Fix second chance

lib/events.ml

@@ -16,7 +16,7 @@ type 'a res = ('a,exn) result
 
 (* Events in progress *)
 type _ in_progress =
-  | Line : Bytes.t * Buffer.t -> string in_progress
+  | Line : int * Bytes.t * Buffer.t -> string in_progress
   | Bytes : int * Bytes.t -> Bytes.t in_progress
 
 (* Reified function composition *)
@@ -126,7 +126,7 @@ let mkReadInProgress fd = function
   | FCons _ as f -> Advanced (ReadInProgress(fd,f))
   | FNil x -> Yes x
 
-let one_line () = Line (Bytes.make 1 '0', Buffer.create 40)
+let one_line ?(at_least=1) () = Line (at_least,Bytes.make at_least '0', Buffer.create (max 40 at_least))
 let some_bytes n ?(buff=Bytes.create n) () = Bytes(n,buff)
 
 module On = struct
@@ -161,10 +161,12 @@ let parse_content_length_or err k s =
   with
     (Scanf.Scan_failure _ | Failure _ | End_of_file | Invalid_argument _) as e ->
       err (Error e)
+
+let len_httpcle_header = String.length "CONTENT-LENGTH: \n"
 
 let an_httpcle (k : Bytes.t res -> 'b) : 'b fcomp  =
   let (--?) x y = err k x y in
-  one_line ()
+  one_line ~at_least:len_httpcle_header ()
   --? (parse_content_length_or (finish_with k) (fun length ->
   one_line ()
   --? (fun _discard ->
@@ -199,19 +201,19 @@ let advance_system ready_fds _ = function
       else ready_fds, Yes (k code)
   | ReadInProgress(_, FNil _) -> assert false
   | ReadInProgress(fd,_) as x when not (List.mem fd ready_fds) -> ready_fds, No x
-  | ReadInProgress(fd, FCons(Line (buff,acc) as line,rest)) ->
+  | ReadInProgress(fd, FCons(Line (m,buff,acc),rest)) ->
     let ready_fds = List.filter ((<>) fd) ready_fds in
     ready_fds,
     begin try
-      let n = Unix.read fd buff 0 1 in
+      let n = Unix.read fd buff 0 m in
       if n = 0 then begin
         Buffer.clear acc;
         mkReadInProgress fd (rest (Error End_of_file))
       end else
-        let c = Bytes.get buff 0 in
+        let c = Bytes.get buff (n-1) in
         if c != '\n' then begin
-          Buffer.add_char acc c; 
-          mkReadInProgress fd (FCons(line,rest))
+          Buffer.add_bytes acc (Bytes.sub buff 0 n); 
+          mkReadInProgress fd (FCons(Line (max (m-n) 1,buff,acc),rest))
         end else begin
           let one_line = Buffer.contents acc in
           Buffer.clear acc;

lib/sel.ml

@@ -92,22 +92,21 @@ end
 (* Like List.filter but also returns the minimum priority of ready events.
    Moreover ~advance can make the event advance (whilst not being ready yet)*)
 let pull_ready ~advance st l =
-  let rec pull_ready yes no min_priority st l =
+  let rec pull_ready yes min_priority_ready no st l =
     match Sorted.look l with
-    | Sorted.Nil -> yes, no, min_priority
+    | Sorted.Nil -> yes, no, min_priority_ready
     | Sorted.Cons(({ WithAttributes.it; cancelled; priority; _ } as e, _), rest) ->
         match advance st cancelled it with
         | st, Yes y ->
-          let min_priority = Sorted.min_user min_priority priority in
+          let min_priority_ready = Sorted.min_user min_priority_ready priority in
           let e = drop_event_type y e in
-          pull_ready (Sorted.cons e e.priority yes) no min_priority st rest
+          pull_ready (Sorted.cons e e.priority yes) min_priority_ready no st rest
         | st, Advanced x  ->
-          let min_priority = Sorted.min_user min_priority priority in
-          pull_ready yes (Sorted.cons { e with it = x } e.priority no) min_priority st rest 
+          pull_ready yes min_priority_ready (Sorted.cons { e with it = x } e.priority no) st rest 
         | st, No x  ->
-          pull_ready yes (Sorted.cons { e with it = x } e.priority no) min_priority st rest 
+          pull_ready yes min_priority_ready (Sorted.cons { e with it = x } e.priority no) st rest 
   in
-    pull_ready Sorted.nil Sorted.nil Sorted.max_priority st l
+    pull_ready Sorted.nil Sorted.max_priority Sorted.nil st l
 
