feat: use System.tmp_dir() rather than Mix.Project.build_path()

Useful when using protox in Livebook, as Mix.Project.build_path() returns an invalid path.

Author: ahamez

lib/protox.ex

@@ -241,7 +241,7 @@ defmodule Protox do
     case Keyword.pop(opts, :schema) do
       {<<text::binary>>, opts} ->
         filename = "#{Base.encode16(:crypto.hash(:sha, text))}.proto"
-        filepath = [Mix.Project.build_path(), filename] |> Path.join() |> Path.expand()
+        filepath = [System.tmp_dir!(), filename] |> Path.join() |> Path.expand()
         File.write!(filepath, text)
         {[filepath], opts}
 

lib/protox/protoc.ex

@@ -25,7 +25,7 @@ defmodule Protox.Protoc do
 
   defp do_run(proto_files, args) do
     outfile_name = "protox_#{random_string()}"
-    outfile_path = Path.join([Mix.Project.build_path(), outfile_name])
+    outfile_path = Path.join([System.tmp_dir!(), outfile_name])
 
     cmd_args = ["--include_imports", "-o", outfile_path] ++ args ++ proto_files