Local echo for redactions

src/base-apis.js

@@ -887,32 +887,6 @@ MatrixBaseApis.prototype.sendStateEvent = function(roomId, eventType, content, s
     );
 };
 
-/**
- * @param {string} roomId
- * @param {string} eventId
- * @param {string} [txnId]  transaction id. One will be made up if not
- *    supplied.
- * @param {module:client.callback} callback Optional.
- * @return {module:client.Promise} Resolves: TODO
- * @return {module:http-api.MatrixError} Rejects: with an error response.
- */
-MatrixBaseApis.prototype.redactEvent = function(
-    roomId, eventId, txnId, callback,
-) {
-    if (arguments.length === 3) {
-        callback = txnId;
-    }
-
-    const path = utils.encodeUri("/rooms/$roomId/redact/$eventId/$txnId", {
-        $roomId: roomId,
-        $eventId: eventId,
-        $txnId: txnId ? txnId : this.makeTxnId(),
-    });
-
-    return this._http.authedRequest(callback, "PUT", path, undefined, {});
-};
-
-
 /**
  * @param {string} roomId
  * @param {Number} limit

src/client.js

@@ -1695,6 +1695,21 @@ MatrixClient.prototype.setPowerLevel = function(roomId, userId, powerLevel,
  */
 MatrixClient.prototype.sendEvent = function(roomId, eventType, content, txnId,
                                             callback) {
+    return this._sendCompleteEvent(roomId, {
+        type: eventType,
+        content: content,
+    }, txnId, callback);
+};
+/**
+ * @param {string} roomId
+ * @param {object} eventObject An object with the partial structure of an event, to which event_id, user_id, room_id and origin_server_ts will be added.
+ * @param {string} txnId the txnId.
+ * @param {module:client.callback} callback Optional.
+ * @return {module:client.Promise} Resolves: TODO
+ * @return {module:http-api.MatrixError} Rejects: with an error response.
+ */
+MatrixClient.prototype._sendCompleteEvent = function(roomId, eventObject, txnId,
+                                            callback) {
     if (utils.isFunction(txnId)) {
         callback = txnId; txnId = undefined;
     }
@@ -1703,20 +1718,20 @@ MatrixClient.prototype.sendEvent = function(roomId, eventType, content, txnId,
         txnId = this.makeTxnId();
     }
 
-    logger.log(`sendEvent of type ${eventType} in ${roomId} with txnId ${txnId}`);
+    const localEvent = new MatrixEvent(Object.assign(eventObject, {
+        event_id: "~" + roomId + ":" + txnId,
+        user_id: this.credentials.userId,
+        room_id: roomId,
+        origin_server_ts: new Date().getTime(),
+    }));
+
+    const type = localEvent.getType();
+    logger.log(`sendEvent of type ${type} in ${roomId} with txnId ${txnId}`);
 
     // we always construct a MatrixEvent when sending because the store and
     // scheduler use them. We'll extract the params back out if it turns out
     // the client has no scheduler or store.
     const room = this.getRoom(roomId);
-    const localEvent = new MatrixEvent({
-        event_id: "~" + roomId + ":" + txnId,
-        user_id: this.credentials.userId,
-        room_id: roomId,
-        type: eventType,
-        origin_server_ts: new Date().getTime(),
-        content: content,
-    });
     localEvent._txnId = txnId;
     localEvent.setStatus(EventStatus.SENDING);
 
@@ -1870,6 +1885,9 @@ function _sendEventHttpRequest(client, event) {
             pathTemplate = "/rooms/$roomId/state/$eventType/$stateKey";
         }
         path = utils.encodeUri(pathTemplate, pathParams);
+    } else if (event.getType() === "m.room.redaction") {
+        const pathTemplate = `/rooms/$roomId/redact/${event.event.redacts}/$txnId`;
+        path = utils.encodeUri(pathTemplate, pathParams);
     } else {
         path = utils.encodeUri(
             "/rooms/$roomId/send/$eventType/$txnId", pathParams,
@@ -1886,6 +1904,23 @@ function _sendEventHttpRequest(client, event) {
     });
 }
 
