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'use strict';
var encoding = require('lib0/dist/encoding.cjs');
var decoding = require('lib0/dist/decoding.cjs');
var time = require('lib0/dist/time.cjs');
var math = require('lib0/dist/math.cjs');
var observable = require('lib0/dist/observable.cjs');
var f = require('lib0/dist/function.cjs');
require('yjs');
function _interopNamespaceDefault(e) {
var n = Object.create(null);
if (e) {
Object.keys(e).forEach(function (k) {
if (k !== 'default') {
var d = Object.getOwnPropertyDescriptor(e, k);
Object.defineProperty(n, k, d.get ? d : {
enumerable: true,
get: function () { return e[k]; }
});
}
});
}
n.default = e;
return Object.freeze(n);
}
var encoding__namespace = /*#__PURE__*/_interopNamespaceDefault(encoding);
var decoding__namespace = /*#__PURE__*/_interopNamespaceDefault(decoding);
var time__namespace = /*#__PURE__*/_interopNamespaceDefault(time);
var math__namespace = /*#__PURE__*/_interopNamespaceDefault(math);
var f__namespace = /*#__PURE__*/_interopNamespaceDefault(f);
/**
* @module awareness-protocol
*/
const outdatedTimeout = 30000;
/**
* @typedef {Object} MetaClientState
* @property {number} MetaClientState.clock
* @property {number} MetaClientState.lastUpdated unix timestamp
*/
/**
* The Awareness class implements a simple shared state protocol that can be used for non-persistent data like awareness information
* (cursor, username, status, ..). Each client can update its own local state and listen to state changes of
* remote clients. Every client may set a state of a remote peer to `null` to mark the client as offline.
*
* Each client is identified by a unique client id (something we borrow from `doc.clientID`). A client can override
* its own state by propagating a message with an increasing timestamp (`clock`). If such a message is received, it is
* applied if the known state of that client is older than the new state (`clock < newClock`). If a client thinks that
* a remote client is offline, it may propagate a message with
* `{ clock: currentClientClock, state: null, client: remoteClient }`. If such a
* message is received, and the known clock of that client equals the received clock, it will override the state with `null`.
*
* Before a client disconnects, it should propagate a `null` state with an updated clock.
*
* Awareness states must be updated every 30 seconds. Otherwise the Awareness instance will delete the client state.
*
* @extends {Observable<string>}
*/
class Awareness extends observable.Observable {
/**
* @param {Y.Doc} doc
*/
constructor (doc) {
super();
this.doc = doc;
/**
* @type {number}
*/
this.clientID = doc.clientID;
/**
* Maps from client id to client state
* @type {Map<number, Object<string, any>>}
*/
this.states = new Map();
/**
* @type {Map<number, MetaClientState>}
*/
this.meta = new Map();
this._checkInterval = /** @type {any} */ (setInterval(() => {
const now = time__namespace.getUnixTime();
if (this.getLocalState() !== null && (outdatedTimeout / 2 <= now - /** @type {{lastUpdated:number}} */ (this.meta.get(this.clientID)).lastUpdated)) {
// renew local clock
this.setLocalState(this.getLocalState());
}
/**
* @type {Array<number>}
*/
const remove = [];
this.meta.forEach((meta, clientid) => {
if (clientid !== this.clientID && outdatedTimeout <= now - meta.lastUpdated && this.states.has(clientid)) {
remove.push(clientid);
}
});
if (remove.length > 0) {
removeAwarenessStates(this, remove, 'timeout');
}
}, math__namespace.floor(outdatedTimeout / 10)));
doc.on('destroy', () => {
this.destroy();
});
this.setLocalState({});
}
destroy () {
this.emit('destroy', [this]);
this.setLocalState(null);
super.destroy();
clearInterval(this._checkInterval);
}
/**
* @return {Object<string,any>|null}
*/
getLocalState () {
return this.states.get(this.clientID) || null
}
/**
* @param {Object<string,any>|null} state
*/
setLocalState (state) {
const clientID = this.clientID;
const currLocalMeta = this.meta.get(clientID);
const clock = currLocalMeta === undefined ? 0 : currLocalMeta.clock + 1;
const prevState = this.states.get(clientID);
if (state === null) {
this.states.delete(clientID);
} else {
this.states.set(clientID, state);
}
this.meta.set(clientID, {
clock,
lastUpdated: time__namespace.getUnixTime()
});
const added = [];
const updated = [];
const filteredUpdated = [];
const removed = [];
if (state === null) {
removed.push(clientID);
} else if (prevState == null) {
if (state != null) {
added.push(clientID);
}
} else {
updated.push(clientID);
if (!f__namespace.equalityDeep(prevState, state)) {
filteredUpdated.push(clientID);
}
}
if (added.length > 0 || filteredUpdated.length > 0 || removed.length > 0) {
this.emit('change', [{ added, updated: filteredUpdated, removed }, 'local']);
}
this.emit('update', [{ added, updated, removed }, 'local']);
}
/**
* @param {string} field
* @param {any} value
*/
setLocalStateField (field, value) {
const state = this.getLocalState();
if (state !== null) {
this.setLocalState({
...state,
[field]: value
});
}
}
/**
* @return {Map<number,Object<string,any>>}
*/
getStates () {
return this.states
}
}
/**
* Mark (remote) clients as inactive and remove them from the list of active peers.
