Merge pull request #342 from vector-im/bwindels/archive-room-on-leave

Archive room on leave

src/domain/session/RoomGridViewModel.js

@@ -15,7 +15,6 @@ limitations under the License.
 */
 
 import {ViewModel} from "../ViewModel.js";
-import {removeRoomFromPath} from "../navigation/index.js";
 
 function dedupeSparse(roomIds) {
     return roomIds.map((id, idx) => {
@@ -33,10 +32,9 @@ export class RoomGridViewModel extends ViewModel {
 
         this._width = options.width;
         this._height = options.height;
-        this._createRoomViewModel = options.createRoomViewModel;
+        this._createRoomViewModelObservable = options.createRoomViewModelObservable;
         this._selectedIndex = 0;
-        this._viewModels = [];
+        this._viewModelsObservables = [];
-        this._refreshRoomViewModel = this._refreshRoomViewModel.bind(this);
         this._setupNavigation();
     }
 
@@ -55,38 +53,17 @@ export class RoomGridViewModel extends ViewModel {
         this.track(focusedRoom.subscribe(roomId => {
             if (roomId) {
                 // as the room will be in the "rooms" observable
-                // (monitored by the parent vm) as well,
+                // (monitored by the parent vmo) as well,
                 // we only change the focus here and trust
-                // setRoomIds to have created the vm already
+                // setRoomIds to have created the vmo already
                 this._setFocusRoom(roomId);
             }
         }));
         // initial focus for a room is set by initializeRoomIdsAndTransferVM
     }
 
-    _refreshRoomViewModel(roomId) {
-        const index = this._viewModels.findIndex(vm => vm?.id === roomId);
-        if (index === -1) {
-            return;
-        }
-        this._viewModels[index] = this.disposeTracked(this._viewModels[index]);
-        // this will create a RoomViewModel because the invite is already
-        // removed from the collection (see Invite.afterSync)
-        const roomVM = this._createRoomViewModel(roomId, this._refreshRoomViewModel);
-        if (roomVM) {
-            this._viewModels[index] = this.track(roomVM);
-            if (this.focusIndex === index) {
-                roomVM.focus();
-            }
-        } else {
-            // close room id
-            this.navigation.applyPath(removeRoomFromPath(this.navigation.path, roomId));
-        }
-        this.emitChange();
-    }
-
     roomViewModelAt(i) {
-        return this._viewModels[i];
+        return this._viewModelsObservables[i]?.get();
     }
 
     get focusIndex() {
@@ -105,9 +82,9 @@ export class RoomGridViewModel extends ViewModel {
         if (index === this._selectedIndex) {
             return;
         }
-        const vm = this._viewModels[index];
+        const vmo = this._viewModelsObservables[index];
-        if (vm) {
+        if (vmo) {
-            this.navigation.push("room", vm.id);
+            this.navigation.push("room", vmo.id);
         } else {
             this.navigation.push("empty-grid-tile", index);
         }
@@ -120,7 +97,8 @@ export class RoomGridViewModel extends ViewModel {
         if (existingRoomVM) {
             const index = roomIds.indexOf(existingRoomVM.id);
             if (index !== -1) {
-                this._viewModels[index] = this.track(existingRoomVM);
+                this._viewModelsObservables[index] = this.track(existingRoomVM);
+                existingRoomVM.subscribe(viewModel => this._refreshRoomViewModel(viewModel));
                 transfered = true;
             }
         }
@@ -128,7 +106,7 @@ export class RoomGridViewModel extends ViewModel {
         // now all view models exist, set the focus to the selected room
         const focusedRoom = this.navigation.path.get("room");
         if (focusedRoom) {
-            const index = this._viewModels.findIndex(vm => vm && vm.id === focusedRoom.value);
+            const index = this._viewModelsObservables.findIndex(vmo => vmo && vmo.id === focusedRoom.value);
             if (index !== -1) {
                 this._selectedIndex = index;
             }
@@ -143,17 +121,17 @@ export class RoomGridViewModel extends ViewModel {
         const len = this._height * this._width;
         for (let i = 0; i < len; i += 1) {
             const newId = roomIds[i];
-            const vm = this._viewModels[i];
+            const vmo = this._viewModelsObservables[i];
             // did anything change?
-            if ((!vm && newId) || (vm && vm.id !== newId)) {
+            if ((!vmo && newId) || (vmo && vmo.id !== newId)) {
-                if (vm) {
+                if (vmo) {
-                    this._viewModels[i] = this.disposeTracked(vm);
+                    this._viewModelsObservables[i] = this.disposeTracked(vmo);
                 }
                 if (newId) {
-                    const newVM = this._createRoomViewModel(newId, this._refreshRoomViewModel);
+                    const vmo = this._createRoomViewModelObservable(newId);
-                    if (newVM) {
+                    this._viewModelsObservables[i] = this.track(vmo);
-                        this._viewModels[i] = this.track(newVM);
+                    vmo.subscribe(viewModel => this._refreshRoomViewModel(viewModel));
-                    }
+                    vmo.initialize();
                 }
                 changed = true;
             }
@@ -163,15 +141,21 @@ export class RoomGridViewModel extends ViewModel {
         }
         return changed;
     }
+
+    _refreshRoomViewModel(viewModel) {
+        this.emitChange();
+        viewModel?.focus();
+    }
     
     /** called from SessionViewModel */
     releaseRoomViewModel(roomId) {
-        const index = this._viewModels.findIndex(vm => vm && vm.id === roomId);
+        const index = this._viewModelsObservables.findIndex(vmo => vmo && vmo.id === roomId);
         if (index !== -1) {
-            const vm = this._viewModels[index];
+            const vmo = this._viewModelsObservables[index];
-            this.untrack(vm);
+            this.untrack(vmo);
-            this._viewModels[index] = null;
+            vmo.unsubscribeAll();
-            return vm;
+            this._viewModelsObservables[index] = null;
+            return vmo;
         }
     }
 
@@ -180,13 +164,13 @@ export class RoomGridViewModel extends ViewModel {
             return;
         }
         this._selectedIndex = idx;
-        const vm = this._viewModels[this._selectedIndex];
+        const vmo = this._viewModelsObservables[this._selectedIndex];
-        vm?.focus();
+        vmo?.get()?.focus();
         this.emitChange("focusIndex");
     }
 
     _setFocusRoom(roomId) {
-        const index = this._viewModels.findIndex(vm => vm?.id === roomId);
+        const index = this._viewModelsObservables.findIndex(vmo => vmo?.id === roomId);
         if (index >= 0) {
             this._setFocusIndex(index);
         }
@@ -194,6 +178,8 @@ export class RoomGridViewModel extends ViewModel {
 }
 
 import {createNavigation} from "../navigation/index.js";
+import {ObservableValue} from "../../observable/ObservableValue.js";
+
 export function tests() { 
     class RoomVMMock {
         constructor(id) {
@@ -209,6 +195,12 @@ export function tests() {
         }
     }
 
+    class RoomViewModelObservableMock extends ObservableValue {
+        async initialize() {}
+        dispose() { this.get()?.dispose(); }
+        get id() { return this.get()?.id; }
+    }
+
     function createNavigationForRoom(rooms, room) {
         const navigation = createNavigation();
         navigation.applyPath(navigation.pathFrom([
@@ -233,7 +225,7 @@ export function tests() {
         "initialize with duplicate set of rooms": assert => {
             const navigation = createNavigationForRoom(["c", "a", "b", undefined, "a"], "a");
             const gridVM = new RoomGridViewModel({
-                createRoomViewModel: id => new RoomVMMock(id),
+                createRoomViewModelObservable: id => new RoomViewModelObservableMock(new RoomVMMock(id)),
                 navigation,
                 width: 3,
                 height: 2,
@@ -250,12 +242,12 @@ export function tests() {
         "transfer room view model": assert => {
             const navigation = createNavigationForRoom(["a"], "a");
             const gridVM = new RoomGridViewModel({
-                createRoomViewModel: () => assert.fail("no vms should be created"),
+                createRoomViewModelObservable: () => assert.fail("no vms should be created"),
                 navigation,
                 width: 3,
                 height: 2,
             });
-            const existingRoomVM = new RoomVMMock("a");
+            const existingRoomVM = new RoomViewModelObservableMock(new RoomVMMock("a"));
             const transfered = gridVM.initializeRoomIdsAndTransferVM(navigation.path.get("rooms").value, existingRoomVM);
             assert.equal(transfered, true);
             assert.equal(gridVM.focusIndex, 0);
@@ -264,12 +256,12 @@ export function tests() {
         "reject transfer for non-matching room view model": assert => {
             const navigation = createNavigationForRoom(["a"], "a");
             const gridVM = new RoomGridViewModel({
-                createRoomViewModel: id => new RoomVMMock(id),
+                createRoomViewModelObservable: id => new RoomViewModelObservableMock(new RoomVMMock(id)),
                 navigation,
                 width: 3,
                 height: 2,
             });
-            const existingRoomVM = new RoomVMMock("f");
+            const existingRoomVM = new RoomViewModelObservableMock(new RoomVMMock("f"));
             const transfered = gridVM.initializeRoomIdsAndTransferVM(navigation.path.get("rooms").value, existingRoomVM);
             assert.equal(transfered, false);
             assert.equal(gridVM.focusIndex, 0);
@@ -278,7 +270,7 @@ export function tests() {
         "created & released room view model is not disposed": assert => {
             const navigation = createNavigationForRoom(["a"], "a");
             const gridVM = new RoomGridViewModel({
-                createRoomViewModel: id => new RoomVMMock(id),
+                createRoomViewModelObservable: id => new RoomViewModelObservableMock(new RoomVMMock(id)),
                 navigation,
                 width: 3,
                 height: 2,
@@ -287,27 +279,27 @@ export function tests() {
             assert.equal(transfered, false);
             const releasedVM = gridVM.releaseRoomViewModel("a");
             gridVM.dispose();
-            assert.equal(releasedVM.disposed, false);
+            assert.equal(releasedVM.get().disposed, false);
         },
         "transfered & released room view model is not disposed": assert => {
             const navigation = createNavigationForRoom([undefined, "a"], "a");
             const gridVM = new RoomGridViewModel({
-                createRoomViewModel: () => assert.fail("no vms should be created"),
+                createRoomViewModelObservable: () => assert.fail("no vms should be created"),
                 navigation,
                 width: 3,
                 height: 2,
             });
-            const existingRoomVM = new RoomVMMock("a");
+            const existingRoomVM = new RoomViewModelObservableMock(new RoomVMMock("a"));
             const transfered = gridVM.initializeRoomIdsAndTransferVM(navigation.path.get("rooms").value, existingRoomVM);
             assert.equal(transfered, true);
             const releasedVM = gridVM.releaseRoomViewModel("a");
             gridVM.dispose();
-            assert.equal(releasedVM.disposed, false);
+            assert.equal(releasedVM.get().disposed, false);
         },
         "try release non-existing room view model is": assert => {
             const navigation = createNavigationForEmptyTile([undefined, "b"], 3);
             const gridVM = new RoomGridViewModel({
-                createRoomViewModel: id => new RoomVMMock(id),
+                createRoomViewModelObservable: id => new RoomViewModelObservableMock(new RoomVMMock(id)),
                 navigation,
                 width: 3,
                 height: 2,
@@ -319,7 +311,7 @@ export function tests() {
         "initial focus is set to empty tile": assert => {
             const navigation = createNavigationForEmptyTile(["a"], 1);
             const gridVM = new RoomGridViewModel({
-                createRoomViewModel: id => new RoomVMMock(id),
+                createRoomViewModelObservable: id => new RoomViewModelObservableMock(new RoomVMMock(id)),
                 navigation,
                 width: 3,
                 height: 2,
@@ -331,7 +323,7 @@ export function tests() {
         "change room ids after creation": assert => {
             const navigation = createNavigationForRoom(["a", "b"], "a");
             const gridVM = new RoomGridViewModel({
-                createRoomViewModel: id => new RoomVMMock(id),
+                createRoomViewModelObservable: id => new RoomViewModelObservableMock(new RoomVMMock(id)),
                 navigation,
                 width: 3,
                 height: 2,

