mirror of
https://github.com/LadybirdBrowser/ladybird
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277551c40f
Add shared helpers for estimating external string and container storage. Use them for symbols, bound function arguments, promise reactions, and promise combinator value lists.
64 lines
1.8 KiB
C++
64 lines
1.8 KiB
C++
/*
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* Copyright (c) 2020, Matthew Olsson <mattco@serenityos.org>
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* Copyright (c) 2022-2023, Linus Groh <linusg@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <LibGC/Heap.h>
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#include <LibJS/Runtime/ExternalMemory.h>
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#include <LibJS/Runtime/Symbol.h>
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#include <LibJS/Runtime/VM.h>
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namespace JS {
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GC_DEFINE_ALLOCATOR(Symbol);
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Symbol::Symbol(Optional<Utf16String> description, bool is_global)
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: m_description(move(description))
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, m_is_global(is_global)
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{
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}
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GC::Ref<Symbol> Symbol::create(VM& vm, Optional<Utf16String> description, bool is_global)
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{
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return vm.heap().allocate<Symbol>(move(description), is_global);
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}
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// 20.4.3.3.1 SymbolDescriptiveString ( sym ), https://tc39.es/ecma262/#sec-symboldescriptivestring
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Utf16String Symbol::descriptive_string() const
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{
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// 1. Let desc be sym's [[Description]] value.
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// 2. If desc is undefined, set desc to the empty String.
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// 3. Assert: desc is a String.
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auto description = m_description.value_or({});
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// 4. Return the string-concatenation of "Symbol(", desc, and ")".
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return Utf16String::formatted("Symbol({})", description);
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}
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// 20.4.5.1 KeyForSymbol ( sym ), https://tc39.es/ecma262/#sec-keyforsymbol
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Optional<Utf16String> Symbol::key() const
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{
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// 1. For each element e of the GlobalSymbolRegistry List, do
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// a. If SameValue(e.[[Symbol]], sym) is true, return e.[[Key]].
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if (m_is_global) {
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// NOTE: Global symbols should always have a description string
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VERIFY(m_description.has_value());
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return m_description;
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}
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// 2. Assert: GlobalSymbolRegistry does not currently contain an entry for sym.
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// 3. Return undefined.
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return {};
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}
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size_t Symbol::external_memory_size() const
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{
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if (!m_description.has_value())
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return 0;
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return utf16_string_external_memory_size(*m_description);
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}
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}
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