Start of thread pool implementation

runtime/bin/thread_pool.h

Index: runtime/bin/thread_pool.h
diff --git a/runtime/bin/thread_pool.h b/runtime/bin/thread_pool.h
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+// 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.
+
+#ifndef BIN_THREAD_POOL_H_
+#define BIN_THREAD_POOL_H_
+
+#include "bin/builtin.h"
+#include "bin/globals.h"
+
+// Declare the OS-specific types ahead of defining the generic classes.
+#if defined(TARGET_OS_LINUX)
+#include "bin/thread_pool_linux.h"
+#elif defined(TARGET_OS_MACOS)
+#include "bin/thread_pool_macos.h"
+#elif defined(TARGET_OS_WINDOWS)
+#include "bin/thread_pool_win.h"
+#else
+#error Unknown target os.
+#endif
+
+
+typedef int Task;
+
+
+class TaskQueueEntry {
+ public:
+  explicit TaskQueueEntry(Task task) : task_(task), next_(NULL) {}
+
+  Task task() { return task_; }
+
+  TaskQueueEntry* next() { return next_; }
+  void set_next(TaskQueueEntry* value) { next_ = value; }
+
+ private:
+  Task task_;
+  TaskQueueEntry* next_;
+};
+
+
+// The task queue is a single linked list. Link direction is from tail
+// to head. New entried are inserted at the tail and entries are
+// removed from the head.
+class TaskQueue {
+ public:
+  TaskQueue();
+
+  void Insert(TaskQueueEntry* task);
+  TaskQueueEntry* Remove();
+
+ private:
+  TaskQueueEntry* head_;
+  TaskQueueEntry* tail_;
+  TaskQueueData data_;
+
+  DISALLOW_COPY_AND_ASSIGN(TaskQueue);
+};
+
+
+class ThreadPool {
+ public:
+  explicit ThreadPool(int initial_size = 4) : size_(initial_size) {}
+
+  void Start();
+  void Shutdown();
+
+  void InsertTask(Task task);
+
+ private:
+  Task WaitForTask();
+
+  static void* Main(void* args);
+
+  TaskQueue queue;
+  int size_;  // Number of threads.
+  ThreadPoolData data_;
+
+  DISALLOW_COPY_AND_ASSIGN(ThreadPool);
+};
+
+#endif  // BIN_THREAD_POOL_H_