gecko-dev/layout/style/nsStyleAutoArray.h

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/* -*- Mode: C++; tab-width: 2; 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 nsStyleAutoArray_h_
#define nsStyleAutoArray_h_
#include "nsTArray.h"
#include "mozilla/Assertions.h"
/**
* An array of objects, similar to AutoTArray<T,1> but which is memmovable. It
* always has length >= 1.
*/
template<typename T>
class nsStyleAutoArray
{
public:
// This constructor places a single element in mFirstElement.
enum WithSingleInitialElement { WITH_SINGLE_INITIAL_ELEMENT };
explicit nsStyleAutoArray(WithSingleInitialElement) {}
nsStyleAutoArray(const nsStyleAutoArray& aOther) { *this = aOther; }
nsStyleAutoArray& operator=(const nsStyleAutoArray& aOther) {
mFirstElement = aOther.mFirstElement;
mOtherElements = aOther.mOtherElements;
return *this;
}
bool operator==(const nsStyleAutoArray& aOther) const {
return Length() == aOther.Length() &&
mFirstElement == aOther.mFirstElement &&
mOtherElements == aOther.mOtherElements;
}
bool operator!=(const nsStyleAutoArray& aOther) const {
return !(*this == aOther);
}
nsStyleAutoArray& operator=(nsStyleAutoArray&& aOther) {
mFirstElement = aOther.mFirstElement;
mOtherElements.SwapElements(aOther.mOtherElements);
return *this;
}
size_t Length() const {
return mOtherElements.Length() + 1;
}
const T& operator[](size_t aIndex) const {
return aIndex == 0 ? mFirstElement : mOtherElements[aIndex - 1];
}
T& operator[](size_t aIndex) {
return aIndex == 0 ? mFirstElement : mOtherElements[aIndex - 1];
}
void EnsureLengthAtLeast(size_t aMinLen) {
if (aMinLen > 0) {
mOtherElements.EnsureLengthAtLeast(aMinLen - 1);
}
}
void SetLengthNonZero(size_t aNewLen) {
MOZ_ASSERT(aNewLen > 0);
mOtherElements.SetLength(aNewLen - 1);
}
void TruncateLengthNonZero(size_t aNewLen) {
MOZ_ASSERT(aNewLen > 0);
MOZ_ASSERT(aNewLen <= Length());
mOtherElements.TruncateLength(aNewLen - 1);
}
private:
T mFirstElement;
nsTArray<T> mOtherElements;
};
#endif /* nsStyleAutoArray_h_ */