cleanup the local storage APIs

src/core/fifo_pool.ml

@@ -2,15 +2,14 @@ open Types_
 include Runner
 
 let ( let@ ) = ( @@ )
-let k_storage = Task_local_storage.Private_.Storage.k_storage
 
 type task_full =
   | T_start of {
-      ls: Task_local_storage.storage ref;
+      ls: Task_local_storage.t;
       f: task;
     }
   | T_resume : {
-      ls: Task_local_storage.storage ref;
+      ls: Task_local_storage.t;
       k: 'a -> unit;
       x: 'a;
     }
@@ -30,7 +29,7 @@ let schedule_ (self : state) (task : task_full) : unit =
   try Bb_queue.push self.q task with Bb_queue.Closed -> raise Shutdown
 
 type around_task = AT_pair : (t -> 'a) * (t -> 'a -> unit) -> around_task
-type worker_state = { mutable cur_ls: Task_local_storage.storage ref option }
+type worker_state = { mutable cur_ls: Task_local_storage.t option }
 
 let k_worker_state : worker_state option ref TLS.key =
   TLS.new_key (fun () -> ref None)
@@ -56,7 +55,7 @@ let worker_thread_ (self : state) (runner : t) ~on_exn ~around_task : unit =
       | T_start { ls; _ } | T_resume { ls; _ } -> ls
     in
     w.cur_ls <- Some ls;
-    TLS.set k_storage (Some ls);
+    TLS.get k_cur_storage := Some ls;
     let _ctx = before_task runner in
 
     (* run the task now, catching errors, handling effects *)
@@ -75,7 +74,7 @@ let worker_thread_ (self : state) (runner : t) ~on_exn ~around_task : unit =
        on_exn e bt);
     after_task runner _ctx;
     w.cur_ls <- None;
-    TLS.set k_storage None
+    TLS.get k_cur_storage := None
   in
 
   let main_loop () =

src/core/immediate_runner.ml

@@ -1,18 +1,15 @@
 open Types_
 include Runner
 
-(* convenient alias *)
-let k_ls = Task_local_storage.Private_.Storage.k_storage
-
 let run_async_ ~ls:cur_ls f =
-  TLS.set k_ls (Some cur_ls);
+  TLS.get k_cur_storage := Some cur_ls;
   try
     let x = f () in
-    TLS.set k_ls None;
+    TLS.get k_cur_storage := None;
     x
   with e ->
     let bt = Printexc.get_raw_backtrace () in
-    TLS.set k_ls None;
+    TLS.get k_cur_storage := None;
     Printexc.raise_with_backtrace e bt
 
 let runner : t =

src/core/moonpool.mli

@@ -26,15 +26,13 @@ val start_thread_on_some_domain : ('a -> unit) -> 'a -> Thread.t
     to run the thread. This ensures that we don't always pick the same domain
     to run all the various threads needed in an application (timers, event loops, etc.) *)
 
-val run_async :
-  ?ls:Task_local_storage.storage ref -> Runner.t -> (unit -> unit) -> unit
+val run_async : ?ls:Task_local_storage.t -> Runner.t -> (unit -> unit) -> unit
 (** [run_async runner task] schedules the task to run
   on the given runner. This means [task()] will be executed
   at some point in the future, possibly in another thread.
   @since 0.5 *)
 
-val run_wait_block :
-  ?ls:Task_local_storage.storage ref -> Runner.t -> (unit -> 'a) -> 'a
+val run_wait_block : ?ls:Task_local_storage.t -> Runner.t -> (unit -> 'a) -> 'a
 (** [run_wait_block runner f] schedules [f] for later execution
     on the runner, like {!run_async}.
     It then blocks the current thread until [f()] is done executing,

src/core/runner.ml

@@ -1,9 +1,10 @@
+open Types_
 module TLS = Thread_local_storage_
 
 type task = unit -> unit
 
-type t = {
-  run_async: ls:Task_local_storage.storage ref -> task -> unit;
+type t = runner = {
+  run_async: ls:local_storage -> task -> unit;
   shutdown: wait:bool -> unit -> unit;
   size: unit -> int;
   num_tasks: unit -> int;
@@ -11,9 +12,7 @@ type t = {
 
