Heartbeat implementation of dart:mirrors.

runtime/vm/message.h

 // Copyright (c) 2011, 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 VM_MESSAGE_H_
 #define VM_MESSAGE_H_
 
 #include "vm/thread.h"
 
 // Duplicated from dart_api.h to avoid including the whole header.
@@ skipping 60 matching lines @@
   // if no message is available. 'millis' is a timeout in
   // milliseconds. If 'millis' is 0, then this means to block
   // indefinitely. May block if no message is available. May return
   // NULL even if 'millis' is 0 due to spurious wakeups.
   Message* Dequeue(int64_t millis);
 
   // Gets the next message from the message queue if available.  Will
   // not block.
   Message* DequeueNoWait();
 
+  // Gets the next message of the specified priority or greater from
+  // the message queue if available.  Will not block.
+  Message* DequeueNoWaitWithPriority(Message::Priority min_priority);
+
   void Flush(Dart_Port port);
   void FlushAll();
 
  private:
   friend class MessageQueueTestPeer;
 
-  Message* DequeueNoWaitHoldsLock();
+  Message* DequeueNoWaitHoldsLock(Message::Priority min_priority);
 
   Monitor monitor_;
   Message* head_[Message::kNumPriorities];
   Message* tail_[Message::kNumPriorities];
 
   DISALLOW_COPY_AND_ASSIGN(MessageQueue);
 };
 
 // A MessageHandler is an entity capable of accepting messages.
 class MessageHandler {
@@ skipping 45 matching lines @@
   MessageQueue* queue() const { return queue_; }
 
  private:
   intptr_t live_ports_;
   MessageQueue* queue_;
 };
 
 }  // namespace dart
 
 #endif  // VM_MESSAGE_H_