone_stampfile}\" IS_NEWER_THAN \"${gitclone_infofile}\")
-  message(STATUS \"Avoiding repeated git clone, stamp file is up to date: '${gitclone_stampfile}'\")
-  return()
-endif()
-
-execute_process(
-  COMMAND \${CMAKE_COMMAND} -E rm -rf \"${source_dir}\"
-  RESULT_VARIABLE error_code
-  )
-if(error_code)
-  message(FATAL_ERROR \"Failed to remove directory: '${source_dir}'\")
-endif()
-
-# try the clone 3 times in case there is an odd git clone issue
-set(error_code 1)
-set(number_of_tries 0)
-while(error_code AND number_of_tries LESS 3)
-  execute_process(
-    COMMAND \"${git_EXECUTABLE}\" ${git_options} clone ${git_clone_options} \"${git_repository}\" \"${src_name}\"
-    WORKING_DIRECTORY \"${work_dir}\"
-    RESULT_VARIABLE error_code
-    )
-  math(EXPR number_of_tries \"\${number_of_tries} + 1\")
-endwhile()
-if(number_of_tries GREATER 1)
-  message(STATUS \"Had to git clone more than once:
-          \${number_of_tries} times.\")
-endif()
-if(error_code)
-  message(FATAL_ERROR \"Failed to clone repository: '${git_repository}'\")
-endif()
-
-execute_process(
-  COMMAND \"${git_EXECUTABLE}\" ${git_options} checkout ${git_tag} ${git_checkout_explicit--}
-  WORKING_DIRECTORY \"${work_dir}/${src_name}\"
-  RESULT_VARIABLE error_code
-  )
-if(error_code)
-  message(FATAL_ERROR \"Failed to checkout tag: '${git_tag}'\")
-endif()
-
-set(init_submodules ${init_submodules})
-if(init_submodules)
-  execute_process(
-    COMMAND \"${git_EXECUTABLE}\" ${git_options} submodule update ${git_submodules_recurse} --init ${git_submodules}
-    WORKING_DIRECTORY \"${work_dir}/${src_name}\"
-    RESULT_VARIABLE error_code
-    )
-endif()
-if(error_code)
-  message(FATAL_ERROR \"Failed to update submodules in: '${work_dir}/${src_name}'\")
-endif()
-
-# Complete success, update the script-last-run stamp file:
-#
-execute_process(
-  COMMAND \${CMAKE_COMMAND} -E copy
-    \"${gitclone_infofile}\"
-    \"${gitclone_stampfile}\"
-  RESULT_VARIABLE error_code
+  configure_file(
+    ${CMAKE_CURRENT_FUNCTION_LIST_DIR}/ExternalProject/gitclone.cmake.in
+    ${script_filename}
+    @ONLY
   )
-if(error_code)
-  message(FATAL_ERROR \"Failed to copy script-last-run stamp file: '${gitclone_stampfile}'\")
-endif()
-
-"
-)
-
 endfunction()
 
-function(_ep_write_hgclone_script script_filename source_dir hg_EXECUTABLE hg_repository hg_tag src_name work_dir hgclone_infofile hgclone_stampfile)
+function(_ep_write_hgclone_script
+         script_filename
+         source_dir
+         hg_EXECUTABLE
+         hg_repository
+         hg_tag
+         src_name
+         work_dir
+         hgclone_infofile
+         hgclone_stampfile)
+
   if("${hg_tag}" STREQUAL "")
     message(FATAL_ERROR "Tag for hg checkout should not be empty.")
   endif()
-  file(WRITE ${script_filename}
-"
-if(EXISTS \"${hgclone_stampfile}\" AND EXISTS \"${hgclone_infofile}\" AND
-  \"${hgclone_stampfile}\" IS_NEWER_THAN \"${hgclone_infofile}\")
-  message(STATUS \"Avoiding repeated hg clone, stamp file is up to date: '${hgclone_stampfile}'\")
-  return()
-endif()
-
-execute_process(
-  COMMAND \${CMAKE_COMMAND} -E rm -rf \"${source_dir}\"
-  RESULT_VARIABLE error_code
-  )
-if(error_code)
-  message(FATAL_ERROR \"Failed to remove directory: '${source_dir}'\")
-endif()
 
