Overleaf/services/web/frontend/js/ide/editor/ShareJsDoc.js

/* eslint-disable
    camelcase,
    max-len,
    no-undef,
    no-unused-vars,
*/
// TODO: This file was created by bulk-decaffeinate.
// Fix any style issues and re-enable lint.
/*
 * decaffeinate suggestions:
 * DS001: Remove Babel/TypeScript constructor workaround
 * DS101: Remove unnecessary use of Array.from
 * DS102: Remove unnecessary code created because of implicit returns
 * DS103: Rewrite code to no longer use __guard__
 * DS205: Consider reworking code to avoid use of IIFEs
 * DS206: Consider reworking classes to avoid initClass
 * DS207: Consider shorter variations of null checks
 * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
 */
define(['../../utils/EventEmitter', 'libs/sharejs'], function(
  EventEmitter,
  ShareJs
) {
  let ShareJsDoc
  const SINGLE_USER_FLUSH_DELAY = 1000 // ms

  return (ShareJsDoc = (function() {
    ShareJsDoc = class ShareJsDoc extends EventEmitter {
      static initClass() {
        this.prototype.INFLIGHT_OP_TIMEOUT = 5000 // Retry sending ops after 5 seconds without an ack
        this.prototype.WAIT_FOR_CONNECTION_TIMEOUT = 500

        this.prototype.FATAL_OP_TIMEOUT = 30000
      }
      constructor(doc_id, docLines, version, socket) {
        super()
        // Dencode any binary bits of data
        // See http://ecmanaut.blogspot.co.uk/2006/07/encoding-decoding-utf8-in-javascript.html
        this.doc_id = doc_id
        this.socket = socket
        this.type = 'text'
        docLines = Array.from(docLines).map(line =>
          decodeURIComponent(escape(line))
        )
        const snapshot = docLines.join('\n')
        this.track_changes = false

        this.connection = {
          send: update => {
            this._startInflightOpTimeout(update)
            if (
              window.disconnectOnUpdate != null &&
              Math.random() < window.disconnectOnUpdate
            ) {
              sl_console.log('Disconnecting on update', update)
              window._ide.socket.socket.disconnect()
            }
            if (
              window.dropUpdates != null &&
              Math.random() < window.dropUpdates
            ) {
              sl_console.log('Simulating a lost update', update)
              return
            }
            if (this.track_changes) {
              if (update.meta == null) {
                update.meta = {}
              }
              update.meta.tc = this.track_changes_id_seeds.inflight
            }
            return this.socket.emit(
              'applyOtUpdate',
              this.doc_id,
              update,
              error => {
                if (error != null) {
                  return this._handleError(error)
                }
              }
            )
          },
          state: 'ok',
          id: this.socket.socket.sessionid
        }

        this._doc = new ShareJs.Doc(this.connection, this.doc_id, {
          type: this.type
        })
        this._doc.setFlushDelay(SINGLE_USER_FLUSH_DELAY)
        this._doc.on('change', (...args) => {
          return this.trigger('change', ...Array.from(args))
        })
        this._doc.on('acknowledge', () => {
          this.lastAcked = new Date() // note time of last ack from server for an op we sent
          return this.trigger('acknowledge')
        })
        this._doc.on('remoteop', (...args) => {
          // As soon as we're working with a collaborator, start sending
          // ops as quickly as possible for low latency.
          this._doc.setFlushDelay(0)
          return this.trigger('remoteop', ...Array.from(args))
        })
        this._doc.on('flipped_pending_to_inflight', () => {
          return this.trigger('flipped_pending_to_inflight')
        })
        this._doc.on('saved', () => {
          return this.trigger('saved')
        })
        this._doc.on('error', e => {
          return this._handleError(e)
        })

        this._bindToDocChanges(this._doc)

        this.processUpdateFromServer({
          open: true,
          v: version,
          snapshot
        })
      }

      submitOp(...args) {
        return this._doc.submitOp(...Array.from(args || []))
      }

      // The following code puts out of order messages into a queue
      // so that they can be processed in order.  This is a workaround
      // for messages being delayed by redis cluster.
      // FIXME: REMOVE THIS WHEN REDIS PUBSUB IS SENDING MESSAGES IN ORDER
      _isAheadOfExpectedVersion(message) {
        return this._doc.version > 0 && message.v > this._doc.version
      }

