1 files changed, 32 insertions, 0 deletions
diff --git a/nix/escapeExecline/default.nix b/nix/escapeExecline/default.nix
new file mode 100644
index 0000000000..d2c39dd398
--- /dev/null
+++ b/nix/escapeExecline/default.nix
@@ -0,0 +1,32 @@
+{ lib, ... }:
+let
+  # replaces " and \ to \" and \\ respectively and quote with "
+  # e.g.
+  #   a"b\c -> "a\"b\\c"
+  #   a\"bc -> "a\\\"bc"
+  escapeExeclineArg = arg:
+    ''"${builtins.replaceStrings [ ''"'' ''\'' ] [ ''\"'' ''\\'' ] (toString arg)}"'';
+
+  # Escapes an execline (list of execline strings) to be passed to execlineb
+  # Give it a nested list of strings. Nested lists are interpolated as execline
+  # blocks ({}).
+  # Everything is quoted correctly.
+  #
+  # Example:
+  #   escapeExecline [ "if" [ "somecommand" ] "true" ]
+  #   == ''"if" { "somecommand" } "true"''
+  escapeExecline = execlineList: lib.concatStringsSep " "
+    (
+      let
+        go = arg:
+          if builtins.isString arg then [ (escapeExeclineArg arg) ]
+          else if builtins.isPath arg then [ (escapeExeclineArg "${arg}") ]
+          else if lib.isDerivation arg then [ (escapeExeclineArg arg) ]
+          else if builtins.isList arg then [ "{" ] ++ builtins.concatMap go arg ++ [ "}" ]
+          else abort "escapeExecline can only hande nested lists of strings, was ${lib.generators.toPretty {} arg}";
+      in
+      builtins.concatMap go execlineList
+    );
+
+in
+escapeExecline