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/*
* Copyright (C) 2018 Yusuke Suzuki <utatane.tea@gmail.com>
* Copyright (C) 2024 Apple Inc. All Rights Reserved.
* Copyright (C) 2025 Comcast Inc.
* Copyright (C) 2025 Igalia S.L.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <span>
#include <string>
#include <type_traits>
#include <wtf/Compiler.h>
#include <wtf/ForbidHeapAllocation.h>
#include <wtf/Forward.h>
#include <wtf/HashFunctions.h>
#include <wtf/StdLibExtras.h>
#include <wtf/text/ASCIILiteral.h>
#include <wtf/text/SuperFastHash.h>
namespace WTF {
class PrintStream;
class String;
// This is a class designed to contain a UTF8 string, untouched. Interactions with other string classes in WebKit should
// be handled with care or perform a string conversion through the String class, with the exception of ASCIILiteral
// because ASCII characters are also UTF8.
class CStringView final {
WTF_FORBID_HEAP_ALLOCATION;
public:
static CStringView unsafeFromUTF8(const char* string)
{
if (!string)
return CStringView();
return CStringView(unsafeMakeSpan(byteCast<char8_t>(string), std::char_traits<char>::length(string) + 1));
}
WTF_EXPORT_PRIVATE void dump(PrintStream& out) const;
CStringView() = default;
constexpr CStringView(std::nullptr_t)
: CStringView()
{ }
CStringView(ASCIILiteral literal LIFETIME_BOUND)
{
if (!literal.length())
return;
m_spanWithNullTerminator = byteCast<char8_t>(literal.spanIncludingNullTerminator());
}
unsigned hash() const;
bool isNull() const { return m_spanWithNullTerminator.empty(); }
// This method is designed to interface with external C functions handling UTF8 strings. Interactions with other
// strings should be done through String with the exception of ASCIILiteral because ASCII is also UTF8.
const char* utf8() const LIFETIME_BOUND { return reinterpret_cast<const char*>(m_spanWithNullTerminator.data()); }
size_t length() const { return m_spanWithNullTerminator.size() > 0 ? m_spanWithNullTerminator.size() - 1 : 0; }
std::span<const char8_t> span8() const LIFETIME_BOUND { return m_spanWithNullTerminator.first(length()); }
std::span<const char8_t> spanIncludingNullTerminator() const LIFETIME_BOUND { return m_spanWithNullTerminator; }
size_t isEmpty() const { return m_spanWithNullTerminator.size() <= 1; }
WTF_EXPORT_PRIVATE String toString() const;
explicit operator bool() const { return !isEmpty(); }
bool operator!() const { return isEmpty(); }
private:
explicit CStringView(std::span<const char8_t> spanWithNullTerminator LIFETIME_BOUND)
: m_spanWithNullTerminator(spanWithNullTerminator)
{
}
std::span<const char8_t> m_spanWithNullTerminator;
};
inline bool operator==(CStringView a, CStringView b)
{
if (!a || !b)
return a.utf8() == b.utf8();
return equalSpans(a.span8(), b.span8());
}
inline bool operator==(CStringView a, ASCIILiteral b)
{
if (a.isEmpty() || b.isEmpty())
return a.utf8() == b.characters();
return equalSpans(a.span8(), byteCast<char8_t>(b.span()));
}
inline bool operator==(ASCIILiteral a, CStringView b)
{
return b == a;
}
// CStringView is null terminated
inline const char* safePrintfType(const CStringView& string) { return string.utf8(); }
} // namespace WTF
using WTF::CStringView;
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