1// Copyright 2015 the V8 project authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef V8_LOCKED_QUEUE_INL_
6#define V8_LOCKED_QUEUE_INL_
7
8#include "src/base/atomic-utils.h"
9#include "src/locked-queue.h"
10
11namespace v8 {
12namespace internal {
13
14template <typename Record>
15struct LockedQueue<Record>::Node : Malloced {
16  Node() : next(nullptr) {}
17  Record value;
18  base::AtomicValue<Node*> next;
19};
20
21
22template <typename Record>
23inline LockedQueue<Record>::LockedQueue() {
24  head_ = new Node();
25  CHECK(head_ != nullptr);
26  tail_ = head_;
27}
28
29
30template <typename Record>
31inline LockedQueue<Record>::~LockedQueue() {
32  // Destroy all remaining nodes. Note that we do not destroy the actual values.
33  Node* old_node = nullptr;
34  Node* cur_node = head_;
35  while (cur_node != nullptr) {
36    old_node = cur_node;
37    cur_node = cur_node->next.Value();
38    delete old_node;
39  }
40}
41
42
43template <typename Record>
44inline void LockedQueue<Record>::Enqueue(const Record& record) {
45  Node* n = new Node();
46  CHECK(n != nullptr);
47  n->value = record;
48  {
49    base::LockGuard<base::Mutex> guard(&tail_mutex_);
50    tail_->next.SetValue(n);
51    tail_ = n;
52  }
53}
54
55
56template <typename Record>
57inline bool LockedQueue<Record>::Dequeue(Record* record) {
58  Node* old_head = nullptr;
59  {
60    base::LockGuard<base::Mutex> guard(&head_mutex_);
61    old_head = head_;
62    Node* const next_node = head_->next.Value();
63    if (next_node == nullptr) return false;
64    *record = next_node->value;
65    head_ = next_node;
66  }
67  delete old_head;
68  return true;
69}
70
71
72template <typename Record>
73inline bool LockedQueue<Record>::IsEmpty() const {
74  base::LockGuard<base::Mutex> guard(&head_mutex_);
75  return head_->next.Value() == nullptr;
76}
77
78
79template <typename Record>
80inline bool LockedQueue<Record>::Peek(Record* record) const {
81  base::LockGuard<base::Mutex> guard(&head_mutex_);
82  Node* const next_node = head_->next.Value();
83  if (next_node == nullptr) return false;
84  *record = next_node->value;
85  return true;
86}
87
88}  // namespace internal
89}  // namespace v8
90
91#endif  // V8_LOCKED_QUEUE_INL_
92