blob: 57255caa72f709dc311a64bca740101257abc5bf [file] [log] [blame]
/*
* Copyright (C) 2017 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <atomic>
#include <wtf/NeverDestroyed.h>
namespace WTF {
template <typename IdentifierType, typename ClassType>
class IdentifiedBase {
public:
IdentifierType identifier() const
{
return m_identifier;
}
protected:
IdentifiedBase(const IdentifiedBase&) = default;
explicit IdentifiedBase(IdentifierType identifier)
: m_identifier(identifier)
{
}
IdentifiedBase& operator=(const IdentifiedBase&) = default;
private:
IdentifierType m_identifier;
};
template <typename T>
class Identified : public IdentifiedBase<uint64_t, T> {
protected:
Identified()
: IdentifiedBase<uint64_t, T>(generateIdentifier())
{
}
Identified(const Identified&) = default;
Identified& operator=(const Identified&) = default;
explicit Identified(uint64_t identifier)
: IdentifiedBase<uint64_t, T>(identifier)
{
}
private:
static uint64_t generateIdentifier()
{
static uint64_t currentIdentifier;
return ++currentIdentifier;
}
};
template <typename T>
class ThreadSafeIdentified : public IdentifiedBase<uint64_t, T> {
protected:
ThreadSafeIdentified()
: IdentifiedBase<uint64_t, T>(generateIdentifier())
{
}
ThreadSafeIdentified(const ThreadSafeIdentified&) = default;
ThreadSafeIdentified& operator=(const ThreadSafeIdentified&) = default;
explicit ThreadSafeIdentified(uint64_t identifier)
: IdentifiedBase<uint64_t, T>(identifier)
{
}
private:
static uint64_t generateIdentifier()
{
static LazyNeverDestroyed<std::atomic<uint64_t>> currentIdentifier;
static std::once_flag initializeCurrentIdentifier;
std::call_once(initializeCurrentIdentifier, [] {
currentIdentifier.construct(0);
});
return ++currentIdentifier.get();
}
};
} // namespace WTF
using WTF::Identified;
using WTF::ThreadSafeIdentified;