121 lines
3.8 KiB
TypeScript
121 lines
3.8 KiB
TypeScript
module TK.SpaceTac.Multi {
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/**
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* Network communication of two peers around a shared session
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*
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* An exchange is a sequence of messages
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*/
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export class Exchange {
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connection: Connection
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token: string
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writing: boolean
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localpeer: string
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count = 0
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remotepeer: string | null = null
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next = "hello"
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closed = false
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timer = new Timer()
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debug = false
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constructor(connection: Connection, token: string, initiator = false, myid = connection.device_id) {
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this.connection = connection;
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this.token = token;
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this.localpeer = myid;
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this.writing = initiator;
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}
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/**
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* Initialize communication with the other peer
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*/
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async start(): Promise<void> {
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if (this.debug) {
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console.debug("Exchange started", this.localpeer);
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}
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if (this.writing) {
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await this.writeMessage(null, true);
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await this.readMessage();
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} else {
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await this.readMessage();
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await this.writeMessage(null, true);
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}
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console.log("Exchange established", this.token, this.localpeer, this.remotepeer);
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}
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/**
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* Get a next frame id
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*/
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getNextId(): string {
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return `${this.token}${this.count}${RandomGenerator.global.id(8)}`;
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}
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/**
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* Push a raw message
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*/
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async writeMessage(message: any, over: boolean) {
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if (this.writing) {
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if (this.debug) {
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console.debug("Exchange write", this.localpeer, this.token, this.next);
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}
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let futurenext = this.getNextId();
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let result = await this.connection.storage.upsert("exchange", { token: this.token, current: this.next },
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{ peer: this.localpeer, over: over, data: message, next: futurenext, count: this.count });
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this.count += 1;
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this.next = futurenext;
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if (over) {
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this.writing = false;
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}
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return result;
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} else {
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throw new Error("[Exchange] Tried to write out-of-turn");
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}
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}
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/**
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* Wait for a single message
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*/
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async readMessage(): Promise<any> {
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if (this.writing) {
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throw new Error("[Exchange] Tried to read out-of-turn");
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} else {
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let message: any;
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do {
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if (this.debug) {
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console.debug("Exchange read", this.localpeer, this.token, this.next);
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}
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message = await this.connection.storage.find("exchange", { token: this.token, current: this.next });
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if (!message) {
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await this.timer.sleep(1000);
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}
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} while (!message);
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if (this.remotepeer) {
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if (message.peer != this.remotepeer) {
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throw new Error("[Exchange] Bad peer id");
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}
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} else {
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if (message.peer) {
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this.remotepeer = message.peer;
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} else {
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throw new Error("[Exchange] No peer id");
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}
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}
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if (message.count != this.count) {
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throw new Error("[Exchange] Bad message count");
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} else {
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this.count += 1;
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}
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this.next = message.next;
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if (message.over) {
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this.writing = true;
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}
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return message.data;
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}
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}
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}
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} |