1/*
2 * Copyright (C) 2015 Yusuke Suzuki <utatane.tea@gmail.com>.
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. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include <wtf/text/StringImpl.h>
29
30namespace WTF {
31
32// It represents that the string impl is uniqued in some ways.
33// When the given 2 string impls are both uniqued string impls, we can compare it just using pointer comparison.
34class UniquedStringImpl : public StringImpl {
35private:
36 UniquedStringImpl() = delete;
37protected:
38 UniquedStringImpl(CreateSymbolTag, const LChar* characters, unsigned length) : StringImpl(CreateSymbol, characters, length) { }
39 UniquedStringImpl(CreateSymbolTag, const UChar* characters, unsigned length) : StringImpl(CreateSymbol, characters, length) { }
40 UniquedStringImpl(CreateSymbolTag) : StringImpl(CreateSymbol) { }
41};
42
43#if !ASSERT_DISABLED
44// UniquedStringImpls created from StaticStringImpl will ASSERT
45// in the generic ValueCheck<T>::checkConsistency
46// as they are not allocated by fastMalloc.
47// We don't currently have any way to detect that case
48// so we ignore the consistency check for all UniquedStringImpls*.
49template<> struct
50ValueCheck<UniquedStringImpl*> {
51 static void checkConsistency(const UniquedStringImpl*) { }
52};
53
54template<> struct
55ValueCheck<const UniquedStringImpl*> {
56 static void checkConsistency(const UniquedStringImpl*) { }
57};
58#endif
59
60} // namespace WTF
61
62using WTF::UniquedStringImpl;
63