overleaf/services/web/public/coffee/ide/editor/ShareJsDoc.coffee
James Allen cde5144c42 Retry updates that have not been acknowledged.
If we do not get a reply from the server acknowledging our update after 5 seconds,
send it again. If it never got to the server, this is like normal. If the update
got to the server, but we never received the ack then we need to rely on ShareJs's
duplicate handling. We set the dupIfSource parameter on any retried updates which
let ShareJs know that it's a dup if we already have an op with this version number
and client id. The doc-updater and real-time services need changes to correctly
send another ack only to the submitting client in the case of a duplicate update.
2015-11-19 12:04:12 +00:00

140 lines
4 KiB
CoffeeScript

define [
"utils/EventEmitter"
"libs/sharejs"
], (EventEmitter, ShareJs) ->
SINGLE_USER_FLUSH_DELAY = 1000 #ms
class ShareJsDoc extends EventEmitter
constructor: (@doc_id, docLines, version, @socket) ->
# Dencode any binary bits of data
# See http://ecmanaut.blogspot.co.uk/2006/07/encoding-decoding-utf8-in-javascript.html
@type = "text"
docLines = for line in docLines
if line.text?
@type = "json"
line.text = decodeURIComponent(escape(line.text))
else
@type = "text"
line = decodeURIComponent(escape(line))
line
if @type == "text"
snapshot = docLines.join("\n")
else if @type == "json"
snapshot = { lines: docLines }
else
throw new Error("Unknown type: #{@type}")
@connection = {
send: (update) =>
@_startInflightOpTimeout(update)
if window.dropUpdates? and Math.random() < window.dropAcks
console.log "Simulating a lost update", update
return
@socket.emit "applyOtUpdate", @doc_id, update
state: "ok"
# Unlike ShareJs, our connection.id never changes, even when we disconnect/reconnect.
# This gives this client a unique id used for detecting duplicates ops.
id: @socket.socket.sessionid
}
@_doc = new ShareJs.Doc @connection, @doc_id,
type: @type
@_doc.setFlushDelay(SINGLE_USER_FLUSH_DELAY)
@_doc.on "change", () =>
@trigger "change"
@_doc.on "acknowledge", () =>
@trigger "acknowledge"
@_doc.on "remoteop", () =>
# As soon as we're working with a collaborator, start sending
# ops as quickly as possible for low latency.
@_doc.setFlushDelay(0)
@trigger "remoteop"
@_doc.on "error", (e) =>
@_handleError(e)
@_bindToDocChanges(@_doc)
@processUpdateFromServer
open: true
v: version
snapshot: snapshot
submitOp: (args...) -> @_doc.submitOp(args...)
processUpdateFromServer: (message) ->
try
@_doc._onMessage message
catch error
# Version mismatches are thrown as errors
@_handleError(error)
if message?.meta?.type == "external"
@trigger "externalUpdate", message
catchUp: (updates) ->
for update, i in updates
update.v = @_doc.version
update.doc = @doc_id
@processUpdateFromServer(update)
getSnapshot: () -> @_doc.snapshot
getVersion: () -> @_doc.version
getType: () -> @type
clearInflightAndPendingOps: () ->
@_doc.inflightOp = null
@_doc.inflightCallbacks = []
@_doc.pendingOp = null
@_doc.pendingCallbacks = []
flushPendingOps: () ->
# This will flush any ops that are pending.
# If there is an inflight op it will do nothing.
@_doc.flush()
updateConnectionState: (state) ->
@connection.state = state
@_doc.autoOpen = false
@_doc._connectionStateChanged(state)
hasBufferedOps: () ->
@_doc.inflightOp? or @_doc.pendingOp?
getInflightOp: () -> @_doc.inflightOp
getPendingOp: () -> @_doc.pendingOp
attachToAce: (ace) -> @_doc.attach_ace(ace, false, window.maxDocLength)
detachFromAce: () -> @_doc.detach_ace?()
INFLIGHT_OP_TIMEOUT: 5000
_startInflightOpTimeout: (update) ->
timer = setTimeout () =>
# 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.
if @_doc.inflightOp?
update.dupIfSource = [@connection.id]
@connection.send(update)
# TODO: Trigger op:timeout only when some max retries have been hit
# and we need to do a full reload.
# @trigger "op:timeout", update
, @INFLIGHT_OP_TIMEOUT
@_doc.inflightCallbacks.push () =>
clearTimeout timer
_handleError: (error, meta = {}) ->
@trigger "error", error, meta
_bindToDocChanges: (doc) ->
submitOp = doc.submitOp
doc.submitOp = (args...) =>
@trigger "op:sent", args...
doc.pendingCallbacks.push () =>
@trigger "op:acknowledged", args...
submitOp.apply(doc, args)
flush = doc.flush
doc.flush = (args...) =>
@trigger "flush", doc.inflightOp, doc.pendingOp, doc.version
flush.apply(doc, args)