 exception Shutdown
 
-let[@inline] run_async
-    ?(ls = ref @@ Task_local_storage.Private_.Storage.create ()) (self : t) f :
-    unit =
+let[@inline] run_async ?(ls = create_local_storage ()) (self : t) f : unit =
   self.run_async ~ls f
 
 let[@inline] shutdown (self : t) : unit = self.shutdown ~wait:true ()
@@ -41,8 +40,8 @@ module For_runner_implementors = struct
   let create ~size ~num_tasks ~shutdown ~run_async () : t =
     { size; num_tasks; shutdown; run_async }
 
-  let k_cur_runner : t option ref TLS.key = TLS.new_key (fun () -> ref None)
+  let k_cur_runner : t option ref TLS.key = Types_.k_cur_runner
 end
 
-let[@inline] get_current_runner () : _ option =
-  !(TLS.get For_runner_implementors.k_cur_runner)
+let get_current_runner = get_current_runner
+let get_current_storage = get_current_storage

src/core/runner.mli

@@ -33,15 +33,14 @@ val shutdown_without_waiting : t -> unit
 
 exception Shutdown
 
-val run_async : ?ls:Task_local_storage.storage ref -> t -> task -> unit
+val run_async : ?ls:Task_local_storage.t -> t -> task -> unit
 (** [run_async pool f] schedules [f] for later execution on the runner
     in one of the threads. [f()] will run on one of the runner's
     worker threads/domains.
     @param ls if provided, run the task with this initial local storage
     @raise Shutdown if the runner was shut down before [run_async] was called. *)
 
-val run_wait_block :
-  ?ls:Task_local_storage.storage ref -> t -> (unit -> 'a) -> 'a
+val run_wait_block : ?ls:Task_local_storage.t -> t -> (unit -> 'a) -> 'a
 (** [run_wait_block pool f] schedules [f] for later execution
     on the pool, like {!run_async}.
     It then blocks the current thread until [f()] is done executing,
@@ -61,7 +60,7 @@ module For_runner_implementors : sig
     size:(unit -> int) ->
     num_tasks:(unit -> int) ->
     shutdown:(wait:bool -> unit -> unit) ->
-    run_async:(ls:Task_local_storage.storage ref -> task -> unit) ->
+    run_async:(ls:Task_local_storage.t -> task -> unit) ->
     unit ->
     t
   (** Create a new runner.
@@ -80,3 +79,7 @@ val get_current_runner : unit -> t option
 (** Access the current runner. This returns [Some r] if the call
     happens on a thread that belongs in a runner.
     @since 0.5 *)
+
+val get_current_storage : unit -> Task_local_storage.t option
+(** [get_current_storage runner] gets the local storage
+    for the currently running task. *)

src/core/task_local_storage.ml

@@ -5,7 +5,44 @@ type 'a key = 'a ls_key
 
 let key_count_ = A.make 0
 
-type storage = task_ls
+type t = local_storage
+type ls_value += Dummy
+
+let dummy : t = ref [||]
+
+(** Resize array of TLS values *)
+let[@inline never] resize_ (cur : ls_value array ref) n =
+  if n > Sys.max_array_length then failwith "too many task local storage keys";
+  let len = Array.length !cur in
+  let new_ls =
+    Array.make (min Sys.max_array_length (max n ((len * 2) + 2))) Dummy
+  in
+  Array.blit !cur 0 new_ls 0 len;
+  cur := new_ls
+
+module Direct = struct
+  type nonrec t = t
+
+  let create = create_local_storage
+  let[@inline] copy (self : t) = ref (Array.copy !self)
+
+  let get (type a) (self : t) ((module K) : a key) : a =
+    if K.offset >= Array.length !self then resize_ self (K.offset + 1);
+    match !self.(K.offset) with
+    | K.V x -> (* common case first *) x
+    | Dummy ->
+      (* first time we access this *)
+      let v = K.init () in
+      !self.(K.offset) <- K.V v;
+      v
+    | _ -> assert false
+
+  let set (type a) (self : t) ((module K) : a key) (v : a) : unit =
+    assert (self != dummy);
+    if K.offset >= Array.length !self then resize_ self (K.offset + 1);
+    !self.(K.offset) <- K.V v;
+    ()
+end
 
