From 8b7a2e86b804a0e54c0a2db92892df30eff9b542 Mon Sep 17 00:00:00 2001
From: Allison Vacanti <alliepiper16@gmail.com>
Date: Thu, 18 Mar 2021 16:07:40 -0400
Subject: [PATCH] Avoid recompiling option_parser every time cmake runs.

Switch to `configure_file`, which won't touch the output file unless
the contents change.
---
 cmake/FileToString.cmake | 6 ++++--
 cmake/FileToString.in    | 1 +
 2 files changed, 5 insertions(+), 2 deletions(-)
 create mode 100644 cmake/FileToString.in

diff --git a/cmake/FileToString.cmake b/cmake/FileToString.cmake
index fd65d6d..3935908 100644
--- a/cmake/FileToString.cmake
+++ b/cmake/FileToString.cmake
@@ -3,11 +3,13 @@
 # Create a C++ file `file_out` that defines a string named `string_name` in
 # `namespace`, which contains the contents of `file_in`.
 
+# Cache this so we can access it from wherever file_to_string is called.
+set(_nvbench_file_to_string_path "${CMAKE_CURRENT_LIST_DIR}/FileToString.in")
 function(file_to_string file_in file_out namespace string_name)
   file(READ "${file_in}" file_in_contents)
 
   set(file_out_contents)
-  string(APPEND file_out_contents
+  string(APPEND file_to_string_payload
     "#include <string>\n"
     "namespace ${namespace} {\n"
     "const std::string ${string_name} =\n"
@@ -15,5 +17,5 @@ function(file_to_string file_in file_out namespace string_name)
     "}\n"
   )
 
-  file(WRITE "${file_out}" "${file_out_contents}")
+  configure_file("${_nvbench_file_to_string_path}" "${file_out}")
 endfunction()
diff --git a/cmake/FileToString.in b/cmake/FileToString.in
new file mode 100644
index 0000000..aeff339
--- /dev/null
+++ b/cmake/FileToString.in
@@ -0,0 +1 @@
+${file_to_string_payload}