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95 lines
2.0 KiB
95 lines
2.0 KiB
import AwaitValue from "./AwaitValue.js"; |
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export default function AsyncGenerator(gen) { |
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var front, back; |
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|
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function send(key, arg) { |
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return new Promise(function (resolve, reject) { |
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var request = { |
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key: key, |
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arg: arg, |
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resolve: resolve, |
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reject: reject, |
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next: null |
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}; |
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if (back) { |
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back = back.next = request; |
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} else { |
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front = back = request; |
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resume(key, arg); |
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} |
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}); |
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} |
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function resume(key, arg) { |
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try { |
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var result = gen[key](arg); |
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var value = result.value; |
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var wrappedAwait = value instanceof AwaitValue; |
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Promise.resolve(wrappedAwait ? value.wrapped : value).then(function (arg) { |
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if (wrappedAwait) { |
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resume(key === "return" ? "return" : "next", arg); |
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return; |
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} |
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settle(result.done ? "return" : "normal", arg); |
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}, function (err) { |
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resume("throw", err); |
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}); |
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} catch (err) { |
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settle("throw", err); |
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} |
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} |
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function settle(type, value) { |
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switch (type) { |
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case "return": |
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front.resolve({ |
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value: value, |
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done: true |
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}); |
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break; |
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case "throw": |
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front.reject(value); |
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break; |
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default: |
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front.resolve({ |
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value: value, |
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done: false |
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}); |
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break; |
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} |
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front = front.next; |
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if (front) { |
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resume(front.key, front.arg); |
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} else { |
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back = null; |
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} |
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} |
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this._invoke = send; |
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if (typeof gen["return"] !== "function") { |
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this["return"] = undefined; |
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} |
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} |
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AsyncGenerator.prototype[typeof Symbol === "function" && Symbol.asyncIterator || "@@asyncIterator"] = function () { |
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return this; |
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}; |
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AsyncGenerator.prototype.next = function (arg) { |
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return this._invoke("next", arg); |
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}; |
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AsyncGenerator.prototype["throw"] = function (arg) { |
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return this._invoke("throw", arg); |
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}; |
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AsyncGenerator.prototype["return"] = function (arg) { |
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return this._invoke("return", arg); |
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}; |