ladybird/Libraries/LibJS/Runtime/PropertyKey.h

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/*
* Copyright (c) 2020, Andreas Kling <andreas@ladybird.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/DeprecatedFlyString.h>
#include <AK/FlyString.h>
#include <LibGC/Root.h>
#include <LibJS/Runtime/Completion.h>
#include <LibJS/Runtime/StringOrSymbol.h>
namespace JS {
class PropertyKey {
public:
enum class Type : u8 {
Invalid,
Number,
String,
Symbol,
};
enum class StringMayBeNumber {
Yes,
No,
};
static ThrowCompletionOr<PropertyKey> from_value(VM& vm, Value value)
{
VERIFY(!value.is_empty());
if (value.is_symbol())
return PropertyKey { value.as_symbol() };
if (value.is_integral_number() && value.as_double() >= 0 && value.as_double() < NumericLimits<u32>::max())
return static_cast<u32>(value.as_double());
return TRY(value.to_byte_string(vm));
}
PropertyKey() = delete;
template<Integral T>
PropertyKey(T index)
{
// FIXME: Replace this with requires(IsUnsigned<T>)?
// Needs changes in various places using `int` (but not actually being in the negative range)
VERIFY(index >= 0);
if constexpr (NumericLimits<T>::max() >= NumericLimits<u32>::max()) {
if (index >= NumericLimits<u32>::max()) {
m_string = ByteString::number(index);
m_type = Type::String;
m_string_may_be_number = false;
return;
}
}
m_type = Type::Number;
m_number = index;
}
PropertyKey(char const* chars)
: m_type(Type::String)
, m_string(DeprecatedFlyString(chars))
{
}
PropertyKey(ByteString const& string)
: m_type(Type::String)
, m_string(DeprecatedFlyString(string))
{
}
PropertyKey(FlyString const& string)
: m_type(Type::String)
, m_string(string.to_deprecated_fly_string())
{
}
PropertyKey(DeprecatedFlyString string, StringMayBeNumber string_may_be_number = StringMayBeNumber::Yes)
: m_string_may_be_number(string_may_be_number == StringMayBeNumber::Yes)
, m_type(Type::String)
, m_string(move(string))
{
}
PropertyKey(GC::Ref<Symbol> symbol)
: m_type(Type::Symbol)
, m_symbol(symbol)
{
}
PropertyKey(StringOrSymbol const& string_or_symbol)
{
if (string_or_symbol.is_string()) {
m_string = string_or_symbol.as_string();
m_type = Type::String;
} else if (string_or_symbol.is_symbol()) {
m_symbol = const_cast<Symbol*>(string_or_symbol.as_symbol());
m_type = Type::Symbol;
}
}
ALWAYS_INLINE Type type() const { return m_type; }
bool is_number() const
{
if (m_type == Type::Number)
return true;
if (m_type != Type::String || !m_string_may_be_number)
return false;
return const_cast<PropertyKey*>(this)->try_coerce_into_number();
}
bool is_string() const
{
if (m_type != Type::String)
return false;
if (!m_string_may_be_number)
return true;
return !const_cast<PropertyKey*>(this)->try_coerce_into_number();
}
bool is_symbol() const { return m_type == Type::Symbol; }
bool try_coerce_into_number()
{
VERIFY(m_string_may_be_number);
if (m_string.is_empty()) {
m_string_may_be_number = false;
return false;
}
if (char first = m_string.characters()[0]; first < '0' || first > '9') {
m_string_may_be_number = false;
return false;
} else if (m_string.length() > 1 && first == '0') {
m_string_may_be_number = false;
return false;
}
auto property_index = m_string.to_number<unsigned>(TrimWhitespace::No);
if (!property_index.has_value() || property_index.value() == NumericLimits<u32>::max()) {
m_string_may_be_number = false;
return false;
}
m_type = Type::Number;
m_number = *property_index;
return true;
}
u32 as_number() const
{
VERIFY(is_number());
return m_number;
}
DeprecatedFlyString const& as_string() const
{
VERIFY(is_string());
return m_string;
}
Symbol const* as_symbol() const
{
VERIFY(is_symbol());
return m_symbol;
}
ByteString to_string() const
{
VERIFY(!is_symbol());
if (is_string())
return as_string();
return ByteString::number(as_number());
}
StringOrSymbol to_string_or_symbol() const
{
VERIFY(!is_number());
if (is_string())
return StringOrSymbol(as_string());
return StringOrSymbol(as_symbol());
}
private:
bool m_string_may_be_number { true };
Type m_type { Type::Invalid };
u32 m_number { 0 };
DeprecatedFlyString m_string;
GC::Root<Symbol> m_symbol;
};
}
namespace AK {
template<>
struct Traits<JS::PropertyKey> : public DefaultTraits<JS::PropertyKey> {
static unsigned hash(JS::PropertyKey const& name)
{
if (name.is_string())
return name.as_string().hash();
if (name.is_number())
return int_hash(name.as_number());
return ptr_hash(name.as_symbol());
}
static bool equals(JS::PropertyKey const& a, JS::PropertyKey const& b)
{
if (a.type() != b.type())
return false;
switch (a.type()) {
case JS::PropertyKey::Type::Number:
return a.as_number() == b.as_number();
case JS::PropertyKey::Type::String:
return a.as_string() == b.as_string();
case JS::PropertyKey::Type::Symbol:
return a.as_symbol() == b.as_symbol();
default:
VERIFY_NOT_REACHED();
}
}
};
template<>
struct Formatter<JS::PropertyKey> : Formatter<StringView> {
ErrorOr<void> format(FormatBuilder& builder, JS::PropertyKey const& property_key)
{
if (property_key.is_number())
return builder.put_u64(property_key.as_number());
return builder.put_string(property_key.to_string_or_symbol().to_display_string());
}
};
}