+/**
+ * @param {string} roomId
+ * @param {string} eventId
+ * @param {string} [txnId]  transaction id. One will be made up if not
+ *    supplied.
+ * @param {module:client.callback} callback Optional.
+ * @return {module:client.Promise} Resolves: TODO
+ * @return {module:http-api.MatrixError} Rejects: with an error response.
+ */
+MatrixClient.prototype.redactEvent = function(roomId, eventId, txnId, callback) {
+    return this._sendCompleteEvent(roomId, {
+        type: "m.room.redaction",
+        content: {},
+        redacts: eventId,
+    }, txnId, callback);
+};
+
 /**
  * @param {string} roomId
  * @param {Object} content

src/models/event.js

@@ -124,6 +124,7 @@ module.exports.MatrixEvent = function MatrixEvent(
     this.forwardLooking = true;
     this._pushActions = null;
     this._replacingEvent = null;
+    this._locallyRedacted = false;
 
     this._clearEvent = {};
 
@@ -228,6 +229,9 @@ utils.extend(module.exports.MatrixEvent.prototype, {
      * @return {Object} The event content JSON, or an empty object.
      */
     getOriginalContent: function() {
+        if (this._locallyRedacted) {
+            return {};
+        }
         return this._clearEvent.content || this.event.content || {};
     },
 
@@ -239,7 +243,9 @@ utils.extend(module.exports.MatrixEvent.prototype, {
      * @return {Object} The event content JSON, or an empty object.
      */
     getContent: function() {
-        if (this._replacingEvent) {
+        if (this._locallyRedacted) {
+            return {};
+        } else if (this._replacingEvent) {
             return this._replacingEvent.getContent()["m.new_content"] || {};
         } else {
             return this.getOriginalContent();
@@ -666,6 +672,27 @@ utils.extend(module.exports.MatrixEvent.prototype, {
         return this.event.unsigned || {};
     },
 
+    unmarkLocallyRedacted: function() {
+        const value = this._locallyRedacted;
+        this._locallyRedacted = false;
+        if (this.event.unsigned) {
+            this.event.unsigned.redacted_because = null;
+        }
+        return value;
+    },
+
+    markLocallyRedacted: function(redactionEvent) {
+        if (this._locallyRedacted) {
+            return;
+        }
+        this.emit("Event.beforeRedaction", this, redactionEvent);
+        this._locallyRedacted = true;
+        if (!this.event.unsigned) {
+            this.event.unsigned = {};
+        }
+        this.event.unsigned.redacted_because = redactionEvent.event;
+    },
+
     /**
      * Update the content of an event in the same way it would be by the server
      * if it were redacted before it was sent to us
@@ -679,6 +706,8 @@ utils.extend(module.exports.MatrixEvent.prototype, {
             throw new Error("invalid redaction_event in makeRedacted");
         }
 
+        this._locallyRedacted = false;
+
         this.emit("Event.beforeRedaction", this, redaction_event);
 
         this._replacingEvent = null;

src/models/room.js

@@ -1111,17 +1111,15 @@ Room.prototype.addPendingEvent = function(event, txnId) {
             // For pending events, add them to the relations collection immediately.
             // (The alternate case below already covers this as part of adding to
             // the timeline set.)
-            // TODO: We should consider whether this means it would be a better
-            // design to lift the relations handling up to the room instead.
-            for (let i = 0; i < this._timelineSets.length; i++) {
-                const timelineSet = this._timelineSets[i];
-                if (timelineSet.getFilter()) {
-                    if (this._filter.filterRoomTimeline([event]).length) {
-                        timelineSet.aggregateRelations(event);
-                    }
-                } else {
-                    timelineSet.aggregateRelations(event);
-                }
+            this._aggregateNonLiveRelation(event);
+        }
+
+        if (event.getType() === "m.room.redaction") {
+            const redactId = event.event.redacts;
+            const redactedEvent = this.getUnfilteredTimelineSet().findEventById(redactId);
+            if (redactedEvent) {
+                redactedEvent.markLocallyRedacted(event);
+                this.emit("Room.redaction", event, this);
             }
         }
     } else {
@@ -1141,6 +1139,30 @@ Room.prototype.addPendingEvent = function(event, txnId) {
 