-execute_process(
-  COMMAND \"${hg_EXECUTABLE}\" clone -U \"${hg_repository}\" \"${src_name}\"
-  WORKING_DIRECTORY \"${work_dir}\"
-  RESULT_VARIABLE error_code
-  )
-if(error_code)
-  message(FATAL_ERROR \"Failed to clone repository: '${hg_repository}'\")
-endif()
-
-execute_process(
-  COMMAND \"${hg_EXECUTABLE}\" update ${hg_tag}
-  WORKING_DIRECTORY \"${work_dir}/${src_name}\"
-  RESULT_VARIABLE error_code
-  )
-if(error_code)
-  message(FATAL_ERROR \"Failed to checkout tag: '${hg_tag}'\")
-endif()
-
-# Complete success, update the script-last-run stamp file:
-#
-execute_process(
-  COMMAND \${CMAKE_COMMAND} -E copy
-    \"${hgclone_infofile}\"
-    \"${hgclone_stampfile}\"
-  RESULT_VARIABLE error_code
+  configure_file(
+    ${CMAKE_CURRENT_FUNCTION_LIST_DIR}/ExternalProject/hgclone.cmake.in
+    ${script_filename}
+    @ONLY
   )
-if(error_code)
-  message(FATAL_ERROR \"Failed to copy script-last-run stamp file: '${hgclone_stampfile}'\")
-endif()
-
-"
-)
-
 endfunction()
 
 
-function(_ep_write_gitupdate_script script_filename git_EXECUTABLE git_tag git_remote_name init_submodules git_submodules_recurse git_submodules git_repository work_dir git_update_strategy)
+function(_ep_write_gitupdate_script
+         script_filename
+         git_EXECUTABLE
+         git_tag
+         git_remote_name
+         init_submodules
+         git_submodules_recurse
+         git_submodules
+         git_repository
+         work_dir
+         git_update_strategy)
+
   if("${git_tag}" STREQUAL "")
     message(FATAL_ERROR "Tag for git checkout should not be empty.")
   endif()
@@ -1449,7 +1379,21 @@ function(_ep_write_gitupdate_script script_filename git_EXECUTABLE git_tag git_r
   )
 endfunction()
 
-function(_ep_write_downloadfile_script script_filename REMOTE LOCAL timeout inactivity_timeout no_progress hash tls_verify tls_cainfo userpwd http_headers netrc netrc_file)
+function(_ep_write_downloadfile_script
+         script_filename
+         REMOTE
+         LOCAL
+         timeout
+         inactivity_timeout
+         no_progress
+         hash
+         tls_verify
+         tls_cainfo
+         userpwd
+         http_headers
+         netrc
+         netrc_file)
+
   if(timeout)
     set(TIMEOUT_ARGS TIMEOUT ${timeout})
     set(TIMEOUT_MSG "${timeout} seconds")
@@ -1465,7 +1409,6 @@ function(_ep_write_downloadfile_script script_filename REMOTE LOCAL timeout inac
     set(INACTIVITY_TIMEOUT_MSG "none")
   endif()
 
-
   if(no_progress)
     set(SHOW_PROGRESS "")
   else()
@@ -1597,68 +1540,11 @@ function(_ep_write_extractfile_script script_filename name filename directory)
     return()
   endif()
 
