WIP

lib/flake_env__util.re

@@ -1,10 +1,55 @@
 open Core;
 module Unix = Core_unix;
 
-let nix = (args) => {
-  let stdout_chan = Unix.open_process_in(
-    "nix --extra-experimental-features \"nix-command flakes\" " ++ (args |> String.concat(~sep=" ")));
+let run_process = (name, args) => {
+  /*** Run a process [name] with args [args], returning (exit_code, stdout text) */
+  let stdout_chan = Unix.open_process_in(name ++ " " ++ (args |> String.concat(~sep=" ")));
   let stdout_content = stdout_chan |> In_channel.input_all;
   let exit_code = Unix.close_process_in(stdout_chan);
   (exit_code, stdout_content)
-}
+ };
+
+let nix = (args) => run_process("nix", ["--extra-experimental-features", "\"nix-command flakes\" ", ...args]);
+
+let hash_files = (filenames) => {
+  /*** Hash all entries in [filenames], returning a hex-encoded string of the hash of their contents */
+  let ctx = Sha1.init();
+  let () = filenames
+  |> Array.filter(~f=f => switch (Sys_unix.file_exists(f)) {
+      | `Yes => true
+      | _ => false
+    })
+  |> Array.iter(~f=(f) => {
+      f |> In_channel.create |> In_channel.input_all |> Sha1.update_string(ctx);
+    });
+  Sha1.finalize(ctx) |> Sha1.to_hex
+};
+
+let rec rmrf = (path) => {
+  switch (Unix.lstat(path).st_kind) {
+  | exception Unix.Unix_error(_, _, _) => ()
+  | S_REG => Unix.unlink(path)
+  | S_LNK => Unix.unlink(path)
+  | S_DIR => {
+      Sys_unix.readdir(path) |> Array.iter(~f=name => rmrf(Filename.concat(path, name)));
+      Unix.rmdir(path)
+    }
+  | S_CHR => Printf.eprintf("Don't know how to handle Character Device file\n")
+  | S_BLK => Printf.eprintf("Don't know how to handle Block Device file\n")
+  | S_FIFO => Printf.eprintf("Don't know how to handle FIFO file\n")
+  | S_SOCK => Printf.eprintf("Don't know how to handle Socket file\n")
+  }
+};
+
+let get_args = (argv) => {
+  switch (Array.length(argv)) {
+  | x when x >= 3 => {
+      let layout_directory = argv[1];
+      let flake_specifier = argv[2];
+      let other_args = snd(List.split_n(List.of_array(argv), 3));
+      Ok((layout_directory, flake_specifier, other_args))
+    }
+  | _ => Error()
+  }
+};
+