DefinePropertyAttributes.h [plain text]
#pragma once
#include <wtf/Optional.h>
#include <wtf/TriState.h>
namespace JSC {
class DefinePropertyAttributes {
public:
static_assert(FalseTriState == 0, "FalseTriState is 0.");
static_assert(TrueTriState == 1, "TrueTriState is 1.");
static_assert(MixedTriState == 2, "MixedTriState is 2.");
static const unsigned ConfigurableShift = 0;
static const unsigned EnumerableShift = 2;
static const unsigned WritableShift = 4;
static const unsigned ValueShift = 6;
static const unsigned GetShift = 7;
static const unsigned SetShift = 8;
DefinePropertyAttributes()
: m_attributes(
(MixedTriState << ConfigurableShift)
| (MixedTriState << EnumerableShift)
| (MixedTriState << WritableShift)
| (0 << ValueShift)
| (0 << GetShift)
| (0 << SetShift))
{
}
explicit DefinePropertyAttributes(unsigned attributes)
: m_attributes(attributes)
{
}
unsigned rawRepresentation() const
{
return m_attributes;
}
bool hasValue() const
{
return m_attributes & (0b1 << ValueShift);
}
void setValue()
{
m_attributes = m_attributes | (0b1 << ValueShift);
}
bool hasGet() const
{
return m_attributes & (0b1 << GetShift);
}
void setGet()
{
m_attributes = m_attributes | (0b1 << GetShift);
}
bool hasSet() const
{
return m_attributes & (0b1 << SetShift);
}
void setSet()
{
m_attributes = m_attributes | (0b1 << SetShift);
}
bool hasWritable() const
{
return extractTriState(WritableShift) != MixedTriState;
}
Optional<bool> writable() const
{
if (!hasWritable())
return WTF::nullopt;
return extractTriState(WritableShift) == TrueTriState;
}
bool hasConfigurable() const
{
return extractTriState(ConfigurableShift) != MixedTriState;
}
Optional<bool> configurable() const
{
if (!hasConfigurable())
return WTF::nullopt;
return extractTriState(ConfigurableShift) == TrueTriState;
}
bool hasEnumerable() const
{
return extractTriState(EnumerableShift) != MixedTriState;
}
Optional<bool> enumerable() const
{
if (!hasEnumerable())
return WTF::nullopt;
return extractTriState(EnumerableShift) == TrueTriState;
}
void setWritable(bool value)
{
fillWithTriState(value ? TrueTriState : FalseTriState, WritableShift);
}
void setConfigurable(bool value)
{
fillWithTriState(value ? TrueTriState : FalseTriState, ConfigurableShift);
}
void setEnumerable(bool value)
{
fillWithTriState(value ? TrueTriState : FalseTriState, EnumerableShift);
}
private:
void fillWithTriState(TriState state, unsigned shift)
{
unsigned mask = 0b11 << shift;
m_attributes = (m_attributes & ~mask) | (state << shift);
}
TriState extractTriState(unsigned shift) const
{
return static_cast<TriState>((m_attributes >> shift) & 0b11);
}
unsigned m_attributes;
};
}