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/*
* Copyright (C) 2014-2017 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 <optional>
#include <wtf/HashFunctions.h>
#include <wtf/HashTraits.h>
namespace PAL {
class SessionID {
public:
SessionID() = delete;
enum SessionConstants : uint64_t {
EphemeralSessionMask = 0x8000000000000000,
DefaultSessionID = 1,
LegacyPrivateSessionID = DefaultSessionID | EphemeralSessionMask,
HashTableEmptyValueID = 0,
HashTableDeletedValueID = std::numeric_limits<uint64_t>::max(),
};
static SessionID defaultSessionID() { return SessionID(DefaultSessionID); }
static SessionID legacyPrivateSessionID() { return SessionID(LegacyPrivateSessionID); }
explicit SessionID(WTF::HashTableDeletedValueType)
: m_identifier(HashTableDeletedValueID)
{
}
explicit SessionID(WTF::HashTableEmptyValueType)
: m_identifier(HashTableEmptyValueID)
{
}
explicit SessionID(uint64_t identifier)
: m_identifier(identifier)
{
}
PAL_EXPORT static SessionID generateEphemeralSessionID();
PAL_EXPORT static SessionID generatePersistentSessionID();
PAL_EXPORT static void enableGenerationProtection();
bool isValid() const { return isValidSessionIDValue(m_identifier); }
bool isEphemeral() const { return m_identifier & EphemeralSessionMask && m_identifier != HashTableDeletedValueID; }
bool isHashTableDeletedValue() const { return m_identifier == HashTableDeletedValueID; }
uint64_t toUInt64() const { return m_identifier; }
bool operator==(SessionID sessionID) const { return m_identifier == sessionID.m_identifier; }
bool isAlwaysOnLoggingAllowed() const { return !isEphemeral(); }
template<class Encoder> void encode(Encoder&) const;
template<class Decoder> static std::optional<SessionID> decode(Decoder&);
SessionID isolatedCopy() const { return *this; }
explicit operator bool() const { return m_identifier; }
private:
static bool isValidSessionIDValue(uint64_t sessionID) { return sessionID != HashTableEmptyValueID && sessionID != HashTableDeletedValueID; }
uint64_t m_identifier;
};
template<class Encoder>
void SessionID::encode(Encoder& encoder) const
{
ASSERT(isValid());
encoder << m_identifier;
}
template<class Decoder>
std::optional<SessionID> SessionID::decode(Decoder& decoder)
{
std::optional<uint64_t> sessionID;
decoder >> sessionID;
if (!sessionID || !isValidSessionIDValue(*sessionID))
return std::nullopt;
return SessionID { *sessionID };
}
} // namespace PAL
namespace WTF {
struct SessionIDHash {
static unsigned hash(const PAL::SessionID& p) { return intHash(p.toUInt64()); }
static bool equal(const PAL::SessionID& a, const PAL::SessionID& b) { return a == b; }
static const bool safeToCompareToEmptyOrDeleted = true;
};
template<> struct HashTraits<PAL::SessionID> : GenericHashTraits<PAL::SessionID> {
static PAL::SessionID emptyValue() { return PAL::SessionID(HashTableEmptyValue); }
static void constructDeletedValue(PAL::SessionID& slot) { new (NotNull, &slot) PAL::SessionID(HashTableDeletedValue); }
static bool isDeletedValue(const PAL::SessionID& slot) { return slot.isHashTableDeletedValue(); }
};
template<> struct DefaultHash<PAL::SessionID> : SessionIDHash { };
} // namespace WTF
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