Source/JavaScriptCore/runtime/JSNativeStdFunction.h

/*
 * Copyright (C) 2015-2022 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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#pragma once

#include <JavaScriptCore/JSFunction.h>

namespace JSC {

class JSGlobalObject;

using NativeStdFunction = WTF::Function<EncodedJSValue(JSGlobalObject*, CallFrame*)>;

class JSNativeStdFunction final : public JSFunction {
public:
    using Base = JSFunction;

    static constexpr unsigned StructureFlags = Base::StructureFlags;
    static constexpr DestructionMode needsDestruction = NeedsDestruction;
    static void destroy(JSCell* cell)
    {
        static_cast<JSNativeStdFunction*>(cell)->JSNativeStdFunction::~JSNativeStdFunction();
    }

    template<typename CellType, SubspaceAccess mode>
    static GCClient::IsoSubspace* subspaceFor(VM& vm)
    {
        return vm.nativeStdFunctionSpace<mode>();
    }

    DECLARE_EXPORT_INFO;

    DECLARE_VISIT_CHILDREN;

    JS_EXPORT_PRIVATE static JSNativeStdFunction* create(VM&, JSGlobalObject*, unsigned length, const String& name, NativeStdFunction&&, Intrinsic = NoIntrinsic, NativeFunction nativeConstructor = callHostFunctionAsConstructor);

    static JSNativeStdFunction* create(VM& vm, JSGlobalObject* globalObject, unsigned length, const String& name, NativeStdFunction&& nativeFunction, auto... captures)
        requires (sizeof...(captures) > 0)
    {
        NativeExecutable* executable = getHostFunction(vm, NoIntrinsic, callHostFunctionAsConstructor, name);
        Structure* structure = globalObject->nativeStdFunctionStructure();
        JSNativeStdFunction* function = new (NotNull, allocateCell<JSNativeStdFunction>(vm)) JSNativeStdFunction(vm, executable, globalObject, structure, WTF::move(nativeFunction), captures...);
        function->finishCreation(vm, executable, length, name);
        return function;
    }

    inline static Structure* createStructure(VM&, JSGlobalObject*, JSValue);

    const NativeStdFunction& function() { return m_function; }

private:
    JSNativeStdFunction(VM& vm, NativeExecutable* executable, JSGlobalObject* globalObject, Structure* structure, NativeStdFunction&& function, auto... captures)
        : Base(vm, executable, globalObject, structure)
        , m_function(WTF::move(function))
        , m_captures { WriteBarrier<Unknown>(vm, this, captures)... }
    {
    }

    JS_EXPORT_PRIVATE void finishCreation(VM&, NativeExecutable*, unsigned length, const String& name);
    JS_EXPORT_PRIVATE static NativeExecutable* getHostFunction(VM&, Intrinsic, NativeFunction, const String& name);

    NativeStdFunction m_function;
    FixedVector<WriteBarrier<Unknown>> m_captures;
};

} // namespace JSC