01c2570678
I wanted to do this for a long time. The guts of Promise are pretty complex, and it's easier to understand with the spec right next to it. Also found a couple of issues along the way :^)
64 lines
1.7 KiB
C++
64 lines
1.7 KiB
C++
/*
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* Copyright (c) 2021, 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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#pragma once
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#include <AK/Vector.h>
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#include <LibJS/Runtime/Object.h>
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namespace JS {
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ThrowCompletionOr<Object*> promise_resolve(GlobalObject&, Object& constructor, Value);
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class Promise : public Object {
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JS_OBJECT(Promise, Object);
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public:
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enum class State {
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Pending,
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Fulfilled,
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Rejected,
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};
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enum class RejectionOperation {
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Reject,
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Handle,
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};
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static Promise* create(GlobalObject&);
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explicit Promise(Object& prototype);
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virtual ~Promise() = default;
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State state() const { return m_state; }
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Value result() const { return m_result; }
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struct ResolvingFunctions {
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FunctionObject& resolve;
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FunctionObject& reject;
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};
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ResolvingFunctions create_resolving_functions();
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Value fulfill(Value value);
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Value reject(Value reason);
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Value perform_then(Value on_fulfilled, Value on_rejected, Optional<PromiseCapability> result_capability);
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protected:
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virtual void visit_edges(Visitor&) override;
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private:
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bool is_settled() const { return m_state == State::Fulfilled || m_state == State::Rejected; }
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void trigger_reactions() const;
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// 27.2.6 Properties of Promise Instances, https://tc39.es/ecma262/#sec-properties-of-promise-instances
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State m_state { State::Pending }; // [[PromiseState]]
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Value m_result; // [[PromiseResult]]
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Vector<PromiseReaction*> m_fulfill_reactions; // [[PromiseFulfillReactions]]
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Vector<PromiseReaction*> m_reject_reactions; // [[PromiseRejectReactions]]
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bool m_is_handled { false }; // [[PromiseIsHandled]]
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};
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}
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