src/domain/session/RoomViewModelObservable.js

@@ -0,0 +1,78 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {ObservableValue} from "../../observable/ObservableValue.js";
+
+/**
+Depending on the status of a room (invited, joined, archived, or none),
+we want to show a different view with a different view model
+when showing a room. Furthermore, this logic is needed both in the 
+single room view and in the grid view. So this logic is extracted here,
+and this observable updates with the right view model as the status for
+a room changes.
+
+To not have to track the subscription manually in the SessionViewModel and
+the RoomGridViewModel, all subscriptions are removed in the dispose method.
+Only when transferring a RoomViewModelObservable between the SessionViewModel
+and RoomGridViewModel, unsubscribeAll should be  called prior to doing
+the transfer, so either parent view model don't keep getting updates for
+the now transferred child view model.
+
+This is also why there is an explicit initialize method, see comment there.
+*/
+export class RoomViewModelObservable extends ObservableValue {
+    constructor(sessionViewModel, roomId) {
+        super(null);
+        this._sessionViewModel = sessionViewModel;
+        this.id = roomId;
+    }
+
+    /**
+    Separate initialize method rather than doing this onSubscribeFirst because 
+    we don't want to run this again when transferring this value between
+    SessionViewModel and RoomGridViewModel, as onUnsubscribeLast and onSubscribeFirst
+    are called in that case.
+    */
+    async initialize() {
+        const {session} = this._sessionViewModel._sessionContainer;
+        this._statusObservable = await session.observeRoomStatus(this.id);
+        this.set(await this._statusToViewModel(this._statusObservable.get()));
+        this._statusObservable.subscribe(async status => {
+            // first dispose existing VM, if any
+            this.get()?.dispose();
+            this.set(await this._statusToViewModel(status));
+        });
+    }
+
+    async _statusToViewModel(status) {
+        if (status.invited) {
+            return this._sessionViewModel._createInviteViewModel(this.id);
+        } else if (status.joined) {
+            return this._sessionViewModel._createRoomViewModel(this.id);
+        } else if (status.archived) {
+            return await this._sessionViewModel._createArchivedRoomViewModel(this.id);
+        }
+        return null;
+    }
+
+    dispose() {
+        if (this._statusSubscription) {
+            this._statusSubscription = this._statusSubscription();
+        }
+        this.unsubscribeAll();
+        this.get()?.dispose();
+    }
+}

src/domain/session/SessionViewModel.js

@@ -15,7 +15,6 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import {removeRoomFromPath} from "../navigation/index.js";
 import {LeftPanelViewModel} from "./leftpanel/LeftPanelViewModel.js";
 import {RoomViewModel} from "./room/RoomViewModel.js";
 import {InviteViewModel} from "./room/InviteViewModel.js";
@@ -24,6 +23,7 @@ import {SessionStatusViewModel} from "./SessionStatusViewModel.js";
 import {RoomGridViewModel} from "./RoomGridViewModel.js";
 import {SettingsViewModel} from "./settings/SettingsViewModel.js";
 import {ViewModel} from "../ViewModel.js";
+import {RoomViewModelObservable} from "./RoomViewModelObservable.js";
 
 export class SessionViewModel extends ViewModel {
     constructor(options) {
@@ -40,10 +40,8 @@ export class SessionViewModel extends ViewModel {
             rooms: this._sessionContainer.session.rooms
         })));
         this._settingsViewModel = null;
-        this._currentRoomViewModel = null;
+        this._roomViewModelObservable = null;
         this._gridViewModel = null;
-        this._refreshRoomViewModel = this._refreshRoomViewModel.bind(this);
-        this._createRoomViewModel = this._createRoomViewModel.bind(this);
         this._setupNavigation();
     }
 
@@ -90,7 +88,7 @@ export class SessionViewModel extends ViewModel {
     }
 
     get activeMiddleViewModel() {
-        return this._currentRoomViewModel || this._gridViewModel || this._settingsViewModel;
+        return this._roomViewModelObservable?.get() || this._gridViewModel || this._settingsViewModel;
     }
 
     get roomGridViewModel() {
@@ -110,7 +108,7 @@ export class SessionViewModel extends ViewModel {
     }
 
     get currentRoomViewModel() {
-        return this._currentRoomViewModel;
+        return this._roomViewModelObservable?.get();
     }
 
     _updateGrid(roomIds) {
@@ -121,12 +119,14 @@ export class SessionViewModel extends ViewModel {
                 this._gridViewModel = this.track(new RoomGridViewModel(this.childOptions({
                     width: 3,
                     height: 2,
-                    createRoomViewModel: this._createRoomViewModel,
+                    createRoomViewModelObservable: roomId => new RoomViewModelObservable(this, roomId),
                 })));
-                if (this._gridViewModel.initializeRoomIdsAndTransferVM(roomIds, this._currentRoomViewModel)) {
+                // try to transfer the current room view model, so we don't have to reload the timeline
-                    this._currentRoomViewModel = this.untrack(this._currentRoomViewModel);
+                this._roomViewModelObservable?.unsubscribeAll();
-                } else if (this._currentRoomViewModel) {
+                if (this._gridViewModel.initializeRoomIdsAndTransferVM(roomIds, this._roomViewModelObservable)) {
-                    this._currentRoomViewModel = this.disposeTracked(this._currentRoomViewModel);
+                    this._roomViewModelObservable = this.untrack(this._roomViewModelObservable);
+                } else if (this._roomViewModelObservable) {
+                    this._roomViewModelObservable = this.disposeTracked(this._roomViewModelObservable);
                 }
             } else {
                 this._gridViewModel.setRoomIds(roomIds);
@@ -134,14 +134,12 @@ export class SessionViewModel extends ViewModel {
         } else if (this._gridViewModel && !roomIds) {
             // closing grid, try to show focused room in grid
             if (currentRoomId) {
-                const vm = this._gridViewModel.releaseRoomViewModel(currentRoomId.value);
+                const vmo = this._gridViewModel.releaseRoomViewModel(currentRoomId.value);
-                if (vm) {
+                if (vmo) {
-                    this._currentRoomViewModel = this.track(vm);
+                    this._roomViewModelObservable = this.track(vmo);
-                } else {
+                    this._roomViewModelObservable.subscribe(() => {
-                    const newVM = this._createRoomViewModel(currentRoomId.value, this._refreshRoomViewModel);
+                        this.emitChange("activeMiddleViewModel");
-                    if (newVM) {
+                    });
-                        this._currentRoomViewModel = this.track(newVM);
-                    }
                 }
             }
             this._gridViewModel = this.disposeTracked(this._gridViewModel);
@@ -151,63 +149,65 @@ export class SessionViewModel extends ViewModel {
         }
     }
 
-    /**
+    _createRoomViewModel(roomId) {
-     * @param  {string} roomId
+        const room = this._sessionContainer.session.rooms.get(roomId);
-     * @param  {function} refreshRoomViewModel passed in as an argument, because the grid needs a different impl of this
+        if (room) {
-     * @return {RoomViewModel | InviteViewModel}
+            const roomVM = new RoomViewModel(this.childOptions({
-     */
+                room,
-    _createRoomViewModel(roomId, refreshRoomViewModel) {
+                ownUserId: this._sessionContainer.session.user.id,
+            }));
+            roomVM.load();
+            return roomVM;
+        }
+        return null;
+    }
+
+    async _createArchivedRoomViewModel(roomId) {
+        const room = await this._sessionContainer.session.loadArchivedRoom(roomId);
+        if (room) {
+            const roomVM = new RoomViewModel(this.childOptions({
+                room,
+                ownUserId: this._sessionContainer.session.user.id,
+            }));
+            roomVM.load();
+            return roomVM;
+        }
+        return null;
+    }
+
+    _createInviteViewModel(roomId) {
         const invite = this._sessionContainer.session.invites.get(roomId);
         if (invite) {
             return new InviteViewModel(this.childOptions({
                 invite,
                 mediaRepository: this._sessionContainer.session.mediaRepository,
-                refreshRoomViewModel,
             }));
-        } else {
-            const room = this._sessionContainer.session.rooms.get(roomId);
-            if (room) {
-                const roomVM = new RoomViewModel(this.childOptions({
-                    room,
-                    ownUserId: this._sessionContainer.session.user.id,
-                    refreshRoomViewModel
-                }));
-                roomVM.load();
-                return roomVM;
-            }
         }
         return null;
     }
 
-    /** refresh the room view model after an internal change that needs
-    to change between invite, room or none state */
-    _refreshRoomViewModel(roomId) {
-        this._currentRoomViewModel = this.disposeTracked(this._currentRoomViewModel);
-        const roomVM = this._createRoomViewModel(roomId, this._refreshRoomViewModel);
-        if (roomVM) {
-            this._currentRoomViewModel = this.track(roomVM);
-        } else {
-            // close room id
-            this.navigation.applyPath(removeRoomFromPath(this.navigation.path, roomId));
-        }
-        this.emitChange("activeMiddleViewModel");
-    }
-
     _updateRoom(roomId) {
         // opening a room and already open?
-        if (this._currentRoomViewModel?.id === roomId) {
+        if (this._roomViewModelObservable?.id === roomId) {
             return;
         }
         // close if needed
-        if (this._currentRoomViewModel) {
+        if (this._roomViewModelObservable) {
-            this._currentRoomViewModel = this.disposeTracked(this._currentRoomViewModel);
+            this._roomViewModelObservable = this.disposeTracked(this._roomViewModelObservable);
         }
-        // and try opening again
+        if (!roomId) {
-        const roomVM = this._createRoomViewModel(roomId, this._refreshRoomViewModel);
+            // if clearing the activeMiddleViewModel rather than changing to a different one,
-        if (roomVM) {
+            // emit so the view picks it up and show the placeholder
-            this._currentRoomViewModel = this.track(roomVM);
+            this.emitChange("activeMiddleViewModel");
+            return;
         }
-        this.emitChange("activeMiddleViewModel");
+        const vmo = new RoomViewModelObservable(this, roomId);
+        this._roomViewModelObservable = this.track(vmo);
+        // subscription is unsubscribed in RoomViewModelObservable.dispose, and thus handled by track
+        this._roomViewModelObservable.subscribe(() => {
+            this.emitChange("activeMiddleViewModel");
+        });
+        vmo.initialize();
     }
 
     _updateSettings(settingsOpen) {

src/domain/session/leftpanel/LeftPanelViewModel.js

@@ -35,9 +35,8 @@ export class LeftPanelViewModel extends ViewModel {
     }
 
     _mapTileViewModels(rooms, invites) {
-        const joinedRooms = rooms.filterValues(room => room.membership === "join");
         // join is not commutative, invites will take precedence over rooms
-        return invites.join(joinedRooms).mapValues((roomOrInvite, emitChange) => {
+        return invites.join(rooms).mapValues((roomOrInvite, emitChange) => {
             const isOpen = this.navigation.path.get("room")?.value === roomOrInvite.id;
             let vm;
             if (roomOrInvite.isInvite) {

src/domain/session/room/InviteViewModel.js

@@ -21,10 +21,9 @@ import {ViewModel} from "../../ViewModel.js";
 export class InviteViewModel extends ViewModel {
     constructor(options) {
         super(options);
-        const {invite, mediaRepository, refreshRoomViewModel} = options;
+        const {invite, mediaRepository} = options;
         this._invite = invite;
         this._mediaRepository = mediaRepository;
-        this._refreshRoomViewModel = refreshRoomViewModel;
         this._onInviteChange = this._onInviteChange.bind(this);
         this._error = null;
         this._closeUrl = this.urlCreator.urlUntilSegment("session");
@@ -107,17 +106,7 @@ export class InviteViewModel extends ViewModel {
     }
 