     this.emit("Room.localEchoUpdated", event, this, null, null);
 };
+/**
+ * Used to aggregate the local echo for a relation, and also
+ * for re-applying a relation after it's redaction has been cancelled,
+ * as the local echo for the redaction of the relation would have
+ * un-aggregated the relation. Note that this is different from regular messages,
+ * which are just kept detached for their local echo.
+ *
+ * Also note that live events are aggregated in the live EventTimelineSet.
+ * @param {module:models/event.MatrixEvent} event the relation event that needs to be aggregated.
+ */
+Room.prototype._aggregateNonLiveRelation = function(event) {
+    // TODO: We should consider whether this means it would be a better
+    // design to lift the relations handling up to the room instead.
+    for (let i = 0; i < this._timelineSets.length; i++) {
+        const timelineSet = this._timelineSets[i];
+        if (timelineSet.getFilter()) {
+            if (this._filter.filterRoomTimeline([event]).length) {
+                timelineSet.aggregateRelations(event);
+            }
+        } else {
+            timelineSet.aggregateRelations(event);
+        }
+    }
+};
 
 /**
  * Deal with the echo of a message we sent.
@@ -1277,19 +1299,37 @@ Room.prototype.updatePendingEvent = function(event, newStatus, newEventId) {
     } else if (newStatus == EventStatus.CANCELLED) {
         // remove it from the pending event list, or the timeline.
         if (this._pendingEventList) {
-            utils.removeElement(
-                this._pendingEventList,
-                function(ev) {
-                    return ev.getId() == oldEventId;
-                }, false,
-            );
+            const idx = this._pendingEventList.findIndex(ev => ev.getId() === oldEventId);
+            if (idx !== -1) {
+                const [removedEvent] = this._pendingEventList.splice(idx, 1);
+                if (removedEvent.getType() === "m.room.redaction") {
+                    this._revertRedactionLocalEcho(removedEvent);
+                }
+            }
         }
         this.removeEvent(oldEventId);
     }
 
     this.emit("Room.localEchoUpdated", event, this, oldEventId, oldStatus);
 };
 
+Room.prototype._revertRedactionLocalEcho = function(redactionEvent) {
+    const redactId = redactionEvent.event.redacts;
+    if (!redactId) {
+        return;
+    }
+    const redactedEvent = this.getUnfilteredTimelineSet()
+        .findEventById(redactId);
+    if (redactedEvent) {
+        redactedEvent.unmarkLocallyRedacted();
+        // re-render after undoing redaction
+        this.emit("Room.redactionCancelled", redactionEvent, this);
+        // reapply relation now redaction failed
+        if (redactedEvent.isRelation()) {
+            this._aggregateNonLiveRelation(redactedEvent);
+        }
+    }
+};
 
 /**
  * Add some events to this room. This can include state events, message
@@ -1368,6 +1408,9 @@ Room.prototype.removeEvent = function(eventId) {
     for (let i = 0; i < this._timelineSets.length; i++) {
         const removed = this._timelineSets[i].removeEvent(eventId);
         if (removed) {
+            if (removed.getType() === "m.room.redaction") {
+                this._revertRedactionLocalEcho(removed);
+            }
             removedAny = true;
         }
     }
@@ -1795,6 +1838,17 @@ module.exports = Room;
  * @param {Room} room The room containing the redacted event
  */
 
+/**
+ * Fires when an event that was previously redacted isn't anymore.
+ * This happens when the redaction couldn't be sent and
+ * was subsequently cancelled by the user. Redactions have a local echo
+ * which is undone in this scenario.
+ *
+ * @event module:client~MatrixClient#"Room.redactionCancelled"
+ * @param {MatrixEvent} event The matrix event which isn't redacted anymore
+ * @param {Room} room The room containing the unredacted event
+ */
+
 /**
  * Fires whenever the name of a room is updated.
  * @event module:client~MatrixClient#"Room.name"

src/sync.js

@@ -127,7 +127,9 @@ SyncApi.prototype.createRoom = function(roomId) {
         timelineSupport,
         unstableClientRelationAggregation,
     });
-    client.reEmitter.reEmit(room, ["Room.name", "Room.timeline", "Room.redaction",
+    client.reEmitter.reEmit(room, ["Room.name", "Room.timeline",
+                          "Room.redaction",
+                          "Room.redactionCancelled",
                           "Room.receipt", "Room.tags",
                           "Room.timelineReset",
                           "Room.localEchoUpdated",