* This change will be propagated to remote clients.
*
* @param {Awareness} awareness
* @param {Array<number>} clients
* @param {any} origin
*/
const removeAwarenessStates = (awareness, clients, origin) => {
const removed = [];
for (let i = 0; i < clients.length; i++) {
const clientID = clients[i];
if (awareness.states.has(clientID)) {
awareness.states.delete(clientID);
if (clientID === awareness.clientID) {
const curMeta = /** @type {MetaClientState} */ (awareness.meta.get(clientID));
awareness.meta.set(clientID, {
clock: curMeta.clock + 1,
lastUpdated: time__namespace.getUnixTime()
});
}
removed.push(clientID);
}
}
if (removed.length > 0) {
awareness.emit('change', [{ added: [], updated: [], removed }, origin]);
awareness.emit('update', [{ added: [], updated: [], removed }, origin]);
}
};
/**
* @param {Awareness} awareness
* @param {Array<number>} clients
* @return {Uint8Array}
*/
const encodeAwarenessUpdate = (awareness, clients, states = awareness.states) => {
const len = clients.length;
const encoder = encoding__namespace.createEncoder();
encoding__namespace.writeVarUint(encoder, len);
for (let i = 0; i < len; i++) {
const clientID = clients[i];
const state = states.get(clientID) || null;
const clock = /** @type {MetaClientState} */ (awareness.meta.get(clientID)).clock;
encoding__namespace.writeVarUint(encoder, clientID);
encoding__namespace.writeVarUint(encoder, clock);
encoding__namespace.writeVarString(encoder, JSON.stringify(state));
}
return encoding__namespace.toUint8Array(encoder)
};
/**
* Modify the content of an awareness update before re-encoding it to an awareness update.
*
* This might be useful when you have a central server that wants to ensure that clients
* cant hijack somebody elses identity.
*
* @param {Uint8Array} update
* @param {function(any):any} modify
* @return {Uint8Array}
*/
const modifyAwarenessUpdate = (update, modify) => {
const decoder = decoding__namespace.createDecoder(update);
const encoder = encoding__namespace.createEncoder();
const len = decoding__namespace.readVarUint(decoder);
encoding__namespace.writeVarUint(encoder, len);
for (let i = 0; i < len; i++) {
const clientID = decoding__namespace.readVarUint(decoder);
const clock = decoding__namespace.readVarUint(decoder);
const state = JSON.parse(decoding__namespace.readVarString(decoder));
const modifiedState = modify(state);
encoding__namespace.writeVarUint(encoder, clientID);
encoding__namespace.writeVarUint(encoder, clock);
encoding__namespace.writeVarString(encoder, JSON.stringify(modifiedState));
}
return encoding__namespace.toUint8Array(encoder)
};
/**
* @param {Awareness} awareness
* @param {Uint8Array} update
* @param {any} origin This will be added to the emitted change event
*/
const applyAwarenessUpdate = (awareness, update, origin) => {
const decoder = decoding__namespace.createDecoder(update);
const timestamp = time__namespace.getUnixTime();
const added = [];
const updated = [];
const filteredUpdated = [];
const removed = [];
const len = decoding__namespace.readVarUint(decoder);
for (let i = 0; i < len; i++) {
const clientID = decoding__namespace.readVarUint(decoder);
let clock = decoding__namespace.readVarUint(decoder);
const state = JSON.parse(decoding__namespace.readVarString(decoder));
const clientMeta = awareness.meta.get(clientID);
const prevState = awareness.states.get(clientID);
const currClock = clientMeta === undefined ? 0 : clientMeta.clock;
if (currClock < clock || (currClock === clock && state === null && awareness.states.has(clientID))) {
if (state === null) {
// never let a remote client remove this local state
if (clientID === awareness.clientID && awareness.getLocalState() != null) {
// remote client removed the local state. Do not remote state. Broadcast a message indicating
// that this client still exists by increasing the clock
clock++;
} else {
awareness.states.delete(clientID);
}
} else {
awareness.states.set(clientID, state);
}
awareness.meta.set(clientID, {
clock,
lastUpdated: timestamp
});
if (clientMeta === undefined && state !== null) {
added.push(clientID);
} else if (clientMeta !== undefined && state === null) {
removed.push(clientID);
} else if (state !== null) {
if (!f__namespace.equalityDeep(state, prevState)) {
filteredUpdated.push(clientID);
}
updated.push(clientID);
}
}
}
if (added.length > 0 || filteredUpdated.length > 0 || removed.length > 0) {
awareness.emit('change', [{
added, updated: filteredUpdated, removed
}, origin]);
}
if (added.length > 0 || updated.length > 0 || removed.length > 0) {
awareness.emit('update', [{
added, updated, removed
}, origin]);
}
};
exports.Awareness = Awareness;
exports.applyAwarenessUpdate = applyAwarenessUpdate;
exports.encodeAwarenessUpdate = encodeAwarenessUpdate;
exports.modifyAwarenessUpdate = modifyAwarenessUpdate;
exports.outdatedTimeout = outdatedTimeout;
exports.removeAwarenessStates = removeAwarenessStates;
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