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1 /* | 1 // Copyright 2017 The Chromium Authors. All rights reserved. |
2 * Copyright (C) 2008 Apple Inc. All rights reserved. | 2 // Use of this source code is governed by a BSD-style license that can be |
3 * | 3 // found in the LICENSE file. |
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 * | |
8 * 1. Redistributions of source code must retain the above copyright | |
9 * notice, this list of conditions and the following disclaimer. | |
10 * 2. Redistributions in binary form must reproduce the above copyright | |
11 * notice, this list of conditions and the following disclaimer in the | |
12 * documentation and/or other materials provided with the distribution. | |
13 * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of | |
14 * its contributors may be used to endorse or promote products derived | |
15 * from this software without specific prior written permission. | |
16 * | |
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY | |
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED | |
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE | |
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY | |
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES | |
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND | |
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
27 */ | |
28 | 4 |
29 #ifndef AtomicStringHash_h | 5 #include "platform/wtf/text/AtomicStringHash.h" |
30 #define AtomicStringHash_h | |
31 | 6 |
32 #include "wtf/HashTraits.h" | 7 // The contents of this header was moved to platform/wtf as part of |
33 #include "wtf/text/AtomicString.h" | 8 // WTF migration project. See the following post for details: |
34 | 9 // https://groups.google.com/a/chromium.org/d/msg/blink-dev/tLdAZCTlcAA/bYXVT8gY
CAAJ |
35 namespace WTF { | |
36 | |
37 struct AtomicStringHash { | |
38 static unsigned hash(const AtomicString& key) { | |
39 return key.impl()->existingHash(); | |
40 } | |
41 | |
42 static bool equal(const AtomicString& a, const AtomicString& b) { | |
43 return a == b; | |
44 } | |
45 | |
46 static const bool safeToCompareToEmptyOrDeleted = false; | |
47 }; | |
48 | |
49 // AtomicStringHash is the default hash for AtomicString | |
50 template <> | |
51 struct HashTraits<AtomicString> : SimpleClassHashTraits<AtomicString> { | |
52 // Unlike other types, we can return a const reference for AtomicString's | |
53 // empty value (nullAtom). | |
54 typedef const AtomicString& PeekOutType; | |
55 | |
56 static const AtomicString& emptyValue() { return nullAtom; } | |
57 static PeekOutType peek(const AtomicString& value) { return value; } | |
58 | |
59 static const bool hasIsEmptyValueFunction = true; | |
60 static bool isEmptyValue(const AtomicString& value) { return value.isNull(); } | |
61 }; | |
62 | |
63 } // namespace WTF | |
64 | |
65 using WTF::AtomicStringHash; | |
66 | |
67 #endif | |
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