time-to-botec/js/node_modules/@stdlib/streams/node/split/lib/main.js

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/**
* @license Apache-2.0
*
* Copyright (c) 2018 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
'use strict';
// MODULES //
var Transform = require( 'readable-stream' ).Transform;
var copy = require( '@stdlib/utils/copy' );
var inherit = require( '@stdlib/utils/inherit' );
var setNonEnumerable = require( '@stdlib/utils/define-nonenumerable-property' );
var setNonEnumerableReadOnly = require( '@stdlib/utils/define-nonenumerable-read-only-property' );
var Buffer = require( '@stdlib/buffer/ctor' );
var nextTick = require( '@stdlib/utils/next-tick' );
var DEFAULTS = require( './defaults.json' );
var validate = require( './validate.js' );
var debug = require( './debug.js' );
var decode = require( './decode.js' );
// VARIABLES //
var RE = /\r?\n/;
// FUNCTIONS //
/**
* Implements the `_transform` method.
*
* @private
* @param {(Uint8Array|Buffer|string)} chunk - streamed chunk
* @param {string} encoding - Buffer encoding
* @param {Callback} clbk - callback to invoke after transforming the streamed chunk
*/
function transform( chunk, encoding, clbk ) {
/* eslint-disable no-invalid-this */
var splits;
var split;
var len;
var i;
this._idx += 1;
debug( 'Received a new chunk. Chunk: %s. Encoding: %s. Index: %d.', chunk.toString(), encoding, this._idx );
if ( encoding === 'buffer' ) {
// Default Buffer decoding is 'utf8':
chunk = chunk.toString();
}
else if ( encoding !== 'utf8' ) {
// Decode the chunk as a 'utf8' string...
chunk = new Buffer( chunk, encoding ); // eslint-disable-line no-buffer-constructor
chunk = chunk.toString( 'utf8' );
}
// Split the chunk:
splits = chunk.split( this._sep );
debug( 'Splits: %s. Index: %d.', JSON.stringify( splits ), this._idx );
// How many splits do we have? We do not count the last "split", as it may be incomplete...
len = splits.length - 1;
debug( '%s splits. Index: %d.', len, this._idx );
// If we do not have any splits, add the chunk to the buffer and wait for more data...
if ( len === 0 ) {
debug( 'No splits. Index: %d.', this._idx );
this._buffer += splits[ len ];
}
// If we have split data, concat any previous partial split, re-decode (if need be) each split according to its original encoding, push each split to the destination, and set anything leftover as the new split buffer...
else {
debug( 'Processing splits. Index: %d.', this._index );
split = this._buffer + splits[ 0 ];
split = decode( split, encoding );
debug( 'Split %d: %s. Index: %d.', 0, split.toString(), this._idx );
this.push( split, encoding );
for ( i = 1; i < len; i++ ) {
split = decode( splits[ i ], encoding );
debug( 'Split %d: %s. Index: %d.', i, split.toString(), this._idx );
this.push( split, encoding );
}
debug( 'Remaining split: %s.', splits[len].toString() );
this._buffer = splits[ len ];
}
clbk();
/* eslint-enable no-invalid-this */
}
/**
* Implements the `_flush` method.
*
* @private
* @param {Callback} clbk - callback to invoke after any final processing
*/
function flush( clbk ) {
/* eslint-disable no-invalid-this */
var split = this._buffer;
if ( split ) {
debug( 'Processing final split...' );
split = decode( split, this._encoding );
this.push( split, this._encoding );
}
debug( 'Flushing the stream...' );
clbk();
/* eslint-enable no-invalid-this */
}
/**
* Gracefully destroys a stream, providing backward compatibility.
*
* @private
* @param {Object} [error] - optional error message
* @returns {SplitStream} Stream instance
*/
function destroy( error ) {
/* eslint-disable no-invalid-this */
var self;
if ( this._destroyed ) {
debug( 'Attempted to destroy an already destroyed stream.' );
return this;
}
self = this;
this._destroyed = true;
nextTick( close );
return this;
/**
* Closes a stream.
*
* @private
*/
function close() {
if ( error ) {
debug( 'Stream was destroyed due to an error. Error: %s.', JSON.stringify( error ) );
self.emit( 'error', error );
}
debug( 'Closing the stream...' );
self.emit( 'close' );
}
/* eslint-enable no-invalid-this */
}
// MAIN //
/**
* Split stream constructor.
*
* @constructor
* @param {Options} [options] - stream options
* @param {(string|RegExp)} [options.sep=/\r?\n/] - separator used to split streamed data
* @param {boolean} [options.objectMode=false] - specifies whether a stream should operate in object mode
* @param {(string|null)} [options.encoding=null] - specifies how `Buffer` objects should be decoded to `strings`
* @param {NonNegativeNumber} [options.highWaterMark] - specifies the `Buffer` level for when `write()` starts returning `false`
* @param {boolean} [options.allowHalfOpen=false] - specifies whether the stream should remain open even if one side ends
* @param {boolean} [options.writableObjectMode=false] - specifies whether the writable side should be in object mode
* @returns {SplitStream} split stream
*
* @example
* var stream = new SplitStream();
*
* stream.write( '1\n2\n3' );
* stream.end();
*/
function SplitStream( options ) {
var opts;
var err;
if ( !( this instanceof SplitStream ) ) {
if ( arguments.length ) {
return new SplitStream( options );
}
return new SplitStream();
}
opts = copy( DEFAULTS );
if ( arguments.length ) {
err = validate( opts, options );
if ( err ) {
throw err;
}
}
// The stream's readable state should always be in object mode to prevent split data from being buffered (concatenated) and no longer being separated...
opts.readableObjectMode = true;
// The stream converts each chunk into a string so no need to encode strings written to the split stream as Buffer objects:
opts.decodeStrings = false;
// Make the stream a Transform stream:
debug( 'Creating a transform stream configured with the following options: %s.', JSON.stringify( opts ) );
Transform.call( this, opts );
// Cache the separator:
setNonEnumerableReadOnly( this, '_sep', ( opts.sep === null ) ? RE : opts.sep );
// The destruction state:
setNonEnumerable( this, '_destroyed', false );
// Cache the encoding:
setNonEnumerableReadOnly( this, '_encoding', opts.encoding );
// Buffer for storing partial splits:
setNonEnumerable( this, '_buffer', '' );
// Chunk counter:
setNonEnumerable( this, '_idx', -1 );
return this;
}
/*
* Inherit from the `Transform` prototype.
*/
inherit( SplitStream, Transform );
/**
* Implements the `_transform` method.
*
* @private
* @name _transform
* @memberof SplitStream.prototype
* @type {Function}
* @param {(Buffer|string)} chunk - streamed chunk
* @param {string} encoding - Buffer encoding
* @param {Callback} clbk - callback to invoke after transforming the streamed chunk
*/
setNonEnumerableReadOnly( SplitStream.prototype, '_transform', transform );
/**
* Implements the `_flush` method.
*
* @private
* @name _flush
* @memberof SplitStream.prototype
* @type {Function}
* @param {Callback} clbk - callback to invoke after any final processing
*/
setNonEnumerableReadOnly( SplitStream.prototype, '_flush', flush );
/**
* Gracefully destroys a stream, providing backward compatibility.
*
* @name destroy
* @memberof SplitStream.prototype
* @type {Function}
* @param {Object} [error] - optional error message
* @returns {SplitStream} Stream instance
*/
setNonEnumerableReadOnly( SplitStream.prototype, 'destroy', destroy );
// EXPORTS //
module.exports = SplitStream;