Remove cancelled relations from the relations collection

This listens for event status changes on sending events in case they might be
cancelled and removes them from aggregation if so.

Part of https://github.com/vector-im/riot-web/issues/9731

src/client.js

@@ -1723,7 +1723,7 @@ MatrixClient.prototype.sendEvent = function(roomId, eventType, content, txnId,
         content: content,
     });
     localEvent._txnId = txnId;
-    localEvent.status = EventStatus.SENDING;
+    localEvent.setStatus(EventStatus.SENDING);
 
     // add this event immediately to the local store as 'sending'.
     if (room) {
@@ -1853,7 +1853,7 @@ function _updatePendingEventStatus(room, event, newStatus) {
     if (room) {
         room.updatePendingEvent(event, newStatus);
     } else {
-        event.status = newStatus;
+        event.setStatus(newStatus);
     }
 }
 

src/models/event.js

@@ -731,7 +731,27 @@ utils.extend(module.exports.MatrixEvent.prototype, {
     handleRemoteEcho: function(event) {
         this.event = event;
         // successfully sent.
-        this.status = null;
+        this.setStatus(null);
+    },
+
+    /**
+     * Whether the event is in any phase of sending, send failure, waiting for
+     * remote echo, etc.
+     *
+     * @return {boolean}
+     */
+    isSending() {
+        return !!this.status;
+    },
+
+    /**
+     * Update the event's sending status and emit an event as well.
+     *
+     * @param {String} status The new status
+     */
+    setStatus(status) {
+        this.status = status;
+        this.emit("Event.status", this, status);
     },
 
     /**

src/models/relations.js

@@ -15,6 +15,7 @@ limitations under the License.
 */
 
 import EventEmitter from 'events';
+import { EventStatus } from '../../lib/models/event';
 
 /**
  * A container for relation events that supports easy access to common ways of
@@ -49,9 +50,55 @@ export default class Relations extends EventEmitter {
      * Add relation events to this collection.
      *
      * @param {MatrixEvent} event
-     * The new relation event to be aggregated.
+     * The new relation event to be added.
      */
     addEvent(event) {
+        if (this._relations.has(event)) {
+            return;
+        }
+
+        const relation = event.getRelation();
+        if (!relation) {
+            console.error("Event must have relation info");
+            return;
+        }
+
+        const relationType = relation.rel_type;
+        const eventType = event.getType();
+
+        if (this.relationType !== relationType || this.eventType !== eventType) {
+            console.error("Event relation info doesn't match this container");
+            return;
+        }
+
+        // If the event is in the process of being sent, listen for cancellation
+        // so we can remove the event from the collection.
+        if (event.isSending()) {
+            event.on("Event.status", this._onEventStatus);
+        }
+
+        if (this.relationType === "m.annotation") {
+            this._addAnnotationToAggregation(event);
+        }
+
+        this._relations.add(event);
+
+        event.on("Event.beforeRedaction", this._onBeforeRedaction);
+
+        this.emit("Relations.add", event);
+    }
+
+    /**
+     * Remove relation event from this collection.
+     *
+     * @param {MatrixEvent} event
+     * The relation event to remove.
+     */
+    _removeEvent(event) {
+        if (!this._relations.has(event)) {
+            return;
+        }
+
         const relation = event.getRelation();
         if (!relation) {
             console.error("Event must have relation info");
@@ -67,15 +114,32 @@ export default class Relations extends EventEmitter {
         }
 
         if (this.relationType === "m.annotation") {
-            const key = relation.key;
-            this._aggregateAnnotation(key, event);
+            this._removeAnnotationFromAggregation(event);
         }
 
-        this._relations.add(event);
+        this._relations.delete(event);
 
-        event.on("Event.beforeRedaction", this._onBeforeRedaction);
+        this.emit("Relations.remove", event);
+    }
 
-        this.emit("Relations.add", event);
+    /**
+     * Listens for event status changes to remove cancelled events.
+     *
+     * @param {MatrixEvent} event The event whose status has changed
+     * @param {EventStatus} status The new status
+     */
+    _onEventStatus = (event, status) => {
+        if (!event.isSending()) {
+            // Sending is done, so we don't need to listen anymore
+            event.removeListener("Event.status", this._onEventStatus);
+            return;
+        }
+        if (status !== EventStatus.CANCELLED) {
+            return;
+        }
+        // Event was cancelled, remove from the collection
+        event.removeListener("Event.status", this._onEventStatus);
+        this._removeEvent(event);
     }
 
     /**
@@ -92,7 +156,8 @@ export default class Relations extends EventEmitter {
         return [...this._relations];
     }
 
-    _aggregateAnnotation(key, event) {
+    _addAnnotationToAggregation(event) {
+        const { key } = event.getRelation();
         if (!key) {
             return;
         }
@@ -120,6 +185,28 @@ export default class Relations extends EventEmitter {
         eventsFromSender.push(event);
     }
 
+    _removeAnnotationFromAggregation(event) {
+        const { key } = event.getRelation();
+        if (!key) {
+            return;
+        }
+
+        const eventsForKey = this._annotationsByKey[key];
+        if (!eventsForKey) {
+            return;
+        }
+        eventsForKey.delete(event);
+
+        // Re-sort the [key, events] pairs in descending order of event count
+        this._sortedAnnotationsByKey.sort((a, b) => {
+            const aEvents = a[1];
+            const bEvents = b[1];
+            return bEvents.size - aEvents.size;
+        });
+
+        // TODO: Remove from events by sender if needed
+    }
+
     /**
      * For relations that have been redacted, we want to remove them from
      * aggregation data sets and emit an update event.
@@ -138,24 +225,7 @@ export default class Relations extends EventEmitter {
 
         if (this.relationType === "m.annotation") {
             // Remove the redacted annotation from aggregation by key
-            const relation = redactedEvent.getRelation();
-            if (!relation) {
-                return;
-            }
-
-            const key = relation.key;
-            const eventsForKey = this._annotationsByKey[key];
-            if (!eventsForKey) {
-                return;
-            }
-            eventsForKey.delete(redactedEvent);
-
-            // Re-sort the [key, events] pairs in descending order of event count
-            this._sortedAnnotationsByKey.sort((a, b) => {
-                const aEvents = a[1];
-                const bEvents = b[1];
-                return bEvents.size - aEvents.size;
-            });
+            this._removeAnnotationFromAggregation(redactedEvent);
         }
 
         redactedEvent.removeListener("Event.beforeRedaction", this._onBeforeRedaction);

src/models/room.js

@@ -1130,7 +1130,7 @@ Room.prototype.addPendingEvent = function(event, txnId) {
     if (this._opts.pendingEventOrdering == "detached") {
         if (this._pendingEventList.some((e) => e.status === EventStatus.NOT_SENT)) {
             console.warn("Setting event as NOT_SENT due to messages in the same state");
-            event.status = EventStatus.NOT_SENT;
+            event.setStatus(EventStatus.NOT_SENT);
         }
         this._pendingEventList.push(event);
 
@@ -1287,7 +1287,7 @@ Room.prototype.updatePendingEvent = function(event, newStatus, newEventId) {
                         newStatus);
     }
 
-    event.status = newStatus;
+    event.setStatus(newStatus);
 
     if (newStatus == EventStatus.SENT) {
         // update the event id