     _onInviteChange() {
-        if (this._invite.accepted || this._invite.rejected) {
+        this.emitChange();
-            // close invite if rejected, or open room if accepted.
-            // Done with a callback rather than manipulating the nav,
-            // as closing the invite changes the nav path depending whether
-            // we're in a grid view, and opening the room doesn't change
-            // the nav path because the url is the same for an
-            // invite and the room.
-            this._refreshRoomViewModel(this.id);
-        } else {
-            this.emitChange();
-        }
     }
 
     dispose() {

src/domain/session/room/RoomViewModel.js

@@ -22,15 +22,19 @@ import {ViewModel} from "../../ViewModel.js";
 export class RoomViewModel extends ViewModel {
     constructor(options) {
         super(options);
-        const {room, ownUserId, refreshRoomViewModel} = options;
+        const {room, ownUserId} = options;
         this._room = room;
         this._ownUserId = ownUserId;
-        this._refreshRoomViewModel = refreshRoomViewModel;
         this._timelineVM = null;
         this._onRoomChange = this._onRoomChange.bind(this);
         this._timelineError = null;
         this._sendError = null;
-        this._composerVM = new ComposerViewModel(this);
+        this._composerVM = null;
+        if (room.isArchived) {
+            this._composerVM = new ArchivedViewModel(this.childOptions({archivedRoom: room}));
+        } else {
+            this._composerVM = new ComposerViewModel(this);
+        }
         this._clearUnreadTimout = null;
         this._closeUrl = this.urlCreator.urlUntilSegment("session");
     }
@@ -55,7 +59,7 @@ export class RoomViewModel extends ViewModel {
     }
 
     async _clearUnreadAfterDelay() {
-        if (this._clearUnreadTimout) {
+        if (this._room.isArchived || this._clearUnreadTimout) {
             return;
         }
         this._clearUnreadTimout = this.clock.createTimeout(2000);
@@ -77,6 +81,9 @@ export class RoomViewModel extends ViewModel {
     dispose() {
         super.dispose();
         this._room.off("change", this._onRoomChange);
+        if (this._room.isArchived) {
+            this._room.release();
+        }
         if (this._clearUnreadTimout) {
             this._clearUnreadTimout.abort();
             this._clearUnreadTimout = null;
@@ -86,13 +93,10 @@ export class RoomViewModel extends ViewModel {
     // room doesn't tell us yet which fields changed,
     // so emit all fields originating from summary
     _onRoomChange() {
-        // if there is now an invite on this (left) room,
+        if (this._room.isArchived) {
-        // show the invite view by refreshing the view model
+            this._composerVM.emitChange();
-        if (this._room.invite) {
-            this._refreshRoomViewModel(this.id);
-        } else {
-            this.emitChange("name");
         }
+        this.emitChange();
     }
 
     get kind() { return "room"; }
@@ -129,7 +133,7 @@ export class RoomViewModel extends ViewModel {
     }
     
     async _sendMessage(message) {
-        if (message) {
+        if (!this._room.isArchived && message) {
             try {
                 let msgtype = "m.text";
                 if (message.startsWith("/me ")) {
@@ -310,6 +314,10 @@ class ComposerViewModel extends ViewModel {
             this.emitChange("canSend");
         }
     }
+
+    get kind() {
+        return "composer";
+    }
 }
 
 function imageToInfo(image) {
@@ -326,3 +334,32 @@ function videoToInfo(video) {
     info.duration = video.duration;
     return info;
 }
+
+class ArchivedViewModel extends ViewModel {
+    constructor(options) {
+        super(options);
+        this._archivedRoom = options.archivedRoom;
+    }
+
+    get description() {
+        if (this._archivedRoom.isKicked) {
+            if (this._archivedRoom.kickReason) {
+                return this.i18n`You were kicked from the room by ${this._archivedRoom.kickedBy.name} because: ${this._archivedRoom.kickReason}`;
+            } else {
+                return this.i18n`You were kicked from the room by ${this._archivedRoom.kickedBy.name}.`;
+            }
+        } else if (this._archivedRoom.isBanned) {
+            if (this._archivedRoom.kickReason) {
+                return this.i18n`You were banned from the room by ${this._archivedRoom.kickedBy.name} because: ${this._archivedRoom.kickReason}`;
+            } else {
+                return this.i18n`You were banned from the room by ${this._archivedRoom.kickedBy.name}.`;
+            }
+        } else {
+            return this.i18n`You left this room`;
+        }
+    }
+
+    get kind() {
+        return "archived";
+    }
+}

src/matrix/Session.js

@@ -16,6 +16,8 @@ limitations under the License.
 */
 
 import {Room} from "./room/Room.js";
+import {ArchivedRoom} from "./room/ArchivedRoom.js";
+import {RoomStatus} from "./room/RoomStatus.js";
 import {Invite} from "./room/Invite.js";
 import {Pusher} from "./push/Pusher.js";
 import { ObservableMap } from "../observable/index.js";
@@ -38,7 +40,7 @@ import {
     writeKey as ssssWriteKey,
 } from "./ssss/index.js";
 import {SecretStorage} from "./ssss/SecretStorage.js";
-import {ObservableValue} from "../observable/ObservableValue.js";
+import {ObservableValue, RetainedObservableValue} from "../observable/ObservableValue.js";
 
 const PICKLE_KEY = "DEFAULT_KEY";
 const PUSHER_KEY = "pusher";
@@ -54,8 +56,8 @@ export class Session {
         this._sessionInfo = sessionInfo;
         this._rooms = new ObservableMap();
         this._roomUpdateCallback = (room, params) => this._rooms.update(room.id, params);
+        this._activeArchivedRooms = new Map();
         this._invites = new ObservableMap();
-        this._inviteRemoveCallback = invite => this._invites.remove(invite.id);
         this._inviteUpdateCallback = (invite, params) => this._invites.update(invite.id, params);
         this._user = new User(sessionInfo.userId);
         this._deviceMessageHandler = new DeviceMessageHandler({storage});
@@ -70,6 +72,7 @@ export class Session {
         this._olmWorker = olmWorker;
         this._sessionBackup = null;
         this._hasSecretStorageKey = new ObservableValue(null);
+        this._observedRoomStatus = new Map();
 
         if (olm) {
             this._olmUtil = new olm.Utility();
@@ -397,8 +400,21 @@ export class Session {
     }
 
     /** @internal */
-    addRoomAfterSync(room) {
+    _createArchivedRoom(roomId) {
-        this._rooms.add(room.id, room);
+        const room = new ArchivedRoom({
+            roomId,
+            getSyncToken: this._getSyncToken,
+            storage: this._storage,
+            emitCollectionChange: () => {},
+            releaseCallback: () => this._activeArchivedRooms.delete(roomId),
+            hsApi: this._hsApi,
+            mediaRepository: this._mediaRepository,
+            user: this._user,
+            createRoomEncryption: this._createRoomEncryption,
+            platform: this._platform
+        });
+        this._activeArchivedRooms.set(roomId, room);
+        return room;
     }
 
     get invites() {
@@ -410,7 +426,6 @@ export class Session {
         return new Invite({
             roomId,
             hsApi: this._hsApi,
-            emitCollectionRemove: this._inviteRemoveCallback,
             emitCollectionUpdate: this._inviteUpdateCallback,
             mediaRepository: this._mediaRepository,
             user: this._user,
@@ -418,11 +433,6 @@ export class Session {
         });
     }
 
-    /** @internal */
-    addInviteAfterSync(invite) {
-        this._invites.add(invite.id, invite);
-    }
-
     async obtainSyncLock(syncResponse) {
         const toDeviceEvents = syncResponse.to_device?.events;
         if (Array.isArray(toDeviceEvents) && toDeviceEvents.length) {
@@ -502,6 +512,49 @@ export class Session {
         }
     }
 
+    applyRoomCollectionChangesAfterSync(inviteStates, roomStates, archivedRoomStates) {
+        // update the collections after sync
+        for (const rs of roomStates) {
+            if (rs.shouldAdd) {
+                this._rooms.add(rs.id, rs.room);
+            } else if (rs.shouldRemove) {
+                this._rooms.remove(rs.id);
+            }
+        }
+        for (const is of inviteStates) {
+            if (is.shouldAdd) {
+                this._invites.add(is.id, is.invite);
+            } else if (is.shouldRemove) {
+                this._invites.remove(is.id);
+            }
+        }
+        // now all the collections are updated, update the room status
+        // so any listeners to the status will find the collections
+        // completely up to date
+        if (this._observedRoomStatus.size !== 0) {
+            for (const ars of archivedRoomStates) {
+                if (ars.shouldAdd) {
+                    this._observedRoomStatus.get(ars.id)?.set(RoomStatus.archived);
+                }
+            }
+            for (const rs of roomStates) {
+                if (rs.shouldAdd) {
+                    this._observedRoomStatus.get(rs.id)?.set(RoomStatus.joined);
+                }
+            }
+            for (const is of inviteStates) {
+                const statusObservable = this._observedRoomStatus.get(is.id);
+                if (statusObservable) {
+                    if (is.shouldAdd) {
+                        statusObservable.set(statusObservable.get().withInvited());
+                    } else if (is.shouldRemove) {
+                        statusObservable.set(statusObservable.get().withoutInvited());
+                    }
+                }
+            }
+        }
+    }
+
     /** @internal */
     get syncToken() {
         return this._syncInfo?.token;
@@ -585,6 +638,76 @@ export class Session {
         const serverPushers = (serverPushersData?.pushers || []).map(data => new Pusher(data));
         return serverPushers.some(p => p.equals(myPusher));
     }
+
+    async getRoomStatus(roomId) {
+        const isJoined = !!this._rooms.get(roomId);
+        if (isJoined) {
+            return RoomStatus.joined;
+        } else {
+            const isInvited = !!this._invites.get(roomId);
+            const txn = await this._storage.readTxn([this._storage.storeNames.archivedRoomSummary]);
+            const isArchived = await txn.archivedRoomSummary.has(roomId);
+            if (isInvited && isArchived) {
+                return RoomStatus.invitedAndArchived;
+            } else if (isInvited) {
+                return RoomStatus.invited;
+            } else if (isArchived) {
+                return RoomStatus.archived;
+            } else {
+                return RoomStatus.none;
+            }
+        }
+    }
+
+    async observeRoomStatus(roomId) {
+        let observable = this._observedRoomStatus.get(roomId);
+        if (!observable) {
+            const status = await this.getRoomStatus(roomId);
+            observable = new RetainedObservableValue(status, () => {
+                this._observedRoomStatus.delete(roomId);
+            });
+            this._observedRoomStatus.set(roomId, observable);
+        }
+        return observable;
+    }
+
+    /**
+    Creates an empty (summary isn't loaded) the archived room if it isn't
+    loaded already, assuming sync will either remove it (when rejoining) or
+    write a full summary adopting it from the joined room when leaving
+    
+    @internal
+    */
+    createOrGetArchivedRoomForSync(roomId) {
+        let archivedRoom = this._activeArchivedRooms.get(roomId);
+        if (archivedRoom) {
+            archivedRoom.retain();
+        } else {
+            archivedRoom = this._createArchivedRoom(roomId);
+        }
+        return archivedRoom;
+    }
+
+    loadArchivedRoom(roomId, log = null) {
+        return this._platform.logger.wrapOrRun(log, "loadArchivedRoom", async log => {
+            log.set("id", roomId);
+            const activeArchivedRoom = this._activeArchivedRooms.get(roomId);
+            if (activeArchivedRoom) {
+                activeArchivedRoom.retain();
+                return activeArchivedRoom;
+            }
+            const txn = await this._storage.readTxn([
+                this._storage.storeNames.archivedRoomSummary,
+                this._storage.storeNames.roomMembers,
+            ]);
+            const summary = await txn.archivedRoomSummary.get(roomId);
+            if (summary) {
+                const room = this._createArchivedRoom(roomId);
+                await room.load(summary, txn, log);
+                return room;
+            }
+        });
+    }
 }
 
 export function tests() {

src/matrix/Sync.js

@@ -192,7 +192,8 @@ export class Sync {
         const isInitialSync = !syncToken;
         const sessionState = new SessionSyncProcessState();
         const inviteStates = this._parseInvites(response.rooms);
-        const roomStates = this._parseRoomsResponse(response.rooms, inviteStates, isInitialSync);
+        const {roomStates, archivedRoomStates} = await this._parseRoomsResponse(
+            response.rooms, inviteStates, isInitialSync, log);
 
         try {
             // take a lock on olm sessions used in this sync so sending a message doesn't change them while syncing
@@ -202,12 +203,14 @@ export class Sync {
                 return rs.room.afterPrepareSync(rs.preparation, log);
             })));
             await log.wrap("write", async log => this._writeSync(
-                sessionState, inviteStates, roomStates, response, syncFilterId, isInitialSync, log));
+                sessionState, inviteStates, roomStates, archivedRoomStates,
+                response, syncFilterId, isInitialSync, log));
         } finally {
             sessionState.dispose();
         }
         // sync txn comitted, emit updates and apply changes to in-memory state
-        log.wrap("after", log => this._afterSync(sessionState, inviteStates, roomStates, log));
+        log.wrap("after", log => this._afterSync(
+            sessionState, inviteStates, roomStates, archivedRoomStates, log));
 
         const toDeviceEvents = response.to_device?.events;
         return {
@@ -223,7 +226,11 @@ export class Sync {
         return this._storage.readTxn([
             storeNames.olmSessions,
             storeNames.inboundGroupSessions,
-            storeNames.timelineEvents // to read events that can now be decrypted
+            // to read fragments when loading sync writer when rejoining archived room
+            storeNames.timelineFragments,
+            // to read fragments when loading sync writer when rejoining archived room
+            // to read events that can now be decrypted
+            storeNames.timelineEvents,
         ]);
     }
 
