generators.js
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"use strict";
module.exports = function(Promise,
apiRejection,
INTERNAL,
tryConvertToPromise) {
var errors = require("./errors.js");
var TypeError = errors.TypeError;
var util = require("./util.js");
var errorObj = util.errorObj;
var tryCatch = util.tryCatch;
var yieldHandlers = [];
function promiseFromYieldHandler(value, yieldHandlers, traceParent) {
for (var i = 0; i < yieldHandlers.length; ++i) {
traceParent._pushContext();
var result = tryCatch(yieldHandlers[i])(value);
traceParent._popContext();
if (result === errorObj) {
traceParent._pushContext();
var ret = Promise.reject(errorObj.e);
traceParent._popContext();
return ret;
}
var maybePromise = tryConvertToPromise(result, traceParent);
if (maybePromise instanceof Promise) return maybePromise;
}
return null;
}
function PromiseSpawn(generatorFunction, receiver, yieldHandler, stack) {
var promise = this._promise = new Promise(INTERNAL);
promise._captureStackTrace();
this._stack = stack;
this._generatorFunction = generatorFunction;
this._receiver = receiver;
this._generator = undefined;
this._yieldHandlers = typeof yieldHandler === "function"
? [yieldHandler].concat(yieldHandlers)
: yieldHandlers;
}
PromiseSpawn.prototype.promise = function () {
return this._promise;
};
PromiseSpawn.prototype._run = function () {
this._generator = this._generatorFunction.call(this._receiver);
this._receiver =
this._generatorFunction = undefined;
this._next(undefined);
};
PromiseSpawn.prototype._continue = function (result) {
if (result === errorObj) {
return this._promise._rejectCallback(result.e, false, true);
}
var value = result.value;
if (result.done === true) {
this._promise._resolveCallback(value);
} else {
var maybePromise = tryConvertToPromise(value, this._promise);
if (!(maybePromise instanceof Promise)) {
maybePromise =
promiseFromYieldHandler(maybePromise,
this._yieldHandlers,
this._promise);
if (maybePromise === null) {
this._throw(
new TypeError(
"A value %s was yielded that could not be treated as a promise\u000a\u000a See http://goo.gl/4Y4pDk\u000a\u000a".replace("%s", value) +
"From coroutine:\u000a" +
this._stack.split("\n").slice(1, -7).join("\n")
)
);
return;
}
}
maybePromise._then(
this._next,
this._throw,
undefined,
this,
null
);
}
};
PromiseSpawn.prototype._throw = function (reason) {
this._promise._attachExtraTrace(reason);
this._promise._pushContext();
var result = tryCatch(this._generator["throw"])
.call(this._generator, reason);
this._promise._popContext();
this._continue(result);
};
PromiseSpawn.prototype._next = function (value) {
this._promise._pushContext();
var result = tryCatch(this._generator.next).call(this._generator, value);
this._promise._popContext();
this._continue(result);
};
Promise.coroutine = function (generatorFunction, options) {
if (typeof generatorFunction !== "function") {
throw new TypeError("generatorFunction must be a function\u000a\u000a See http://goo.gl/6Vqhm0\u000a");
}
var yieldHandler = Object(options).yieldHandler;
var PromiseSpawn$ = PromiseSpawn;
var stack = new Error().stack;
return function () {
var generator = generatorFunction.apply(this, arguments);
var spawn = new PromiseSpawn$(undefined, undefined, yieldHandler,
stack);
spawn._generator = generator;
spawn._next(undefined);
return spawn.promise();
};
};
Promise.coroutine.addYieldHandler = function(fn) {
if (typeof fn !== "function") throw new TypeError("fn must be a function\u000a\u000a See http://goo.gl/916lJJ\u000a");
yieldHandlers.push(fn);
};
Promise.spawn = function (generatorFunction) {
if (typeof generatorFunction !== "function") {
return apiRejection("generatorFunction must be a function\u000a\u000a See http://goo.gl/6Vqhm0\u000a");
}
var spawn = new PromiseSpawn(generatorFunction, this);
var ret = spawn.promise();
spawn._run(Promise.spawn);
return ret;
};
};