cc/base/scoped_ptr_deque.h

// Copyright 2012 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 CC_BASE_SCOPED_PTR_DEQUE_H_
#define CC_BASE_SCOPED_PTR_DEQUE_H_

#include <algorithm>
#include <deque>

#include "base/basictypes.h"
#include "base/logging.h"
#include "base/memory/scoped_ptr.h"
#include "base/stl_util.h"

namespace cc {

// This type acts like a deque<scoped_ptr> based on top of std::deque. The
// ScopedPtrDeque has ownership of all elements in the deque.
template <typename T>
class ScopedPtrDeque {
 public:
  typedef typename std::deque<T*>::const_iterator const_iterator;
  typedef typename std::deque<T*>::reverse_iterator reverse_iterator;
  typedef typename std::deque<T*>::const_reverse_iterator
      const_reverse_iterator;

#if defined(OS_ANDROID)
  // On Android the iterator is not a class, so we can't block assignment.
  typedef typename std::deque<T*>::iterator iterator;
#else
  // Ban setting values on the iterator directly. New pointers must be passed
  // to methods on the ScopedPtrDeque class to appear in the deque.
  class iterator : public std::deque<T*>::iterator {
   public:
    explicit iterator(const typename std::deque<T*>::iterator& other)
        : std::deque<T*>::iterator(other) {}
    T* const& operator*() { return std::deque<T*>::iterator::operator*(); }
  };
#endif

  ScopedPtrDeque() {}

  ~ScopedPtrDeque() { clear(); }

  size_t size() const {
    return data_.size();
  }

  T* at(size_t index) const {
    DCHECK(index < size());
    return data_[index];
  }

  T* operator[](size_t index) const {
    return at(index);
  }

  T* front() const {
    DCHECK(!empty());
    return at(0);
  }

  T* back() const {
    DCHECK(!empty());
    return at(size() - 1);
  }

  bool empty() const {
    return data_.empty();
  }

  scoped_ptr<T> take_front() {
    scoped_ptr<T> ret(front());
    data_.pop_front();
    return ret.Pass();
  }

  scoped_ptr<T> take_back() {
    scoped_ptr<T> ret(back());
    data_.pop_back();
    return ret.Pass();
  }

  void clear() {
    STLDeleteElements(&data_);
  }

  void push_front(scoped_ptr<T> item) {
    data_.push_front(item.release());
  }

  void push_back(scoped_ptr<T> item) {
    data_.push_back(item.release());
  }

  void insert(iterator position, scoped_ptr<T> item) {
    DCHECK(position <= end());
    data_.insert(position, item.release());
  }

  scoped_ptr<T> take(iterator position) {
    DCHECK(position < end());
    scoped_ptr<T> ret(*position);
    data_.erase(position);
    return ret.Pass();
  }

  void swap(iterator a, iterator b) {
    DCHECK(a < end());
    DCHECK(b < end());
    if (a == end() || b == end() || a == b)
      return;
    typename std::deque<T*>::iterator writable_a = a;
    typename std::deque<T*>::iterator writable_b = b;
    std::swap(*writable_a, *writable_b);
  }

  iterator begin() { return static_cast<iterator>(data_.begin()); }
  const_iterator begin() const { return data_.begin(); }
  iterator end() { return static_cast<iterator>(data_.end()); }
  const_iterator end() const { return data_.end(); }

  reverse_iterator rbegin() { return data_.rbegin(); }
  const_reverse_iterator rbegin() const { return data_.rbegin(); }
  reverse_iterator rend() { return data_.rend(); }
  const_reverse_iterator rend() const { return data_.rend(); }

 private:
  std::deque<T*> data_;

  DISALLOW_COPY_AND_ASSIGN(ScopedPtrDeque);
};

}  // namespace cc

#endif  // CC_BASE_SCOPED_PTR_DEQUE_H_