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 "StringHash.h"

    30 

    31 namespace WebCore {

    32 

    33 class AtomicString;

    34 class KURL;

    35 

    36 typedef uint64_t LinkHash;

    37 

    38 // Use the low 32-bits of the 64-bit LinkHash as the key for HashSets.

    39 struct 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 has of the string that will be used for visited link coloring.

    57 LinkHash visitedLinkHash(const UChar* url, unsigned length);

    58 

    59 // Resolves the potentially relative URL "attributeURL" relative to the given

    60 // base URL, and returns the hash of the string that will be used for visited

    61 // link coloring. It will return the special value of 0 if attributeURL does not

    62 // look like a relative URL.

    63 LinkHash visitedLinkHash(const KURL& base, const AtomicString& attributeURL);

    64 

    65 // Resolves the potentially relative URL "attributeURL" relative to the given

    66 // base URL, and returns the hash of the string that will be used for visited.

    67 // It will return an empty Vector in case of errors.

    68 void visitedURL(const KURL& base, const AtomicString& attributeURL, Vector<UChar, 512>&);

    69 

    70 

    71 }  // namespace WebCore

    72 

    73 #endif  // LinkHash_h