@@ -250,15 +257,22 @@ export class Sync {
         
         await Promise.all(roomStates.map(async rs => {
             const newKeys = newKeysByRoom?.get(rs.room.id);
-            rs.preparation = await log.wrap("room", log => rs.room.prepareSync(
+            rs.preparation = await log.wrap("room", async log => {
-                rs.roomResponse, rs.membership, rs.invite, newKeys, prepareTxn, log), log.level.Detail);
+                // if previously joined and we still have the timeline for it,
+                // this loads the syncWriter at the correct position to continue writing the timeline
+                if (rs.isNewRoom) {
+                    await rs.room.load(null, prepareTxn, log);
+                }
+                return rs.room.prepareSync(
+                    rs.roomResponse, rs.membership, rs.invite, newKeys, prepareTxn, log)
+            }, log.level.Detail);
         }));
 
         // This is needed for safari to not throw TransactionInactiveErrors on the syncTxn. See docs/INDEXEDDB.md
         await prepareTxn.complete();
     }
 
-    async _writeSync(sessionState, inviteStates, roomStates, response, syncFilterId, isInitialSync, log) {
+    async _writeSync(sessionState, inviteStates, roomStates, archivedRoomStates, response, syncFilterId, isInitialSync, log) {
         const syncTxn = await this._openSyncTxn();
         try {
             sessionState.changes = await log.wrap("session", log => this._session.writeSync(
@@ -271,6 +285,13 @@ export class Sync {
                 rs.changes = await log.wrap("room", log => rs.room.writeSync(
                     rs.roomResponse, isInitialSync, rs.preparation, syncTxn, log));
             }));
+            // important to do this after roomStates,
+            // as we're referring to the roomState to get the summaryChanges
+            await Promise.all(archivedRoomStates.map(async ars => {
+                const summaryChanges = ars.roomState?.summaryChanges;
+                ars.changes = await log.wrap("archivedRoom", log => ars.archivedRoom.writeSync(
+                    summaryChanges, ars.roomResponse, ars.membership, syncTxn, log));
+            }));
         } catch(err) {
             // avoid corrupting state by only
             // storing the sync up till the point
@@ -285,30 +306,21 @@ export class Sync {
         await syncTxn.complete();
     }
 
-    _afterSync(sessionState, inviteStates, roomStates, log) {
+    _afterSync(sessionState, inviteStates, roomStates, archivedRoomStates, log) {
         log.wrap("session", log => this._session.afterSync(sessionState.changes, log), log.level.Detail);
-        // emit room related events after txn has been closed
+        for(let ars of archivedRoomStates) {
+            log.wrap("archivedRoom", log => {
+                ars.archivedRoom.afterSync(ars.changes, log);
+                ars.archivedRoom.release();
+            }, log.level.Detail);
+        }
         for(let rs of roomStates) {
             log.wrap("room", log => rs.room.afterSync(rs.changes, log), log.level.Detail);
-            if (rs.isNewRoom) {
-                // important to add the room before removing the invite,
-                // so the room will be found if looking for it when the invite
-                // is removed
-                this._session.addRoomAfterSync(rs.room);
-            }
         }
-        // emit invite related events after txn has been closed
         for(let is of inviteStates) {
-            log.wrap("invite", () => is.invite.afterSync(is.changes), log.level.Detail);
+            log.wrap("invite", log => is.invite.afterSync(is.changes, log), log.level.Detail);
-            if (is.isNewInvite) {
-                this._session.addInviteAfterSync(is.invite);
-            }
-            // if we haven't archived or forgotten the (left) room yet,
-            // notify there is an invite now, so we can update the UI
-            if (is.room) {
-                is.room.setInvite(is.invite);
-            }
         }
+        this._session.applyRoomCollectionChangesAfterSync(inviteStates, roomStates, archivedRoomStates);
     }
 
     _openSyncTxn() {
@@ -316,6 +328,7 @@ export class Sync {
         return this._storage.readWriteTxn([
             storeNames.session,
             storeNames.roomSummary,
+            storeNames.archivedRoomSummary,
             storeNames.invites,
             storeNames.roomState,
             storeNames.roomMembers,
@@ -336,8 +349,9 @@ export class Sync {
         ]);
     }
     
-    _parseRoomsResponse(roomsSection, inviteStates, isInitialSync) {
+    async _parseRoomsResponse(roomsSection, inviteStates, isInitialSync, log) {
         const roomStates = [];
+        const archivedRoomStates = [];
         if (roomsSection) {
             const allMemberships = ["join", "leave"];
             for(const membership of allMemberships) {
@@ -349,28 +363,71 @@ export class Sync {
                         if (isInitialSync && timelineIsEmpty(roomResponse)) {
                             continue;
                         }
-                        let isNewRoom = false;
-                        let room = this._session.rooms.get(roomId);
-                        // don't create a room for a rejected invite
-                        if (!room && membership === "join") {
-                            room = this._session.createRoom(roomId);
-                            isNewRoom = true;
-                        }
                         const invite = this._session.invites.get(roomId);
                         // if there is an existing invite, add a process state for it
                         // so its writeSync and afterSync will run and remove the invite
                         if (invite) {
-                            inviteStates.push(new InviteSyncProcessState(invite, false, null, membership, null));
+                            inviteStates.push(new InviteSyncProcessState(invite, false, null, membership));
                         }
-                        if (room) {
+                        const roomState = this._createRoomSyncState(roomId, invite, roomResponse, membership, isInitialSync);
-                            roomStates.push(new RoomSyncProcessState(
+                        if (roomState) {
-                                room, isNewRoom, invite, roomResponse, membership));
+                            roomStates.push(roomState);
+                        }
+                        const ars = await this._createArchivedRoomSyncState(roomId, roomState, roomResponse, membership, isInitialSync, log);
+                        if (ars) {
+                            archivedRoomStates.push(ars);
                         }
                     }
                 }
             }
         }
-        return roomStates;
+        return {roomStates, archivedRoomStates};
+    }
+
+    _createRoomSyncState(roomId, invite, roomResponse, membership, isInitialSync) {
+        let isNewRoom = false;
+        let room = this._session.rooms.get(roomId);
+        // create room only either on new join,
+        // or for an archived room during initial sync,
+        // where we create the summaryChanges with a joined
+        // room to then adopt by the archived room.
+        // This way the limited timeline, members, ...
+        // we receive also gets written.
+        // In any case, don't create a room for a rejected invite
+        if (!room && (membership === "join" || (isInitialSync && membership === "leave"))) {
+            room = this._session.createRoom(roomId);
+            isNewRoom = true;
+        }
+        if (room) {
+            return new RoomSyncProcessState(
+                room, isNewRoom, invite, roomResponse, membership);
+        }
+    }
+
+    async _createArchivedRoomSyncState(roomId, roomState, roomResponse, membership, isInitialSync, log) {
+        let archivedRoom;
+        if (roomState?.shouldAdd && !isInitialSync) {
+            // when adding a joined room during incremental sync,
+            // always create the archived room to write the removal
+            // of the archived summary
+            archivedRoom = this._session.createOrGetArchivedRoomForSync(roomId);
+        } else if (membership === "leave") {
+            if (roomState) {
+                // we still have a roomState, so we just left it
+                // in this case, create a new archivedRoom
+                archivedRoom = this._session.createOrGetArchivedRoomForSync(roomId);
+            } else {
+                // this is an update of an already left room, restore
+                // it from storage first, so we can increment it.
+                // this happens for example when our membership changes
+                // after leaving (e.g. being (un)banned, possibly after being kicked), etc
+                archivedRoom = await this._session.loadArchivedRoom(roomId, log);
+            }
+        }
+        if (archivedRoom) {
+            return new ArchivedRoomSyncProcessState(
+                archivedRoom, roomState, roomResponse, membership);
+        }
     }
 
     _parseInvites(roomsSection) {
@@ -383,8 +440,7 @@ export class Sync {
                     invite = this._session.createInvite(roomId);
                     isNewInvite = true;
                 }
-                const room = this._session.rooms.get(roomId);
+                inviteStates.push(new InviteSyncProcessState(invite, isNewInvite, roomResponse, "invite"));
-                inviteStates.push(new InviteSyncProcessState(invite, isNewInvite, room, "invite", roomResponse));
             }
         }
         return inviteStates;
@@ -425,15 +481,66 @@ class RoomSyncProcessState {
         this.preparation = null;
         this.changes = null;
     }
+
+    get id() {
+        return this.room.id;
+    }
+
+    get shouldAdd() {
+        return this.isNewRoom && this.membership === "join";
+    }
+
+    get shouldRemove() {
+        return !this.isNewRoom && this.membership !== "join";
+    }
+
+    get summaryChanges() {
+        return this.changes?.summaryChanges;
+    }
+}
+
+
+class ArchivedRoomSyncProcessState {
+    constructor(archivedRoom, roomState, roomResponse, membership, isInitialSync) {
+        this.archivedRoom = archivedRoom;
+        this.roomState = roomState;
+        this.roomResponse = roomResponse;
+        this.membership = membership;
+        this.isInitialSync = isInitialSync;
+        this.changes = null;
+    }
+
+    get id() {
+        return this.archivedRoom.id;
+    }
+
+    get shouldAdd() {
+        return (this.roomState || this.isInitialSync) && this.membership === "leave";
+    }
+
+    get shouldRemove() {
+        return this.membership === "join";
+    }
 }
 
 class InviteSyncProcessState {
-    constructor(invite, isNewInvite, room, membership, roomResponse) {
+    constructor(invite, isNewInvite, roomResponse, membership) {
         this.invite = invite;
         this.isNewInvite = isNewInvite;
-        this.room = room;
         this.membership = membership;
         this.roomResponse = roomResponse;
         this.changes = null;
     }
+
+    get id() {
+        return this.invite.id;
+    }
+
+    get shouldAdd() {
+        return this.isNewInvite;
+    }
+
+    get shouldRemove() {
+        return this.membership !== "invite";
+    }
 }

