bitwig-nks-preview-generator/lib/gulp-plugin-wrapper.js

Streaming convert NKSF files to preview audio with using Bitwig Studio.

const through = require('through2'),
      chalk = require('chalk'),
      PluginError = require('plugin-error'),
      log = require('../lib/logger')('gulp-plugin-wrapper')

class PluginProcessingError extends PluginError {
  /**
   * Constructor.
   * @param {String} plugin - Plugin name
   * @param {Error} causedBy - Base error
   * @param {VnylFile} file -  VinylFile
   * @param {boolean} stop -  stop processing
   * @param {Object} options - options for PluginErro
   */
  constructor(pluginName = '(unnamed)', causedBy, file, stop, options) {
    super(pluginName, `Failed processing file: "${file.basename}"`,
      Object.assign({
        showStack: true,
        showProperties: true
      }, options))
    this.file = file.path
    this.srcFile = file.history[0]
    this.causedBy = causedBy
    this.stop = stop
    this.name = 'Gulp Plugin Error'
  }
};

class PluginDiscardFile extends PluginError {
  /**
   * Constructor.
   * @param {String} plugin - Plugin name
   * @param {String} reason - Base error
   * @param {VnylFile} file -  VinylFile
   * @param {Object} options - options for PluginError
   */
  constructor(pluginName, reason, file, options) {
    super(pluginName, `Discard processing file: "${file.basename}" reason: ${reason}`,
      Object.assign({
        showStack: false,
        showProperties: false
      }, options))
    this.reason = reason
    this.file = file.path
    this.srcFile = file.history[0]
    this.name = 'Gulp Plugin Notice'
  }
};

/**
 * Gulp plugin wrapper.
 * @param {Stirng} pluginName - gulp plugin name
 * @param {function} processor - function to process file
 * @param {Object} options - options for processor
 * @param {Object} throughOpts - options for throught2.obj
 * @return {Stream} - through2.obj() stream
 */
function plugin(pluginName, processor, options, throughOpts) {
  const stream = through.obj(function(file, enc, cb) {
    const ctx = this
    const onError = (err) => {
      const wrappedError = new PluginProcessingError(
        pluginName, err, file,
        !(options && options.skipError)) // stop
      if (options && options.skipError) {
        // continue processing
        ctx.emit('error', wrappedError)
        cb()
      } else {
        // stop
        cb(wrappedError)
        ctx.emit('end')
      }
      log.error(chalk.redBright.bold(`[${pluginName}]`), wrappedError)
    }
    const onComplete = (discardReason) => {
      if (discardReason) {
        const wrappedError = new PluginDiscardFile(pluginName, discardReason, file)
        // discard file from stream.
        ctx.emit('error', wrappedError)
        cb()
        log.info(chalk.yellowBright.bold(`[${pluginName}]`), wrappedError)
      } else {
        cb(undefined, file)
      }
    }
    let result
    try {
      result = processor(file, options)
    } catch (err) {
      onError(err)
      return
    }
    // Promise ?
    if (result && typeof result.then === 'function') {
      result.then(onComplete, onError)
    } else {
      onComplete(result)
    }
  }, throughOpts)
  // logger
  stream.on('data', (file) => {
    log.info(chalk.greenBright.bold(`[${pluginName}] processing complete.`), file.relative)
  })
  return stream
}

plugin.PluginProcessingError = PluginProcessingError
plugin.PluginDiscardFile = PluginDiscardFile
module.exports = plugin