mirror of https://github.com/nodejs/node.git
82 lines
2.6 KiB
JavaScript
82 lines
2.6 KiB
JavaScript
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// Copyright Joyent, Inc. and other Node contributors.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a
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// copy of this software and associated documentation files (the
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// "Software"), to deal in the Software without restriction, including
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// without limitation the rights to use, copy, modify, merge, publish,
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// distribute, sublicense, and/or sell copies of the Software, and to permit
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// persons to whom the Software is furnished to do so, subject to the
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// following conditions:
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//
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// The above copyright notice and this permission notice shall be included
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// in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
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// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
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// USE OR OTHER DEALINGS IN THE SOFTWARE.
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// 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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var util = require('util');
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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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Object.keys(Writable.prototype).forEach(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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Readable.call(this, options);
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Writable.call(this, options);
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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('finish', onfinish);
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this.once('end', onend);
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}
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// the no-half-open enforcers.
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function onfinish() {
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// if we allow half-open state, or if the readable side ended,
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// then we're ok.
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if (this.allowHalfOpen || this._readableState.ended)
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return;
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// mark that we're done.
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this._readableState.ended = true;
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// tell the user
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if (this._readableState.length === 0)
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this.emit('end');
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else
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this.emit('readable');
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}
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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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// just in case the user is about to call write() again.
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this.write = function() {
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return false;
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};
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// no more data can be written.
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this.end();
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}
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