rename add_data_to_current_span; give it span explicitly

src/core/collector.ml

@@ -53,8 +53,8 @@ module type S = sig
   (** Exit an explicit span.
       @since 0.3 *)
 
-  val add_data_to_current_span : (string * user_data) list -> unit
-  (** @since Adds data to the current, implicit span.
+  val add_data_to_span : span -> (string * user_data) list -> unit
+  (** @since Adds data to the current span.
       NEXT_RELEASE *)
 
   val add_data_to_manual_span :

src/core/trace_core.ml

@@ -55,11 +55,11 @@ let[@inline] exit_manual_span espan : unit =
   | None -> ()
   | Some (module C) -> C.exit_manual_span espan
 
-let[@inline] add_data_to_current_span data : unit =
+let[@inline] add_data_to_span sp data : unit =
   if data <> [] then (
     match A.get collector with
     | None -> ()
-    | Some (module C) -> C.add_data_to_current_span data
+    | Some (module C) -> C.add_data_to_span sp data
   )
 
 let[@inline] add_data_to_manual_span esp data : unit =

src/core/trace_core.mli

@@ -34,9 +34,9 @@ val with_span :
     see {!enter_manual_span}.
 *)
 
-val add_data_to_current_span : (string * user_data) list -> unit
-(** Add structured data to the current, implicit span (see {!with_span}).
-    Behavior is not specified if there is no current span.
+val add_data_to_span : span -> (string * user_data) list -> unit
+(** Add structured data to the given active span (see {!with_span}).
+    Behavior is not specified if the span has been exited.
     @since NEXT_RELEASE *)
 
 val enter_manual_sub_span :

src/tef/trace_tef.ml

@@ -55,7 +55,7 @@ type event =
       time_us: float;
     }
   | E_add_data of {
-      tid: int;
+      id: span;
       data: (string * user_data) list;
     }
   | E_enter_manual_span of {
@@ -93,13 +93,6 @@ module Span_tbl = Hashtbl.Make (struct
   let hash : t -> int = Hashtbl.hash
 end)
 
-module Int_tbl = Hashtbl.Make (struct
-  type t = int
-
-  let equal : t -> t -> bool = ( = )
-  let hash : t -> int = Hashtbl.hash
-end)
-
 type span_info = {
   tid: int;
   name: string;
@@ -280,7 +273,6 @@ let bg_thread ~out (events : event B_queue.t) : unit =
   Writer.with_ ~out @@ fun writer ->
   (* local state, to keep track of span information and implicit stack context *)
   let spans : span_info Span_tbl.t = Span_tbl.create 32 in
-  let ambient_span : span_info Int_tbl.t = Int_tbl.create 16 in
   let local_q = Queue.create () in
 
   (* add function name, if provided, to the metadata *)
@@ -299,8 +291,6 @@ let bg_thread ~out (events : event B_queue.t) : unit =
     | E_define_span { tid; name; id; time_us; fun_name; data } ->
       let data = add_fun_name_ fun_name data in
       let info = { tid; name; start_us = time_us; data } in
-      (* make this span the "ambient" one for the given thread *)
-      Int_tbl.add ambient_span tid info;
       (* save the span so we find it at exit *)
       Span_tbl.add spans id info
     | E_exit_span { id; time_us = stop_us } ->
@@ -308,14 +298,11 @@ let bg_thread ~out (events : event B_queue.t) : unit =
       | None -> !on_tracing_error (Printf.sprintf "cannot find span %Ld" id)
       | Some { tid; name; start_us; data } ->
         Span_tbl.remove spans id;
-        Int_tbl.remove ambient_span tid;
         Writer.emit_duration_event ~tid ~name ~start:start_us ~end_:stop_us
           ~args:data writer)
-    | E_add_data { tid; data } ->
-      (match Int_tbl.find_opt ambient_span tid with
-      | None ->
-        !on_tracing_error
-          (Printf.sprintf "cannot find ambient span for thread %d" tid)
+    | E_add_data { id; data } ->
+      (match Span_tbl.find_opt spans id with
+      | None -> !on_tracing_error (Printf.sprintf "cannot find span %Ld" id)
       | Some info -> info.data <- List.rev_append data info.data)
     | E_enter_manual_span { tid; time_us; name; id; data; fun_name; flavor } ->
       let data = add_fun_name_ fun_name data in
@@ -410,11 +397,8 @@ let collector ~out () : collector =
 
       Fun.protect ~finally (fun () -> f span)
 
-    let add_data_to_current_span data =
-      if data <> [] then (
-        let tid = get_tid_ () in
-        B_queue.push events (E_add_data { tid; data })
-      )
+    let add_data_to_span span data =
+      if data <> [] then B_queue.push events (E_add_data { id = span; data })
 
     let enter_manual_span ~(parent : explicit_span option) ~flavor
         ~__FUNCTION__:fun_name ~__FILE__:_ ~__LINE__:_ ~data name :

test/t1.ml

@@ -17,10 +17,10 @@ let run () =
       Trace.message "world";
       Trace.counter_int "n" !n;
 
-      Trace.add_data_to_current_span [ "i", `Int _i ];
+      Trace.add_data_to_span _sp [ "i", `Int _i ];
 
       if _j = 2 then (
-        Trace.add_data_to_current_span [ "j", `Int _j ];
+        Trace.add_data_to_span _sp [ "j", `Int _j ];
         let _sp =
           Trace.enter_manual_sub_span ~parent:pseudo_async_sp
             ~flavor: