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 COMPUTER, 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 COMPUTER, 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#ifndef LinkHash_h
27#define LinkHash_h
28
29#include <wtf/Forward.h>
30#include <wtf/text/StringHash.h>
31
32namespace WebCore {
33
34class KURL;
35
36typedef uint64_t LinkHash;
37
38// Use the low 32-bits of the 64-bit LinkHash as the key for HashSets.
39struct LinkHashHash {
40    static unsigned hash(LinkHash key) { return static_cast<unsigned>(key); }
41    static bool equal(LinkHash a, LinkHash b) { return a == b; }
42    static const bool safeToCompareToEmptyOrDeleted = true;
43
44    // See AlreadyHashed::avoidDeletedValue.
45    static unsigned avoidDeletedValue(LinkHash hash64)
46    {
47        ASSERT(hash64);
48        unsigned hash = static_cast<unsigned>(hash64);
49        unsigned newHash = hash | (!(hash + 1) << 31);
50        ASSERT(newHash);
51        ASSERT(newHash != 0xFFFFFFFF);
52        return newHash;
53    }
54};
55
56// Returns the hash of the string that will be used for visited link coloring.
57LinkHash visitedLinkHash(const String& url);
58LinkHash visitedLinkHash(const UChar* url, unsigned length);
59
60// Resolves the potentially relative URL "attributeURL" relative to the given
61// base URL, and returns the hash of the string that will be used for visited
62// link coloring. It will return the special value of 0 if attributeURL does not
63// look like a relative URL.
64LinkHash visitedLinkHash(const KURL& base, const AtomicString& attributeURL);
65
66// Resolves the potentially relative URL "attributeURL" relative to the given
67// base URL, and returns the hash of the string that will be used for visited.
68// It will return an empty Vector in case of errors.
69void visitedURL(const KURL& base, const AtomicString& attributeURL, Vector<UChar, 512>&);
70
71
72}  // namespace WebCore
73
74#endif  // LinkHash_h
75