Line data    Source code

       1             : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
       2             : /* This Source Code Form is subject to the terms of the Mozilla Public
       3             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       4             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       5             : 
       6             : #ifndef txStack_h___
       7             : #define txStack_h___
       8             : 
       9             : #include "nsTArray.h"
      10             : 
      11           0 : class txStack : private nsTArray<void*>
      12             : {
      13             : public:
      14             :     /**
      15             :      * Returns the specified object from the top of this stack,
      16             :      * without removing it from the stack.
      17             :      *
      18             :      * @return a pointer to the object that is the top of this stack.
      19             :      */
      20           0 :     inline void* peek()
      21             :     {
      22           0 :         NS_ASSERTION(!isEmpty(), "peeking at empty stack");
      23           0 :         return !isEmpty() ? ElementAt(Length() - 1) : nullptr;
      24             :     }
      25             : 
      26             :     /**
      27             :      * Adds the specified object to the top of this stack.
      28             :      *
      29             :      * @param obj a pointer to the object that is to be added to the
      30             :      * top of this stack.
      31             :      */
      32           0 :     inline nsresult push(void* aObject)
      33             :     {
      34           0 :         return AppendElement(aObject) ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
      35             :     }
      36             : 
      37             :     /**
      38             :      * Removes and returns the specified object from the top of this
      39             :      * stack.
      40             :      *
      41             :      * @return a pointer to the object that was the top of this stack.
      42             :      */
      43           0 :     inline void* pop()
      44             :     {
      45           0 :         void* object = nullptr;
      46           0 :         NS_ASSERTION(!isEmpty(), "popping from empty stack");
      47           0 :         if (!isEmpty())
      48             :         {
      49           0 :             const uint32_t count = Length() - 1;
      50           0 :             object = ElementAt(count);
      51           0 :             RemoveElementAt(count);
      52             :         }
      53           0 :         return object;
      54             :     }
      55             : 
      56             :     /**
      57             :      * Returns true if there are no objects in the stack.
      58             :      *
      59             :      * @return true if there are no objects in the stack.
      60             :      */
      61           0 :     inline bool isEmpty()
      62             :     {
      63           0 :         return IsEmpty();
      64             :     }
      65             : 
      66             :     /**
      67             :      * Returns the number of elements in the Stack.
      68             :      *
      69             :      * @return the number of elements in the Stack.
      70             :      */
      71           0 :     inline int32_t size()
      72             :     {
      73           0 :         return Length();
      74             :     }
      75             : 
      76             : private:
      77             :     friend class txStackIterator;
      78             : };
      79             : 
      80             : class txStackIterator
      81             : {
      82             : public:
      83             :     /**
      84             :      * Creates an iterator for the given stack.
      85             :      *
      86             :      * @param aStack the stack to create an iterator for.
      87             :      */
      88             :     inline
      89           0 :     explicit txStackIterator(txStack* aStack) : mStack(aStack),
      90           0 :                                                 mPosition(0)
      91             :     {
      92           0 :     }
      93             : 
      94             :     /**
      95             :      * Returns true if there is more objects on the stack.
      96             :      *
      97             :      * @return .
      98             :      */
      99           0 :     inline bool hasNext()
     100             :     {
     101           0 :         return (mPosition < mStack->Length());
     102             :     }
     103             : 
     104             :     /**
     105             :      * Returns the next object pointer from the stack.
     106             :      *
     107             :      * @return .
     108             :      */
     109           0 :     inline void* next()
     110             :     {
     111           0 :         if (mPosition == mStack->Length()) {
     112           0 :             return nullptr;
     113             :         }
     114           0 :         return mStack->ElementAt(mPosition++);
     115             :     }
     116             : 
     117             : private:
     118             :     txStack* mStack;
     119             :     uint32_t mPosition;
     120             : };
     121             : 
     122             : #endif /* txStack_h___ */