Add support for native ports in the vm.

runtime/vm/message_queue.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_queue.h"
-
-namespace dart {
-
-MessageQueue::MessageQueue() {
-  for (int p = Message::kFirstPriority; p < Message::kNumPriorities; p++) {
-    head_[p] = NULL;
-    tail_[p] = NULL;
-  }
-}
-
-
-MessageQueue::~MessageQueue() {
-  // Ensure that all pending messages have been released.
-#if defined(DEBUG)
-  for (int p = Message::kFirstPriority; p < Message::kNumPriorities; p++) {
-    ASSERT(head_[p] == NULL);
-  }
-#endif
-}
-
-
-void MessageQueue::Enqueue(Message* msg) {
-  // TODO(turnidge): Add a scoped locker for monitors which is not a
-  // stack resource.  This would probably be useful in the platform
-  // headers.
-  monitor_.Enter();
-
-  Message::Priority p = msg->priority();
-  // Make sure messages are not reused.
-  ASSERT(msg->next_ == NULL);
-  if (head_[p] == NULL) {
-    // Only element in the queue.
-    head_[p] = msg;
-    tail_[p] = msg;
-
-    // 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;
-  }
-
-  monitor_.Exit();
-}
-
-Message* MessageQueue::DequeueNoWait() {
-  MonitorLocker ml(&monitor_);
-  return DequeueNoWaitHoldsLock();
-}
-
-Message* MessageQueue::DequeueNoWaitHoldsLock() {
-  // Look for the highest priority available message.
-  for (int p = Message::kNumPriorities-1; p >= Message::kFirstPriority; 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();
-  if (result == NULL) {
-    // No message available at any priority.
-    ml.Wait(millis);
-    result = DequeueNoWaitHoldsLock();
-  }
-  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;
-    while (cur != NULL) {
-      Message* next = cur->next_;
-      // If the message matches, then remove it from the queue and delete it.
-      if (cur->dest_port() == port) {
-        if (prev != NULL) {
-          prev->next_ = next;
-        } else {
-          head_[p] = next;
-        }
-        delete cur;
-      } else {
-        // Move prev forward.
-        prev = cur;
-      }
-      // Advance to the next message in the queue.
-      cur = next;
-    }
-    tail_[p] = prev;
-  }
-}
-
-
-void MessageQueue::FlushAll() {
-  MonitorLocker ml(&monitor_);
-  for (int p = Message::kFirstPriority; p < Message::kNumPriorities; p++) {
-    Message* cur = head_[p];
-    head_[p] = NULL;
-    tail_[p] = NULL;
-    while (cur != NULL) {
-      Message* next = cur->next_;
-      delete cur;
-      cur = next;
-    }
-  }
-}
-
-
-}  // namespace dart