mirror of https://github.com/nodejs/node.git
69 lines
1.6 KiB
JavaScript
69 lines
1.6 KiB
JavaScript
// a duplex stream is just a stream that is both readable and writable.
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// Since JS doesn't have multiple prototypal inheritance, this class
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// prototypally inherits from Readable, and then parasitically from
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// Writable.
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module.exports = Duplex;
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/*<replacement>*/
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var objectKeys = Object.keys || function (obj) {
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var keys = [];
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for (var key in obj) keys.push(key);
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return keys;
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}
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/*</replacement>*/
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/*<replacement>*/
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var util = require('core-util-is');
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util.inherits = require('inherits');
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/*</replacement>*/
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var Readable = require('./_stream_readable');
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var Writable = require('./_stream_writable');
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util.inherits(Duplex, Readable);
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forEach(objectKeys(Writable.prototype), function(method) {
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if (!Duplex.prototype[method])
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Duplex.prototype[method] = Writable.prototype[method];
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});
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function Duplex(options) {
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if (!(this instanceof Duplex))
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return new Duplex(options);
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Readable.call(this, options);
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Writable.call(this, options);
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if (options && options.readable === false)
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this.readable = false;
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if (options && options.writable === false)
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this.writable = false;
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this.allowHalfOpen = true;
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if (options && options.allowHalfOpen === false)
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this.allowHalfOpen = false;
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this.once('end', onend);
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}
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// the no-half-open enforcer
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function onend() {
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// if we allow half-open state, or if the writable side ended,
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// then we're ok.
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if (this.allowHalfOpen || this._writableState.ended)
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return;
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// no more data can be written.
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// But allow more writes to happen in this tick.
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process.nextTick(this.end.bind(this));
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}
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function forEach (xs, f) {
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for (var i = 0, l = xs.length; i < l; i++) {
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f(xs[i], i);
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}
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}
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