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/*
* Copyright (c) 2020, Matthew Olsson <mattco@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/FlyString.h>
#include <LibJS/Runtime/PrimitiveString.h>
#include <LibJS/Runtime/Symbol.h>
#include <LibJS/Runtime/Value.h>
namespace JS {
class StringOrSymbol {
public:
StringOrSymbol() = default;
StringOrSymbol(char const* chars)
: StringOrSymbol(FlyString(chars))
{
}
StringOrSymbol(String const& string)
: StringOrSymbol(FlyString(string))
{
}
StringOrSymbol(FlyString const& string)
: m_ptr(string.impl())
{
VERIFY(!string.is_null());
as_string_impl().ref();
}
~StringOrSymbol()
{
if (is_string())
as_string_impl().unref();
}
StringOrSymbol(Symbol const* symbol)
: m_ptr(symbol)
{
set_symbol_flag();
}
StringOrSymbol(StringOrSymbol const& other)
{
m_ptr = other.m_ptr;
if (is_string())
as_string_impl().ref();
}
StringOrSymbol(StringOrSymbol&& other)
{
m_ptr = exchange(other.m_ptr, nullptr);
}
ALWAYS_INLINE bool is_valid() const { return m_ptr != nullptr; }
ALWAYS_INLINE bool is_symbol() const { return is_valid() && (bits() & 1ul); }
ALWAYS_INLINE bool is_string() const { return is_valid() && !(bits() & 1ul); }
ALWAYS_INLINE FlyString as_string() const
{
VERIFY(is_string());
return FlyString::from_fly_impl(as_string_impl());
}
ALWAYS_INLINE Symbol const* as_symbol() const
{
VERIFY(is_symbol());
return reinterpret_cast<Symbol const*>(bits() & ~1ul);
}
String to_display_string() const
{
if (is_string())
return as_string();
if (is_symbol())
return as_symbol()->to_string();
VERIFY_NOT_REACHED();
}
Value to_value(VM& vm) const
{
if (is_string())
return js_string(vm, as_string());
if (is_symbol())
return const_cast<Symbol*>(as_symbol());
return {};
}
void visit_edges(Cell::Visitor& visitor)
{
if (is_symbol())
visitor.visit(const_cast<Symbol*>(as_symbol()));
}
ALWAYS_INLINE bool operator==(StringOrSymbol const& other) const
{
if (is_string())
return other.is_string() && &as_string_impl() == &other.as_string_impl();
if (is_symbol())
return other.is_symbol() && as_symbol() == other.as_symbol();
return true;
}
StringOrSymbol& operator=(StringOrSymbol const& other)
{
if (this == &other)
return *this;
m_ptr = other.m_ptr;
if (is_string())
as_string_impl().ref();
return *this;
}
StringOrSymbol& operator=(StringOrSymbol&& other)
{
if (this != &other)
m_ptr = exchange(other.m_ptr, nullptr);
return *this;
}
unsigned hash() const
{
if (is_string())
return as_string_impl().hash();
return ptr_hash(as_symbol());
}
private:
ALWAYS_INLINE u64 bits() const
{
return reinterpret_cast<uintptr_t>(m_ptr);
}
ALWAYS_INLINE void set_symbol_flag()
{
m_ptr = reinterpret_cast<void const*>(bits() | 1ul);
}
ALWAYS_INLINE StringImpl const& as_string_impl() const
{
VERIFY(is_string());
return *reinterpret_cast<StringImpl const*>(m_ptr);
}
void const* m_ptr { nullptr };
};
}
template<>
struct AK::Traits<JS::StringOrSymbol> : public GenericTraits<JS::StringOrSymbol> {
static unsigned hash(JS::StringOrSymbol const& key)
{
return key.hash();
}
};
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