-  file(WRITE ${script_filename}
-"# Make file names absolute:
-#
-get_filename_component(filename \"${filename}\" ABSOLUTE)
-get_filename_component(directory \"${directory}\" ABSOLUTE)
-
-message(STATUS \"extracting...
-     src='\${filename}'
-     dst='\${directory}'\")
-
-if(NOT EXISTS \"\${filename}\")
-  message(FATAL_ERROR \"error: file to extract does not exist: '\${filename}'\")
-endif()
-
-# Prepare a space for extracting:
-#
-set(i 1234)
-while(EXISTS \"\${directory}/../ex-${name}\${i}\")
-  math(EXPR i \"\${i} + 1\")
-endwhile()
-set(ut_dir \"\${directory}/../ex-${name}\${i}\")
-file(MAKE_DIRECTORY \"\${ut_dir}\")
-
-# Extract it:
-#
-message(STATUS \"extracting... [tar ${args}]\")
-execute_process(COMMAND \${CMAKE_COMMAND} -E tar ${args} \${filename}
-  WORKING_DIRECTORY \${ut_dir}
-  RESULT_VARIABLE rv)
-
-if(NOT rv EQUAL 0)
-  message(STATUS \"extracting... [error clean up]\")
-  file(REMOVE_RECURSE \"\${ut_dir}\")
-  message(FATAL_ERROR \"error: extract of '\${filename}' failed\")
-endif()
-
-# Analyze what came out of the tar file:
-#
-message(STATUS \"extracting... [analysis]\")
-file(GLOB contents \"\${ut_dir}/*\")
-list(REMOVE_ITEM contents \"\${ut_dir}/.DS_Store\")
-list(LENGTH contents n)
-if(NOT n EQUAL 1 OR NOT IS_DIRECTORY \"\${contents}\")
-  set(contents \"\${ut_dir}\")
-endif()
-
-# Move \"the one\" directory to the final directory:
-#
-message(STATUS \"extracting... [rename]\")
-file(REMOVE_RECURSE \${directory})
-get_filename_component(contents \${contents} ABSOLUTE)
-file(RENAME \${contents} \${directory})
-
-# Clean up:
-#
-message(STATUS \"extracting... [clean up]\")
-file(REMOVE_RECURSE \"\${ut_dir}\")
-
-message(STATUS \"extracting... done\")
-"
-)
-
+  configure_file(
+    "${CMAKE_CURRENT_FUNCTION_LIST_DIR}/ExternalProject/extractfile.cmake.in"
+    "${script_filename}"
+    @ONLY
+  )
 endfunction()
 
 
@@ -1747,22 +1633,19 @@ function(_ep_set_directories name)
     endif()
   endif()
 
-  # Make the directories at CMake configure time *and* add a custom command
-  # to make them at build time. They need to exist at makefile generation
-  # time for Borland make and wmake so that CMake may generate makefiles
-  # with "cd C:\short\paths\with\no\spaces" commands in them.
-  #
-  # Additionally, the add_custom_command is still used in case somebody
-  # removes one of the necessary directories and tries to rebuild without
-  # re-running cmake.
-  foreach(var ${places})
-    string(TOUPPER "${var}" VAR)
-    get_property(dir TARGET ${name} PROPERTY _EP_${VAR}_DIR)
-    file(MAKE_DIRECTORY "${dir}")
-    if(NOT EXISTS "${dir}")
-      message(FATAL_ERROR "dir '${dir}' does not exist after file(MAKE_DIRECTORY)")
-    endif()
-  endforeach()
+  # This script will be used both here and by the mkdir step. We create the
+  # directories now at configure time and ensure they exist again at build
+  # time (since somebody might remove one of the required directories and try
+  # to rebuild without re-running cmake). They need to exist now at makefile
+  # generation time for Borland make and wmake so that CMake may generate
+  # makefiles with "cd C:\short\paths\with\no\spaces" commands in them.
+  set(script_filename "${tmp_dir}/${name}-mkdirs.cmake")
+  configure_file(
+    ${CMAKE_CURRENT_FUNCTION_LIST_DIR}/ExternalProject/mkdirs.cmake.in
+    ${script_filename}
+    @ONLY
+  )
+  include(${script_filename})
 endfunction()
 
 
@@ -2528,22 +2411,14 @@ endfunction()
 
 
 function(_ep_add_mkdir_command name)
-  ExternalProject_Get_Property(${name}
-    source_dir binary_dir install_dir stamp_dir download_dir tmp_dir log_dir)
-
-  _ep_get_configuration_subdir_suffix(cfgdir)
+  ExternalProject_Get_Property(${name} tmp_dir)
+  set(script_filename "${tmp_dir}/${name}-mkdirs.cmake")
 
   ExternalProject_Add_Step(${name} mkdir
     INDEPENDENT TRUE
     COMMENT "Creating directories for '${name}'"
-    COMMAND ${CMAKE_COMMAND} -E make_directory ${source_dir}
-    COMMAND ${CMAKE_COMMAND} -E make_directory ${binary_dir}
-    COMMAND ${CMAKE_COMMAND} -E make_directory ${install_dir}
-    COMMAND ${CMAKE_COMMAND} -E make_directory ${tmp_dir}
-    COMMAND ${CMAKE_COMMAND} -E make_directory ${stamp_dir}${cfgdir}
-    COMMAND ${CMAKE_COMMAND} -E make_directory ${download_dir}
-    COMMAND ${CMAKE_COMMAND} -E make_directory ${log_dir}
-    )
+    COMMAND ${CMAKE_COMMAND} -P ${script_filename}
+  )
 endfunction()
 
