yjs/lib/Engine.coffee
2015-02-17 19:23:27 +00:00

116 lines
3.1 KiB
CoffeeScript

window?.unprocessed_counter = 0 # del this
window?.unprocessed_exec_counter = 0 # TODO
window?.unprocessed_types = []
#
# @nodoc
# The Engine handles how and in which order to execute operations and add operations to the HistoryBuffer.
#
class Engine
#
# @param {HistoryBuffer} HB
# @param {Object} types list of available types
#
constructor: (@HB, @types)->
@unprocessed_ops = []
#
# Parses an operatio from the json format. It uses the specified parser in your OperationType module.
#
parseOperation: (json)->
type = @types[json.type]
if type?.parse?
type.parse json
else
throw new Error "You forgot to specify a parser for type #{json.type}. The message is #{JSON.stringify json}."
#
# Apply a set of operations. E.g. the operations you received from another users HB._encode().
# @note You must not use this method when you already have ops in your HB!
###
applyOpsBundle: (ops_json)->
ops = []
for o in ops_json
ops.push @parseOperation o
for o in ops
if not o.execute()
@unprocessed_ops.push o
@tryUnprocessed()
###
#
# Same as applyOps but operations that are already in the HB are not applied.
# @see Engine.applyOps
#
applyOpsCheckDouble: (ops_json)->
for o in ops_json
if not @HB.getOperation(o.uid)?
@applyOp o
#
# Apply a set of operations. (Helper for using applyOp on Arrays)
# @see Engine.applyOp
applyOps: (ops_json)->
@applyOp ops_json
#
# Apply an operation that you received from another peer.
# TODO: make this more efficient!!
# - operations may only executed in order by creator, order them in object of arrays (key by creator)
# - you can probably make something like dependencies (creator1 waits for creator2)
applyOp: (op_json_array, fromHB = false)->
if op_json_array.constructor isnt Array
op_json_array = [op_json_array]
for op_json in op_json_array
if fromHB
op_json.fromHB = "true" # execute immediately, if
# $parse_and_execute will return false if $o_json was parsed and executed, otherwise the parsed operadion
o = @parseOperation op_json
o.parsed_from_json = op_json
if op_json.fromHB?
o.fromHB = op_json.fromHB
# @HB.addOperation o
if @HB.getOperation(o)?
# nop
else if ((not @HB.isExpectedOperation(o)) and (not o.fromHB?)) or (not o.execute())
@unprocessed_ops.push o
window?.unprocessed_types.push o.type # TODO: delete this
@tryUnprocessed()
#
# Call this method when you applied a new operation.
# It checks if operations that were previously not executable are now executable.
#
tryUnprocessed: ()->
while true
old_length = @unprocessed_ops.length
unprocessed = []
for op in @unprocessed_ops
if @HB.getOperation(op)?
# nop
else if (not @HB.isExpectedOperation(op) and (not op.fromHB?)) or (not op.execute())
unprocessed.push op
@unprocessed_ops = unprocessed
if @unprocessed_ops.length is old_length
break
if @unprocessed_ops.length isnt 0
@HB.invokeSync()
module.exports = Engine