src/matrix/e2ee/DeviceTracker.js

@@ -121,24 +121,38 @@ export class DeviceTracker {
         }
     }
 
+    async _removeRoomFromUserIdentity(roomId, userId, txn) {
+        const {userIdentities, deviceIdentities} = txn;
+        const identity = await userIdentities.get(userId);
+        if (identity) {
+            identity.roomIds = identity.roomIds.filter(id => id !== roomId);
+            // no more encrypted rooms with this user, remove
+            if (identity.roomIds.length === 0) {
+                userIdentities.remove(userId);
+                deviceIdentities.removeAllForUser(userId);
+            } else {
+                userIdentities.set(identity);
+            }
+        }
+    }
+
     async _applyMemberChange(memberChange, txn) {
         // TODO: depends whether we encrypt for invited users??
         // add room
-        if (memberChange.previousMembership !== "join" && memberChange.membership === "join") {
+        if (memberChange.hasJoined) {
             await this._writeMember(memberChange.member, txn);
         }
         // remove room
-        else if (memberChange.previousMembership === "join" && memberChange.membership !== "join") {
+        else if (memberChange.hasLeft) {
-            const {userIdentities} = txn;
+            const {roomId} = memberChange;
-            const identity = await userIdentities.get(memberChange.userId);
+            // if we left the room, remove room from all user identities in the room
-            if (identity) {
+            if (memberChange.userId === this._ownUserId) {
-                identity.roomIds = identity.roomIds.filter(roomId => roomId !== memberChange.roomId);
+                const userIds = await txn.roomMembers.getAllUserIds(roomId);
-                // no more encrypted rooms with this user, remove
+                await Promise.all(userIds.map(userId => {
-                if (identity.roomIds.length === 0) {
+                    return this._removeRoomFromUserIdentity(roomId, userId, txn);
-                    userIdentities.remove(identity.userId);
+                }));
-                } else {
+            } else {
-                    userIdentities.set(identity);
+                await this._removeRoomFromUserIdentity(roomId, memberChange.userId, txn);
-                }
             }
         }
     }

src/matrix/e2ee/RoomEncryption.js

@@ -83,8 +83,9 @@ export class RoomEncryption {
     }
 
     async writeMemberChanges(memberChanges, txn, log) {
-        let shouldFlush;
+        let shouldFlush = false;
         const memberChangesArray = Array.from(memberChanges.values());
+        // this also clears our session if we leave the room ourselves
         if (memberChangesArray.some(m => m.hasLeft)) {
             log.log({
                 l: "discardOutboundSession",

src/matrix/room/ArchivedRoom.js

@@ -0,0 +1,193 @@
+/*
+Copyright 2020 Bruno Windels <bruno@windels.cloud>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {reduceStateEvents} from "./RoomSummary.js";
+import {BaseRoom} from "./BaseRoom.js";
+import {RoomMember, EVENT_TYPE as MEMBER_EVENT_TYPE} from "./members/RoomMember.js";
+
+export class ArchivedRoom extends BaseRoom {
+    constructor(options) {
+        super(options);
+        // archived rooms are reference counted,
+        // as they are not kept in memory when not needed
+        this._releaseCallback = options.releaseCallback;
+        this._retentionCount = 1;
+        /**
+        Some details from our own member event when being kicked or banned.
+        We can't get this from the member store, because we don't store the reason field there.
+        */
+        this._kickDetails = null;
+        this._kickedBy = null;
+    }
+
+    retain() {
+        this._retentionCount += 1;
+    }
+
+    release() {
+        this._retentionCount -= 1;
+        if (this._retentionCount === 0) {
+            this._releaseCallback();
+        }
+    }
+
+    async _getKickAuthor(sender, txn) {
+        const senderMember = await txn.roomMembers.get(this.id, sender);
+        if (senderMember) {
+            return new RoomMember(senderMember);
+        } else {
+            return RoomMember.fromUserId(this.id, sender, "join");
+        }
+    }
+    
+    async load(archivedRoomSummary, txn, log) {
+        const {summary, kickDetails} = archivedRoomSummary;
+        this._kickDetails = kickDetails;
+        if (this._kickDetails) {
+            this._kickedBy = await this._getKickAuthor(this._kickDetails.sender, txn);
+        }
+        return super.load(summary, txn, log);
+    }
+
+    /** @package */
+    async writeSync(joinedSummaryData, roomResponse, membership, txn, log) {
+        log.set("id", this.id);
+        if (membership === "leave") {
+            const newKickDetails = findKickDetails(roomResponse, this._user.id);
+            if (newKickDetails || joinedSummaryData) {
+                const kickDetails = newKickDetails || this._kickDetails;
+                let kickedBy;
+                if (newKickDetails) {
+                    kickedBy = await this._getKickAuthor(newKickDetails.sender, txn);
+                }
+                const summaryData = joinedSummaryData || this._summary.data;
+                txn.archivedRoomSummary.set({
+                    summary: summaryData.serialize(),
+                    kickDetails,
+                });
+                return {kickDetails, kickedBy, summaryData};
+            }
+        } else if (membership === "join") {
+            txn.archivedRoomSummary.remove(this.id);
+        }
+        // always return object
+        return {};
+    }
+
+    /**
+     * @package
+     * Called with the changes returned from `writeSync` to apply them and emit changes.
+     * No storage or network operations should be done here.
+     */
+    afterSync({summaryData, kickDetails, kickedBy}, log) {
+        log.set("id", this.id);
+        if (summaryData) {
+            this._summary.applyChanges(summaryData);
+        }
+        if (kickDetails) {
+            this._kickDetails = kickDetails;
+        }
+        if (kickedBy) {
+            this._kickedBy = kickedBy;
+        }
+        this._emitUpdate();
+    }
+
+    get isKicked() {
+        return this._kickDetails?.membership === "leave";
+    }
+
+    get isBanned() {
+        return this._kickDetails?.membership === "ban";
+    }
+
+    get kickedBy() {
+        return this._kickedBy;
+    }
+
+    get kickReason() {
+        return this._kickDetails?.reason;
+    }
+
+    isArchived() {
+        return true;
+    }
+
+    forget() {
+
+    }
+}
+
+function findKickDetails(roomResponse, ownUserId) {
+    const kickEvent = reduceStateEvents(roomResponse, (kickEvent, event) => {
+        if (event.type === MEMBER_EVENT_TYPE) {
+            // did we get kicked?
+            if (event.state_key === ownUserId && event.sender !== event.state_key) {
+                kickEvent = event;
+            }
+        }
+        return kickEvent;
+    }, null);
+    if (kickEvent) {
+        return {
+            // this is different from the room membership in the sync section, which can only be leave
+            membership: kickEvent.content?.membership, // could be leave or ban
+            reason: kickEvent.content?.reason,
+            sender: kickEvent.sender,
+        };
+    }
+}
+
+export function tests() {
+    function createMemberEvent(sender, target, membership, reason) {
+        return {
+            sender,
+            state_key: target,
+            type: "m.room.member",
+            content: { reason, membership }
+        };
+    }
+    const bob = "@bob:hs.tld";
+    const alice = "@alice:hs.tld";
+
+    return {
+        "ban/kick sets kickDetails from state event": assert => {
+            const reason = "Bye!";
+            const leaveEvent = createMemberEvent(alice, bob, "ban", reason);
+            const kickDetails = findKickDetails({state: {events: [leaveEvent]}}, bob);
+            assert.equal(kickDetails.membership, "ban");
+            assert.equal(kickDetails.reason, reason);
+            assert.equal(kickDetails.sender, alice);
+        },
+        "ban/kick sets kickDetails from timeline state event, taking precedence over state": assert => {
+            const reason = "Bye!";
+            const inviteEvent = createMemberEvent(alice, bob, "invite");
+            const leaveEvent = createMemberEvent(alice, bob, "ban", reason);
+            const kickDetails = findKickDetails({
+                state: { events: [inviteEvent] },
+                timeline: {events: [leaveEvent] }
+            }, bob);
+            assert.equal(kickDetails.membership, "ban");
+            assert.equal(kickDetails.reason, reason);
+            assert.equal(kickDetails.sender, alice);
+        },
+        "leaving without being kicked doesn't produce kickDetails": assert => {
+            const leaveEvent = createMemberEvent(bob, bob, "leave");
+            const kickDetails = findKickDetails({state: {events: [leaveEvent]}}, bob);
+            assert.equal(kickDetails, null);
+        }
+    }
+}

