104 lines
2.7 KiB
JavaScript
104 lines
2.7 KiB
JavaScript
/**
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* @module awareness-protocol
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*/
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import * as encoding from '../lib/encoding.js'
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import * as decoding from '../lib/decoding.js'
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import { Y } from '../utils/Y.js' // eslint-disable-line
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const messageUsersStateChanged = 0
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/**
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* @typedef {Object} UserStateUpdate
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* @property {number} UserStateUpdate.userID
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* @property {Object} state
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*/
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/**
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* @param {encoding.Encoder} encoder
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* @param {Array<UserStateUpdate>} stateUpdates
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*/
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export const writeUsersStateChange = (encoder, stateUpdates) => {
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const len = stateUpdates.length
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encoding.writeVarUint(encoder, messageUsersStateChanged)
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encoding.writeVarUint(encoder, len)
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for (let i = 0; i < len; i++) {
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const {userID, state} = stateUpdates[i]
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encoding.writeVarUint(encoder, userID)
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encoding.writeVarString(encoder, JSON.stringify(state))
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}
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}
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export const readUsersStateChange = (decoder, y) => {
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const added = []
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const updated = []
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const removed = []
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const len = decoding.readVarUint(decoder)
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for (let i = 0; i < len; i++) {
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const userID = decoding.readVarUint(decoder)
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const state = JSON.parse(decoding.readVarString(decoder))
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if (userID !== y.userID) {
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if (state === null) {
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if (y.awareness.has(userID)) {
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y.awareness.delete(userID)
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removed.push(userID)
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}
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} else {
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if (y.awareness.has(userID)) {
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updated.push(userID)
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} else {
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added.push(userID)
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}
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y.awareness.set(userID, state)
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}
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}
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}
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if (added.length > 0 || updated.length > 0 || removed.length > 0) {
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y.emit('awareness', {
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added, updated, removed
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})
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}
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}
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/**
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* @param {decoding.Decoder} decoder
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* @param {encoding.Encoder} encoder
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*/
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export const forwardUsersStateChange = (decoder, encoder) => {
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const len = decoding.readVarUint(decoder)
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const updates = []
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encoding.writeVarUint(encoder, messageUsersStateChanged)
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encoding.writeVarUint(encoder, len)
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for (let i = 0; i < len; i++) {
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const userID = decoding.readVarUint(decoder)
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const state = decoding.readVarString(decoder)
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encoding.writeVarUint(encoder, userID)
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encoding.writeVarString(encoder, state)
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updates.push({userID, state: JSON.parse(state)})
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}
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return updates
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}
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/**
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* @param {decoding.Decoder} decoder
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* @param {Y} y
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*/
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export const readAwarenessMessage = (decoder, y) => {
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switch (decoding.readVarUint(decoder)) {
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case messageUsersStateChanged:
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readUsersStateChange(decoder, y)
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break
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}
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}
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/**
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* @param {decoding.Decoder} decoder
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* @param {encoding.Encoder} encoder
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*/
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export const forwardAwarenessMessage = (decoder, encoder) => {
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switch (decoding.readVarUint(decoder)) {
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case messageUsersStateChanged:
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return forwardUsersStateChange(decoder, encoder)
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}
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}
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