 let new_key (type t) ~init () : t key =
   let offset = A.fetch_and_add key_count_ 1 in
@@ -18,68 +55,25 @@ let new_key (type t) ~init () : t key =
   end : LS_KEY
     with type t = t)
 
-type ls_value += Dummy
-
-(** Resize array of TLS values *)
-let[@inline never] resize_ (cur : ls_value array ref) n =
-  if n > Sys.max_array_length then failwith "too many task local storage keys";
-  let len = Array.length !cur in
-  let new_ls =
-    Array.make (min Sys.max_array_length (max n ((len * 2) + 2))) Dummy
-  in
-  Array.blit !cur 0 new_ls 0 len;
-  cur := new_ls
-
 let[@inline] get_cur_ () : ls_value array ref =
-  match TLS.get k_ls_values with
+  match get_current_storage () with
   | Some r -> r
   | None -> failwith "Task local storage must be accessed from within a runner."
 
-let get_from_ (type a) cur ((module K) : a key) : a =
-  if K.offset >= Array.length !cur then resize_ cur (K.offset + 1);
-  match !cur.(K.offset) with
-  | K.V x -> (* common case first *) x
-  | Dummy ->
-    (* first time we access this *)
-    let v = K.init () in
-    !cur.(K.offset) <- K.V v;
-    v
-  | _ -> assert false
-
 let[@inline] get (key : 'a key) : 'a =
   let cur = get_cur_ () in
-  get_from_ cur key
+  Direct.get cur key
 
 let[@inline] get_opt key =
-  match TLS.get k_ls_values with
+  match get_current_storage () with
   | None -> None
-  | Some cur -> Some (get_from_ cur key)
-
-let set_into_ (type a) cur ((module K) : a key) (v : a) : unit =
-  if K.offset >= Array.length !cur then resize_ cur (K.offset + 1);
-  !cur.(K.offset) <- K.V v;
-  ()
+  | Some cur -> Some (Direct.get cur key)
 
 let[@inline] set key v : unit =
   let cur = get_cur_ () in
-  set_into_ cur key v
+  Direct.set cur key v
 
 let with_value key x f =
   let old = get key in
   set key x;
   Fun.protect ~finally:(fun () -> set key old) f
-
-module Private_ = struct
-  module Storage = struct
-    type t = storage
-
-    let k_storage = k_ls_values
-    let[@inline] create () = [||]
-    let[@inline] get_cur_opt () = TLS.get k_storage
-    let copy = Array.copy
-    let get = get_from_
-    let set = set_into_
-    let[@inline] copy_of_current () = copy @@ !(get_cur_ ())
-    let dummy = [||]
-  end
-end

src/core/task_local_storage.mli

@@ -8,8 +8,11 @@
     @since NEXT_RELEASE
 *)
 
-type storage
-(** Underlying storage for a task *)
+type t = Types_.local_storage
+(** Underlying storage for a task. This is mutable and
+    not thread-safe. *)
+
+val dummy : t
 
 type 'a key
 (** A key used to access a particular (typed) storage slot on every task. *)
@@ -49,22 +52,12 @@ val with_value : 'a key -> 'a -> (unit -> 'b) -> 'b
     to [f()]. When [f()] returns (or fails), [k] is restored
     to its old value. *)
 
-(**/**)
+(** Direct access to values from a storage handle *)
+module Direct : sig
+  val get : t -> 'a key -> 'a
+  (** Access a key *)
 