src/matrix/room/BaseRoom.js

@@ -0,0 +1,482 @@
+/*
+Copyright 2020 Bruno Windels <bruno@windels.cloud>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {EventEmitter} from "../../utils/EventEmitter.js";
+import {RoomSummary} from "./RoomSummary.js";
+import {GapWriter} from "./timeline/persistence/GapWriter.js";
+import {Timeline} from "./timeline/Timeline.js";
+import {FragmentIdComparer} from "./timeline/FragmentIdComparer.js";
+import {WrappedError} from "../error.js"
+import {fetchOrLoadMembers} from "./members/load.js";
+import {MemberList} from "./members/MemberList.js";
+import {Heroes} from "./members/Heroes.js";
+import {EventEntry} from "./timeline/entries/EventEntry.js";
+import {ObservedEventMap} from "./ObservedEventMap.js";
+import {DecryptionSource} from "../e2ee/common.js";
+import {ensureLogItem} from "../../logging/utils.js";
+
+const EVENT_ENCRYPTED_TYPE = "m.room.encrypted";
+
+export class BaseRoom extends EventEmitter {
+    constructor({roomId, storage, hsApi, mediaRepository, emitCollectionChange, user, createRoomEncryption, getSyncToken, platform}) {
+        super();
+        this._roomId = roomId;
+        this._storage = storage;
+        this._hsApi = hsApi;
+        this._mediaRepository = mediaRepository;
+        this._summary = new RoomSummary(roomId);
+        this._fragmentIdComparer = new FragmentIdComparer([]);
+        this._emitCollectionChange = emitCollectionChange;
+        this._timeline = null;
+        this._user = user;
+        this._changedMembersDuringSync = null;
+        this._memberList = null;
+        this._createRoomEncryption = createRoomEncryption;
+        this._roomEncryption = null;
+        this._getSyncToken = getSyncToken;
+        this._platform = platform;
+        this._observedEvents = null;
+    }
+
+    async _eventIdsToEntries(eventIds, txn) {
+        const retryEntries = [];
+        await Promise.all(eventIds.map(async eventId => {
+            const storageEntry = await txn.timelineEvents.getByEventId(this._roomId, eventId);
+            if (storageEntry) {
+                retryEntries.push(new EventEntry(storageEntry, this._fragmentIdComparer));
+            }
+        }));
+        return retryEntries;
+    }
+
+    _getAdditionalTimelineRetryEntries(otherRetryEntries, roomKeys) {
+        let retryTimelineEntries = this._roomEncryption.filterUndecryptedEventEntriesForKeys(this._timeline.remoteEntries, roomKeys);
+        // filter out any entries already in retryEntries so we don't decrypt them twice
+        const existingIds = otherRetryEntries.reduce((ids, e) => {ids.add(e.id); return ids;}, new Set());
+        retryTimelineEntries = retryTimelineEntries.filter(e => !existingIds.has(e.id));
+        return retryTimelineEntries;
+    }
+
+    /**
+     * Used for retrying decryption from other sources than sync, like key backup.
+     * @internal
+     * @param  {RoomKey} roomKey
+     * @param  {Array<string>} eventIds any event ids that should be retried. There might be more in the timeline though for this key.
+     * @return {Promise}
+     */
+    async notifyRoomKey(roomKey, eventIds, log) {
+        if (!this._roomEncryption) {
+            return;
+        }
+        const txn = await this._storage.readTxn([
+            this._storage.storeNames.timelineEvents,
+            this._storage.storeNames.inboundGroupSessions,
+        ]);
+        let retryEntries = await this._eventIdsToEntries(eventIds, txn);
+        if (this._timeline) {
+            const retryTimelineEntries = this._getAdditionalTimelineRetryEntries(retryEntries, [roomKey]);
+            retryEntries = retryEntries.concat(retryTimelineEntries);
+        }
+        if (retryEntries.length) {
+            const decryptRequest = this._decryptEntries(DecryptionSource.Retry, retryEntries, txn, log);
+            // this will close txn while awaiting decryption
+            await decryptRequest.complete();
+
+            this._timeline?.replaceEntries(retryEntries);
+            // we would ideally write the room summary in the same txn as the groupSessionDecryptions in the
+            // _decryptEntries entries and could even know which events have been decrypted for the first
+            // time from DecryptionChanges.write and only pass those to the summary. As timeline changes
+            // are not essential to the room summary, it's fine to write this in a separate txn for now.
+            const changes = this._summary.data.applyTimelineEntries(retryEntries, false, false);
+            if (await this._summary.writeAndApplyData(changes, this._storage)) {
+                this._emitUpdate();
+            }
+        }
+    }
+
+    _setEncryption(roomEncryption) {
+        if (roomEncryption && !this._roomEncryption) {
+            this._roomEncryption = roomEncryption;
+            if (this._timeline) {
+                this._timeline.enableEncryption(this._decryptEntries.bind(this, DecryptionSource.Timeline));
+            }
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * Used for decrypting when loading/filling the timeline, and retrying decryption,
+     * not during sync, where it is split up during the multiple phases.
+     */
+    _decryptEntries(source, entries, inboundSessionTxn, log = null) {
+        const request = new DecryptionRequest(async (r, log) => {
+            if (!inboundSessionTxn) {
+                inboundSessionTxn = await this._storage.readTxn([this._storage.storeNames.inboundGroupSessions]);
+            }
+            if (r.cancelled) return;
+            const events = entries.filter(entry => {
+                return entry.eventType === EVENT_ENCRYPTED_TYPE;
+            }).map(entry => entry.event);
+            r.preparation = await this._roomEncryption.prepareDecryptAll(events, null, source, inboundSessionTxn);
+            if (r.cancelled) return;
+            const changes = await r.preparation.decrypt();
+            r.preparation = null;
+            if (r.cancelled) return;
+            const stores = [this._storage.storeNames.groupSessionDecryptions];
+            const isTimelineOpen = this._isTimelineOpen;
+            if (isTimelineOpen) {
+                // read to fetch devices if timeline is open
+                stores.push(this._storage.storeNames.deviceIdentities);
+            }
+            const writeTxn = await this._storage.readWriteTxn(stores);
+            let decryption;
+            try {
+                decryption = await changes.write(writeTxn, log);
+                if (isTimelineOpen) {
+                    await decryption.verifySenders(writeTxn);
+                }
+            } catch (err) {
+                writeTxn.abort();
+                throw err;
+            }
+            await writeTxn.complete();
+            // TODO: log decryption errors here
+            decryption.applyToEntries(entries);
+            if (this._observedEvents) {
+                this._observedEvents.updateEvents(entries);
+            }
+        }, ensureLogItem(log));
+        return request;
+    }
+
+    async _getSyncRetryDecryptEntries(newKeys, roomEncryption, txn) {
+        const entriesPerKey = await Promise.all(newKeys.map(async key => {
+            const retryEventIds = await roomEncryption.getEventIdsForMissingKey(key, txn);
+            if (retryEventIds) {
+                return this._eventIdsToEntries(retryEventIds, txn);
+            }
+        }));
+        let retryEntries = entriesPerKey.reduce((allEntries, entries) => entries ? allEntries.concat(entries) : allEntries, []);
+        // If we have the timeline open, see if there are more entries for the new keys
+        // as we only store missing session information for synced events, not backfilled.
+        // We want to decrypt all events we can though if the user is looking
+        // at them when the timeline is open
+        if (this._timeline) {
+            const retryTimelineEntries = this._getAdditionalTimelineRetryEntries(retryEntries, newKeys);
+            // make copies so we don't modify the original entry in writeSync, before the afterSync stage
+            const retryTimelineEntriesCopies = retryTimelineEntries.map(e => e.clone());
+            // add to other retry entries
+            retryEntries = retryEntries.concat(retryTimelineEntriesCopies);
+        }
+        return retryEntries;
+    }
+
+    /** @package */
+    async load(summary, txn, log) {
+        log.set("id", this.id);
+        try {
+            // if called from sync, there is no summary yet
+            if (summary) {
+                this._summary.load(summary);
+            }
+            if (this._summary.data.encryption) {
+                const roomEncryption = this._createRoomEncryption(this, this._summary.data.encryption);
+                this._setEncryption(roomEncryption);
+            }
+            // need to load members for name?
+            if (this._summary.data.needsHeroes) {
+                this._heroes = new Heroes(this._roomId);
+                const changes = await this._heroes.calculateChanges(this._summary.data.heroes, [], txn);
+                this._heroes.applyChanges(changes, this._summary.data);
+            }
+        } catch (err) {
+            throw new WrappedError(`Could not load room ${this._roomId}`, err);
+        }
+    }
+
+    /** @public */
+    async loadMemberList(log = null) {
+        if (this._memberList) {
+            // TODO: also await fetchOrLoadMembers promise here
+            this._memberList.retain();
+            return this._memberList;
+        } else {
+            const members = await fetchOrLoadMembers({
+                summary: this._summary,
+                roomId: this._roomId,
+                hsApi: this._hsApi,
+                storage: this._storage,
+                syncToken: this._getSyncToken(),
+                // to handle race between /members and /sync
+                setChangedMembersMap: map => this._changedMembersDuringSync = map,
+                log,
+            }, this._platform.logger);
+            this._memberList = new MemberList({
+                members,
+                closeCallback: () => { this._memberList = null; }
+            });
+            return this._memberList;
+        }
+    } 
+
+    /** @public */
+    fillGap(fragmentEntry, amount, log = null) {
+        // TODO move some/all of this out of BaseRoom
+        return this._platform.logger.wrapOrRun(log, "fillGap", async log => {
+            log.set("id", this.id);
+            log.set("fragment", fragmentEntry.fragmentId);
+            log.set("dir", fragmentEntry.direction.asApiString());
+            if (fragmentEntry.edgeReached) {
+                log.set("edgeReached", true);
+                return;
+            }
+            const response = await this._hsApi.messages(this._roomId, {
+                from: fragmentEntry.token,
+                dir: fragmentEntry.direction.asApiString(),
+                limit: amount,
+                filter: {
+                    lazy_load_members: true,
+                    include_redundant_members: true,
+                }
+            }, {log}).response();
+
+            const txn = await this._storage.readWriteTxn([
+                this._storage.storeNames.pendingEvents,
+                this._storage.storeNames.timelineEvents,
+                this._storage.storeNames.timelineFragments,
+            ]);
+            let extraGapFillChanges;
+            let gapResult;
+            try {
+                // detect remote echos of pending messages in the gap
+                extraGapFillChanges = this._writeGapFill(response.chunk, txn, log);
+                // write new events into gap
+                const gapWriter = new GapWriter({
+                    roomId: this._roomId,
+                    storage: this._storage,
+                    fragmentIdComparer: this._fragmentIdComparer,
+                });
+                gapResult = await gapWriter.writeFragmentFill(fragmentEntry, response, txn, log);
+            } catch (err) {
+                txn.abort();
+                throw err;
+            }
+            await txn.complete();
+            if (this._roomEncryption) {
+                const decryptRequest = this._decryptEntries(DecryptionSource.Timeline, gapResult.entries, null, log);
+                await decryptRequest.complete();
+            }
+            // once txn is committed, update in-memory state & emit events
+            for (const fragment of gapResult.fragments) {
+                this._fragmentIdComparer.add(fragment);
+            }
+            if (extraGapFillChanges) {
+                this._applyGapFill(extraGapFillChanges);
+            }
+            if (this._timeline) {
+                this._timeline.addOrReplaceEntries(gapResult.entries);
+            }
+        });
+    }
+
+    /**
+    allow sub classes to integrate in the gap fill lifecycle.
+    JoinedRoom uses this update remote echos.
+    */
+    // eslint-disable-next-line no-unused-vars
+    _writeGapFill(chunk, txn, log) {}
+    _applyGapFill() {}
+
+    /** @public */
+    get name() {
+        if (this._heroes) {
+            return this._heroes.roomName;
+        }
+        const summaryData = this._summary.data;
+        if (summaryData.name) {
+            return summaryData.name;
+        }
+        if (summaryData.canonicalAlias) {
+            return summaryData.canonicalAlias;
+        }
+        return null;
+    }
+
+    /** @public */
+    get id() {
+        return this._roomId;
+    }
+
+    get avatarUrl() {
+        if (this._summary.data.avatarUrl) {
+            return this._summary.data.avatarUrl;
+        } else if (this._heroes) {
+            return this._heroes.roomAvatarUrl;
+        }
+        return null;
+    }
+
+    get lastMessageTimestamp() {
+        return this._summary.data.lastMessageTimestamp;
+    }
+
+    get isLowPriority() {
+        const tags = this._summary.data.tags;
+        return !!(tags && tags['m.lowpriority']);
+    }
+
+    get isEncrypted() {
+        return !!this._summary.data.encryption;
+    }
+
+    get isJoined() {
+        return this.membership === "join";
+    }
+
+    get isLeft() {
+        return this.membership === "leave";
+    }
+
+    get mediaRepository() {
+        return this._mediaRepository;
+    }
+
+    get membership() {
+        return this._summary.data.membership;
+    }
+
+    enableSessionBackup(sessionBackup) {
+        this._roomEncryption?.enableSessionBackup(sessionBackup);
+        // TODO: do we really want to do this every time you open the app?
+        if (this._timeline) {
+            this._platform.logger.run("enableSessionBackup", log => {
+                return this._roomEncryption.restoreMissingSessionsFromBackup(this._timeline.remoteEntries, log);
+            });
+        }
+    }
+
+    get _isTimelineOpen() {
+        return !!this._timeline;
+    }
+
+    _emitUpdate() {
+        // once for event emitter listeners
+        this.emit("change");
+        // and once for collection listeners
+        this._emitCollectionChange(this);
+    }
+
+    /** @public */
+    openTimeline(log = null) {
+        return this._platform.logger.wrapOrRun(log, "open timeline", async log => {
+            log.set("id", this.id);
+            if (this._timeline) {
+                throw new Error("not dealing with load race here for now");
+            }
+            this._timeline = new Timeline({
+                roomId: this.id,
+                storage: this._storage,
+                fragmentIdComparer: this._fragmentIdComparer,
+                pendingEvents: this._getPendingEvents(),
+                closeCallback: () => {
+                    this._timeline = null;
+                    if (this._roomEncryption) {
+                        this._roomEncryption.notifyTimelineClosed();
+                    }
+                },
+                clock: this._platform.clock,
+                logger: this._platform.logger,
+            });
+            if (this._roomEncryption) {
+                this._timeline.enableEncryption(this._decryptEntries.bind(this, DecryptionSource.Timeline));
+            }
+            await this._timeline.load(this._user, this.membership, log);
+            return this._timeline;
+        });
+    }
+
+    /* allow subclasses to provide an observable list with pending events when opening the timeline */
+    _getPendingEvents() { return null; }
+
+    observeEvent(eventId) {
+        if (!this._observedEvents) {
+            this._observedEvents = new ObservedEventMap(() => {
+                this._observedEvents = null;
+            });
+        }
+        let entry = null;
+        if (this._timeline) {
+            entry = this._timeline.getByEventId(eventId);
+        }
+        const observable = this._observedEvents.observe(eventId, entry);
+        if (!entry) {
+            // update in the background
+            this._readEventById(eventId).then(entry => {
+                observable.update(entry);
+            }).catch(err => {
+                console.warn(`could not load event ${eventId} from storage`, err);
+            });
+        }
+        return observable;
+    }
+
+    async _readEventById(eventId) {
+        let stores = [this._storage.storeNames.timelineEvents];
+        if (this.isEncrypted) {
+            stores.push(this._storage.storeNames.inboundGroupSessions);
+        }
+        const txn = await this._storage.readTxn(stores);
+        const storageEntry = await txn.timelineEvents.getByEventId(this._roomId, eventId);
+        if (storageEntry) {
+            const entry = new EventEntry(storageEntry, this._fragmentIdComparer);
+            if (entry.eventType === EVENT_ENCRYPTED_TYPE) {
+                const request = this._decryptEntries(DecryptionSource.Timeline, [entry], txn);
+                await request.complete();
+            }
+            return entry;
+        }
+    }
+
+
+    dispose() {
+        this._roomEncryption?.dispose();
+        this._timeline?.dispose();
+    }
+}
+
+class DecryptionRequest {
+    constructor(decryptFn, log) {
+        this._cancelled = false;
+        this.preparation = null;
+        this._promise = log.wrap("decryptEntries", log => decryptFn(this, log));
+    }
+
+    complete() {
+        return this._promise;
+    }
+
+    get cancelled() {
+        return this._cancelled;
+    }
+
+    dispose() {
+        this._cancelled = true;
+        if (this.preparation) {
+            this.preparation.dispose();
+        }
+    }
+}

