From b4b01bc2f7a35c93cde067a756cb32f847f16f4d Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Mon, 31 Aug 2015 22:46:27 +0200
Subject: [PATCH] modify `CCThread`, add tests

---
 src/threads/CCThread.ml  | 34 +++++++++++++++++++++++++++++-----
 src/threads/CCThread.mli |  2 +-
 2 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/src/threads/CCThread.ml b/src/threads/CCThread.ml
index b509d24a..f34d597c 100644
--- a/src/threads/CCThread.ml
+++ b/src/threads/CCThread.ml
@@ -9,7 +9,7 @@ let spawn f = Thread.create f ()
 
 let detach f = ignore (Thread.create f ())
 
-module Array = struct
+module Arr = struct
   let spawn n f =
     Array.init n (fun i -> Thread.create f i)
 
@@ -18,8 +18,8 @@ end
 
 (*$R
   let l = CCLock.create 0 in
-  let a = Array.spawn 101 (fun i -> CCLock.update l ((+) i)) in
-  Array.join a;
+  let a = Arr.spawn 101 (fun i -> CCLock.update l ((+) i)) in
+  Arr.join a;
   let n = Sequence.(1 -- 100 |> fold (+) 0) in
   assert_equal ~printer:CCInt.to_string n (CCLock.get l)
 *)
@@ -45,7 +45,7 @@ module Queue = struct
     q
       
   let incr_size_ q = assert(q.size < q.capacity); q.size <- q.size + 1
-  let decr_size_ q = q.size <- q.size - 1
+  let decr_size_ q = assert(q.size > 0); q.size <- q.size - 1
 
   let with_lock_ q f =
     Mutex.lock q.lock;
@@ -65,6 +65,7 @@ module Queue = struct
         done;
         assert (q.size < q.capacity);
         Queue.push x q.q;
+        (* if there are blocked receivers, awake them *)
         if q.size = 0 then Condition.signal q.cond;
         incr_size_ q;
       )
@@ -76,7 +77,8 @@ module Queue = struct
           Condition.wait q.cond q.lock
         done;
         let x = Queue.take q.q in
-        if q.size = q.capacity then Condition.signal q.cond;
+        (* if there are blocked senders, awake them *)
+        if q.size = q.capacity then Condition.broadcast q.cond;
         decr_size_ q;
         x
       )
@@ -105,6 +107,28 @@ module Queue = struct
       let x = take q in
       x :: take_list q (n-1)
 
+  (*$R
+    let lists = [| CCList.(1 -- 100) ; CCList.(101 -- 200); CCList.(201 -- 300) |] in
+    let q = Queue.create 2 in
+    let senders = Arr.spawn 3
+      (fun i ->
+        List.iter (Queue.push q) lists.(i)
+      )
+    in
+    let l = CCLock.create [] in
+    let receivers = Arr.spawn 3
+      (fun _ ->
+        for i = 1 to 100 do
+          let x = Queue.take q in
+          CCLock.update l (fun acc -> x::acc)
+        done
+      )
+    in
+    Arr.join senders; Arr.join receivers;
+    let l = CCLock.get l |> List.sort Pervasives.compare in
+    assert_equal CCList.(1 -- 300) l
+  *)
+
   let try_take q =
     with_lock_ q
       (fun () ->
diff --git a/src/threads/CCThread.mli b/src/threads/CCThread.mli
index c7e02743..1ef7b0bc 100644
--- a/src/threads/CCThread.mli
+++ b/src/threads/CCThread.mli
@@ -15,7 +15,7 @@ val detach : (unit -> 'a) -> unit
 (** [detach f] is the same as [ignore (spawn f)] *)
 
 (** {2 Array of threads} *)
-module Array : sig
+module Arr : sig
   val spawn : int -> (int -> 'a) -> t array
   (** [A.spawn n f] creates an array [res] of length [n], such that
       [res.(i) = spawn (fun () -> f i)] *)