prefer scalable byte strings;

--- a/src/Pure/PIDE/command.ML	Tue Jun 21 22:17:11 2022 +0200
+++ b/src/Pure/PIDE/command.ML	Tue Jun 21 23:05:37 2022 +0200
@@ -72,7 +72,7 @@
 
     fun read_url () =
       let
-        val text = Isabelle_System.download file_node;
+        val text = Bytes.content (Isabelle_System.download file_node);
         val file_pos = Position.file file_node;
       in (text, file_pos) end;
 

--- a/src/Pure/System/isabelle_system.ML	Tue Jun 21 22:17:11 2022 +0200
+++ b/src/Pure/System/isabelle_system.ML	Tue Jun 21 23:05:37 2022 +0200
@@ -20,10 +20,10 @@
   val with_tmp_file: string -> string -> (Path.T -> 'a) -> 'a
   val rm_tree: Path.T -> unit
   val with_tmp_dir: string -> (Path.T -> 'a) -> 'a
-  val download: string -> string
+  val download: string -> Bytes.T
   val download_file: string -> Path.T -> unit
-  val decode_base64: string -> string
-  val encode_base64: string -> string
+  val decode_base64: Bytes.T -> Bytes.T
+  val encode_base64: Bytes.T -> Bytes.T
   val isabelle_id: unit -> string
   val isabelle_identifier: unit -> string option
   val isabelle_heading: unit -> string
@@ -156,15 +156,15 @@
 
 (* download file *)
 
-val download = Scala.function1 "download";
+val download = Bytes.string #> Scala.function1_bytes "download";
 
-fun download_file url path = File.write path (download url);
+fun download_file url path = Bytes.write path (download url);
 
 
 (* base64 *)
 
-val decode_base64 = Scala.function1 "decode_base64";
-val encode_base64 = Scala.function1 "encode_base64";
+val decode_base64 = Scala.function1_bytes "decode_base64";
+val encode_base64 = Scala.function1_bytes "encode_base64";
 
 
 (* Isabelle distribution identification *)