Ushio-cn-old/yimian/iot/mqtt/smartfarm/node_modules/levelup/lib/batch.js

/* Copyright (c) 2012-2016 LevelUP contributors
 * See list at <https://github.com/level/levelup#contributing>
 * MIT License
 * <https://github.com/level/levelup/blob/master/LICENSE.md>
 */

var util = require('./util')
var WriteError = require('level-errors').WriteError
var getOptions = util.getOptions
var dispatchError = util.dispatchError

function Batch (levelup, codec) {
  this._levelup = levelup
  this._codec = codec
  this.batch = levelup.db.batch()
  this.ops = []
  this.length = 0
}

Batch.prototype.put = function (key_, value_, options) {
  options = getOptions(options)

  var key = this._codec.encodeKey(key_, options)
  var value = this._codec.encodeValue(value_, options)

  try {
    this.batch.put(key, value)
  } catch (e) {
    throw new WriteError(e)
  }

  this.ops.push({ type: 'put', key: key, value: value })
  this.length++

  return this
}

Batch.prototype.del = function (key_, options) {
  options = getOptions(options)

  var key = this._codec.encodeKey(key_, options)

  try {
    this.batch.del(key)
  } catch (err) {
    throw new WriteError(err)
  }

  this.ops.push({ type: 'del', key: key })
  this.length++

  return this
}

Batch.prototype.clear = function () {
  try {
    this.batch.clear()
  } catch (err) {
    throw new WriteError(err)
  }

  this.ops = []
  this.length = 0

  return this
}

Batch.prototype.write = function (callback) {
  var levelup = this._levelup
  var ops = this.ops

  try {
    this.batch.write(function (err) {
      if (err) { return dispatchError(levelup, new WriteError(err), callback) }
      levelup.emit('batch', ops)
      if (callback) { callback() }
    })
  } catch (err) {
    throw new WriteError(err)
  }
}

module.exports = Batch