ager@google.com
08b1e44502
BUG= Review URL: https://codereview.chromium.org//11647038 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@16394 260f80e4-7a28-3924-810f-c04153c831b5
69 lines
1.3 KiB
C++
69 lines
1.3 KiB
C++
// Copyright (c) 2011, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#include "vm/message.h"
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namespace dart {
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MessageQueue::MessageQueue() {
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head_ = NULL;
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tail_ = NULL;
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}
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MessageQueue::~MessageQueue() {
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// Ensure that all pending messages have been released.
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Clear();
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ASSERT(head_ == NULL);
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}
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void MessageQueue::Enqueue(Message* msg) {
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// Make sure messages are not reused.
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ASSERT(msg->next_ == NULL);
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if (head_ == NULL) {
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// Only element in the queue.
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ASSERT(tail_ == NULL);
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head_ = msg;
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tail_ = msg;
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} else {
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ASSERT(tail_ != NULL);
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// Append at the tail.
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tail_->next_ = msg;
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tail_ = msg;
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}
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}
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Message* MessageQueue::Dequeue() {
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Message* result = head_;
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if (result != NULL) {
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head_ = result->next_;
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// The following update to tail_ is not strictly needed.
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if (head_ == NULL) {
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tail_ = NULL;
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}
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#if defined(DEBUG)
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result->next_ = result; // Make sure to trigger ASSERT in Enqueue.
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#endif // DEBUG
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return result;
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}
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return NULL;
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}
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void MessageQueue::Clear() {
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Message* cur = head_;
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head_ = NULL;
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tail_ = NULL;
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while (cur != NULL) {
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Message* next = cur->next_;
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delete cur;
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cur = next;
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}
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}
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} // namespace dart
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