Start of thread pool implementation

runtime/bin/thread_pool_linux.cc

+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#include <pthread.h>
+
+#include "bin/thread_pool.h"
+
+TaskQueue::TaskQueue() : head_(NULL), tail_(NULL) {
+  int result;
+
+  result = pthread_mutex_init(data_.mutex(), NULL);
+  if (result != 0) {
+    FATAL("pthread_mutex_init failed");
+  }
+
+  result = pthread_cond_init(data_.cond(), NULL);
+  if (result != 0) {
+    FATAL("pthread_cond_init failed");
+  }
+}
+
+
+void TaskQueue::Insert(TaskQueueEntry* entry) {
+  pthread_mutex_lock(data_.mutex());
+  if (head_ == NULL) {
+    ASSERT(tail_ == NULL);

[Mads Ager (google), 2012/01/04 14:32:46]

Maybe not assert here? We don't really care about tail in this case and it is
only NULL in release mode.

[Søren Gjesse, 2012/01/04 15:15:07]

Right, removed the asserts.

+    head_ = entry;
+    tail_ = entry;
+    pthread_cond_signal(data_.cond());
+  } else {
+    ASSERT(tail_ != NULL);
+    tail_->set_next(entry);
+    tail_ = entry;
+  }
+  pthread_mutex_unlock(data_.mutex());
+}
+
+
+TaskQueueEntry* TaskQueue::Remove() {
+  pthread_mutex_lock(data_.mutex());
+  TaskQueueEntry* result = head_;
+  while (result == NULL) {
+    pthread_cond_wait(data_.cond(), data_.mutex());
+    result = head_;
+  }
+  head_ = result->next();
+#ifdef DEBUG

[Mads Ager (google), 2012/01/04 14:32:46]

Maybe just

ASSERT(head_ != NULL || tail_ == result)

and not change tail_?

[Søren Gjesse, 2012/01/04 15:15:07]

Done.

+  if (head_ == NULL) {
+    ASSERT(tail_ == result);
+    tail_ = NULL;
+  }
+#endif
+  pthread_mutex_unlock(data_.mutex());
+  return result;
+}
+
+
+void ThreadPool::Start() {
+  for (int i = 0; i < size_; i++) {
+    pthread_t handler_thread;
+    int result = pthread_create(&handler_thread,
+                                NULL,
+                                &ThreadPool::Main,
+                                this);
+    if (result != 0) {
+      FATAL("Create and start thread pool thread");
+    }
+    data_.threads()[i] = handler_thread;
+  }
+}