1/*
2 * Copyright (C) 2008 Google 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. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include <wtf/Forward.h>
29#include <wtf/text/StringHash.h>
30
31namespace WebCore {
32
33typedef uint64_t SharedStringHash;
34
35// Use the low 32-bits of the 64-bit SharedStringHash as the key for HashSets.
36struct SharedStringHashHash {
37 static unsigned hash(SharedStringHash key) { return static_cast<unsigned>(key); }
38 static bool equal(SharedStringHash a, SharedStringHash b) { return a == b; }
39 static const bool safeToCompareToEmptyOrDeleted = true;
40
41 // See AlreadyHashed::avoidDeletedValue.
42 static unsigned avoidDeletedValue(SharedStringHash hash64)
43 {
44 ASSERT(hash64);
45 unsigned hash = static_cast<unsigned>(hash64);
46 unsigned newHash = hash | (!(hash + 1) << 31);
47 ASSERT(newHash);
48 ASSERT(newHash != 0xFFFFFFFF);
49 return newHash;
50 }
51};
52
53// Returns the hash of the string that will be used for visited link coloring.
54WEBCORE_EXPORT SharedStringHash computeSharedStringHash(const String& url);
55WEBCORE_EXPORT SharedStringHash computeSharedStringHash(const UChar* url, unsigned length);
56
57// Resolves the potentially relative URL "attributeURL" relative to the given
58// base URL, and returns the hash of the string that will be used for visited
59// link coloring. It will return the special value of 0 if attributeURL does not
60// look like a relative URL.
61SharedStringHash computeVisitedLinkHash(const URL& base, const AtomString& attributeURL);
62
63} // namespace WebCore
64