Change the thread interface in runtime/platform and use it starting all threads

runtime/bin/thread_pool.cc

Index: runtime/bin/thread_pool.cc
diff --git a/runtime/bin/thread_pool.cc b/runtime/bin/thread_pool.cc
index 36960a72303b798454eb01b72b3cfa802a1044ce..90cd9d30604588d8c30e21aeb103d1699424f0ac 100644
--- a/runtime/bin/thread_pool.cc
+++ b/runtime/bin/thread_pool.cc
@@ -63,7 +63,33 @@ Task ThreadPool::WaitForTask() {
 }
 
 
-void* ThreadPool::Main(void* args) {
+void ThreadPool::Start() {
+  MonitorLocker monitor(&monitor_);
+  for (int i = 0; i < size_; i++) {
+    dart::Thread::Start(&ThreadPool::Main,
+                        reinterpret_cast<uword>(this));

[siva, 2012/01/24 02:26:05]

If you choose to have an error return value for Thread::Start you should decide
here whether you want to abort the start and shutdown the threadpool or continue
with whatever number of threads we created (e.g we wanted to create a thread
pool with 100 threads but we are only able to create 70)

[Søren Gjesse, 2012/01/24 12:07:55]

Added return code to Thread::Start. For now just abort here on failure.

+  }
+}
+
+
+void ThreadPool::Shutdown() {
+  terminate_ = true;

[Ivan Posva, 2012/01/24 02:04:01]

Please do not access shared state outside the lock protecting it. The lock
protecting this should be the lock protecting access to the queue. In essence
you need to protections: one for the size of the thread pool and one for the
queue and termination.

[Søren Gjesse, 2012/01/24 12:07:55]

Agree, moved thread_pool cleanup to separate CL,
https://chromiumcodereview.appspot.com/9212043.

+  queue_.Shutdown();
+  MonitorLocker monitor(&monitor_);

[Ivan Posva, 2012/01/24 02:04:01]

The TaskQueue should be an implementation detail of ThreadPool and not be
exposed.

[Søren Gjesse, 2012/01/24 12:07:55]

Agree, moved thread_pool cleanup to separate CL,
https://chromiumcodereview.appspot.com/9212043.

+  while (size_ > 0) {
+    monitor.Wait();
+  }
+}
+
+
+void ThreadPool::ThreadTerminated() {
+  MonitorLocker monitor(&monitor_);
+  size_--;
+  monitor.Notify();
+}
+
+
+void ThreadPool::Main(uword args) {
   if (Dart_IsVMFlagSet("trace_thread_pool")) {
     printf("Thread pool thread started\n");
   }
@@ -73,8 +99,8 @@ void* ThreadPool::Main(void* args) {
       printf("Waiting for task\n");
     }
     Task task = pool->WaitForTask();
-    if (pool->terminate_) return NULL;
+    if (pool->terminate_) continue;

[siva, 2012/01/24 02:26:05]

Why continue and not a break?

[Søren Gjesse, 2012/01/24 12:07:55]

No particular reason, changed to break.

     (*(pool->task_handler_))(task);
   }
-  return NULL;
+  pool->ThreadTerminated();
 };