bluebird/js/zalgo/promise_spawn.js

Full featured Promises/A+ implementation with exceptionally good performance

/**
 * Copyright (c) 2013 Petka Antonov
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:</p>
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
"use strict";
var Promise = require("./get_promise.js").get();
var errors = require( "./errors.js" );
var TypeError = errors.TypeError;
var ensureNotHandled = errors.ensureNotHandled;
var util = require("./util.js");
var errorObj = util.errorObj;
var tryCatch1 = util.tryCatch1;

function PromiseSpawn( generatorFunction, receiver, caller ) {
    this._resolver = Promise.pending( caller );
    this._generatorFunction = generatorFunction;
    this._receiver = receiver;
    this._generator = void 0;
}

PromiseSpawn.prototype.promise = function PromiseSpawn$promise() {
    return this._resolver.promise;
};

PromiseSpawn.prototype._run = function PromiseSpawn$_run() {
    this._generator = this._generatorFunction.call( this._receiver );
    this._receiver =
        this._generatorFunction = void 0;
    this._next( void 0 );
};

PromiseSpawn.prototype._continue = function PromiseSpawn$_continue( result ) {
    if( result === errorObj ) {
        this._generator = void 0;
        this._resolver.reject( result.e );
        return;
    }

    var value = result.value;
    if( result.done === true ) {
        this._generator = void 0;
        this._resolver.fulfill( value );
    }
    else {
        var maybePromise = Promise._cast( value, PromiseSpawn$_continue );
        if( !( maybePromise instanceof Promise ) ) {
            this._throw( new TypeError(
                "A value was yielded that could not be treated as a promise"
            ) );
            return;
        }
        maybePromise._then(
            this._next,
            this._throw,
            void 0,
            this,
            null,
            void 0
        );
    }
};

PromiseSpawn.prototype._throw = function PromiseSpawn$_throw( reason ) {
    ensureNotHandled( reason );
    this.promise()._attachExtraTrace( reason );
    this._continue(
        tryCatch1( this._generator["throw"], this._generator, reason )
    );
};

PromiseSpawn.prototype._next = function PromiseSpawn$_next( value ) {
    this._continue(
        tryCatch1( this._generator.next, this._generator, value )
    );
};

module.exports = PromiseSpawn;