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refactor: Improvements
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@DimaDemchenko
DimaDemchenko committed Jun 21, 2024
1 parent 0826465 commit 8d667a5
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Showing 2 changed files with 57 additions and 94 deletions.
147 changes: 55 additions & 92 deletions lib/fast-tracker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,7 @@ export class FastTracker implements Tracker {
public readonly settings: Settings;

readonly #swarms = new Map<string, Swarm>();
readonly #peersContext = new Map<string, PeerContext>();
readonly #peers = new Map<string, PeerContext>();

#clearPeersInterval?: NodeJS.Timeout;

Expand All @@ -57,7 +57,7 @@ export class FastTracker implements Tracker {

this.#clearPeersInterval = setInterval(() => {
const now = performance.now();
for (const peer of this.#peersContext.values()) {
for (const peer of this.#peers.values()) {
if (
now - peer.lastAccessed >
this.settings.announceInterval * 2 * 1000
Expand All @@ -68,7 +68,7 @@ export class FastTracker implements Tracker {
}, this.settings.announceInterval * 1000);
}

private removeEmptySwarm(swarm: Swarm) {
private removeSwarmIfEmpty(swarm: Swarm) {
if (swarm.peers.length === 0) {
if (debugEnabled) {
debug(
Expand All @@ -80,31 +80,24 @@ export class FastTracker implements Tracker {
}
}

private removePeer(peerContext: PeerContext) {
const swarm = peerContext.swarm;

if (swarm === undefined) {
throw new TrackerError("disconnect peer: swarm is undefined");
}
private removePeer(peer: PeerContext) {
const swarm = peer.swarm;

if (debugEnabled) {
debug(
"disconnect peer: peer",
Buffer.from(peerContext.peerId).toString("hex"),
Buffer.from(peer.peerId).toString("hex"),
"removed from swarm",
Buffer.from(swarm.infoHash).toString("hex"),
);
}

swarm.removePeer(peerContext);
swarm.removePeer(peer);

this.removeEmptySwarm(swarm);
this.removeSwarmIfEmpty(swarm);
this.#peers.delete(peer.peerId);

this.#peersContext.delete(peerContext.peerId);

delete (peerContext.socketContext as unknown as UnknownObject)[
peerContext.peerId
];
delete (peer.socket as unknown as UnknownObject)[peer.peerId];
}

public get swarms(): ReadonlyMap<string, { peers: readonly PeerContext[] }> {
Expand Down Expand Up @@ -139,103 +132,83 @@ export class FastTracker implements Tracker {
}
}

public disconnectPeersFromSocket(peerSocket: SocketContext): void {
for (const peerId in peerSocket) {
const peerContext = (peerSocket as unknown as UnknownObject)[
peerId
] as PeerContext;
public disconnectPeersFromSocket(socket: SocketContext): void {
for (const peerId in socket) {
const peer = (socket as unknown as UnknownObject)[peerId] as PeerContext;

if (peerContext.peerId === undefined) continue;
this.removePeer(peerContext);
if (peer.peerId === undefined) continue;
this.removePeer(peer);
}
}

private processAnnounce(
json: UnknownObject,
peer: SocketContext,
socket: SocketContext,
completed = false,
): void {
const infoHash = json.info_hash as string;
const peerId = json.peer_id as string;
let swarm: Swarm | undefined;
const isPeerCompleted = completed || json.left === 0;

let peerContext = (peer as unknown as UnknownObject)[peerId] as
let peer = (socket as unknown as UnknownObject)[peerId] as
| PeerContext
| undefined;

if (peerContext === undefined) {
peerContext = this.#peersContext.get(peerId);
if (peer === undefined) {
const existingPeer = this.#peers.get(peerId);
if (existingPeer) this.removePeer(existingPeer);

if (peerContext !== undefined) return;
swarm = this.getOrCreateSwarm(infoHash);

peerContext = {
peer = {
peerId,
sendMessage: peer.sendMessage,
socketContext: peer,
sendMessage: socket.sendMessage,
socket,
lastAccessed: performance.now(),
swarm,
};

swarm = this.addPeerToSwarm(peer, peerContext, infoHash, isPeerCompleted);

peerContext.swarm = swarm;
swarm.addPeer(peer, isPeerCompleted);

(peer as unknown as UnknownObject)[peerId] = peerContext;
this.#peersContext.set(peerId, peerContext);
} else if (peerContext.peerId === peerId) {
peerContext.lastAccessed = performance.now();
(socket as unknown as UnknownObject)[peerId] = peer;
this.#peers.set(peerId, peer);
} else if (peer.peerId === peerId) {
peer.lastAccessed = performance.now();

if (peerContext.swarm === undefined) {
throw new TrackerError("announce: peerContext.swarm is undefined");
}

if (infoHash !== peerContext.swarm.infoHash) {
const oldSwarm = this.#swarms.get(peerContext.swarm.infoHash);

if (oldSwarm === undefined) {
throw new TrackerError("announce: old swarm is undefined");
}
if (infoHash !== peer.swarm.infoHash) {
const oldSwarm = peer.swarm;

