src/Struct/GC.js
import { getStructReference } from '../Util/structReferences.js'
import { RootFakeUserID } from '../Util/ID/RootID.js'
import ID from '../Util/ID/ID.js'
// TODO should have the same base class as Item
export default class GC {
constructor () {
this._id = null
this._length = 0
}
get _deleted () {
return true
}
_integrate (y) {
const id = this._id
const userState = y.ss.getState(id.user)
if (id.clock === userState) {
y.ss.setState(id.user, id.clock + this._length)
}
y.ds.mark(this._id, this._length, true)
let n = y.os.put(this)
const prev = n.prev().val
if (prev !== null && prev.constructor === GC && prev._id.user === n.val._id.user && prev._id.clock + prev._length === n.val._id.clock) {
// TODO: do merging for all items!
prev._length += n.val._length
y.os.delete(n.val._id)
n = prev
}
if (n.val) {
n = n.val
}
const next = y.os.findNext(n._id)
if (next !== null && next.constructor === GC && next._id.user === n._id.user && next._id.clock === n._id.clock + n._length) {
n._length += next._length
y.os.delete(next._id)
}
if (id.user !== RootFakeUserID) {
if (y.connector !== null && (y.connector._forwardAppliedStructs || id.user === y.userID)) {
y.connector.broadcastStruct(this)
}
if (y.persistence !== null) {
y.persistence.saveStruct(y, this)
}
}
}
/**
* Transform the properties of this type to binary and write it to an
* BinaryEncoder.
*
* This is called when this Item is sent to a remote peer.
*
* @param {BinaryEncoder} encoder The encoder to write data to.
* @private
*/
_toBinary (encoder) {
encoder.writeUint8(getStructReference(this.constructor))
encoder.writeID(this._id)
encoder.writeVarUint(this._length)
}
/**
* Read the next Item in a Decoder and fill this Item with the read data.
*
* This is called when data is received from a remote peer.
*
* @param {Y} y The Yjs instance that this Item belongs to.
* @param {BinaryDecoder} decoder The decoder object to read data from.
* @private
*/
_fromBinary (y, decoder) {
const id = decoder.readID()
this._id = id
this._length = decoder.readVarUint()
const missing = []
if (y.ss.getState(id.user) < id.clock) {
missing.push(new ID(id.user, id.clock - 1))
}
return missing
}
_splitAt () {
return this
}
_clonePartial (diff) {
const gc = new GC()
gc._id = new ID(this._id.user, this._id.clock + diff)
gc._length = this._length - diff
return gc
}
}