FS: Fix hotpatching and add more throttling (#7878)

- `writeUpdate` state is now stored in a global variable, so hotpatching doesn't crash it
- throttling now writes on the tail (so two throttled `writeUpdate` calls will write one update, not two)
- room settings, punishments, and helptickets are now throttled

lib/fs.ts

@@ -35,7 +35,13 @@ interface PendingUpdate {
 	throttleTimer: NodeJS.Timer | null;
 }
 
-const pendingUpdates = new Map<string, PendingUpdate>();
+declare const __fsState: {pendingUpdates: Map<string, PendingUpdate>};
+declare const global: {__fsState: typeof __fsState};
+if (!global.__fsState) {
+	global.__fsState = {
+		pendingUpdates: new Map(),
+	};
+}
 
 export class FSPath {
 	path: string;
@@ -152,9 +158,8 @@ export class FSPath {
 	 */
 	writeUpdate(dataFetcher: () => string | Buffer, options: AnyObject = {}) {
 		if (Config.nofswriting) return;
-		const pendingUpdate: PendingUpdate | undefined = pendingUpdates.get(this.path);
+		const pendingUpdate: PendingUpdate | undefined = __fsState.pendingUpdates.get(this.path);
 
-		// @ts-ignore
 		const throttleTime = options.throttle ? Date.now() + options.throttle : 0;
 
 		if (pendingUpdate) {
@@ -168,11 +173,22 @@ export class FSPath {
 			return;
 		}
 
-		this.writeUpdateNow(dataFetcher, options);
+		if (!throttleTime) {
+			this.writeUpdateNow(dataFetcher, options);
+			return;
+		}
+
+		const update: PendingUpdate = {
+			isWriting: false,
+			pendingDataFetcher: dataFetcher,
+			pendingOptions: options,
+			throttleTime,
+			throttleTimer: setTimeout(() => this.checkNextUpdate(), throttleTime - Date.now()),
+		};
+		__fsState.pendingUpdates.set(this.path, update);
 	}
 
 	writeUpdateNow(dataFetcher: () => string | Buffer, options: AnyObject) {
-		// @ts-ignore
 		const throttleTime = options.throttle ? Date.now() + options.throttle : 0;
 		const update = {
 			isWriting: true,
@@ -181,25 +197,25 @@ export class FSPath {
 			throttleTime,
 			throttleTimer: null,
 		};
-		pendingUpdates.set(this.path, update);
+		__fsState.pendingUpdates.set(this.path, update);
 		void this.safeWrite(dataFetcher(), options).then(() => this.finishUpdate());
 	}
 	checkNextUpdate() {
-		const pendingUpdate = pendingUpdates.get(this.path);
+		const pendingUpdate = __fsState.pendingUpdates.get(this.path);
 		if (!pendingUpdate) throw new Error(`FS: Pending update not found`);
 		if (pendingUpdate.isWriting) throw new Error(`FS: Conflicting update`);
 
 		const {pendingDataFetcher: dataFetcher, pendingOptions: options} = pendingUpdate;
 		if (!dataFetcher || !options) {
 			// no pending update
-			pendingUpdates.delete(this.path);
+			__fsState.pendingUpdates.delete(this.path);
 			return;
 		}
 
 		this.writeUpdateNow(dataFetcher, options);
 	}
 	finishUpdate() {
-		const pendingUpdate = pendingUpdates.get(this.path);
+		const pendingUpdate = __fsState.pendingUpdates.get(this.path);
 		if (!pendingUpdate) throw new Error(`FS: Pending update not found`);
 		if (!pendingUpdate.isWriting) throw new Error(`FS: Conflicting update`);
 
@@ -491,4 +507,3 @@ function getFs(path: string) {
 export const FS = Object.assign(getFs, {
 	FileReadStream,
 });
-

server/chat-plugins/helptickets.ts

@@ -55,7 +55,7 @@ try {
 
 export function writeTickets() {
 	FS(TICKET_FILE).writeUpdate(
-		() => JSON.stringify(tickets)
+		() => JSON.stringify(tickets), {throttle: 5000}
 	);
 }
 

server/punishments.ts

@@ -286,7 +286,7 @@ export const Punishments = new class {
 				buf += Punishments.renderEntry(entry, id);
 			}
 			return buf;
-		});
+		}, {throttle: 5000});
 	}
 
 	saveRoomPunishments() {
@@ -302,7 +302,7 @@ export const Punishments = new class {
 				buf += Punishments.renderEntry(entry, id);
 			}
 			return buf;
-		});
+		}, {throttle: 5000});
 	}
 
 	getEntry(entryId: string) {

server/rooms.ts

@@ -1143,7 +1143,7 @@ export class GlobalRoomState {
 			JSON.stringify(this.settingsList)
 				.replace(/\{"title":/g, '\n{"title":')
 				.replace(/\]$/, '\n]')
-		));
+		), {throttle: 5000});
 	}
 
 	writeNumRooms() {