-(** Private API *)
-module Private_ : sig
-  module Storage : sig
-    type t = storage
-
-    val get : t ref -> 'a key -> 'a
-    val set : t ref -> 'a key -> 'a -> unit
-    val k_storage : t ref option Thread_local_storage_.key
-    val get_cur_opt : unit -> t ref option
-    val create : unit -> t
-    val copy : t -> t
-    val copy_of_current : unit -> t
-    val dummy : t
-  end
+  val set : t -> 'a key -> 'a -> unit
+  val create : unit -> t
+  val copy : t -> t
 end
-
-(**/**)

src/core/types_.ml

@@ -16,11 +16,21 @@ end
 type 'a ls_key = (module LS_KEY with type t = 'a)
 (** A LS key (task local storage) *)
 
-type task_ls = ls_value array
+type task = unit -> unit
+type local_storage = ls_value array ref
 
-(** Store the current LS values for the current thread.
+type runner = {
+  run_async: ls:local_storage -> task -> unit;
+  shutdown: wait:bool -> unit -> unit;
+  size: unit -> int;
+  num_tasks: unit -> int;
+}
 
-    A worker thread is going to cycle through many tasks, each of which
-    has its own storage.  This key allows tasks running on the worker
-    to access their own storage *)
-let k_ls_values : task_ls ref option TLS.key = TLS.new_key (fun () -> None)
+let k_cur_runner : runner option ref TLS.key = TLS.new_key (fun () -> ref None)
+
+let k_cur_storage : local_storage option ref TLS.key =
+  TLS.new_key (fun () -> ref None)
+
+let[@inline] get_current_runner () : _ option = !(TLS.get k_cur_runner)
+let[@inline] get_current_storage () : _ option = !(TLS.get k_cur_storage)
+let[@inline] create_local_storage () = ref [||]

src/core/ws_pool.ml

@@ -1,10 +1,10 @@
+open Types_
 module WSQ = Ws_deque_
 module A = Atomic_
 module TLS = Thread_local_storage_
 include Runner
 
 let ( let@ ) = ( @@ )
-let k_storage = Task_local_storage.Private_.Storage.k_storage
 
 module Id = struct
   type t = unit ref
@@ -18,11 +18,11 @@ type around_task = AT_pair : (t -> 'a) * (t -> 'a -> unit) -> around_task
 
 type task_full =
   | T_start of {
-      ls: Task_local_storage.storage ref;
+      ls: Task_local_storage.t;
       f: task;
     }
   | T_resume : {
-      ls: Task_local_storage.storage ref;
+      ls: Task_local_storage.t;
       k: 'a -> unit;
       x: 'a;
     }
@@ -32,7 +32,7 @@ type worker_state = {
   pool_id_: Id.t;  (** Unique per pool *)
   mutable thread: Thread.t;
   q: task_full WSQ.t;  (** Work stealing queue *)
-  mutable cur_ls: Task_local_storage.storage ref option;  (** Task storage *)
+  mutable cur_ls: Task_local_storage.t option;  (** Task storage *)
   rng: Random.State.t;
 }
 (** State for a given worker. Only this worker is
@@ -121,7 +121,7 @@ let run_task_now_ (self : state) ~runner ~(w : worker_state) (task : task_full)
   in
 
   w.cur_ls <- Some ls;
-  TLS.set k_storage (Some ls);
+  TLS.get k_cur_storage := Some ls;
   let _ctx = before_task runner in
 
   let[@inline] on_suspend () : _ ref =
@@ -136,7 +136,7 @@ let run_task_now_ (self : state) ~runner ~(w : worker_state) (task : task_full)
       | Some w when Id.equal w.pool_id_ self.id_ -> Some w
       | _ -> None
     in
-    let ls' = ref @@ Task_local_storage.Private_.Storage.copy !ls in
+    let ls' = Task_local_storage.Direct.copy ls in
     schedule_task_ self ~w @@ T_start { ls = ls'; f = task' }
   in
 