 
@@ -2855,7 +2730,21 @@ function(_ep_add_download_command name)
         get_property(http_password TARGET ${name} PROPERTY _EP_HTTP_PASSWORD)
         get_property(http_headers TARGET ${name} PROPERTY _EP_HTTP_HEADER)
         set(download_script "${stamp_dir}/download-${name}.cmake")
-        _ep_write_downloadfile_script("${download_script}" "${url}" "${file}" "${timeout}" "${inactivity_timeout}" "${no_progress}" "${hash}" "${tls_verify}" "${tls_cainfo}" "${http_username}:${http_password}" "${http_headers}" "${netrc}" "${netrc_file}")
+        _ep_write_downloadfile_script(
+          "${download_script}"
+          "${url}"
+          "${file}"
+          "${timeout}"
+          "${inactivity_timeout}"
+          "${no_progress}"
+          "${hash}"
+          "${tls_verify}"
+          "${tls_cainfo}"
+          "${http_username}:${http_password}"
+          "${http_headers}"
+          "${netrc}"
+          "${netrc_file}"
+        )
         set(cmd ${CMAKE_COMMAND} -P "${download_script}"
           COMMAND)
         if (no_extract)
@@ -2873,11 +2762,20 @@ function(_ep_add_download_command name)
           set(steps "verify and extract")
         endif ()
         set(comment "Performing download step (${steps}) for '${name}'")
-        _ep_write_verifyfile_script("${stamp_dir}/verify-${name}.cmake" "${file}" "${hash}")
+        _ep_write_verifyfile_script(
+          "${stamp_dir}/verify-${name}.cmake"
+          "${file}"
+          "${hash}"
+        )
       endif()
       list(APPEND cmd ${CMAKE_COMMAND} -P ${stamp_dir}/verify-${name}.cmake)
       if (NOT no_extract)
-        _ep_write_extractfile_script("${stamp_dir}/extract-${name}.cmake" "${name}" "${file}" "${source_dir}")
+        _ep_write_extractfile_script(
+          "${stamp_dir}/extract-${name}.cmake"
+          "${name}"
+          "${file}"
+          "${source_dir}"
+        )
         list(APPEND cmd COMMAND ${CMAKE_COMMAND} -P ${stamp_dir}/extract-${name}.cmake)
       else ()
         set_property(TARGET ${name} PROPERTY _EP_DOWNLOADED_FILE ${file})
@@ -3040,9 +2938,18 @@ function(_ep_add_update_command name)
 
     _ep_get_git_submodules_recurse(git_submodules_recurse)
 
-    _ep_write_gitupdate_script(${tmp_dir}/${name}-gitupdate.cmake
-      ${GIT_EXECUTABLE} ${git_tag} ${git_remote_name} ${git_init_submodules} "${git_submodules_recurse}" "${git_submodules}" ${git_repository} ${work_dir} ${git_update_strategy}
-      )
+    _ep_write_gitupdate_script(
+      "${tmp_dir}/${name}-gitupdate.cmake"
+      "${GIT_EXECUTABLE}"
+      "${git_tag}"
+      "${git_remote_name}"
+      "${git_init_submodules}"
+      "${git_submodules_recurse}"
+      "${git_submodules}"
+      "${git_repository}"
+      "${work_dir}"
+      "${git_update_strategy}"
+    )
     set(cmd ${CMAKE_COMMAND} -P ${tmp_dir}/${name}-gitupdate.cmake)
     set(always 1)
   elseif(hg_repository)
@@ -3284,10 +3191,11 @@ function(_ep_add_configure_command name)
   # used, cmake args or cmake generator) then re-run the configure step.
   # Fixes issue https://gitlab.kitware.com/cmake/cmake/-/issues/10258
   #
-  if(NOT EXISTS ${tmp_dir}/${name}-cfgcmd.txt.in)
-    file(WRITE ${tmp_dir}/${name}-cfgcmd.txt.in "cmd='\@cmd\@'\n")
-  endif()
-  configure_file(${tmp_dir}/${name}-cfgcmd.txt.in ${tmp_dir}/${name}-cfgcmd.txt)
+  configure_file(
+    ${CMAKE_CURRENT_FUNCTION_LIST_DIR}/ExternalProject/cfgcmd.txt.in
+    ${tmp_dir}/${name}-cfgcmd.txt
+    @ONLY
+  )
   list(APPEND file_deps ${tmp_dir}/${name}-cfgcmd.txt)
   list(APPEND file_deps ${_ep_cache_args_script})
 

