/src/serenity/Userland/Libraries/LibJS/Runtime/StringOrSymbol.h

Source
/*
 * Copyright (c) 2020, Matthew Olsson <mattco@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <AK/DeprecatedFlyString.h>
#include <LibJS/Runtime/PrimitiveString.h>
#include <LibJS/Runtime/Symbol.h>
#include <LibJS/Runtime/Value.h>

namespace JS {

class StringOrSymbol {
public:
    StringOrSymbol()
        : m_bits(0)
    {
    }

    StringOrSymbol(char const* chars)
        : StringOrSymbol(DeprecatedFlyString(chars))
    {
    }

    StringOrSymbol(ByteString const& string)
        : StringOrSymbol(DeprecatedFlyString(string))
    {
    }

    StringOrSymbol(DeprecatedFlyString const& string)
        : m_string(string)
    {
    }

    ~StringOrSymbol()
    {
        if (is_string())
            m_string.~DeprecatedFlyString();
    }

    StringOrSymbol(Symbol const* symbol)
        : m_symbol_with_tag(symbol)
    {
        set_symbol_flag();
    }

    StringOrSymbol(StringOrSymbol const& other)
    {
        if (other.is_string())
            new (&m_string) DeprecatedFlyString(other.m_string);
        else
            m_bits = other.m_bits;
    }

    StringOrSymbol(StringOrSymbol&& other)
    {
        if (other.is_string())
            new (&m_string) DeprecatedFlyString(move(other.m_string));
        else
            m_bits = exchange(other.m_bits, 0);
    }

    ALWAYS_INLINE bool is_valid() const { return m_bits != 0; }
    ALWAYS_INLINE bool is_symbol() const { return is_valid() && (m_bits & 2); }
    ALWAYS_INLINE bool is_string() const { return is_valid() && !(m_bits & 2); }

    ALWAYS_INLINE DeprecatedFlyString as_string() const
    {
        VERIFY(is_string());
        return m_string;
    }

    ALWAYS_INLINE Symbol const* as_symbol() const
    {
        VERIFY(is_symbol());
        return reinterpret_cast<Symbol const*>(m_bits & ~2ULL);
    }

    ByteString to_display_string() const
    {
        if (is_string())
            return as_string();
        if (is_symbol())
            return as_symbol()->descriptive_string().release_value_but_fixme_should_propagate_errors().to_byte_string();
        VERIFY_NOT_REACHED();
    }

    Value to_value(VM& vm) const
    {
        if (is_string())
            return PrimitiveString::create(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() && m_string == other.m_string;
        if (is_symbol())
            return other.is_symbol() && as_symbol() == other.as_symbol();
        return true;
    }

    StringOrSymbol& operator=(StringOrSymbol const& other)
    {
        if (this != &other) {
            this->~StringOrSymbol();
            new (this) StringOrSymbol(other);
        }
        return *this;
    }

    StringOrSymbol& operator=(StringOrSymbol&& other)
    {
        if (this != &other) {
            this->~StringOrSymbol();
            new (this) StringOrSymbol(move(other));
        }
        return *this;
    }

    unsigned hash() const
    {
        if (is_string())
            return m_string.hash();
        return ptr_hash(as_symbol());
    }

private:
    ALWAYS_INLINE void set_symbol_flag()
    {
        m_bits |= 2;
    }

    union {
        DeprecatedFlyString m_string;
        Symbol const* m_symbol_with_tag;
        uintptr_t m_bits;
    };
};

static_assert(sizeof(StringOrSymbol) == sizeof(uintptr_t));

}

template<>
struct AK::Traits<JS::StringOrSymbol> : public DefaultTraits<JS::StringOrSymbol> {
    static unsigned hash(JS::StringOrSymbol const& key)
    {
        return key.hash();
    }
};