oldSwarm.removePeer(peerContext);
oldSwarm.removePeer(peer);

this.removeEmptySwarm(oldSwarm);
this.removeSwarmIfEmpty(oldSwarm);

swarm = this.addPeerToSwarm(
peer,
peerContext,
infoHash,
isPeerCompleted,
);
peerContext.swarm = swarm;
swarm = this.getOrCreateSwarm(infoHash);
peer.swarm = swarm;
swarm.addPeer(peer, isPeerCompleted);
} else {
swarm = peerContext.swarm;

if (isPeerCompleted) swarm.setCompleted(peerContext);
swarm = peer.swarm;
if (isPeerCompleted) swarm.setCompleted(peer);
}
} else {
throw new TrackerError("announce: peerId mismatch");
}

if (swarm === undefined) return;

peer.sendMessage(
socket.sendMessage(
{
action: "announce",
interval: this.settings.announceInterval,
info_hash: infoHash,
complete: swarm.completedCount,
incomplete: swarm.peers.length - swarm.completedCount,
},
peer,
socket,
);

this.sendOffersToPeers(json, swarm.peers, peerContext, infoHash);
this.sendOffersToPeers(json, swarm.peers, peer, infoHash);
}

private addPeerToSwarm(
peer: SocketContext,
peerContext: PeerContext,
infoHash: unknown,
completed: boolean,
): Swarm {
private getOrCreateSwarm(infoHash: unknown): Swarm {
let swarm = this.#swarms.get(infoHash as string);

if (swarm === undefined) {
Expand All @@ -254,16 +227,6 @@ export class FastTracker implements Tracker {
this.#swarms.set(infoHash, swarm);
}

if (debugEnabled) {
debug(
"announce: peer",
Buffer.from(peerContext.peerId).toString("hex"),
"added to swarm",
Buffer.from(infoHash as string).toString("hex"),
);
}

swarm.addPeer(peerContext, completed);
return swarm;
}

Expand Down Expand Up @@ -305,7 +268,7 @@ export class FastTracker implements Tracker {
sendOffer(
offersIterator.next().value,
peer.peerId,
toPeer.socketContext,
toPeer.socket,
infoHash,
);
}
Expand All @@ -320,7 +283,7 @@ export class FastTracker implements Tracker {
if (toPeer === peer) {
i--; // do one more iteration
} else {
sendOffer(offers[i], peer.peerId, toPeer.socketContext, infoHash);
sendOffer(offers[i], peer.peerId, toPeer.socket, infoHash);
}

peerIndex++;
Expand All @@ -338,13 +301,13 @@ export class FastTracker implements Tracker {

private processAnswer(json: UnknownObject): void {
const toPeerId = json.to_peer_id as string;
const toPeer = this.#peersContext.get(toPeerId);
const toPeer = this.#peers.get(toPeerId);
if (toPeer === undefined) {
throw new TrackerError("answer: to_peer_id is not in the swarm");
}

delete json.to_peer_id;
toPeer.sendMessage(json, toPeer.socketContext);
toPeer.sendMessage(json, toPeer.socket);

if (debugEnabled) {
debug(
Expand All @@ -359,13 +322,13 @@ export class FastTracker implements Tracker {
private processStop(json: UnknownObject): void {
const peerId = json.peer_id as string;

const peer = this.#peersContext.get(peerId);
const peer = this.#peers.get(peerId);
if (peer === undefined) return;

this.removePeer(peer);
}

private processScrape(json: UnknownObject, peer: SocketContext): void {
private processScrape(json: UnknownObject, socket: SocketContext): void {
const infoHash = json.info_hash;
const files: {
[key: string]: {
Expand Down Expand Up @@ -417,7 +380,7 @@ export class FastTracker implements Tracker {
}
}

peer.sendMessage({ action: "scrape", files }, peer);
socket.sendMessage({ action: "scrape", files }, socket);
}
}

Expand Down Expand Up @@ -473,7 +436,7 @@ export class Swarm {
function sendOffer(
offerItem: unknown,
fromPeerId: string,
toPeer: SocketContext,
socket: SocketContext,
infoHash: string,
): void {
if (!(offerItem instanceof Object)) {
Expand All @@ -487,7 +450,7 @@ function sendOffer(
throw new TrackerError("announce: wrong offer item field format");
}

toPeer.sendMessage(
socket.sendMessage(
{
action: "announce",
info_hash: infoHash,
Expand All @@ -498,6 +461,6 @@ function sendOffer(
sdp: (offer as UnknownObject).sdp, // offer.sdp is not validated to be a string
},
},
toPeer,
socket,
);
}
4 changes: 2 additions & 2 deletions lib/tracker.ts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,9 +23,9 @@ export interface SocketContext {
export interface PeerContext {
peerId: string;
sendMessage: (json: object, peer: SocketContext) => void;
socketContext: SocketContext;
socket: SocketContext;
lastAccessed: number;
swarm?: Swarm;
swarm: Swarm;
}

export interface Tracker {
Expand Down

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