Modules/ExternalProject/cfgcmd.txt.in

@@ -0,0 +1 @@
+cmd='@cmd@'

Modules/ExternalProject/extractfile.cmake.in

@@ -0,0 +1,65 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+cmake_minimum_required(VERSION 3.5)
+
+# Make file names absolute:
+#
+get_filename_component(filename "@filename@" ABSOLUTE)
+get_filename_component(directory "@directory@" ABSOLUTE)
+
+message(STATUS "extracting...
+     src='${filename}'
+     dst='${directory}'"
+)
+
+if(NOT EXISTS "${filename}")
+  message(FATAL_ERROR "File to extract does not exist: '${filename}'")
+endif()
+
+# Prepare a space for extracting:
+#
+set(i 1234)
+while(EXISTS "${directory}/../ex-@name@${i}")
+  math(EXPR i "${i} + 1")
+endwhile()
+set(ut_dir "${directory}/../ex-@name@${i}")
+file(MAKE_DIRECTORY "${ut_dir}")
+
+# Extract it:
+#
+message(STATUS "extracting... [tar @args@]")
+execute_process(COMMAND ${CMAKE_COMMAND} -E tar @args@ ${filename}
+  WORKING_DIRECTORY ${ut_dir}
+  RESULT_VARIABLE rv
+)
+
+if(NOT rv EQUAL 0)
+  message(STATUS "extracting... [error clean up]")
+  file(REMOVE_RECURSE "${ut_dir}")
+  message(FATAL_ERROR "Extract of '${filename}' failed")
+endif()
+
+# Analyze what came out of the tar file:
+#
+message(STATUS "extracting... [analysis]")
+file(GLOB contents "${ut_dir}/*")
+list(REMOVE_ITEM contents "${ut_dir}/.DS_Store")
+list(LENGTH contents n)
+if(NOT n EQUAL 1 OR NOT IS_DIRECTORY "${contents}")
+  set(contents "${ut_dir}")
+endif()
+
+# Move "the one" directory to the final directory:
+#
+message(STATUS "extracting... [rename]")
+file(REMOVE_RECURSE ${directory})
+get_filename_component(contents ${contents} ABSOLUTE)
+file(RENAME ${contents} ${directory})
+
+# Clean up:
+#
+message(STATUS "extracting... [clean up]")
+file(REMOVE_RECURSE "${ut_dir}")
+
+message(STATUS "extracting... done")

