1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
|
/*
* Copyright (C) 2017-2019 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 <mutex>
#include <wtf/HashTraits.h>
#include <wtf/NeverDestroyed.h>
#include <wtf/text/TextStream.h>
#include <wtf/text/WTFString.h>
namespace WTF {
class ObjectIdentifierBase {
protected:
WTF_EXPORT_PRIVATE static uint64_t generateIdentifierInternal();
WTF_EXPORT_PRIVATE static uint64_t generateThreadSafeIdentifierInternal();
};
template<typename T> class ObjectIdentifier : private ObjectIdentifierBase {
public:
static ObjectIdentifier generate()
{
RELEASE_ASSERT(!m_generationProtected);
return ObjectIdentifier { generateIdentifierInternal() };
}
static ObjectIdentifier generateThreadSafe()
{
RELEASE_ASSERT(!m_generationProtected);
return ObjectIdentifier { generateThreadSafeIdentifierInternal() };
}
static void enableGenerationProtection()
{
m_generationProtected = true;
}
ObjectIdentifier() = default;
ObjectIdentifier(HashTableDeletedValueType) : m_identifier(hashTableDeletedValue()) { }
bool isHashTableDeletedValue() const { return m_identifier == hashTableDeletedValue(); }
bool isValid() const { return isValidIdentifier(m_identifier); }
template<typename Encoder> void encode(Encoder& encoder) const
{
ASSERT(isValidIdentifier(m_identifier));
encoder << m_identifier;
}
template<typename Decoder> static std::optional<ObjectIdentifier> decode(Decoder& decoder)
{
std::optional<uint64_t> identifier;
decoder >> identifier;
if (!identifier || !isValidIdentifier(*identifier))
return std::nullopt;
return ObjectIdentifier { *identifier };
}
bool operator==(const ObjectIdentifier& other) const
{
return m_identifier == other.m_identifier;
}
bool operator!=(const ObjectIdentifier& other) const
{
return m_identifier != other.m_identifier;
}
uint64_t toUInt64() const { return m_identifier; }
explicit operator bool() const { return m_identifier; }
String loggingString() const
{
return String::number(m_identifier);
}
struct MarkableTraits {
static bool isEmptyValue(ObjectIdentifier identifier)
{
return !identifier.m_identifier;
}
static constexpr ObjectIdentifier emptyValue()
{
return ObjectIdentifier();
}
};
private:
template<typename U> friend ObjectIdentifier<U> makeObjectIdentifier(uint64_t);
friend struct HashTraits<ObjectIdentifier>;
template<typename U> friend struct ObjectIdentifierHash;
static uint64_t hashTableDeletedValue() { return std::numeric_limits<uint64_t>::max(); }
static bool isValidIdentifier(uint64_t identifier) { return identifier && identifier != hashTableDeletedValue(); }
explicit constexpr ObjectIdentifier(uint64_t identifier)
: m_identifier(identifier)
{
}
uint64_t m_identifier { 0 };
inline static bool m_generationProtected { false };
};
template<typename T> inline ObjectIdentifier<T> makeObjectIdentifier(uint64_t identifier)
{
return ObjectIdentifier<T> { identifier };
}
template<typename T> inline void add(Hasher& hasher, ObjectIdentifier<T> identifier)
{
add(hasher, identifier.toUInt64());
}
template<typename T> struct ObjectIdentifierHash {
static unsigned hash(const ObjectIdentifier<T>& identifier) { return intHash(identifier.m_identifier); }
static bool equal(const ObjectIdentifier<T>& a, const ObjectIdentifier<T>& b) { return a == b; }
static constexpr bool safeToCompareToEmptyOrDeleted = true;
};
template<typename T> struct HashTraits<ObjectIdentifier<T>> : SimpleClassHashTraits<ObjectIdentifier<T>> { };
template<typename T> struct DefaultHash<ObjectIdentifier<T>> : ObjectIdentifierHash<T> { };
template<typename T>
TextStream& operator<<(TextStream& ts, const ObjectIdentifier<T>& identifier)
{
ts << identifier.toUInt64();
return ts;
}
} // namespace WTF
using WTF::ObjectIdentifier;
using WTF::makeObjectIdentifier;
|
