yjs/src/utils/ID.js
2019-05-27 12:50:12 +02:00

91 lines
1.9 KiB
JavaScript

import { AbstractType } from '../internals.js' // eslint-disable-line
import * as decoding from 'lib0/decoding.js'
import * as encoding from 'lib0/encoding.js'
import * as error from 'lib0/error.js'
export class ID {
/**
* @param {number} client client id
* @param {number} clock unique per client id, continuous number
*/
constructor (client, clock) {
/**
* Client id
* @type {number}
*/
this.client = client
/**
* unique per client id, continuous number
* @type {number}
*/
this.clock = clock
}
}
/**
* @param {ID | null} a
* @param {ID | null} b
* @return {boolean}
*
* @function
*/
export const compareIDs = (a, b) => a === b || (a !== null && b !== null && a.client === b.client && a.clock === b.clock)
/**
* @param {number} client
* @param {number} clock
*
* @private
* @function
*/
export const createID = (client, clock) => new ID(client, clock)
/**
* @param {encoding.Encoder} encoder
* @param {ID} id
*
* @private
* @function
*/
export const writeID = (encoder, id) => {
encoding.writeVarUint(encoder, id.client)
encoding.writeVarUint(encoder, id.clock)
}
/**
* Read ID.
* * If first varUint read is 0xFFFFFF a RootID is returned.
* * Otherwise an ID is returned
*
* @param {decoding.Decoder} decoder
* @return {ID}
*
* @private
* @function
*/
export const readID = decoder =>
createID(decoding.readVarUint(decoder), decoding.readVarUint(decoder))
/**
* The top types are mapped from y.share.get(keyname) => type.
* `type` does not store any information about the `keyname`.
* This function finds the correct `keyname` for `type` and throws otherwise.
*
* @param {AbstractType<any>} type
* @return {string}
*
* @private
* @function
*/
export const findRootTypeKey = type => {
// @ts-ignore _y must be defined, otherwise unexpected case
for (let [key, value] of type.doc.share) {
if (value === type) {
return key
}
}
throw error.unexpectedCase()
}