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/atomic-utils.h"
9 #include "src/locked-queue.h"
10 
11 namespace v8 {
12 namespace internal {
13 
14 template <typename Record>
15 struct LockedQueue<Record>::Node : Malloced {
16   Node() : next(nullptr) {}
17   Record value;
18   AtomicValue<Node*> next;
19 };
20 
21 
22 template <typename Record>
23 inline LockedQueue<Record>::LockedQueue() {
24   head_ = new Node();
25   CHECK(head_ != nullptr);
26   tail_ = head_;
27 }
28 
29 
30 template <typename Record>
31 inline 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 
43 template <typename Record>
44 inline 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 
56 template <typename Record>
57 inline 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 
72 template <typename Record>
73 inline bool LockedQueue<Record>::IsEmpty() const {
74   base::LockGuard<base::Mutex> guard(&head_mutex_);
75   return head_->next.Value() == nullptr;
76 }
77 
78 
79 template <typename Record>
80 inline 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