mirror of https://github.com/seald/nedb
parent
631d672af8
commit
ec5f3ffb13
@ -0,0 +1,157 @@ |
||||
// Forked from https://github.com/jahewson/node-byline
|
||||
|
||||
// Copyright (C) 2011-2015 John Hewson
|
||||
//
|
||||
// Permission is hereby granted, free of charge, to any person obtaining a copy
|
||||
// of this software and associated documentation files (the "Software"), to
|
||||
// deal in the Software without restriction, including without limitation the
|
||||
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
|
||||
// sell copies of the Software, and to permit persons to whom the Software is
|
||||
// furnished to do so, subject to the following conditions:
|
||||
//
|
||||
// The above copyright notice and this permission notice shall be included in
|
||||
// all copies or substantial portions of the Software.
|
||||
//
|
||||
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
||||
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
||||
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
||||
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
||||
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
|
||||
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
|
||||
// IN THE SOFTWARE.
|
||||
|
||||
var stream = require('stream'), |
||||
util = require('util'), |
||||
timers = require('timers'); |
||||
|
||||
// convinience API
|
||||
module.exports = function(readStream, options) { |
||||
return module.exports.createStream(readStream, options); |
||||
}; |
||||
|
||||
// basic API
|
||||
module.exports.createStream = function(readStream, options) { |
||||
if (readStream) { |
||||
return createLineStream(readStream, options); |
||||
} else { |
||||
return new LineStream(options); |
||||
} |
||||
}; |
||||
|
||||
// deprecated API
|
||||
module.exports.createLineStream = function(readStream) { |
||||
console.log('WARNING: byline#createLineStream is deprecated and will be removed soon'); |
||||
return createLineStream(readStream); |
||||
}; |
||||
|
||||
function createLineStream(readStream, options) { |
||||
if (!readStream) { |
||||
throw new Error('expected readStream'); |
||||
} |
||||
if (!readStream.readable) { |
||||
throw new Error('readStream must be readable'); |
||||
} |
||||
var ls = new LineStream(options); |
||||
readStream.pipe(ls); |
||||
return ls; |
||||
} |
||||
|
||||
//
|
||||
// using the new node v0.10 "streams2" API
|
||||
//
|
||||
|
||||
module.exports.LineStream = LineStream; |
||||
|
||||
function LineStream(options) { |
||||
stream.Transform.call(this, options); |
||||
options = options || {}; |
||||
|
||||
// use objectMode to stop the output from being buffered
|
||||
// which re-concatanates the lines, just without newlines.
|
||||
this._readableState.objectMode = true; |
||||
this._lineBuffer = []; |
||||
this._keepEmptyLines = options.keepEmptyLines || false; |
||||
this._lastChunkEndedWithCR = false; |
||||
|
||||
// take the source's encoding if we don't have one
|
||||
var self = this; |
||||
this.on('pipe', function(src) { |
||||
if (!self.encoding) { |
||||
// but we can't do this for old-style streams
|
||||
if (src instanceof stream.Readable) { |
||||
self.encoding = src._readableState.encoding; |
||||
} |
||||
} |
||||
}); |
||||
} |
||||
util.inherits(LineStream, stream.Transform); |
||||
|
||||
LineStream.prototype._transform = function(chunk, encoding, done) { |
||||
// decode binary chunks as UTF-8
|
||||
encoding = encoding || 'utf8'; |
||||
|
||||
if (Buffer.isBuffer(chunk)) { |
||||
if (encoding == 'buffer') { |
||||
chunk = chunk.toString(); // utf8
|
||||
encoding = 'utf8'; |
||||
} |
||||
else { |
||||
chunk = chunk.toString(encoding); |
||||
} |
||||
} |
||||
this._chunkEncoding = encoding; |
||||
|
||||
// see: http://www.unicode.org/reports/tr18/#Line_Boundaries
|
||||
var lines = chunk.split(/\r\n|[\n\v\f\r\x85\u2028\u2029]/g); |
||||
|
||||
// don't split CRLF which spans chunks
|
||||
if (this._lastChunkEndedWithCR && chunk[0] == '\n') { |
||||
lines.shift(); |
||||
} |
||||
|
||||
if (this._lineBuffer.length > 0) { |
||||
this._lineBuffer[this._lineBuffer.length - 1] += lines[0]; |
||||
lines.shift(); |
||||
} |
||||
|
||||
this._lastChunkEndedWithCR = chunk[chunk.length - 1] == '\r'; |
||||
this._lineBuffer = this._lineBuffer.concat(lines); |
||||
this._pushBuffer(encoding, 1, done); |
||||
}; |
||||
|
||||
LineStream.prototype._pushBuffer = function(encoding, keep, done) { |
||||
// always buffer the last (possibly partial) line
|
||||
while (this._lineBuffer.length > keep) { |
||||
var line = this._lineBuffer.shift(); |
||||
// skip empty lines
|
||||
if (this._keepEmptyLines || line.length > 0 ) { |
||||
if (!this.push(this._reencode(line, encoding))) { |
||||
// when the high-water mark is reached, defer pushes until the next tick
|
||||
var self = this; |
||||
timers.setImmediate(function() { |
||||
self._pushBuffer(encoding, keep, done); |
||||
}); |
||||
return; |
||||
} |
||||
} |
||||
} |
||||
done(); |
||||
}; |
||||
|
||||
LineStream.prototype._flush = function(done) { |
||||
this._pushBuffer(this._chunkEncoding, 0, done); |
||||
}; |
||||
|
||||
// see Readable::push
|
||||
LineStream.prototype._reencode = function(line, chunkEncoding) { |
||||
if (this.encoding && this.encoding != chunkEncoding) { |
||||
return new Buffer(line, chunkEncoding).toString(this.encoding); |
||||
} |
||||
else if (this.encoding) { |
||||
// this should be the most common case, i.e. we're using an encoded source stream
|
||||
return line; |
||||
} |
||||
else { |
||||
return new Buffer(line, chunkEncoding); |
||||
} |
||||
}; |
Loading…
Reference in new issue