pthreads: reimplement `Barrier` to be more portable

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>

diff --git a/lib/pthreads/pthreads.nit b/lib/pthreads/pthreads.nit
index 047ebfd..b0be71e 100644 (file)
--- a/lib/pthreads/pthreads.nit
+++ b/lib/pthreads/pthreads.nit
@@ -218,6 +218,27 @@ private extern class NativePthreadKey in "C" `{ pthread_key_t * `}
        `}
 end
 
+private extern class NativePthreadCond in "C" `{ pthread_cond_t * `}
+       new `{
+               pthread_cond_t cond;
+               int r = pthread_cond_init(&cond, NULL);
+               if (r == 0) {
+                       pthread_cond_t *pcond = malloc(sizeof(pthread_cond_t));
+                       memmove(pcond, &cond, sizeof(pthread_cond_t));
+                       return pcond;
+               }
+               return NULL;
+       `}
+
+       fun destroy `{ pthread_cond_destroy(recv); `}
+
+       fun signal `{ pthread_cond_signal(recv); `}
+
+       fun broadcast `{ pthread_cond_broadcast(recv);  `}
+
+       fun wait(mutex: NativePthreadMutex) `{ pthread_cond_wait(recv, mutex); `}
+end
+
 #
 ## Nity part
 #
@@ -349,24 +370,36 @@ end
 class Barrier
        super Finalizable
 
+       private var mutex = new Mutex
+       private var cond: nullable NativePthreadCond = new NativePthreadCond
+
        # Number of threads that must be waiting for `wait` to unblock
        var count: Int
 
-       private var native: nullable NativePthreadBarrier is noinit
-
-       init do native = new NativePthreadBarrier(count)
+       private var threads_waiting = 0
 
        # Wait at this barrier and block until there are a `count` threads waiting
-       fun wait do native.wait
+       fun wait
+       do
+               mutex.lock
+               threads_waiting += 1
+               if threads_waiting == count then
+                       threads_waiting = 0
+                       cond.broadcast
+               else
+                       cond.wait(mutex.native.as(not null))
+               end
+               mutex.unlock
+       end
 
        redef fun finalize
        do
-               var native = self.native
-               if native != null then
-                       native.destroy
-                       native.free
+               var cond = self.cond
+               if cond != null then
+                       cond.destroy
+                       cond.free
                end
-               self.native = null
+               self.cond = null
        end
 end