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/*
* Copyright (C) 2020 Apple Inc. All rights reserved.
*
* 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 <tuple>
#include <unicode/utypes.h>
#include <wtf/Forward.h>
#include <wtf/FunctionTraits.h>
namespace WTF {
constexpr bool needsToGrowToProduceBuffer(UErrorCode);
constexpr bool needsToGrowToProduceCString(UErrorCode);
// Use this to call a function from ICU that has the following properties:
// - Takes a buffer pointer and capacity.
// - Returns the length of the buffer needed.
// - Takes a UErrorCode* as its last argument, returning the status, including U_BUFFER_OVERFLOW_ERROR.
// Pass the arguments, but pass a Vector in place of the buffer pointer and capacity, and don't pass a UErrorCode*.
// This will call the function, once or twice as needed, resizing the buffer as needed.
//
// Example:
//
// Vector<UChar, 32> buffer;
// auto status = callBufferProducingFunction(ucal_getDefaultTimeZone, buffer);
//
template<typename FunctionType, typename ...ArgumentTypes> UErrorCode callBufferProducingFunction(const FunctionType&, ArgumentTypes&&...);
// Implementations of the functions declared above.
constexpr bool needsToGrowToProduceBuffer(UErrorCode errorCode)
{
return errorCode == U_BUFFER_OVERFLOW_ERROR;
}
constexpr bool needsToGrowToProduceCString(UErrorCode errorCode)
{
return needsToGrowToProduceBuffer(errorCode) || errorCode == U_STRING_NOT_TERMINATED_WARNING;
}
namespace CallBufferProducingFunction {
template<typename CharacterType, size_t inlineCapacity, typename ...ArgumentTypes> auto& findVector(Vector<CharacterType, inlineCapacity>& buffer, ArgumentTypes&&...)
{
return buffer;
}
template<typename FirstArgumentType, typename ...ArgumentTypes> auto& findVector(FirstArgumentType&&, ArgumentTypes&&... arguments)
{
return findVector(std::forward<ArgumentTypes>(arguments)...);
}
constexpr std::tuple<> argumentTuple() { return { }; }
template<typename FirstArgumentType, typename ...OtherArgumentTypes> auto argumentTuple(FirstArgumentType&&, OtherArgumentTypes&&...);
template<typename CharacterType, size_t inlineCapacity, typename ...OtherArgumentTypes> auto argumentTuple(Vector<CharacterType, inlineCapacity>& buffer, OtherArgumentTypes&&... otherArguments)
{
return tuple_cat(std::make_tuple(buffer.data(), buffer.size()), argumentTuple(std::forward<OtherArgumentTypes>(otherArguments)...));
}
template<typename FirstArgumentType, typename ...OtherArgumentTypes> auto argumentTuple(FirstArgumentType&& firstArgument, OtherArgumentTypes&&... otherArguments)
{
// This technique of building a tuple and passing it twice does not work well for complex types, so assert this is a relatively simple one.
static_assert(std::is_trivial_v<std::remove_reference_t<FirstArgumentType>>);
return tuple_cat(std::make_tuple(firstArgument), argumentTuple(std::forward<OtherArgumentTypes>(otherArguments)...));
}
}
template<typename FunctionType, typename ...ArgumentTypes> UErrorCode callBufferProducingFunction(const FunctionType& function, ArgumentTypes&&... arguments)
{
auto& buffer = CallBufferProducingFunction::findVector(std::forward<ArgumentTypes>(arguments)...);
buffer.grow(buffer.capacity());
auto status = U_ZERO_ERROR;
auto resultLength = std::apply(function, CallBufferProducingFunction::argumentTuple(std::forward<ArgumentTypes>(arguments)..., &status));
if (U_SUCCESS(status))
buffer.shrink(resultLength);
else if (needsToGrowToProduceBuffer(status)) {
status = U_ZERO_ERROR;
buffer.grow(resultLength);
std::apply(function, CallBufferProducingFunction::argumentTuple(std::forward<ArgumentTypes>(arguments)..., &status));
ASSERT(U_SUCCESS(status));
}
return status;
}
template<auto deleteFunction>
struct ICUDeleter {
void operator()(typename FunctionTraits<decltype(deleteFunction)>::template ArgumentType<0> pointer)
{
if (pointer)
deleteFunction(pointer);
}
};
namespace ICU {
WTF_EXPORT_PRIVATE unsigned majorVersion();
WTF_EXPORT_PRIVATE unsigned minorVersion();
} // namespace ICU
} // namespace WTF
using WTF::callBufferProducingFunction;
using WTF::needsToGrowToProduceCString;
using WTF::needsToGrowToProduceBuffer;
using WTF::ICUDeleter;
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