src/matrix/room/Invite.js

@@ -152,7 +152,8 @@ export class Invite extends EventEmitter {
         }
     }
 
-    afterSync(changes) {
+    afterSync(changes, log) {
+        log.set("id", this.id);
         if (changes) {
             if (changes.removed) {
                 this._accepting = false;
@@ -162,16 +163,11 @@ export class Invite extends EventEmitter {
                 } else {
                     this._rejected = true;
                 }
-                // important to remove before emitting change
-                // so code checking session.invites.get(id) won't
-                // find the invite anymore on update
-                this._emitCollectionRemove(this);
                 this.emit("change");
             } else {
+                // no emit change, adding to the collection is done by sync
                 this._inviteData = changes.inviteData;
                 this._inviter = changes.inviter;
-                // sync will add the invite to the collection by
-                // calling session.addInviteAfterSync
             }
         }
     }
@@ -277,7 +273,7 @@ export function tests() {
             const txn = createStorage();
             const changes = await invite.writeSync("invite", roomInviteFixture, txn, new NullLogItem());
             assert.equal(txn.invitesMap.get(roomId).roomId, roomId);
-            invite.afterSync(changes);
+            invite.afterSync(changes, new NullLogItem());
             assert.equal(invite.name, "Invite example");
             assert.equal(invite.avatarUrl, roomAvatarUrl);
             assert.equal(invite.isPublic, false);
@@ -298,7 +294,7 @@ export function tests() {
             const txn = createStorage();
             const changes = await invite.writeSync("invite", dmInviteFixture, txn, new NullLogItem());
             assert.equal(txn.invitesMap.get(roomId).roomId, roomId);
-            invite.afterSync(changes);
+            invite.afterSync(changes, new NullLogItem());
             assert.equal(invite.name, "Alice");
             assert.equal(invite.avatarUrl, aliceAvatarUrl);
             assert.equal(invite.timestamp, 1003);
@@ -329,28 +325,25 @@ export function tests() {
             assert.equal(invite.inviter.displayName, "Alice");
             assert.equal(invite.inviter.avatarUrl, aliceAvatarUrl);
         },
-        "syncing with membership from invite removes the invite": async assert => {
+        "syncing join sets accepted": async assert => {
-            let removedEmitted = false;
+            let changeEmitCount = 0;
             const invite = new Invite({
                 roomId,
                 platform: {clock: new MockClock(1003)},
                 user: {id: "@bob:hs.tld"},
-                emitCollectionRemove: emittingInvite => {
-                    assert.equal(emittingInvite, invite);
-                    removedEmitted = true;
-                } 
             });
+            invite.on("change", () => { changeEmitCount += 1; });
             const txn = createStorage();
             const changes = await invite.writeSync("invite", dmInviteFixture, txn, new NullLogItem());
             assert.equal(txn.invitesMap.get(roomId).roomId, roomId);
-            invite.afterSync(changes);
+            invite.afterSync(changes, new NullLogItem());
             const joinChanges = await invite.writeSync("join", null, txn, new NullLogItem());
-            assert(!removedEmitted);
+            assert.strictEqual(changeEmitCount, 0);
-            invite.afterSync(joinChanges);
+            invite.afterSync(joinChanges, new NullLogItem());
+            assert.strictEqual(changeEmitCount, 1);
             assert.equal(txn.invitesMap.get(roomId), undefined);
             assert.equal(invite.rejected, false);
             assert.equal(invite.accepted, true);
-            assert(removedEmitted);
         }
     }
 }

src/matrix/room/Room.js

@@ -14,180 +14,30 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import {EventEmitter} from "../../utils/EventEmitter.js";
+import {BaseRoom} from "./BaseRoom.js";
-import {RoomSummary} from "./RoomSummary.js";
 import {SyncWriter} from "./timeline/persistence/SyncWriter.js";
-import {GapWriter} from "./timeline/persistence/GapWriter.js";
-import {Timeline} from "./timeline/Timeline.js";
-import {FragmentIdComparer} from "./timeline/FragmentIdComparer.js";
 import {SendQueue} from "./sending/SendQueue.js";
 import {WrappedError} from "../error.js"
-import {fetchOrLoadMembers} from "./members/load.js";
-import {MemberList} from "./members/MemberList.js";
 import {Heroes} from "./members/Heroes.js";
-import {EventEntry} from "./timeline/entries/EventEntry.js";
-import {ObservedEventMap} from "./ObservedEventMap.js";
 import {AttachmentUpload} from "./AttachmentUpload.js";
 import {DecryptionSource} from "../e2ee/common.js";
-import {ensureLogItem} from "../../logging/utils.js";
 
 const EVENT_ENCRYPTED_TYPE = "m.room.encrypted";
 
-export class Room extends EventEmitter {
+export class Room extends BaseRoom {
-    constructor({roomId, storage, hsApi, mediaRepository, emitCollectionChange, pendingEvents, user, createRoomEncryption, getSyncToken, platform}) {
+    constructor(options) {
-        super();
+        super(options);
-        this._roomId = roomId;
+        const {pendingEvents} = options;
-        this._storage = storage;
+        this._syncWriter = new SyncWriter({roomId: this.id, fragmentIdComparer: this._fragmentIdComparer});
-        this._hsApi = hsApi;
+        this._sendQueue = new SendQueue({roomId: this.id, storage: this._storage, hsApi: this._hsApi, pendingEvents});
-        this._mediaRepository = mediaRepository;
-        this._summary = new RoomSummary(roomId);
-        this._fragmentIdComparer = new FragmentIdComparer([]);
-        this._syncWriter = new SyncWriter({roomId, fragmentIdComparer: this._fragmentIdComparer});
-        this._emitCollectionChange = emitCollectionChange;
-        this._sendQueue = new SendQueue({roomId, storage, hsApi, pendingEvents});
-        this._timeline = null;
-        this._user = user;
-        this._changedMembersDuringSync = null;
-        this._memberList = null;
-        this._createRoomEncryption = createRoomEncryption;
-        this._roomEncryption = null;
-        this._getSyncToken = getSyncToken;
-        this._platform = platform;
-        this._observedEvents = null;
-        this._invite = null;
-    }
-
-    async _eventIdsToEntries(eventIds, txn) {
-        const retryEntries = [];
-        await Promise.all(eventIds.map(async eventId => {
-            const storageEntry = await txn.timelineEvents.getByEventId(this._roomId, eventId);
-            if (storageEntry) {
-                retryEntries.push(new EventEntry(storageEntry, this._fragmentIdComparer));
-            }
-        }));
-        return retryEntries;
-    }
-
-    _getAdditionalTimelineRetryEntries(otherRetryEntries, roomKeys) {
-        let retryTimelineEntries = this._roomEncryption.filterUndecryptedEventEntriesForKeys(this._timeline.remoteEntries, roomKeys);
-        // filter out any entries already in retryEntries so we don't decrypt them twice
-        const existingIds = otherRetryEntries.reduce((ids, e) => {ids.add(e.id); return ids;}, new Set());
-        retryTimelineEntries = retryTimelineEntries.filter(e => !existingIds.has(e.id));
-        return retryTimelineEntries;
-    }
-
-    /**
-     * Used for retrying decryption from other sources than sync, like key backup.
-     * @internal
-     * @param  {RoomKey} roomKey
-     * @param  {Array<string>} eventIds any event ids that should be retried. There might be more in the timeline though for this key.
-     * @return {Promise}
-     */
-    async notifyRoomKey(roomKey, eventIds, log) {
-        if (!this._roomEncryption) {
-            return;
-        }
-        const txn = await this._storage.readTxn([
-            this._storage.storeNames.timelineEvents,
-            this._storage.storeNames.inboundGroupSessions,
-        ]);
-        let retryEntries = await this._eventIdsToEntries(eventIds, txn);
-        if (this._timeline) {
-            const retryTimelineEntries = this._getAdditionalTimelineRetryEntries(retryEntries, [roomKey]);
-            retryEntries = retryEntries.concat(retryTimelineEntries);
-        }
-        if (retryEntries.length) {
-            const decryptRequest = this._decryptEntries(DecryptionSource.Retry, retryEntries, txn, log);
-            // this will close txn while awaiting decryption
-            await decryptRequest.complete();
-
-            this._timeline?.replaceEntries(retryEntries);
-            // we would ideally write the room summary in the same txn as the groupSessionDecryptions in the
-            // _decryptEntries entries and could even know which events have been decrypted for the first
-            // time from DecryptionChanges.write and only pass those to the summary. As timeline changes
-            // are not essential to the room summary, it's fine to write this in a separate txn for now.
-            const changes = this._summary.data.applyTimelineEntries(retryEntries, false, false);
-            if (await this._summary.writeAndApplyData(changes, this._storage)) {
-                this._emitUpdate();
-            }
-        }
     }
 
     _setEncryption(roomEncryption) {
-        if (roomEncryption && !this._roomEncryption) {
+        if (super._setEncryption(roomEncryption)) {
-            this._roomEncryption = roomEncryption;
             this._sendQueue.enableEncryption(this._roomEncryption);
-            if (this._timeline) {
+            return true;
-                this._timeline.enableEncryption(this._decryptEntries.bind(this, DecryptionSource.Timeline));
-            }
         }
-    }
+        return false;
-
-    /**
-     * Used for decrypting when loading/filling the timeline, and retrying decryption,
-     * not during sync, where it is split up during the multiple phases.
-     */
-    _decryptEntries(source, entries, inboundSessionTxn, log = null) {
-        const request = new DecryptionRequest(async (r, log) => {
-            if (!inboundSessionTxn) {
-                inboundSessionTxn = await this._storage.readTxn([this._storage.storeNames.inboundGroupSessions]);
-            }
-            if (r.cancelled) return;
-            const events = entries.filter(entry => {
-                return entry.eventType === EVENT_ENCRYPTED_TYPE;
-            }).map(entry => entry.event);
-            r.preparation = await this._roomEncryption.prepareDecryptAll(events, null, source, inboundSessionTxn);
-            if (r.cancelled) return;
-            const changes = await r.preparation.decrypt();
-            r.preparation = null;
-            if (r.cancelled) return;
-            const stores = [this._storage.storeNames.groupSessionDecryptions];
-            const isTimelineOpen = this._isTimelineOpen;
-            if (isTimelineOpen) {
-                // read to fetch devices if timeline is open
-                stores.push(this._storage.storeNames.deviceIdentities);
-            }
-            const writeTxn = await this._storage.readWriteTxn(stores);
-            let decryption;
-            try {
-                decryption = await changes.write(writeTxn, log);
-                if (isTimelineOpen) {
-                    await decryption.verifySenders(writeTxn);
-                }
-            } catch (err) {
-                writeTxn.abort();
-                throw err;
-            }
-            await writeTxn.complete();
-            // TODO: log decryption errors here
-            decryption.applyToEntries(entries);
-            if (this._observedEvents) {
-                this._observedEvents.updateEvents(entries);
-            }
-        }, ensureLogItem(log));
-        return request;
-    }
-
-    async _getSyncRetryDecryptEntries(newKeys, roomEncryption, txn) {
-        const entriesPerKey = await Promise.all(newKeys.map(async key => {
-            const retryEventIds = await roomEncryption.getEventIdsForMissingKey(key, txn);
-            if (retryEventIds) {
-                return this._eventIdsToEntries(retryEventIds, txn);
-            }
-        }));
-        let retryEntries = entriesPerKey.reduce((allEntries, entries) => entries ? allEntries.concat(entries) : allEntries, []);
-        // If we have the timeline open, see if there are more entries for the new keys
-        // as we only store missing session information for synced events, not backfilled.
-        // We want to decrypt all events we can though if the user is looking
-        // at them when the timeline is open
-        if (this._timeline) {
-            const retryTimelineEntries = this._getAdditionalTimelineRetryEntries(retryEntries, newKeys);
-            // make copies so we don't modify the original entry in writeSync, before the afterSync stage
-            const retryTimelineEntriesCopies = retryTimelineEntries.map(e => e.clone());
-            // add to other retry entries
-            retryEntries = retryEntries.concat(retryTimelineEntriesCopies);
-        }
-        return retryEntries;
     }
 
