161 lines
5.3 KiB
C++
161 lines
5.3 KiB
C++
/*
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* Copyright (C) 2017-2019 Apple Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#include <atomic>
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#include <mutex>
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#include <wtf/HashTraits.h>
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#include <wtf/NeverDestroyed.h>
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#include <wtf/text/TextStream.h>
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#include <wtf/text/WTFString.h>
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namespace WTF {
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class ObjectIdentifierBase {
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protected:
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WTF_EXPORT_PRIVATE static uint64_t generateIdentifierInternal();
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WTF_EXPORT_PRIVATE static uint64_t generateThreadSafeIdentifierInternal();
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};
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template<typename T> class ObjectIdentifier : private ObjectIdentifierBase {
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public:
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static ObjectIdentifier generate()
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{
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RELEASE_ASSERT(!m_generationProtected);
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return ObjectIdentifier { generateIdentifierInternal() };
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}
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static ObjectIdentifier generateThreadSafe()
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{
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RELEASE_ASSERT(!m_generationProtected);
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return ObjectIdentifier { generateThreadSafeIdentifierInternal() };
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}
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static void enableGenerationProtection()
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{
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m_generationProtected = true;
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}
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ObjectIdentifier() = default;
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ObjectIdentifier(HashTableDeletedValueType) : m_identifier(hashTableDeletedValue()) { }
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bool isHashTableDeletedValue() const { return m_identifier == hashTableDeletedValue(); }
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bool isValid() const { return isValidIdentifier(m_identifier); }
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template<typename Encoder> void encode(Encoder& encoder) const
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{
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ASSERT(isValidIdentifier(m_identifier));
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encoder << m_identifier;
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}
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template<typename Decoder> static std::optional<ObjectIdentifier> decode(Decoder& decoder)
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{
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std::optional<uint64_t> identifier;
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decoder >> identifier;
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if (!identifier || !isValidIdentifier(*identifier))
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return std::nullopt;
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return ObjectIdentifier { *identifier };
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}
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bool operator==(const ObjectIdentifier& other) const
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{
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return m_identifier == other.m_identifier;
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}
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bool operator!=(const ObjectIdentifier& other) const
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{
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return m_identifier != other.m_identifier;
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}
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uint64_t toUInt64() const { return m_identifier; }
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explicit operator bool() const { return m_identifier; }
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String loggingString() const
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{
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return String::number(m_identifier);
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}
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struct MarkableTraits {
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static bool isEmptyValue(ObjectIdentifier identifier)
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{
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return !identifier.m_identifier;
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}
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static constexpr ObjectIdentifier emptyValue()
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{
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return ObjectIdentifier();
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}
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};
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private:
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template<typename U> friend ObjectIdentifier<U> makeObjectIdentifier(uint64_t);
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friend struct HashTraits<ObjectIdentifier>;
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template<typename U> friend struct ObjectIdentifierHash;
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static uint64_t hashTableDeletedValue() { return std::numeric_limits<uint64_t>::max(); }
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static bool isValidIdentifier(uint64_t identifier) { return identifier && identifier != hashTableDeletedValue(); }
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explicit constexpr ObjectIdentifier(uint64_t identifier)
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: m_identifier(identifier)
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{
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}
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uint64_t m_identifier { 0 };
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inline static bool m_generationProtected { false };
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};
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template<typename T> inline ObjectIdentifier<T> makeObjectIdentifier(uint64_t identifier)
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{
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return ObjectIdentifier<T> { identifier };
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}
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template<typename T> inline void add(Hasher& hasher, ObjectIdentifier<T> identifier)
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{
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add(hasher, identifier.toUInt64());
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}
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template<typename T> struct ObjectIdentifierHash {
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static unsigned hash(const ObjectIdentifier<T>& identifier) { return intHash(identifier.m_identifier); }
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static bool equal(const ObjectIdentifier<T>& a, const ObjectIdentifier<T>& b) { return a == b; }
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static constexpr bool safeToCompareToEmptyOrDeleted = true;
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};
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template<typename T> struct HashTraits<ObjectIdentifier<T>> : SimpleClassHashTraits<ObjectIdentifier<T>> { };
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template<typename T> struct DefaultHash<ObjectIdentifier<T>> : ObjectIdentifierHash<T> { };
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template<typename T>
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TextStream& operator<<(TextStream& ts, const ObjectIdentifier<T>& identifier)
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{
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ts << identifier.toUInt64();
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return ts;
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}
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} // namespace WTF
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using WTF::ObjectIdentifier;
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using WTF::makeObjectIdentifier;
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