Coverage Report

Created: 2026-11-13 08:07

next uncovered line (L), next uncovered region (R), next uncovered branch (B)
/src/serenity/Userland/Libraries/LibJS/Runtime/BoundFunction.cpp
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/*
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 * Copyright (c) 2020, Jack Karamanian <karamanian.jack@gmail.com>
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 * Copyright (c) 2021-2022, 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 <LibJS/Runtime/AbstractOperations.h>
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#include <LibJS/Runtime/BoundFunction.h>
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#include <LibJS/Runtime/GlobalObject.h>
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namespace JS {
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JS_DEFINE_ALLOCATOR(BoundFunction);
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// 10.4.1.3 BoundFunctionCreate ( targetFunction, boundThis, boundArgs ), https://tc39.es/ecma262/#sec-boundfunctioncreate
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ThrowCompletionOr<NonnullGCPtr<BoundFunction>> BoundFunction::create(Realm& realm, FunctionObject& target_function, Value bound_this, Vector<Value> bound_arguments)
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{
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    // 1. Let proto be ? targetFunction.[[GetPrototypeOf]]().
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    auto* prototype = TRY(target_function.internal_get_prototype_of());
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    // 2. Let internalSlotsList be the list-concatenation of « [[Prototype]], [[Extensible]] » and the internal slots listed in Table 34.
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    // 3. Let obj be MakeBasicObject(internalSlotsList).
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    // 4. Set obj.[[Prototype]] to proto.
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    // 5. Set obj.[[Call]] as described in 10.4.1.1.
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    // 6. If IsConstructor(targetFunction) is true, then
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    //    a. Set obj.[[Construct]] as described in 10.4.1.2.
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    // 7. Set obj.[[BoundTargetFunction]] to targetFunction.
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    // 8. Set obj.[[BoundThis]] to boundThis.
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    // 9. Set obj.[[BoundArguments]] to boundArgs.
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    auto object = realm.heap().allocate<BoundFunction>(realm, realm, target_function, bound_this, move(bound_arguments), prototype);
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    // 10. Return obj.
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    return object;
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}
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BoundFunction::BoundFunction(Realm& realm, FunctionObject& bound_target_function, Value bound_this, Vector<Value> bound_arguments, Object* prototype)
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    : FunctionObject(realm, prototype)
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    , m_bound_target_function(&bound_target_function)
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    , m_bound_this(bound_this)
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    , m_bound_arguments(move(bound_arguments))
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    // FIXME: Non-standard and redundant, remove.
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    , m_name(ByteString::formatted("bound {}", bound_target_function.name()))
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{
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}
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// 10.4.1.1 [[Call]] ( thisArgument, argumentsList ), https://tc39.es/ecma262/#sec-bound-function-exotic-objects-call-thisargument-argumentslist
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ThrowCompletionOr<Value> BoundFunction::internal_call([[maybe_unused]] Value this_argument, ReadonlySpan<Value> arguments_list)
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{
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    auto& vm = this->vm();
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    // 1. Let target be F.[[BoundTargetFunction]].
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    auto& target = *m_bound_target_function;
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    // 2. Let boundThis be F.[[BoundThis]].
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    auto bound_this = m_bound_this;
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    // 3. Let boundArgs be F.[[BoundArguments]].
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    auto& bound_args = m_bound_arguments;
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    // 4. Let args be the list-concatenation of boundArgs and argumentsList.
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    Vector<Value> args;
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    args.ensure_capacity(bound_args.size() + arguments_list.size());
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    args.extend(bound_args);
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    args.append(arguments_list.data(), arguments_list.size());
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    // 5. Return ? Call(target, boundThis, args).
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    return call(vm, &target, bound_this, args.span());
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}
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// 10.4.1.2 [[Construct]] ( argumentsList, newTarget ), https://tc39.es/ecma262/#sec-bound-function-exotic-objects-construct-argumentslist-newtarget
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ThrowCompletionOr<NonnullGCPtr<Object>> BoundFunction::internal_construct(ReadonlySpan<Value> arguments_list, FunctionObject& new_target)
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{
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    auto& vm = this->vm();
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    // 1. Let target be F.[[BoundTargetFunction]].
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    auto& target = *m_bound_target_function;
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    // 2. Assert: IsConstructor(target) is true.
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    VERIFY(Value(&target).is_constructor());
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    // 3. Let boundArgs be F.[[BoundArguments]].
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    auto& bound_args = m_bound_arguments;
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    // 4. Let args be the list-concatenation of boundArgs and argumentsList.
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    auto args = MarkedVector<Value> { heap() };
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    args.extend(bound_args);
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    args.append(arguments_list.data(), arguments_list.size());
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    // 5. If SameValue(F, newTarget) is true, set newTarget to target.
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    auto* final_new_target = &new_target;
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    if (this == &new_target)
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        final_new_target = &target;
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    // 6. Return ? Construct(target, args, newTarget).
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    return construct(vm, target, args.span(), final_new_target);
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}
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void BoundFunction::visit_edges(Visitor& visitor)
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{
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    Base::visit_edges(visitor);
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    visitor.visit(m_bound_target_function);
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    visitor.visit(m_bound_this);
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    visitor.visit(m_bound_arguments);
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}
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}