 type ('a,'b) ev_checker =
   'a WithAttributes.t Sorted.t -> 'b WithAttributes.t Sorted.t * 'a WithAttributes.t Sorted.t * Sorted.priority
@@ -128,21 +127,21 @@ let filter_file_descriptor fds = function
    The result is that it when reading 'n' bytes, it is no longer necessary to interleave up to 'n' ready tasks.
 *)
 let check_for_system_events min_prio_task_queue : ('a system_event,'a) ev_checker = fun waiting ->
-  let rec check_for_system_events new_ready waiting_skipped min_prio waiting =
+  let rec check_for_system_events new_ready waiting_skipped min_prio_ready waiting =
     let fds = file_descriptors_of waiting in
     let ready_fds, _, _ = Unix.select fds [] [] 0.0 in
-    let new_ready_1, waiting, min_prio_1 = pull_ready ~advance:advance_system ready_fds waiting in
+    let new_ready_1, waiting, min_prio_ready_1 = pull_ready ~advance:advance_system ready_fds waiting in
     let new_ready = Sorted.append new_ready_1 new_ready in
-    let min_prio = Sorted.min_user min_prio_1 min_prio in
+    let min_prio_ready = Sorted.min_user min_prio_ready_1 min_prio_ready in
     if ready_fds = [] then
-      new_ready, Sorted.append waiting waiting_skipped, min_prio
+      new_ready, Sorted.append waiting waiting_skipped, min_prio_ready
     else
       let waiting, waiting_skipped_1 = Sorted.partition (filter_file_descriptor ready_fds) waiting in
-      let waiting, waiting_skipped_2 = Sorted.partition_priority (Sorted.le_user min_prio) waiting in
-      let waiting_skipped = Sorted.concat [waiting_skipped_2; waiting_skipped_1; waiting_skipped] in
-      check_for_system_events new_ready waiting_skipped min_prio waiting
+      let waiting_skipped = Sorted.concat [waiting_skipped_1; waiting_skipped] in
+      check_for_system_events new_ready waiting_skipped min_prio_ready waiting
   in
-    check_for_system_events Sorted.nil Sorted.nil min_prio_task_queue waiting
+    let waiting, waiting_skipped = Sorted.partition_priority (fun x -> Sorted.le_user x min_prio_task_queue) waiting in
+    check_for_system_events Sorted.nil waiting_skipped Sorted.max_priority waiting
 
 let check_for_queue_events : ('a queue_event,'a) ev_checker =
   fun waiting ->
@@ -158,7 +157,10 @@ let rec wait_for_system_or_queue_events ~deadline (fds,sys) queue =
     let ready_sys, waiting_sys, min_prio_sys = pull_ready ~advance:advance_system ready_fds sys in
     let ready_queue, waiting_queue, min_prio_queue = pull_ready ~advance:advance_queue () queue in
     if ready_sys <> Sorted.nil || ready_queue <> Sorted.nil
-    then ready_sys, ready_queue, waiting_sys, waiting_queue, Sorted.min_priority min_prio_queue min_prio_sys
+    then
+      let min_prio =  Sorted.min_priority min_prio_queue min_prio_sys in
+      let new_ready_sys, waiting_sys, min_prio_new_ready_sys = check_for_system_events min_prio waiting_sys in
+      Sorted.append new_ready_sys ready_sys, ready_queue, waiting_sys, waiting_queue, Sorted.min_priority min_prio_new_ready_sys min_prio
     else wait_for_system_or_queue_events ~deadline (fds,waiting_sys) queue
 
 let wait_for_system_or_queue_events ~deadline sys queue =

test/fairness_prio.ml

@@ -62,7 +62,7 @@ let%test_unit "sel.loop" =
   write "Content-Length: 3\n\n123\n";
   let x = Sel.now ~priority:2 (Ok "bad") in
   let todo = Todo.add Todo.empty [e;x] in
-  let rec loop todo =
+  let loop todo =
     let ready, _todo = Sel.pop todo in
     match ready with
     | Ok "bad" -> [%test_eq: string] "" "bad1"
@@ -71,3 +71,34 @@ let%test_unit "sel.loop" =
     | Error e -> [%test_eq: string] "" (Stdlib.Printexc.to_string e) in
   loop todo
 
