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_UTILS_LOCKED_QUEUE_INL_H_ 6 #define V8_UTILS_LOCKED_QUEUE_INL_H_ 7 8 #include "src/base/atomic-utils.h" 9 #include "src/utils/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 base::AtomicValue<Node*> next; 19 }; 20 21 template <typename Record> 22 inline LockedQueue<Record>::LockedQueue() { 23 head_ = new Node(); 24 CHECK_NOT_NULL(head_); 25 tail_ = head_; 26 size_ = 0; 27 } 28 29 template <typename Record> 30 inline LockedQueue<Record>::~LockedQueue() { 31 // Destroy all remaining nodes. Note that we do not destroy the actual values. 32 Node* old_node = nullptr; 33 Node* cur_node = head_; 34 while (cur_node != nullptr) { 35 old_node = cur_node; 36 cur_node = cur_node->next.Value(); 37 delete old_node; 38 } 39 } 40 41 template <typename Record> 42 inline void LockedQueue<Record>::Enqueue(Record record) { 43 Node* n = new Node(); 44 CHECK_NOT_NULL(n); 45 n->value = std::move(record); 46 { 47 base::MutexGuard guard(&tail_mutex_); 48 size_++; 49 tail_->next.SetValue(n); 50 tail_ = n; 51 } 52 } 53 54 template <typename Record> 55 inline bool LockedQueue<Record>::Dequeue(Record* record) { 56 Node* old_head = nullptr; 57 { 58 base::MutexGuard guard(&head_mutex_); 59 old_head = head_; 60 Node* const next_node = head_->next.Value(); 61 if (next_node == nullptr) return false; 62 *record = std::move(next_node->value); 63 head_ = next_node; 64 size_t old_size = size_.fetch_sub(1); 65 USE(old_size); 66 DCHECK_GT(old_size, 0); 67 } 68 delete old_head; 69 return true; 70 } 71 72 template <typename Record> 73 inline bool LockedQueue<Record>::IsEmpty() const { 74 base::MutexGuard guard(&head_mutex_); 75 return head_->next.Value() == nullptr; 76 } 77 78 template <typename Record> 79 inline bool LockedQueue<Record>::Peek(Record* record) const { 80 base::MutexGuard guard(&head_mutex_); 81 Node* const next_node = head_->next.Value(); 82 if (next_node == nullptr) return false; 83 *record = next_node->value; 84 return true; 85 } 86 87 template <typename Record> 88 inline size_t LockedQueue<Record>::size() const { 89 return size_; 90 } 91 92 } // namespace internal 93 } // namespace v8 94 95 #endif // V8_UTILS_LOCKED_QUEUE_INL_H_ 96