yjs/src/utils/integrateRemoteStructs.js
2019-03-13 01:16:31 +01:00

115 lines
3.3 KiB
JavaScript

/**
* @module utils
*/
import { getStruct } from '../utils/structReferences.js'
import * as decoding from 'lib0/decoding.js'
import { GC } from '../structs/GC.js'
import { Y } from '../utils/Y.js' // eslint-disable-line
import { Item } from '../structs/Item.js' // eslint-disable-line
class MissingEntry {
constructor (decoder, missing, struct) {
this.decoder = decoder
this.missing = missing.length
this.struct = struct
}
}
/**
* @private
* Integrate remote struct
* When a remote struct is integrated, other structs might be ready to ready to
* integrate.
* @param {Y} y
* @param {Item} struct
*/
function _integrateRemoteStructHelper (y, struct) {
const id = struct._id
if (id === undefined) {
struct._integrate(y)
} else {
if (y.ss.getState(id.user) > id.clock) {
return
}
if (!y.gcEnabled || struct.constructor === GC || (struct._parent.constructor !== GC && struct._parent._deleted === false)) {
// Is either a GC or Item with an undeleted parent
// save to integrate
struct._integrate(y)
} else {
// Is an Item. parent was deleted.
struct._gc(y)
}
let msu = y._missingStructs.get(id.user)
if (msu != null) {
let clock = id.clock
const finalClock = clock + struct._length
for (;clock < finalClock; clock++) {
const missingStructs = msu.get(clock)
if (missingStructs !== undefined) {
missingStructs.forEach(missingDef => {
missingDef.missing--
if (missingDef.missing === 0) {
y._readyToIntegrate.push(missingDef)
}
})
msu.delete(clock)
}
}
if (msu.size === 0) {
y._missingStructs.delete(id.user)
}
}
}
}
/**
* @param {decoding.Decoder} decoder
* @param {Y} y
*/
export const integrateRemoteStructs = (decoder, y) => {
const len = decoding.readUint32(decoder)
for (let i = 0; i < len; i++) {
let reference = decoding.readVarUint(decoder)
let Constr = getStruct(reference)
let struct = new Constr()
let decoderPos = decoder.pos
let missing = struct._fromBinary(y, decoder)
if (missing.length === 0) {
while (struct !== null) {
_integrateRemoteStructHelper(y, struct)
struct = null
if (y._readyToIntegrate.length > 0) {
const missingDef = y._readyToIntegrate.shift()
const decoder = missingDef.decoder
let oldPos = decoder.pos
let missing = missingDef.struct._fromBinary(y, decoder)
decoder.pos = oldPos
if (missing.length === 0) {
struct = missingDef.struct
} else {
throw new Error('Missing should be empty')
}
}
}
} else {
let _decoder = decoding.createDecoder(decoder.arr.buffer)
_decoder.pos = decoderPos
let missingEntry = new MissingEntry(_decoder, missing, struct)
let missingStructs = y._missingStructs
for (let i = missing.length - 1; i >= 0; i--) {
let m = missing[i]
if (!missingStructs.has(m.user)) {
missingStructs.set(m.user, new Map())
}
let msu = missingStructs.get(m.user)
if (!msu.has(m.clock)) {
msu.set(m.clock, [])
}
let mArray = msu = msu.get(m.clock)
mArray.push(missingEntry)
}
}
}
}