+let%test_unit "sel.loop2" =
+  let read, write = pipe () in
+  let e = On.httpcle ~priority:1 read (fun x -> Result.map ~f:Bytes.to_string x) in
+  write "Content-Length: 3\n\n12";
+  let x = Sel.now ~priority:2 (Ok "bad") in
+  let todo = Todo.add Todo.empty [e;x] in
+  let loop todo =
+    let ready, _todo = Sel.pop todo in
+    match ready with
+    | Ok "bad" -> ()
+    | Ok _ -> [%test_eq: string] "" "bad2"
+    | Error e -> [%test_eq: string] "" (Stdlib.Printexc.to_string e) in
+  loop todo
+
+(* pop_opt terminates *)
+let%test_unit "sel.loop3" =
+  let read, write = pipe () in
+  let e = On.line ~priority:1 read (fun x -> x) in
+  write "aa\nbb\ncc\n";
+  let read2, write2 = pipe () in
+  let x = On.bytes ~priority:2 read2 2 (function Error e -> Error e | Ok s -> Error (Failure (Stdlib.Format.asprintf "lower priority event triggered: '%s'" (Bytes.to_string s)))) in
+  let todo = Todo.add Todo.empty [e;x] in
+  let rec loop todo =
+    let ready, todo = Sel.pop todo in
+    match ready with
+    | Ok "cc" -> ()
+    | Ok s -> write2 s; loop (Todo.add todo [e])
+    | Error End_of_file -> ()
+    | Error e -> [%test_eq: string] "" (Stdlib.Printexc.to_string e) in
+  loop todo
+

test/perf.ml

@@ -55,20 +55,18 @@ let read_leftover read n =
 
 (*****************************************************************************)
 
-(* pop_opt terminates *)
-let%test_unit "sel.loop" =
+let %test_unit "sel.event.http_cle" =
   let read, write = pipe () in
-  let e = On.line ~priority:1 read (fun x -> x) in
-  write "aa\nbb\ncc\n";
-  let read2, write2 = pipe () in
-  let x = On.bytes ~priority:2 read2 2 (function Error e -> Error e | Ok s -> Error (Failure (Stdlib.Format.asprintf "lower priority event triggered: '%s'" (Bytes.to_string s)))) in
-  let todo = Todo.add Todo.empty [e;x] in
-  let rec loop todo =
-    let ready, todo = Sel.pop todo in
-    match ready with
-    | Ok "cc" -> ()
-    | Ok s -> write2 s; loop (Todo.add todo [e])
-    | Error End_of_file -> ()
-    | Error e -> [%test_eq: string] "" (Stdlib.Printexc.to_string e) in
-  loop todo
-
+  let e = On.httpcle read b2s in
+  let t0 = Unix.gettimeofday () in
+  let n = 99999 in
+  for _i = 1 to n do
+    let todo = Todo.add Todo.empty [e] in
+    write "content-Length: 4\n\n1\n3.";
+    let ready, todo = pop_opt todo in
+    [%test_eq: bool] (Todo.is_empty todo) true;
+    [%test_eq: string option] ready (Some "1\n3.");
+  done;
+  let t1 = Unix.gettimeofday () in
+  Stdlib.Printf.eprintf "time to pop %d httpcle events: %f\n" n (t1 -. t0)
+;;

test/test1.ml

@@ -222,6 +222,12 @@ let %test_unit "sel.event.http_cle.recurring.err" =
   write "a\n";
   let ready, todo = pop_opt todo in
   [%test_eq: bool] (Todo.is_empty todo) true;
+  (* depending on how eager the event is to read data *)
+  [%test_eq: bool] (osmatch "\\(.*Scan_failure.*\\|End_of_file\\)" ready) true;
+  let todo = Todo.add todo [e] in
+  write "content-Lengtx: 2\n";
+  let ready, todo = pop_opt todo in
+  [%test_eq: bool] (Todo.is_empty todo) true;
   [%test_eq: bool] (osmatch ".*Scan_failure.*" ready) true;
   let todo = Todo.add todo [e] in
   write "content-Length: 4\n\n4\n6.";