      _pushOntoQueue(message) {
        sl_console.log(`[processUpdate] push onto queue ${message.v}`)
        // set a timer so that we never leave messages in the queue indefinitely
        if (!this.queuedMessageTimer) {
          this.queuedMessageTimer = setTimeout(() => {
            sl_console.log(
              `[processUpdate] queue timeout fired for ${message.v}`
            )
            // force the message to be processed after the timeout,
            // it will cause an error if the missing update has not arrived
            this.processUpdateFromServer(message)
          }, this.INFLIGHT_OP_TIMEOUT)
        }
        this.queuedMessages.push(message)
        // keep the queue in order, lowest version first
        this.queuedMessages.sort(function(a, b) {
          return a.v - b.v
        })
      }

      _clearQueue() {
        this.queuedMessages = []
      }

      _processQueue() {
        if (this.queuedMessages.length > 0) {
          nextAvailableVersion = this.queuedMessages[0].v
          if (nextAvailableVersion > this._doc.version) {
            // there are updates we still can't apply yet
          } else {
            // there's a version we can accept on the queue, apply it
            sl_console.log(
              `[processUpdate] taken from queue ${nextAvailableVersion}`
            )
            this.processUpdateFromServerInOrder(this.queuedMessages.shift())
            // clear the pending timer if the queue has now been cleared
            if (this.queuedMessages.length === 0 && this.queuedMessageTimer) {
              sl_console.log('[processUpdate] queue is empty, cleared timeout')
              clearTimeout(this.queuedMessageTimer)
              this.queuedMessageTimer = null
            }
          }
        }
      }

      // FIXME: This is the new method which reorders incoming updates if needed
      // called from Document.js
      processUpdateFromServerInOrder(message) {
        // Create an array to hold queued messages
        if (!this.queuedMessages) {
          this.queuedMessages = []
        }
        // Is this update ahead of the next expected update?
        // If so, put it on a queue to be handled later.
        if (this._isAheadOfExpectedVersion(message)) {
          this._pushOntoQueue(message)
          return // defer processing this update for now
        }
        var error = this.processUpdateFromServer(message)
        if (
          error instanceof Error &&
          error.message === 'Invalid version from server'
        ) {
          // if there was an error, abandon the queued updates ahead of this one
          this._clearQueue()
          return
        }
        // Do we have any messages queued up?
        // find the next message if available
        this._processQueue()
      }

      // FIXME: This is the original method. Switch back to this when redis
      // issues are resolved.
      processUpdateFromServer(message) {
        try {
          this._doc._onMessage(message)
        } catch (error) {
          // Version mismatches are thrown as errors
          console.log(error)
          this._handleError(error)
          return error // return the error for queue handling
        }

        if (
          __guard__(message != null ? message.meta : undefined, x => x.type) ===
          'external'
        ) {
          return this.trigger('externalUpdate', message)
        }
      }

      catchUp(updates) {
        return (() => {
          const result = []
          for (let i = 0; i < updates.length; i++) {
            const update = updates[i]
            update.v = this._doc.version
            update.doc = this.doc_id
            result.push(this.processUpdateFromServer(update))
          }
          return result
        })()
      }

      getSnapshot() {
        return this._doc.snapshot
      }
      getVersion() {
        return this._doc.version
      }
      getType() {
        return this.type
      }

      clearInflightAndPendingOps() {
        this._doc.inflightOp = null
        this._doc.inflightCallbacks = []
        this._doc.pendingOp = null
        return (this._doc.pendingCallbacks = [])
      }

      flushPendingOps() {
        // This will flush any ops that are pending.
        // If there is an inflight op it will do nothing.
        return this._doc.flush()
      }

      updateConnectionState(state) {
        sl_console.log(`[updateConnectionState] Setting state to ${state}`)
        this.connection.state = state
        this.connection.id = this.socket.socket.sessionid
        this._doc.autoOpen = false
        this._doc._connectionStateChanged(state)
        return (this.lastAcked = null) // reset the last ack time when connection changes
      }

      hasBufferedOps() {
        return this._doc.inflightOp != null || this._doc.pendingOp != null
      }

