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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef txStack_h___
#define txStack_h___
#include "nsTArray.h"
class txStack : private nsTArray<void*> {
public:
/**
* Returns the specified object from the top of this stack,
* without removing it from the stack.
*
* @return a pointer to the object that is the top of this stack.
*/
inline void* peek() {
NS_ASSERTION(!isEmpty(), "peeking at empty stack");
return !isEmpty() ? ElementAt(Length() - 1) : nullptr;
}
/**
* Adds the specified object to the top of this stack.
*
* @param obj a pointer to the object that is to be added to the
* top of this stack.
*/
inline nsresult push(void* aObject) {
// XXX(Bug 1631371) Check if this should use a fallible operation as it
// pretended earlier, or change the return type to void.
AppendElement(aObject);
return NS_OK;
}
/**
* Removes and returns the specified object from the top of this
* stack.
*
* @return a pointer to the object that was the top of this stack.
*/
inline void* pop() {
void* object = nullptr;
NS_ASSERTION(!isEmpty(), "popping from empty stack");
if (!isEmpty()) {
object = PopLastElement();
}
return object;
}
/**
* Returns true if there are no objects in the stack.
*
* @return true if there are no objects in the stack.
*/
inline bool isEmpty() { return IsEmpty(); }
/**
* Returns the number of elements in the Stack.
*
* @return the number of elements in the Stack.
*/
inline int32_t size() { return Length(); }
private:
friend class txStackIterator;
};
class txStackIterator {
public:
/**
* Creates an iterator for the given stack.
*
* @param aStack the stack to create an iterator for.
*/
inline explicit txStackIterator(txStack* aStack)
: mStack(aStack), mPosition(0) {}
/**
* Returns true if there is more objects on the stack.
*
* @return .
*/
inline bool hasNext() { return (mPosition < mStack->Length()); }
/**
* Returns the next object pointer from the stack.
*
* @return .
*/
inline void* next() {
if (mPosition == mStack->Length()) {
return nullptr;
}
return mStack->ElementAt(mPosition++);
}
private:
txStack* mStack;
uint32_t mPosition;
};
#endif /* txStack_h___ */
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