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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 mozilla_dom_indexeddb_flippedonce_h__
#define mozilla_dom_indexeddb_flippedonce_h__
#include "mozilla/Assertions.h"
#include "mozilla/Attributes.h"
namespace mozilla {
// A state-restricted bool, which can only be flipped once. It isn't required to
// be flipped during its lifetime.
template <bool Initial>
class FlippedOnce {
public:
FlippedOnce(const FlippedOnce&) = delete;
FlippedOnce& operator=(const FlippedOnce&) = delete;
FlippedOnce(FlippedOnce&&) = default;
FlippedOnce& operator=(FlippedOnce&&) = default;
constexpr FlippedOnce() = default;
MOZ_IMPLICIT constexpr operator bool() const { return mValue; };
constexpr void Flip() {
MOZ_ASSERT(mValue == Initial);
EnsureFlipped();
}
constexpr void EnsureFlipped() { mValue = !Initial; }
private:
bool mValue = Initial;
};
} // namespace mozilla
#endif
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