Merge pull request #60 from kuviman/fix-eio-spawn

Make template-eio handle requests concurrently

CHANGES.md

@@ -1,4 +1,9 @@
 
+# 0.11
+
+- breaking: the Eio library now needs the output channel to be paired with
+    an `Eio.Mutex.t` to prevent race conditions (#58)
+
 # 0.10
 
 - use `git subtree` to vendor lsp+jsonrpc, so that they

dune-project

@@ -24,7 +24,7 @@
  (synopsis "LSP server library")
  (depends
   ("yojson"
-   (>= "1.6"))
+   (and (>= "1.6") (< "3.0")))
   "logs"
   ("trace"
    (>= "0.4"))

example/template-eio/main.ml

@@ -37,7 +37,7 @@ let diagnostics (_state : state_after_processing) : Lsp.Types.Diagnostic.t list
    so that users only need to override methods that they want the server to
    actually meaningfully interpret and respond to.
 *)
-class lsp_server =
+class lsp_server ~(sw: Eio.Switch.t) =
   object (self)
     inherit Linol_eio.Jsonrpc2.server
 
@@ -45,7 +45,7 @@ class lsp_server =
     val buffers : (Lsp.Types.DocumentUri.t, state_after_processing) Hashtbl.t =
       Hashtbl.create 32
 
-    method spawn_query_handler f = Linol_eio.spawn f
+    method spawn_query_handler f = Linol_eio.spawn ~sw f
 
     (* We define here a helper method that will:
        - process a document
@@ -82,7 +82,8 @@ class lsp_server =
    and runs it as a task. *)
 let run () =
   Eio_main.run @@ fun env ->
-  let s = new lsp_server in
+  Eio.Switch.run @@ fun sw ->
+  let s = new lsp_server ~sw in
   let server = Linol_eio.Jsonrpc2.create_stdio ~env s in
   let task () =
     let shutdown () = s#get_status = `ReceivedExit in

linol.opam

@@ -9,7 +9,7 @@ homepage: "https://github.com/c-cube/linol"
 bug-reports: "https://github.com/c-cube/linol/issues"
 depends: [
   "dune" {>= "2.0"}
-  "yojson" {>= "1.6"}
+  "yojson" {>= "1.6" & < "3.0"}
   "logs"
   "trace" {>= "0.4"}
   "ocaml" {>= "4.14"}

src/eio/linol_eio.ml

@@ -9,7 +9,7 @@ module IO_eio :
     with type 'a t = 'a
      and type env = Eio_unix.Stdenv.base
      and type in_channel = Eio.Buf_read.t
-     and type out_channel = Eio_unix.sink_ty Eio.Std.r = struct
+     and type out_channel = Eio.Mutex.t * Eio_unix.sink_ty Eio.Std.r = struct
   type 'a t = 'a
 
   let ( let+ ) x f = f x
@@ -28,17 +28,21 @@ module IO_eio :
   let stdin env =
     Eio.Buf_read.of_flow ~max_size:1_000_000 (Eio.Stdenv.stdin env)
 
-  let stdout = Eio.Stdenv.stdout
+  let stdout_mutex = Eio.Mutex.create ()
+  let stdout env = stdout_mutex, Eio.Stdenv.stdout env
 
   type env = Eio_unix.Stdenv.base
   type in_channel = Eio.Buf_read.t
-  type out_channel = Eio_unix.sink_ty Eio.Std.r
+  type out_channel = Eio.Mutex.t * Eio_unix.sink_ty Eio.Std.r
 
-  let write_string out_ch str = Eio.Flow.copy_string str out_ch
+  let write_string (mutex, out_ch) str =
+    Eio.Mutex.use_rw ~protect:false mutex (fun () ->
+        Eio.Flow.copy_string str out_ch)
 
-  let write out_ch bytes off len =
-    Eio.Buf_write.with_flow out_ch @@ fun w ->
-    Eio.Buf_write.bytes w ~off ~len bytes
+  let write (mutex, out_ch) bytes off len =
+    Eio.Mutex.use_rw ~protect:false mutex (fun () ->
+        Eio.Buf_write.with_flow out_ch @@ fun w ->
+        Eio.Buf_write.bytes w ~off ~len bytes)
 
   let read in_ch bytes off len =
     let str = Eio.Buf_read.take len in_ch in
@@ -48,17 +52,14 @@ module IO_eio :
 end
 
 (** Spawn function. *)
-let spawn f =
-  let promise, resolver = Eio.Promise.create () in
-  (try
-     f ();
-     Eio.Promise.resolve_ok resolver ()
+let spawn ~sw f =
+  Eio.Fiber.fork ~sw (fun () ->
+   try
+     f ()
    with exn ->
      Printf.eprintf "uncaught exception in `spawn`:\n%s\n%!"
        (Printexc.to_string exn);
-     Eio.Promise.resolve_error resolver exn);
-
-  Eio.Promise.await_exn promise
+     raise exn)
 
 include Lsp.Types
 include IO_eio