| // Copyright 2017 The Cobalt Authors. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #ifndef COBALT_SCRIPT_PROMISE_H_ |
| #define COBALT_SCRIPT_PROMISE_H_ |
| |
| #include "base/memory/ref_counted.h" |
| #include "cobalt/script/exception_message.h" |
| #include "cobalt/script/script_exception.h" |
| #include "cobalt/script/script_value.h" |
| |
| namespace cobalt { |
| namespace script { |
| |
| // TODO: Just use JavaScript undefined once abstracted JavaScript values are |
| // exposed to code outside of engine specific script implementations. |
| struct PromiseResultUndefined {}; |
| |
| // See [[PromiseState]] in |
| // https://tc39.github.io/ecma262/#sec-properties-of-promise-instances |
| enum class PromiseState { |
| kPending, |
| kFulfilled, |
| kRejected, |
| }; |
| |
| // Interface for interacting with a JavaScript Promise object that is resolved |
| // or rejected from native code. |
| template <typename T> |
| class Promise { |
| public: |
| // Call the |resolve| function that was passed as an argument to the Promise's |
| // executor function supplying |result| as its argument. |
| virtual void Resolve(const T& result) const { NOTREACHED(); } |
| |
| // Call the |reject| function passed as an argument to the Promise's executor |
| // function. |
| virtual void Reject() const { NOTREACHED(); } |
| virtual void Reject(SimpleExceptionType exception) const { NOTREACHED(); } |
| virtual void Reject(const scoped_refptr<ScriptException>& result) const { |
| NOTREACHED(); |
| } |
| |
| // Returns the value of the [[PromiseState]] field. |
| virtual PromiseState State() const { |
| NOTREACHED(); |
| return PromiseState::kRejected; |
| } |
| |
| virtual ~Promise() {} |
| }; |
| |
| // A convenience specialization in order to facilitate not having to |
| // explicitly pass in |PromiseResultUndefined| when resolving a |Promise| with |
| // no value. |
| template <> |
| class Promise<void> : public Promise<PromiseResultUndefined> { |
| public: |
| using Promise<PromiseResultUndefined>::Resolve; |
| |
| void Resolve() const { Resolve(PromiseResultUndefined()); } |
| }; |
| |
| #if !defined(COBALT_BUILD_TYPE_GOLD) |
| |
| inline std::ostream& operator<<(std::ostream& os, const PromiseState state) { |
| switch (state) { |
| case PromiseState::kFulfilled: |
| os << "Fulfilled"; |
| return os; |
| case PromiseState::kPending: |
| os << "Pending"; |
| return os; |
| case PromiseState::kRejected: |
| os << "Rejected"; |
| return os; |
| } |
| DCHECK(false); |
| os << "Unknown promise state"; |
| return os; |
| } |
| |
| #endif // !defined(COBALT_BUILD_TYPE_GOLD) |
| |
| } // namespace script |
| } // namespace cobalt |
| |
| #endif // COBALT_SCRIPT_PROMISE_H_ |