Modules/ExternalProject/gitclone.cmake.in

@@ -0,0 +1,73 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+cmake_minimum_required(VERSION 3.5)
+
+if(EXISTS "@gitclone_stampfile@" AND EXISTS "@gitclone_infofile@" AND
+  "@gitclone_stampfile@" IS_NEWER_THAN "@gitclone_infofile@")
+  message(STATUS
+    "Avoiding repeated git clone, stamp file is up to date: "
+    "'@gitclone_stampfile@'"
+  )
+  return()
+endif()
+
+execute_process(
+  COMMAND ${CMAKE_COMMAND} -E rm -rf "@source_dir@"
+  RESULT_VARIABLE error_code
+)
+if(error_code)
+  message(FATAL_ERROR "Failed to remove directory: '@source_dir@'")
+endif()
+
+# try the clone 3 times in case there is an odd git clone issue
+set(error_code 1)
+set(number_of_tries 0)
+while(error_code AND number_of_tries LESS 3)
+  execute_process(
+    COMMAND "@git_EXECUTABLE@" @git_options@
+            clone @git_clone_options@ "@git_repository@" "@src_name@"
+    WORKING_DIRECTORY "@work_dir@"
+    RESULT_VARIABLE error_code
+  )
+  math(EXPR number_of_tries "${number_of_tries} + 1")
+endwhile()
+if(number_of_tries GREATER 1)
+  message(STATUS "Had to git clone more than once: ${number_of_tries} times.")
+endif()
+if(error_code)
+  message(FATAL_ERROR "Failed to clone repository: '@git_repository@'")
+endif()
+
+execute_process(
+  COMMAND "@git_EXECUTABLE@" @git_options@
+          checkout "@git_tag@" @git_checkout_explicit--@
+  WORKING_DIRECTORY "@work_dir@/@src_name@"
+  RESULT_VARIABLE error_code
+)
+if(error_code)
+  message(FATAL_ERROR "Failed to checkout tag: '@git_tag@'")
+endif()
+
+set(init_submodules @init_submodules@)
+if(init_submodules)
+  execute_process(
+    COMMAND "@git_EXECUTABLE@" @git_options@
+            submodule update @git_submodules_recurse@ --init @git_submodules@
+    WORKING_DIRECTORY "@work_dir@/@src_name@"
+    RESULT_VARIABLE error_code
+  )
+endif()
+if(error_code)
+  message(FATAL_ERROR "Failed to update submodules in: '@work_dir@/@src_name@'")
+endif()
+
+# Complete success, update the script-last-run stamp file:
+#
+execute_process(
+  COMMAND ${CMAKE_COMMAND} -E copy "@gitclone_infofile@" "@gitclone_stampfile@"
+  RESULT_VARIABLE error_code
+)
+if(error_code)
+  message(FATAL_ERROR "Failed to copy script-last-run stamp file: '@gitclone_stampfile@'")
+endif()

Modules/ExternalProject/hgclone.cmake.in

@@ -0,0 +1,49 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+cmake_minimum_required(VERSION 3.5)
+
+if(EXISTS "@hgclone_stampfile@" AND EXISTS "@hgclone_infofile@" AND
+  "@hgclone_stampfile@" IS_NEWER_THAN "@hgclone_infofile@")
+  message(STATUS
+    "Avoiding repeated hg clone, stamp file is up to date: "
+    "'@hgclone_stampfile@'"
+  )
+  return()
+endif()
+
+execute_process(
+  COMMAND ${CMAKE_COMMAND} -E rm -rf "@source_dir@"
+  RESULT_VARIABLE error_code
+)
+if(error_code)
+  message(FATAL_ERROR "Failed to remove directory: '@source_dir@'")
+endif()
+
+execute_process(
+  COMMAND "@hg_EXECUTABLE@" clone -U "@hg_repository@" "@src_name@"
+  WORKING_DIRECTORY "@work_dir@"
+  RESULT_VARIABLE error_code
+)
+if(error_code)
+  message(FATAL_ERROR "Failed to clone repository: '@hg_repository@'")
+endif()
+
+execute_process(
+  COMMAND "@hg_EXECUTABLE@" update @hg_tag@
+  WORKING_DIRECTORY "@work_dir@/@src_name@"
+  RESULT_VARIABLE error_code
+)
+if(error_code)
+  message(FATAL_ERROR "Failed to checkout tag: '@hg_tag@'")
+endif()
+
+# Complete success, update the script-last-run stamp file:
+#
+execute_process(
+  COMMAND ${CMAKE_COMMAND} -E copy "@hgclone_infofile@" "@hgclone_stampfile@"
+  RESULT_VARIABLE error_code
+)
+if(error_code)
+  message(FATAL_ERROR "Failed to copy script-last-run stamp file: '@hgclone_stampfile@'")
+endif()

Modules/ExternalProject/mkdirs.cmake.in

@@ -0,0 +1,19 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+cmake_minimum_required(VERSION 3.5)
+
+file(MAKE_DIRECTORY
+  "@source_dir@"
+  "@binary_dir@"
+  "@install_dir@"
+  "@tmp_dir@"
+  "@stamp_dir@"
+  "@download_dir@"
+  "@log_dir@"
+)
+
+set(configSubDirs @CMAKE_CONFIGURATION_TYPES@)
+foreach(subDir IN LISTS configSubDirs)
+    file(MAKE_DIRECTORY "@stamp_dir@/${subDir}")
+endforeach()