a_star: don't crash on deserialization errors and limit static types

[nit.git] / lib / pthreads / threadpool.nit

diff --git a/lib/pthreads/threadpool.nit b/lib/pthreads/threadpool.nit
index 02042ba..927cdbf 100644 (file)
--- a/lib/pthreads/threadpool.nit
+++ b/lib/pthreads/threadpool.nit
@@ -20,40 +20,50 @@ import concurrent_collections
 
 # A simple ThreadPool implemented with an array
 class ThreadPool
-       private var queue = new ConcurrentList[JoinTask].wrap(new List[JoinTask])
+       private var queue = new ConcurrentList[Task]
        private var mutex = new Mutex
        private var cond = new NativePthreadCond
+       private var threads = new Array[PoolThread]
 
-       # Number of threads used
-       var nb_threads: Int is noinit
+       # Number of threads used, can only grow after the first call to `execute`
+       var nb_threads = 5 is optional, writable
 
-       init do
-               for i in [0..nb_threads[ do
+       private fun create_threads do
+               while threads.length < nb_threads do
                        var t = new PoolThread(queue, mutex, cond)
                        t.start
+                       threads.add t
                end
        end
 
-       private fun set_nb_threads(nb: nullable Int) is autoinit do nb_threads = nb or else 5
-
        # Adds a Task into the queue
-       fun execute(task: JoinTask) do
+       fun execute(task: Task) do
+               create_threads
                queue.push(task)
                cond.signal
        end
+
+       # Join all threads, waiting for all tasks to be completed
+       fun join_all do
+               # Wait
+               for t in threads do t.join
+
+               # Reset
+               threads.clear
+       end
 end
 
 # A Thread running in a threadpool
 private class PoolThread
        super Thread
 
-       var queue: ConcurrentList[JoinTask]
+       var queue: ConcurrentList[Task]
        var mutex: Mutex
        var cond : NativePthreadCond
 
        redef fun main do
                loop
-                       var t: nullable JoinTask = null
+                       var t = null
                        mutex.lock
                        if queue.is_empty then cond.wait(mutex.native.as(not null))
                        if not queue.is_empty then
@@ -62,21 +72,22 @@ private class PoolThread
                        mutex.unlock
                        if t != null then
                                t.main
-                               t.mutex.lock
-                               t.is_done = true
-                               var tcond = t.cond
-                               if tcond != null then tcond.signal
-                               t.mutex.unlock
+                               t.after_main
                        end
                end
        end
 end
 
+redef class Task
+       # Additional work executed after `main` from a `ThreadPool`
+       private fun after_main do end
+end
+
 # A Task which is joinable, meaning it can return a value and if the value is not set yet, it blocks the execution
 class JoinTask
        super Task
 
-       # Is `self` done ?
+       # Is `self` done?
        var is_done = false
 
        private var mutex = new Mutex
@@ -92,4 +103,15 @@ class JoinTask
                end
                mutex.unlock
        end
+
+       redef fun after_main do
+               # TODO move this at the end of main so all `JoinTask` can be joined
+               # no matter what calls `main`.
+
+               mutex.lock
+               is_done = true
+               var tcond = cond
+               if tcond != null then tcond.signal
+               mutex.unlock
+       end
 end