158 lines
3.5 KiB
JavaScript
158 lines
3.5 KiB
JavaScript
/*
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Copyright (c) 2014, Matteo Collina <hello@matteocollina.com>
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Permission to use, copy, modify, and/or distribute this software for any
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purpose with or without fee is hereby granted, provided that the above
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copyright notice and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
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IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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'use strict';
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var Duplex = require('readable-stream').Duplex
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, Writable = require('readable-stream').Writable
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, inherits = require('inherits')
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function ReaDuplexer(writable, readable, options) {
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if (!(this instanceof ReaDuplexer))
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return new ReaDuplexer(writable, readable, options)
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this._options = options
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Duplex.call(this, options)
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this.hook(writable, readable)
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this.on('finish', function() {
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if (this._writable)
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this._writable.end()
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})
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this._lastReadCallback = null
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}
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inherits(ReaDuplexer, Duplex)
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function callWrite2Args(chunk, enc, cb) {
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this._writable.write(chunk, enc)
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cb()
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return true
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}
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function callWrite3Args(chunk, enc, cb) {
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return this._writable.write(chunk, enc, cb)
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}
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ReaDuplexer.prototype.hookWritable = function hookWritable(writable) {
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var that = this
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if (this._writable)
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throw new Error('already hooked to a Writable')
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if (!writable)
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throw new Error('missing writable')
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this._writable = writable
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writable.on('drain', function() {
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that.emit('drain')
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})
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writable.on('error', function(err) {
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that.emit('error', err)
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})
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if (this._writable.write.length === 3) {
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this._callWrite = callWrite3Args
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} else {
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this._callWrite = callWrite2Args
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}
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if (this._firstPayload) {
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this._callWrite(
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this._firstPayload.chunk
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, this._firstPayload.enc
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, this._firstPayload.cb)
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delete this._firstPayload
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}
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return this
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}
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ReaDuplexer.prototype.hookReadable = function hookReadable(readable) {
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var that = this
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, dummyWritable = new Writable(this._options)
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if (this._readable)
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throw new Error('already hooked to a Readable')
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if (!readable)
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throw new Error('missing readable')
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this._readable = readable
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dummyWritable._write = function dummyWrite(chunk, enc, cb) {
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if (that.push(chunk, enc))
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cb()
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else
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that._lastReadCallback = cb
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}
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dummyWritable.on('finish', function() {
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that.push(null)
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})
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;[readable, dummyWritable].forEach(function(stream) {
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stream.on('error', function(err) {
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that.emit('error', err)
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})
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})
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readable.pipe(dummyWritable)
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return this
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}
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ReaDuplexer.prototype.hook = function hook(writable, readable) {
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if (writable)
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this.hookWritable(writable)
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if (readable)
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this.hookReadable(readable)
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return this
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}
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ReaDuplexer.prototype._read = function read(n) {
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if (this._lastReadCallback)
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this._lastReadCallback()
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this._lastReadCallback = null
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}
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ReaDuplexer.prototype._callWrite = function nop() {
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throw new Error('hook Writable to use')
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}
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ReaDuplexer.prototype._write = function write(chunk, enc, cb) {
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if (this._writable)
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return this._callWrite(chunk, enc, cb)
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// we are in delayed open
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this._firstPayload = {
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chunk: chunk
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, enc: enc
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, cb: cb
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}
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}
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module.exports = ReaDuplexer
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