137 lines
3.8 KiB
JavaScript
137 lines
3.8 KiB
JavaScript
/**
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* @license Apache-2.0
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*
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* Copyright (c) 2018 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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// MODULES //
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var InspectStream = require( './../../../node/inspect' );
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var isFunction = require( '@stdlib/assert/is-function' );
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var isBuffer = require( '@stdlib/assert/is-buffer' );
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var copy = require( '@stdlib/utils/copy' );
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var inherit = require( '@stdlib/utils/inherit' );
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var debug = require( './debug.js' );
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var DEFAULTS = require( './defaults.json' );
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var NAMESPACE = require( './namespace.js' );
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var validate = require( './validate.js' );
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var logger = require( './logger.js' );
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// MAIN //
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/**
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* Debug stream constructor.
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*
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* @constructor
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* @param {Options} [options] - stream options
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* @param {string} [options.name] - debug namespace
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* @param {boolean} [options.objectMode=false] - specifies whether the stream should operate in object mode
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* @param {NonNegativeNumber} [options.highWaterMark] - specifies the `Buffer` level for when `write()` starts returning `false`
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* @param {boolean} [options.allowHalfOpen=false] - specifies whether the stream should remain open even if one side ends
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* @param {boolean} [options.readableObjectMode=false] - specifies whether the readable side should be in object mode
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* @param {Callback} [clbk] - callback to invoke upon receiving data
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* @throws {TypeError} must provide valid options
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* @throws {TypeError} must a valid callback argument
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* @returns {DebugStream} debug stream
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*
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* @example
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* var stream = new DebugStream({
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* 'name': 'my-stream'
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* });
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*
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* stream.write( 'a' );
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* stream.write( 'b' );
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* stream.write( 'c' );
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* stream.end();
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*/
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function DebugStream( options, clbk ) {
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var opts;
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var name;
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var log;
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var err;
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var cb;
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if ( !(this instanceof DebugStream) ) {
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if ( arguments.length > 1 ) {
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return new DebugStream( options, clbk );
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}
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if ( arguments.length === 1 ) {
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return new DebugStream( options );
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}
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return new DebugStream();
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}
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opts = copy( DEFAULTS );
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if ( arguments.length > 1 ) {
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if ( !isFunction( clbk ) ) {
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throw new TypeError( 'invalid argument. Callback argument must be a function. Value: `' + clbk + '`.' );
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}
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cb = clbk;
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err = validate( opts, options );
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} else if ( arguments.length ) {
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if ( isFunction( options ) ) {
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cb = options;
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} else {
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err = validate( opts, options );
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}
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}
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if ( err ) {
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throw err;
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}
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if ( opts.name ) {
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name = NAMESPACE + ':' + opts.name;
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} else {
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name = NAMESPACE;
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}
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log = logger( name );
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debug( 'Creating a transform stream configured with the following options: %s.', JSON.stringify( opts ) );
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InspectStream.call( this, opts, inspect );
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return this;
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/**
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* Callback invoked upon receiving a new chunk.
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*
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* @private
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* @param {*} chunk - received chunk
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* @param {NonNegativeInteger} idx - chunk index
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* @returns {void}
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*/
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function inspect( chunk, idx ) {
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if ( cb ) {
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debug( 'Received a new chunk. Chunk: %s. Index: %d.', chunk.toString(), idx );
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return cb( log, chunk, idx );
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}
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if ( isBuffer( chunk ) ) {
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chunk = chunk.toString();
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}
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chunk = JSON.stringify( chunk );
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debug( 'Received a new chunk. Chunk: %s. Index: %d.', chunk, idx );
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log( 'Chunk: %s. Index: %d.', chunk, idx );
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}
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}
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/*
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* Inherit from the `InspectStream` prototype.
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*/
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inherit( DebugStream, InspectStream );
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// EXPORTS //
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module.exports = DebugStream;
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