| // Copyright 2016 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef BASE_TASK_SCHEDULER_SCHEDULER_UNIQUE_STACK_H_ |
| #define BASE_TASK_SCHEDULER_SCHEDULER_UNIQUE_STACK_H_ |
| |
| #include <stddef.h> |
| |
| #include <algorithm> |
| #include <vector> |
| |
| #include "base/logging.h" |
| #include "base/macros.h" |
| |
| namespace base { |
| namespace internal { |
| |
| // A stack that supports removal of arbitrary values and doesn't allow multiple |
| // insertions of the same value. This class is NOT thread-safe. |
| template <typename T> |
| class SchedulerUniqueStack { |
| public: |
| SchedulerUniqueStack(); |
| ~SchedulerUniqueStack(); |
| |
| // Inserts |val| at the top of the stack. |val| must not already be on the |
| // stack. |
| void Push(const T& val); |
| |
| // Removes the top value from the stack and returns it. Cannot be called on an |
| // empty stack. |
| T Pop(); |
| |
| // Removes |val| from the stack. |
| void Remove(const T& val); |
| |
| // Returns the number of values on the stack. |
| size_t Size() const; |
| |
| // Returns true if the stack is empty. |
| bool Empty() const; |
| |
| private: |
| std::vector<T> stack_; |
| |
| DISALLOW_COPY_AND_ASSIGN(SchedulerUniqueStack); |
| }; |
| |
| template <typename T> |
| SchedulerUniqueStack<T>::SchedulerUniqueStack() = default; |
| |
| template <typename T> |
| SchedulerUniqueStack<T>::~SchedulerUniqueStack() = default; |
| |
| template <typename T> |
| void SchedulerUniqueStack<T>::Push(const T& val) { |
| DCHECK(std::find(stack_.begin(), stack_.end(), val) == stack_.end()) |
| << "Value already on stack"; |
| stack_.push_back(val); |
| } |
| |
| template <typename T> |
| T SchedulerUniqueStack<T>::Pop() { |
| DCHECK(!stack_.empty()); |
| const T val = stack_.back(); |
| stack_.pop_back(); |
| return val; |
| } |
| |
| template <typename T> |
| void SchedulerUniqueStack<T>::Remove(const T& val) { |
| auto it = std::find(stack_.begin(), stack_.end(), val); |
| if (it != stack_.end()) |
| stack_.erase(it); |
| } |
| |
| template <typename T> |
| size_t SchedulerUniqueStack<T>::Size() const { |
| return stack_.size(); |
| } |
| |
| template <typename T> |
| bool SchedulerUniqueStack<T>::Empty() const { |
| return stack_.empty(); |
| } |
| |
| } // namespace internal |
| } // namespace base |
| |
| #endif // BASE_TASK_SCHEDULER_SCHEDULER_UNIQUE_STACK_H_ |