forked from mirrors/gecko-dev
30812bc3a6
Differential Revision: https://phabricator.services.mozilla.com/D56007 --HG-- extra : moz-landing-system : lando
41 lines
1.2 KiB
C++
41 lines
1.2 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_dom_indexeddb_flippedonce_h__
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#define mozilla_dom_indexeddb_flippedonce_h__
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#include "mozilla/Assertions.h"
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#include "mozilla/Attributes.h"
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namespace mozilla {
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// A state-restricted bool, which can only be flipped once. It isn't required to
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// be flipped during its lifetime.
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template <bool Initial>
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class FlippedOnce {
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public:
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FlippedOnce(const FlippedOnce&) = delete;
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FlippedOnce& operator=(const FlippedOnce&) = delete;
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FlippedOnce(FlippedOnce&&) = default;
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FlippedOnce& operator=(FlippedOnce&&) = default;
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constexpr FlippedOnce() = default;
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MOZ_IMPLICIT constexpr operator bool() const { return mValue; };
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constexpr void Flip() {
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MOZ_ASSERT(mValue == Initial);
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EnsureFlipped();
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}
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constexpr void EnsureFlipped() { mValue = !Initial; }
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private:
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bool mValue = Initial;
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};
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} // namespace mozilla
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#endif
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