init

node_modules/matrix-js-sdk/src/matrixrtc/MembershipManagerActionScheduler.ts

@@ -0,0 +1,138 @@
+import { type Logger, logger as rootLogger } from "../logger.ts";
+import { type EmptyObject } from "../matrix.ts";
+import { sleep } from "../utils.ts";
+import { MembershipActionType } from "./MembershipManager.ts";
+
+/** @internal */
+export interface Action {
+    /**
+     * When this action should be executed
+     */
+    ts: number;
+    /**
+     * The state of the different loops
+     * can also be thought of as the type of the action
+     */
+    type: MembershipActionType;
+}
+
+/** @internal */
+export type ActionUpdate =
+    | {
+          /** Replace all existing scheduled actions with this new array */
+          replace: Action[];
+      }
+    | {
+          /** Add these actions to the existing scheduled actions */
+          insert: Action[];
+      }
+    | EmptyObject;
+
+/**
+ * This scheduler tracks the state of the current membership participation
+ * and runs one central timer that wakes up a handler callback with the correct action + state
+ * whenever necessary.
+ *
+ * It can also be awakened whenever a new action is added which is
+ * earlier then the current "next awake".
+ * @internal
+ */
+export class ActionScheduler {
+    private logger: Logger;
+    /**
+     * This is tracking the state of the scheduler loop.
+     * Only used to prevent starting the loop twice.
+     */
+    public running = false;
+
+    public constructor(
+        /** This is the callback called for each scheduled action (`this.addAction()`) */
+        private membershipLoopHandler: (type: MembershipActionType) => Promise<ActionUpdate>,
+        parentLogger?: Logger,
+    ) {
+        this.logger = (parentLogger ?? rootLogger).getChild(`[NewMembershipActionScheduler]`);
+    }
+
+    // function for the wakeup mechanism (in case we add an action externally and need to leave the current sleep)
+    private wakeup: (update: ActionUpdate) => void = (update: ActionUpdate): void => {
+        this.logger.error("Cannot call wakeup before calling `startWithJoin()`");
+    };
+    private _actions: Action[] = [];
+    public get actions(): Action[] {
+        return this._actions;
+    }
+
+    /**
+     * This starts the main loop of the membership manager that handles event sending, delayed event sending and delayed event restarting.
+     * @param initialActions The initial actions the manager will start with. It should be enough to pass: DelayedLeaveActionType.Initial
+     * @returns Promise that resolves once all actions have run and no more are scheduled.
+     * @throws This throws an error if one of the actions throws.
+     * In most other error cases the manager will try to handle any server errors by itself.
+     */
+    public async startWithJoin(): Promise<void> {
+        if (this.running) {
+            this.logger.error("Cannot call startWithJoin() on NewMembershipActionScheduler while already running");
+            return;
+        }
+        this.running = true;
+        this._actions = [{ ts: Date.now(), type: MembershipActionType.SendDelayedEvent }];
+        try {
+            while (this._actions.length > 0) {
+                // Sort so next (smallest ts) action is at the beginning
+                this._actions.sort((a, b) => a.ts - b.ts);
+                const nextAction = this._actions[0];
+                let wakeupUpdate: ActionUpdate | undefined = undefined;
+
+                // while we await for the next action, wakeup has to resolve the wakeupPromise
+                const wakeupPromise = new Promise<void>((resolve) => {
+                    this.wakeup = (update: ActionUpdate): void => {
+                        wakeupUpdate = update;
+                        resolve();
+                    };
+                });
+                if (nextAction.ts > Date.now()) await Promise.race([wakeupPromise, sleep(nextAction.ts - Date.now())]);
+
+                let handlerResult: ActionUpdate = {};
+                if (!wakeupUpdate) {
+                    this.logger.debug(
+                        `Current MembershipManager processing: ${nextAction.type}\nQueue:`,
+                        this._actions,
+                        `\nDate.now: "${Date.now()}`,
+                    );
+                    try {
+                        // `this.wakeup` can also be called and sets the `wakeupUpdate` object while we are in the handler.
+                        handlerResult = await this.membershipLoopHandler(nextAction.type);
+                    } catch (e) {
+                        // Preserve the original error as `cause`.
+                        throw new Error(`The MembershipManager shut down because of the end condition: ${e}`, {
+                            cause: e,
+                        });
+                    }
+                }
+                // remove the processed action only after we are done processing
+                this._actions.splice(0, 1);
+                // The wakeupUpdate always wins since that is a direct external update.
+                const actionUpdate = wakeupUpdate ?? handlerResult;
+
+                if ("replace" in actionUpdate) {
+                    this._actions = actionUpdate.replace;
+                } else if ("insert" in actionUpdate) {
+                    this._actions.push(...actionUpdate.insert);
+                }
+            }
+        } finally {
+            // Set the rtc session running state since we cannot recover from here and the consumer user of the
+            // MatrixRTCSession class needs to manually rejoin.
+            this.running = false;
+        }
+
+        this.logger.debug("Leave MembershipManager ActionScheduler loop (no more actions)");
+    }
+
+    public initiateJoin(): void {
+        this.wakeup?.({ replace: [{ ts: Date.now(), type: MembershipActionType.SendDelayedEvent }] });
+    }
+    public initiateLeave(): void {
+        this.wakeup?.({ replace: [{ ts: Date.now(), type: MembershipActionType.SendScheduledDelayedLeaveEvent }] });
+    }
+}