Line	Count	Source
1		/*
2		* Copyright (c) 2020, Matthew Olsson <mattco@serenityos.org>
3		*
4		* SPDX-License-Identifier: BSD-2-Clause
5		*/
6
7		#pragma once
8
9		#include <AK/DeprecatedFlyString.h>
10		#include <LibJS/Runtime/PrimitiveString.h>
11		#include <LibJS/Runtime/Symbol.h>
12		#include <LibJS/Runtime/Value.h>
13
14		namespace JS {
15
16		class StringOrSymbol {
17		public:
18		StringOrSymbol()
19	1.22k	: m_bits(0)
20	1.22k	{
21	1.22k	}
22
23		StringOrSymbol(char const* chars)
24		: StringOrSymbol(DeprecatedFlyString(chars))
25	0	{
26	0	}
27
28		StringOrSymbol(ByteString const& string)
29		: StringOrSymbol(DeprecatedFlyString(string))
30	0	{
31	0	}
32
33		StringOrSymbol(DeprecatedFlyString const& string)
34	84.5k	: m_string(string)
35	84.5k	{
36	84.5k	}
37
38		~StringOrSymbol()
39	480k	{
40	480k	if (is_string())
41	422k	m_string.~DeprecatedFlyString();
42	480k	}
43
44		StringOrSymbol(Symbol const* symbol)
45	1.30k	: m_symbol_with_tag(symbol)
46	1.30k	{
47	1.30k	set_symbol_flag();
48	1.30k	}
49
50		StringOrSymbol(StringOrSymbol const& other)
51	343k	{
52	343k	if (other.is_string())
53	337k	new (&m_string) DeprecatedFlyString(other.m_string);
54	5.10k	else
55	5.10k	m_bits = other.m_bits;
56	343k	}
57
58		StringOrSymbol(StringOrSymbol&& other)
59	50.4k	{
60	50.4k	if (other.is_string())
61	48.6k	new (&m_string) DeprecatedFlyString(move(other.m_string));
62	1.76k	else
63	1.76k	m_bits = exchange(other.m_bits, 0);
64	50.4k	}
65
66	1.64M	ALWAYS_INLINE bool is_valid() const { return m_bits != 0; }
67	7.23k	ALWAYS_INLINE bool is_symbol() const { return is_valid() && (m_bits & 2); }
68	1.62M	ALWAYS_INLINE bool is_string() const { return is_valid() && !(m_bits & 2); }
69
70		ALWAYS_INLINE DeprecatedFlyString as_string() const
71	0	{
72	0	VERIFY(is_string());
73	0	return m_string;
74	0	}
75
76		ALWAYS_INLINE Symbol const* as_symbol() const
77	5.36k	{
78	5.36k	VERIFY(is_symbol());
79	5.36k	return reinterpret_cast<Symbol const*>(m_bits & ~2ULL);
80	5.36k	}
81
82		ByteString to_display_string() const
83	0	{
84	0	if (is_string())
85	0	return as_string();
86	0	if (is_symbol())
87	0	return as_symbol()->descriptive_string().release_value_but_fixme_should_propagate_errors().to_byte_string();
88	0	VERIFY_NOT_REACHED();
89	0	}
90
91		Value to_value(VM& vm) const
92	0	{
93	0	if (is_string())
94	0	return PrimitiveString::create(vm, as_string());
95	0	if (is_symbol())
96	0	return const_cast<Symbol*>(as_symbol());
97	0	return {};
98	0	}
99
100		void visit_edges(Cell::Visitor& visitor)
101	0	{
102	0	if (is_symbol())
103	0	visitor.visit(const_cast<Symbol*>(as_symbol()));
104	0	}
105
106		ALWAYS_INLINE bool operator==(StringOrSymbol const& other) const
107	184k	{
108	184k	if (is_string())
109	183k	return other.is_string() && m_string == other.m_string;
110	936	if (is_symbol())
111	936	return other.is_symbol() && as_symbol() == other.as_symbol();
112	0	return true;
113	936	}
114
115		StringOrSymbol& operator=(StringOrSymbol const& other)
116	0	{
117	0	if (this != &other) {
118	0	this->~StringOrSymbol();
119	0	new (this) StringOrSymbol(other);
120	0	}
121	0	return *this;
122	0	}
123
124		StringOrSymbol& operator=(StringOrSymbol&& other)
125	0	{
126	0	if (this != &other) {
127	0	this->~StringOrSymbol();
128	0	new (this) StringOrSymbol(move(other));
129	0	}
130	0	return *this;
131	0	}
132
133		unsigned hash() const
134	380k	{
135	380k	if (is_string())
136	375k	return m_string.hash();
137	4.73k	return ptr_hash(as_symbol());
138	380k	}
139
140		private:
141		ALWAYS_INLINE void set_symbol_flag()
142	1.30k	{
143	1.30k	m_bits \|= 2;
144	1.30k	}
145
146		union {
147		DeprecatedFlyString m_string;
148		Symbol const* m_symbol_with_tag;
149		uintptr_t m_bits;
150		};
151		};
152
153		static_assert(sizeof(StringOrSymbol) == sizeof(uintptr_t));
154
155		}
156
157		template<>
158		struct AK::Traits<JS::StringOrSymbol> : public DefaultTraits<JS::StringOrSymbol> {
159		static unsigned hash(JS::StringOrSymbol const& key)
160	380k	{
161	380k	return key.hash();
162	380k	}
163		};

Coverage Report

Created: 2026-10-28 07:05