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 "platform/PlatformExport.h" 30 #include "wtf/Forward.h" 31 #include "wtf/text/StringHash.h" 32 33 namespace blink { 34 35 class KURL; 36 37 typedef uint64_t LinkHash; 38 39 // Use the low 32-bits of the 64-bit LinkHash as the key for HashSets. 40 struct LinkHashHash { 41 static unsigned hash(LinkHash key) { return static_cast<unsigned>(key); } 42 static bool equal(LinkHash a, LinkHash b) { return a == b; } 43 static const bool safeToCompareToEmptyOrDeleted = true; 44 45 // See AlreadyHashed::avoidDeletedValue. 46 static unsigned avoidDeletedValue(LinkHash hash64) 47 { 48 ASSERT(hash64); 49 unsigned hash = static_cast<unsigned>(hash64); 50 unsigned newHash = hash | (!(hash + 1) << 31); 51 ASSERT(newHash); 52 ASSERT(newHash != 0xFFFFFFFF); 53 return newHash; 54 } 55 }; 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. 61 PLATFORM_EXPORT LinkHash visitedLinkHash(const KURL& base, const AtomicString& attributeURL); 62 63 } // namespace blink 64 65 #endif // LinkHash_h 66
