1 // Copyright Joyent, Inc. and other Node contributors.
3 // Permission is hereby granted, free of charge, to any person obtaining a
4 // copy of this software and associated documentation files (the
5 // "Software"), to deal in the Software without restriction, including
6 // without limitation the rights to use, copy, modify, merge, publish,
7 // distribute, sublicense, and/or sell copies of the Software, and to permit
8 // persons to whom the Software is furnished to do so, subject to the
9 // following conditions:
11 // The above copyright notice and this permission notice shall be included
12 // in all copies or substantial portions of the Software.
14 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
15 // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
16 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
17 // NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
18 // DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
19 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
20 // USE OR OTHER DEALINGS IN THE SOFTWARE.
22 // a duplex stream is just a stream that is both readable and writable.
23 // Since JS doesn't have multiple prototypal inheritance, this class
24 // prototypally inherits from Readable, and then parasitically from
27 module.exports = Duplex;
30 var objectKeys = Object.keys || function (obj) {
32 for (var key in obj) keys.push(key);
39 var util = require('core-util-is');
40 util.inherits = require('inherits');
43 var Readable = require('./_stream_readable');
44 var Writable = require('./_stream_writable');
46 util.inherits(Duplex, Readable);
48 forEach(objectKeys(Writable.prototype), function(method) {
49 if (!Duplex.prototype[method])
50 Duplex.prototype[method] = Writable.prototype[method];
53 function Duplex(options) {
54 if (!(this instanceof Duplex))
55 return new Duplex(options);
57 Readable.call(this, options);
58 Writable.call(this, options);
60 if (options && options.readable === false)
61 this.readable = false;
63 if (options && options.writable === false)
64 this.writable = false;
66 this.allowHalfOpen = true;
67 if (options && options.allowHalfOpen === false)
68 this.allowHalfOpen = false;
70 this.once('end', onend);
73 // the no-half-open enforcer
75 // if we allow half-open state, or if the writable side ended,
77 if (this.allowHalfOpen || this._writableState.ended)
80 // no more data can be written.
81 // But allow more writes to happen in this tick.
82 process.nextTick(this.end.bind(this));
85 function forEach (xs, f) {
86 for (var i = 0, l = xs.length; i < l; i++) {