1/*
2 * Copyright (C) 2014-2017 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include <wtf/HashFunctions.h>
29#include <wtf/HashTraits.h>
30
31namespace PAL {
32
33class SessionID {
34public:
35 SessionID()
36 : SessionID(emptySessionID())
37 {
38 }
39
40 enum SessionConstants : uint64_t {
41 EphemeralSessionMask = 0x8000000000000000,
42 DefaultSessionID = 1,
43 LegacyPrivateSessionID = DefaultSessionID | EphemeralSessionMask,
44 HashTableEmptyValueID = 0,
45 HashTableDeletedValueID = std::numeric_limits<uint64_t>::max(),
46 };
47
48 static SessionID emptySessionID() { return SessionID(HashTableEmptyValueID); }
49 static SessionID hashTableDeletedValue() { return SessionID(HashTableDeletedValueID); }
50 static SessionID defaultSessionID() { return SessionID(DefaultSessionID); }
51 static SessionID legacyPrivateSessionID() { return SessionID(LegacyPrivateSessionID); }
52
53 bool isValid() const { return m_sessionID != HashTableEmptyValueID && m_sessionID != HashTableDeletedValueID; }
54 bool isEphemeral() const { return m_sessionID & EphemeralSessionMask && m_sessionID != HashTableDeletedValueID; }
55
56 PAL_EXPORT static SessionID generateEphemeralSessionID();
57 PAL_EXPORT static SessionID generatePersistentSessionID();
58 PAL_EXPORT static void enableGenerationProtection();
59
60 uint64_t sessionID() const { return m_sessionID; }
61 bool operator==(SessionID sessionID) const { return m_sessionID == sessionID.m_sessionID; }
62 bool operator!=(SessionID sessionID) const { return m_sessionID != sessionID.m_sessionID; }
63 bool isAlwaysOnLoggingAllowed() const { return !isEphemeral(); }
64
65 template<class Encoder> void encode(Encoder&) const;
66 template<class Decoder> static bool decode(Decoder&, SessionID&);
67 template<class Decoder> static Optional<SessionID> decode(Decoder&);
68
69 SessionID isolatedCopy() const;
70
71private:
72 explicit SessionID(uint64_t sessionID)
73 : m_sessionID(sessionID)
74 {
75 }
76
77 uint64_t m_sessionID;
78};
79
80template<class Encoder>
81void SessionID::encode(Encoder& encoder) const
82{
83 // FIXME: Eliminate places that encode invalid SessionIDs, then ASSERT here that the sessionID is valid.
84 encoder << m_sessionID;
85}
86
87template<class Decoder>
88bool SessionID::decode(Decoder& decoder, SessionID& sessionID)
89{
90 Optional<SessionID> decodedSessionID;
91 decoder >> decodedSessionID;
92 if (!decodedSessionID)
93 return false;
94
95 sessionID = decodedSessionID.value();
96 return true;
97}
98
99template<class Decoder>
100Optional<SessionID> SessionID::decode(Decoder& decoder)
101{
102 Optional<uint64_t> sessionID;
103 decoder >> sessionID;
104 if (!sessionID)
105 return WTF::nullopt;
106
107 // FIXME: Eliminate places that encode invalid SessionIDs, then fail to decode an invalid sessionID.
108 return SessionID { *sessionID };
109}
110
111} // namespace PAL
112
113namespace WTF {
114
115struct SessionIDHash {
116 static unsigned hash(const PAL::SessionID& p) { return intHash(p.sessionID()); }
117 static bool equal(const PAL::SessionID& a, const PAL::SessionID& b) { return a == b; }
118 static const bool safeToCompareToEmptyOrDeleted = true;
119};
120template<> struct HashTraits<PAL::SessionID> : GenericHashTraits<PAL::SessionID> {
121 static PAL::SessionID emptyValue() { return PAL::SessionID::emptySessionID(); }
122
123 static void constructDeletedValue(PAL::SessionID& slot) { slot = PAL::SessionID::hashTableDeletedValue(); }
124 static bool isDeletedValue(const PAL::SessionID& slot) { return slot == PAL::SessionID::hashTableDeletedValue(); }
125};
126template<> struct DefaultHash<PAL::SessionID> {
127 typedef SessionIDHash Hash;
128};
129
130} // namespace WTF
131