@@ -166,7 +166,7 @@ let run_task_now_ (self : state) ~runner ~(w : worker_state) (task : task_full)
 
   after_task runner _ctx;
   w.cur_ls <- None;
-  TLS.set k_storage None
+  TLS.get k_cur_storage := None
 
 let run_async_ (self : state) ~ls (f : task) : unit =
   let w = find_current_worker_ () in
@@ -289,7 +289,7 @@ type ('a, 'b) create_args =
 (** Arguments used in {!create}. See {!create} for explanations. *)
 
 let dummy_task_ : task_full =
-  T_start { f = ignore; ls = ref Task_local_storage.Private_.Storage.dummy }
+  T_start { f = ignore; ls = Task_local_storage.dummy }
 
 let create ?(on_init_thread = default_thread_init_exit_)
     ?(on_exit_thread = default_thread_init_exit_) ?(on_exn = fun _ _ -> ())
@@ -358,7 +358,7 @@ let create ?(on_init_thread = default_thread_init_exit_)
       let thread = Thread.self () in
       let t_id = Thread.id thread in
       on_init_thread ~dom_id:dom_idx ~t_id ();
-      TLS.set k_storage None;
+      TLS.get k_cur_storage := None;
 
       (* set thread name *)
       Option.iter

src/fib/fiber.ml

@@ -16,7 +16,7 @@ module Private_ = struct
     state: 'a state A.t;  (** Current state in the lifetime of the fiber *)
     res: 'a Fut.t;
     runner: Runner.t;
-    ls: Task_local_storage.storage ref;
+    ls: Task_local_storage.t;
   }
 
   and 'a state =
@@ -248,7 +248,7 @@ let spawn_ ~ls (Nursery n) (f : nursery -> 'a) : 'a t =
 
 let spawn (Nursery n) ?(protect = true) f : _ t =
   (* spawn [f()] with a copy of our local storage *)
-  let ls = ref (Task_local_storage.Private_.Storage.copy !(n.ls)) in
+  let ls = Task_local_storage.Direct.copy n.ls in
   let child = spawn_ ~ls (Nursery n) f in
   add_child_ ~protect n child;
   child
@@ -259,6 +259,8 @@ let[@inline] spawn_ignore n ?protect f : unit =
 module Nursery = struct
   type t = nursery
 
+  let[@inline] runner (Nursery n) = n.runner
+
   let[@inline] await (Nursery n) : unit =
     ignore (await n);
     ()
@@ -266,17 +268,13 @@ module Nursery = struct
   let cancel_with (Nursery n) ebt : unit = resolve_as_failed_ n ebt
 
   let with_create_top ~on () f =
-    let n =
-      create_
-        ~ls:(ref @@ Task_local_storage.Private_.Storage.create ())
-        ~runner:on ()
-    in
+    let n = create_ ~ls:(Task_local_storage.Direct.create ()) ~runner:on () in
     Fun.protect ~finally:(fun () -> resolve_ok_ n ()) (fun () -> f (Nursery n))
 
   let with_create_sub ~protect (Nursery parent : t) f =
     let n =
       create_
-        ~ls:(ref @@ Task_local_storage.Private_.Storage.copy !(parent.ls))
+        ~ls:(Task_local_storage.Direct.copy parent.ls)
         ~runner:parent.runner ()
     in
     add_child_ ~protect parent n;

src/fib/fiber.mli

@@ -27,6 +27,9 @@ type cancel_callback = Exn_bt.t -> unit
 module Nursery : sig
   type t
 
+  val runner : t -> Runner.t
+  (** Recover the runner this nursery uses to spawn fibers *)
+
   val await : t -> unit
   (** Await for the nursery to exit. *)
 
@@ -59,7 +62,7 @@ module Private_ : sig
     state: 'a state Atomic.t;  (** Current state in the lifetime of the fiber *)
     res: 'a Fut.t;
     runner: Runner.t;
-    ls: Task_local_storage.storage ref;
+    ls: Task_local_storage.t;
   }
   (** Type definition, exposed so that {!any} can be unboxed.
       Please do not rely on that. *)

src/fib/moonpool_fib.ml

@@ -0,0 +1,6 @@
+(** Fiber for moonpool *)
+
+module Fiber = Fiber
+module Fls = Fls
+module Handle = Handle
+include Fiber