From 78bb1841172381cd9e6746daf40b471bfd91e19b Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Mon, 5 Apr 2021 11:56:40 -0400
Subject: [PATCH] add some basic logging

---
 src/blocking_IO.ml | 8 ++++++--
 src/jsonrpc2.ml    | 2 ++
 src/jsonrpc2.mli   | 4 ++++
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/blocking_IO.ml b/src/blocking_IO.ml
index 58b1ceb4..8b72da0d 100644
--- a/src/blocking_IO.ml
+++ b/src/blocking_IO.ml
@@ -18,8 +18,12 @@ let spawn f =
   let run () =
     try f()
     with e ->
-      Printf.eprintf "linol: uncaught exception in `spawn`:\n%s\n%!"
-        (Printexc.to_string e);
+      let msg =
+        Printf.sprintf "linol: uncaught exception in `spawn`:\n%s\n%!"
+          (Printexc.to_string e)
+      in
+      !Jsonrpc2._log (fun () -> msg);
+      Printf.eprintf "%s\n%!" msg;
       raise e
 in
   ignore (Thread.create run () : Thread.t)
diff --git a/src/jsonrpc2.ml b/src/jsonrpc2.ml
index 8d387d4f..eba4a553 100644
--- a/src/jsonrpc2.ml
+++ b/src/jsonrpc2.ml
@@ -10,6 +10,8 @@ type json = Yojson.Safe.t
 
 module type IO = Sigs.IO
 
+let _log : ((unit -> string) -> unit) ref = ref (fun _ -> ())
+
 module type S = sig
   module IO : IO
 
diff --git a/src/jsonrpc2.mli b/src/jsonrpc2.mli
index 72c12f41..f14b05bb 100644
--- a/src/jsonrpc2.mli
+++ b/src/jsonrpc2.mli
@@ -30,3 +30,7 @@ module type S = sig
 end
 
 module Make(IO : IO) : S with module IO = IO
+
+(**/**)
+val _log : ((unit -> string) -> unit) ref
+(**/**)