Heartbeat implementation of dart:mirrors.

runtime/vm/message.cc

 // 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.
 
 #include "vm/message.h"
 
 namespace dart {
 
 DECLARE_FLAG(bool, trace_isolates);
 
@@ skipping 92 matching lines @@
     // We only need to notify if the queue was empty.
     monitor_.Notify();
   } else {
     ASSERT(tail_[p] != NULL);
     // Append at the tail.
     tail_[p]->next_ = msg;
     tail_[p] = msg;
   }
 }
 
+
 Message* MessageQueue::DequeueNoWait() {
   MonitorLocker ml(&monitor_);
-  return DequeueNoWaitHoldsLock();
+  return DequeueNoWaitHoldsLock(Message::kFirstPriority);
 }
 
-Message* MessageQueue::DequeueNoWaitHoldsLock() {
+
+Message* MessageQueue::DequeueNoWaitWithPriority(
+    Message::Priority min_priority) {
+  MonitorLocker ml(&monitor_);
+  return DequeueNoWaitHoldsLock(min_priority);
+}
+
+
+Message* MessageQueue::DequeueNoWaitHoldsLock(Message::Priority min_priority) {
   // Look for the highest priority available message.
-  for (int p = Message::kNumPriorities-1; p >= Message::kFirstPriority; p--) {
+  for (int p = Message::kNumPriorities-1; p >= min_priority; p--) {
     Message* result = head_[p];
     if (result != NULL) {
       head_[p] = result->next_;
       // The following update to tail_ is not strictly needed.
       if (head_[p] == NULL) {
         tail_[p] = NULL;
       }
 #if defined(DEBUG)
       result->next_ = result;  // Make sure to trigger ASSERT in Enqueue.
 #endif  // DEBUG
       return result;
     }
   }
   return NULL;
 }
 
 
 Message* MessageQueue::Dequeue(int64_t millis) {
   ASSERT(millis >= 0);
   MonitorLocker ml(&monitor_);
-  Message* result = DequeueNoWaitHoldsLock();
+  Message* result = DequeueNoWaitHoldsLock(Message::kFirstPriority);
   if (result == NULL) {
     // No message available at any priority.
     monitor_.Wait(millis);
-    result = DequeueNoWaitHoldsLock();
+    result = DequeueNoWaitHoldsLock(Message::kFirstPriority);
   }
   return result;
 }
 
 
 void MessageQueue::Flush(Dart_Port port) {
   MonitorLocker ml(&monitor_);
   for (int p = Message::kFirstPriority; p < Message::kNumPriorities; p++) {
     Message* cur = head_[p];
     Message* prev = NULL;
@@ skipping 28 matching lines @@
     while (cur != NULL) {
       Message* next = cur->next_;
       delete cur;
       cur = next;
     }
   }
 }
 
 
 }  // namespace dart