third_party/WebKit/Source/wtf/LinkedStack.h

   1 /*
   2  * Copyright (C) 2013 Google Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  *     * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *     * Redistributions in binary form must reproduce the above
  11  * copyright notice, this list of conditions and the following disclaimer
  12  * in the documentation and/or other materials provided with the
  13  * distribution.
  14  *     * Neither the name of Google Inc. nor the names of its
  15  * contributors may be used to endorse or promote products derived from
  16  * this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #ifndef LinkedStack_h
  32 #define LinkedStack_h
  33
  34 #include "wtf/FastAllocBase.h"
  35 #include "wtf/OwnPtr.h"
  36
  37 namespace WTF {
  38
  39 template <typename T>
  40 class LinkedStack {
  41     WTF_MAKE_FAST_ALLOCATED(LinkedStack);
  42 public:
  43     LinkedStack() : m_size(0) { }
  44
  45     // Iterative cleanup to prevent stack overflow problems.
  46     ~LinkedStack()
  47     {
  48         OwnPtr<Node> ptr = m_head.release();
  49         while (ptr)
  50             ptr = ptr->m_next.release();
  51     }
  52
  53     bool isEmpty();
  54
  55     void push(const T&);
  56     const T& peek();
  57     void pop();
  58
  59     size_t size();
  60
  61     // This inner class used to be private but is now public on account of a
  62     // possible MSVC bug. It can be made private again if we get rid of
  63     // WTF_MAKE_FAST_ALLOCATED ever.
  64     class Node {
  65         WTF_MAKE_FAST_ALLOCATED(LinkedStack::Node);
  66     public:
  67         Node(const T&, PassOwnPtr<Node> next);
  68
  69         T m_data;
  70         OwnPtr<Node> m_next;
  71     };
  72
  73 private:
  74     OwnPtr<Node> m_head;
  75     size_t m_size;
  76 };
  77
  78 template <typename T>
  79 LinkedStack<T>::Node::Node(const T& data, PassOwnPtr<Node> next)
  80     : m_data(data)
  81     , m_next(next)
  82 {
  83 }
  84
  85 template <typename T>
  86 inline bool LinkedStack<T>::isEmpty()
  87 {
  88     return !m_head;
  89 }
  90
  91 template <typename T>
  92 inline void LinkedStack<T>::push(const T& data)
  93 {
  94     m_head = adoptPtr(new Node(data, m_head.release()));
  95     ++m_size;
  96 }
  97
  98 template <typename T>
  99 inline const T& LinkedStack<T>::peek()
 100 {
 101     return m_head->m_data;
 102 }
 103
 104 template <typename T>
 105 inline void LinkedStack<T>::pop()
 106 {
 107     ASSERT(m_head && m_size);
 108     m_head = m_head->m_next.release();
 109     --m_size;
 110 }
 111
 112 template <typename T>
 113 inline size_t LinkedStack<T>::size()
 114 {
 115     return m_size;
 116 }
 117
 118 }
 119
 120 using WTF::LinkedStack;
 121
 122 #endif