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124 lines
3.3 KiB
124 lines
3.3 KiB
/* |
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Copyright (c) 2014-2018, 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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const { Transform } = require('readable-stream') |
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const { StringDecoder } = require('string_decoder') |
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const kLast = Symbol('last') |
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const kDecoder = Symbol('decoder') |
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function transform (chunk, enc, cb) { |
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var list |
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if (this.overflow) { // Line buffer is full. Skip to start of next line. |
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var buf = this[kDecoder].write(chunk) |
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list = buf.split(this.matcher) |
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if (list.length === 1) return cb() // Line ending not found. Discard entire chunk. |
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// Line ending found. Discard trailing fragment of previous line and reset overflow state. |
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list.shift() |
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this.overflow = false |
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} else { |
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this[kLast] += this[kDecoder].write(chunk) |
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list = this[kLast].split(this.matcher) |
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} |
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this[kLast] = list.pop() |
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for (var i = 0; i < list.length; i++) { |
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push(this, this.mapper(list[i])) |
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} |
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this.overflow = this[kLast].length > this.maxLength |
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if (this.overflow && !this.skipOverflow) return cb(new Error('maximum buffer reached')) |
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cb() |
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} |
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function flush (cb) { |
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// forward any gibberish left in there |
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this[kLast] += this[kDecoder].end() |
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if (this[kLast]) { |
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push(this, this.mapper(this[kLast])) |
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} |
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cb() |
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} |
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function push (self, val) { |
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if (val !== undefined) { |
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self.push(val) |
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} |
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} |
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function noop (incoming) { |
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return incoming |
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} |
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function split (matcher, mapper, options) { |
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// Set defaults for any arguments not supplied. |
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matcher = matcher || /\r?\n/ |
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mapper = mapper || noop |
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options = options || {} |
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// Test arguments explicitly. |
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switch (arguments.length) { |
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case 1: |
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// If mapper is only argument. |
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if (typeof matcher === 'function') { |
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mapper = matcher |
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matcher = /\r?\n/ |
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// If options is only argument. |
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} else if (typeof matcher === 'object' && !(matcher instanceof RegExp)) { |
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options = matcher |
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matcher = /\r?\n/ |
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} |
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break |
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case 2: |
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// If mapper and options are arguments. |
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if (typeof matcher === 'function') { |
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options = mapper |
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mapper = matcher |
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matcher = /\r?\n/ |
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// If matcher and options are arguments. |
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} else if (typeof mapper === 'object') { |
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options = mapper |
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mapper = noop |
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} |
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} |
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options = Object.assign({}, options) |
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options.transform = transform |
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options.flush = flush |
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options.readableObjectMode = true |
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const stream = new Transform(options) |
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stream[kLast] = '' |
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stream[kDecoder] = new StringDecoder('utf8') |
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stream.matcher = matcher |
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stream.mapper = mapper |
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stream.maxLength = options.maxLength |
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stream.skipOverflow = options.skipOverflow |
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stream.overflow = false |
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return stream |
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} |
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module.exports = split
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