      getInflightOp() {
        return this._doc.inflightOp
      }
      getPendingOp() {
        return this._doc.pendingOp
      }
      getRecentAck() {
        // check if we have received an ack recently (within a factor of two of the single user flush delay)
        return (
          this.lastAcked != null &&
          new Date() - this.lastAcked < 2 * SINGLE_USER_FLUSH_DELAY
        )
      }
      getOpSize(op) {
        // compute size of an op from its components
        // (total number of characters inserted and deleted)
        let size = 0
        for (let component of Array.from(op || [])) {
          if ((component != null ? component.i : undefined) != null) {
            size += component.i.length
          }
          if ((component != null ? component.d : undefined) != null) {
            size += component.d.length
          }
        }
        return size
      }

      attachToAce(ace) {
        return this._doc.attach_ace(ace, false, window.maxDocLength)
      }
      detachFromAce() {
        return typeof this._doc.detach_ace === 'function'
          ? this._doc.detach_ace()
          : undefined
      }

      attachToCM(cm) {
        return this._doc.attach_cm(cm, false)
      }
      detachFromCM() {
        return typeof this._doc.detach_cm === 'function'
          ? this._doc.detach_cm()
          : undefined
      } // If we're waiting for the project to join, try again in 0.5 seconds
      _startInflightOpTimeout(update) {
        this._startFatalTimeoutTimer(update)
        var retryOp = () => {
          // Only send the update again if inflightOp is still populated
          // This can be cleared when hard reloading the document in which
          // case we don't want to keep trying to send it.
          sl_console.log('[inflightOpTimeout] Trying op again')
          if (this._doc.inflightOp != null) {
            // When there is a socket.io disconnect, @_doc.inflightSubmittedIds
            // is updated with the socket.io client id of the current op in flight
            // (meta.source of the op).
            // @connection.id is the client id of the current socket.io session.
            // So we need both depending on whether the op was submitted before
            // one or more disconnects, or if it was submitted during the current session.
            update.dupIfSource = [
              this.connection.id,
              ...Array.from(this._doc.inflightSubmittedIds)
            ]

            // We must be joined to a project for applyOtUpdate to work on the real-time
            // service, so don't send an op if we're not. Connection state is set to 'ok'
            // when we've joined the project
            if (this.connection.state !== 'ok') {
              let timer
              sl_console.log(
                '[inflightOpTimeout] Not connected, retrying in 0.5s'
              )
              return (timer = setTimeout(
                retryOp,
                this.WAIT_FOR_CONNECTION_TIMEOUT
              ))
            } else {
              sl_console.log('[inflightOpTimeout] Sending')
              return this.connection.send(update)
            }
          }
        }

        const timer = setTimeout(retryOp, this.INFLIGHT_OP_TIMEOUT)
        return this._doc.inflightCallbacks.push(() => {
          this._clearFatalTimeoutTimer()
          return clearTimeout(timer)
        }) // 30 seconds
      }
      _startFatalTimeoutTimer(update) {
        // If an op doesn't get acked within FATAL_OP_TIMEOUT, something has
        // gone unrecoverably wrong (the op will have been retried multiple times)
        if (this._timeoutTimer != null) {
          return
        }
        return (this._timeoutTimer = setTimeout(() => {
          this._clearFatalTimeoutTimer()
          return this.trigger('op:timeout', update)
        }, this.FATAL_OP_TIMEOUT))
      }

      _clearFatalTimeoutTimer() {
        if (this._timeoutTimer == null) {
          return
        }
        clearTimeout(this._timeoutTimer)
        return (this._timeoutTimer = null)
      }

      _handleError(error, meta) {
        if (meta == null) {
          meta = {}
        }
        return this.trigger('error', error, meta)
      }

      _bindToDocChanges(doc) {
        const { submitOp } = doc
        doc.submitOp = (...args) => {
          this.trigger('op:sent', ...Array.from(args))
          doc.pendingCallbacks.push(() => {
            return this.trigger('op:acknowledged', ...Array.from(args))
          })
          return submitOp.apply(doc, args)
        }

        const { flush } = doc
        return (doc.flush = (...args) => {
          this.trigger('flush', doc.inflightOp, doc.pendingOp, doc.version)
          return flush.apply(doc, args)
        })
      }
    }
    ShareJsDoc.initClass()
    return ShareJsDoc
  })())
})

function __guard__(value, transform) {
  return typeof value !== 'undefined' && value !== null
    ? transform(value)
    : undefined
}