     async prepareSync(roomResponse, membership, invite, newKeys, txn, log) {
@@ -249,7 +99,13 @@ export class Room extends EventEmitter {
     /** @package */
     async writeSync(roomResponse, isInitialSync, {summaryChanges, decryptChanges, roomEncryption, retryEntries}, txn, log) {
         log.set("id", this.id);
-        const isRejoin = summaryChanges.membership === "join" && this._summary.data.membership === "leave";
+        const isRejoin = summaryChanges.isNewJoin(this._summary.data);
+        if (isRejoin) {
+            // remove all room state before calling syncWriter,
+            // so no old state sticks around
+            txn.roomState.removeAllForRoom(this.id);
+            txn.roomMembers.removeAllForRoom(this.id);
+        }
         const {entries: newEntries, newLiveKey, memberChanges} =
             await log.wrap("syncWriter", log => this._syncWriter.writeSync(roomResponse, isRejoin, txn, log), log.level.Detail);
         let allEntries = newEntries;
@@ -276,8 +132,14 @@ export class Room extends EventEmitter {
         // also apply (decrypted) timeline entries to the summary changes
         summaryChanges = summaryChanges.applyTimelineEntries(
             allEntries, isInitialSync, !this._isTimelineOpen, this._user.id);
-        // write summary changes, and unset if nothing was actually changed
+        
-        summaryChanges = this._summary.writeData(summaryChanges, txn);
+        // if we've have left the room, remove the summary
+        if (summaryChanges.membership !== "join") {
+            txn.roomSummary.remove(this.id);
+        } else {
+            // write summary changes, and unset if nothing was actually changed
+            summaryChanges = this._summary.writeData(summaryChanges, txn);
+        }
         if (summaryChanges) {
             log.set("summaryChanges", summaryChanges.diff(this._summary.data));
         }
@@ -345,10 +207,6 @@ export class Room extends EventEmitter {
         }
         let emitChange = false;
         if (summaryChanges) {
-            // if we joined the room, we can't have an invite anymore
-            if (summaryChanges.membership === "join" && this._summary.data.membership !== "join") {
-                this._invite = null;
-            }
             this._summary.applyChanges(summaryChanges);
             if (!this._summary.data.needsHeroes) {
                 this._heroes = null;
@@ -413,31 +271,21 @@ export class Room extends EventEmitter {
 
     /** @package */
     async load(summary, txn, log) {
-        log.set("id", this.id);
         try {
-            this._summary.load(summary);
+            super.load(summary, txn, log);
-            if (this._summary.data.encryption) {
+            this._syncWriter.load(txn, log);
-                const roomEncryption = this._createRoomEncryption(this, this._summary.data.encryption);
-                this._setEncryption(roomEncryption);
-            }
-            // need to load members for name?
-            if (this._summary.data.needsHeroes) {
-                this._heroes = new Heroes(this._roomId);
-                const changes = await this._heroes.calculateChanges(this._summary.data.heroes, [], txn);
-                this._heroes.applyChanges(changes, this._summary.data);
-            }
-            return this._syncWriter.load(txn, log);
         } catch (err) {
             throw new WrappedError(`Could not load room ${this._roomId}`, err);
         }
     }
 
-    /** @internal */
+    _writeGapFill(gapChunk, txn, log) {
-    setInvite(invite) {
+        const removedPendingEvents = this._sendQueue.removeRemoteEchos(gapChunk, txn, log);
-        // called when an invite comes in for this room
+        return removedPendingEvents;
-        // (e.g. when we're in membership leave and haven't been archived or forgotten yet)
+    }
-        this._invite = invite;
+
-        this._emitUpdate();
+    _applyGapFill(removedPendingEvents) {
+        this._sendQueue.emitRemovals(removedPendingEvents);
     }
 
     /** @public */
@@ -459,124 +307,6 @@ export class Room extends EventEmitter {
         });
     }
 
-    /** @public */
-    async loadMemberList(log = null) {
-        if (this._memberList) {
-            // TODO: also await fetchOrLoadMembers promise here
-            this._memberList.retain();
-            return this._memberList;
-        } else {
-            const members = await fetchOrLoadMembers({
-                summary: this._summary,
-                roomId: this._roomId,
-                hsApi: this._hsApi,
-                storage: this._storage,
-                syncToken: this._getSyncToken(),
-                // to handle race between /members and /sync
-                setChangedMembersMap: map => this._changedMembersDuringSync = map,
-                log,
-            }, this._platform.logger);
-            this._memberList = new MemberList({
-                members,
-                closeCallback: () => { this._memberList = null; }
-            });
-            return this._memberList;
-        }
-    } 
-
-    /** @public */
-    fillGap(fragmentEntry, amount, log = null) {
-        // TODO move some/all of this out of Room
-        return this._platform.logger.wrapOrRun(log, "fillGap", async log => {
-            log.set("id", this.id);
-            log.set("fragment", fragmentEntry.fragmentId);
-            log.set("dir", fragmentEntry.direction.asApiString());
-            if (fragmentEntry.edgeReached) {
-                log.set("edgeReached", true);
-                return;
-            }
-            const response = await this._hsApi.messages(this._roomId, {
-                from: fragmentEntry.token,
-                dir: fragmentEntry.direction.asApiString(),
-                limit: amount,
-                filter: {
-                    lazy_load_members: true,
-                    include_redundant_members: true,
-                }
-            }, {log}).response();
-
-            const txn = await this._storage.readWriteTxn([
-                this._storage.storeNames.pendingEvents,
-                this._storage.storeNames.timelineEvents,
-                this._storage.storeNames.timelineFragments,
-            ]);
-            let removedPendingEvents;
-            let gapResult;
-            try {
-                // detect remote echos of pending messages in the gap
-                removedPendingEvents = this._sendQueue.removeRemoteEchos(response.chunk, txn, log);
-                // write new events into gap
-                const gapWriter = new GapWriter({
-                    roomId: this._roomId,
-                    storage: this._storage,
-                    fragmentIdComparer: this._fragmentIdComparer,
-                });
-                gapResult = await gapWriter.writeFragmentFill(fragmentEntry, response, txn, log);
-            } catch (err) {
-                txn.abort();
-                throw err;
-            }
-            await txn.complete();
-            if (this._roomEncryption) {
-                const decryptRequest = this._decryptEntries(DecryptionSource.Timeline, gapResult.entries, null, log);
-                await decryptRequest.complete();
-            }
-            // once txn is committed, update in-memory state & emit events
-            for (const fragment of gapResult.fragments) {
-                this._fragmentIdComparer.add(fragment);
-            }
-            if (removedPendingEvents) {
-                this._sendQueue.emitRemovals(removedPendingEvents);
-            }
-            if (this._timeline) {
-                this._timeline.addOrReplaceEntries(gapResult.entries);
-            }
-        });
-    }
-
-    /** @public */
-    get name() {
-        if (this._heroes) {
-            return this._heroes.roomName;
-        }
-        const summaryData = this._summary.data;
-        if (summaryData.name) {
-            return summaryData.name;
-        }
-        if (summaryData.canonicalAlias) {
-            return summaryData.canonicalAlias;
-        }
-        return null;
-    }
-
-    /** @public */
-    get id() {
-        return this._roomId;
-    }
-
-    get avatarUrl() {
-        if (this._summary.data.avatarUrl) {
-            return this._summary.data.avatarUrl;
-        } else if (this._heroes) {
-            return this._heroes.roomAvatarUrl;
-        }
-        return null;
-    }
-
-    get lastMessageTimestamp() {
-        return this._summary.data.lastMessageTimestamp;
-    }
-
     get isUnread() {
         return this._summary.data.isUnread;
     }
@@ -589,40 +319,6 @@ export class Room extends EventEmitter {
         return this._summary.data.highlightCount;
     }
 
-    get isLowPriority() {
-        const tags = this._summary.data.tags;
-        return !!(tags && tags['m.lowpriority']);
-    }
-
-    get isEncrypted() {
-        return !!this._summary.data.encryption;
-    }
-
-    get membership() {
-        return this._summary.data.membership;
-    }
-
-    /**
-     * The invite for this room, if any.
-     * This will only be set if you've left a room, and
-     * don't archive or forget it, and then receive an invite
-     * for it again
-     * @return {Invite?}
-     */
-    get invite() {
-        return this._invite;
-    }
-
-    enableSessionBackup(sessionBackup) {
-        this._roomEncryption?.enableSessionBackup(sessionBackup);
-        // TODO: do we really want to do this every time you open the app?
-        if (this._timeline) {
-            this._platform.logger.run("enableSessionBackup", log => {
-                return this._roomEncryption.restoreMissingSessionsFromBackup(this._timeline.remoteEntries, log);
-            });
-        }
-    }
-
     get isTrackingMembers() {
         return this._summary.data.isTrackingMembers;
     }
@@ -638,17 +334,6 @@ export class Room extends EventEmitter {
         }
     }
 
-    get _isTimelineOpen() {
-        return !!this._timeline;
-    }
-
-    _emitUpdate() {
-        // once for event emitter listeners
-        this.emit("change");
-        // and once for collection listeners
-        this._emitCollectionChange(this);
-    }
-
     async clearUnread(log = null) {
         if (this.isUnread || this.notificationCount) {
             return await this._platform.logger.wrapOrRun(log, "clearUnread", async log => {
@@ -682,37 +367,9 @@ export class Room extends EventEmitter {
         }
     }
 
-    /** @public */
+    /* called by BaseRoom to pass pendingEvents when opening the timeline */
-    openTimeline(log = null) {
+    _getPendingEvents() {
-        return this._platform.logger.wrapOrRun(log, "open timeline", async log => {
+        return this._sendQueue.pendingEvents;
-            log.set("id", this.id);
-            if (this._timeline) {
-                throw new Error("not dealing with load race here for now");
-            }
-            this._timeline = new Timeline({
-                roomId: this.id,
-                storage: this._storage,
-                fragmentIdComparer: this._fragmentIdComparer,
-                pendingEvents: this._sendQueue.pendingEvents,
-                closeCallback: () => {
-                    this._timeline = null;
-                    if (this._roomEncryption) {
-                        this._roomEncryption.notifyTimelineClosed();
-                    }
-                },
-                clock: this._platform.clock,
-                logger: this._platform.logger,
-            });
-            if (this._roomEncryption) {
-                this._timeline.enableEncryption(this._decryptEntries.bind(this, DecryptionSource.Timeline));
-            }
-            await this._timeline.load(this._user, this._summary.data.membership, log);
-            return this._timeline;
-        });
-    }
-
-    get mediaRepository() {
-        return this._mediaRepository;
     }
 
     /** @package */
@@ -725,75 +382,12 @@ export class Room extends EventEmitter {
         this._summary.applyChanges(changes);
     }
 
-    observeEvent(eventId) {
-        if (!this._observedEvents) {
-            this._observedEvents = new ObservedEventMap(() => {
-                this._observedEvents = null;
-            });
-        }
-        let entry = null;
-        if (this._timeline) {
-            entry = this._timeline.getByEventId(eventId);
-        }
-        const observable = this._observedEvents.observe(eventId, entry);
-        if (!entry) {
-            // update in the background
-            this._readEventById(eventId).then(entry => {
-                observable.update(entry);
-            }).catch(err => {
-                console.warn(`could not load event ${eventId} from storage`, err);
-            });
-        }
-        return observable;
-    }
-
-    async _readEventById(eventId) {
-        let stores = [this._storage.storeNames.timelineEvents];
-        if (this.isEncrypted) {
-            stores.push(this._storage.storeNames.inboundGroupSessions);
-        }
-        const txn = await this._storage.readTxn(stores);
-        const storageEntry = await txn.timelineEvents.getByEventId(this._roomId, eventId);
-        if (storageEntry) {
-            const entry = new EventEntry(storageEntry, this._fragmentIdComparer);
-            if (entry.eventType === EVENT_ENCRYPTED_TYPE) {
-                const request = this._decryptEntries(DecryptionSource.Timeline, [entry], txn);
-                await request.complete();
-            }
-            return entry;
-        }
-    }
-
     createAttachment(blob, filename) {
         return new AttachmentUpload({blob, filename, platform: this._platform});
     }
 
     dispose() {
-        this._roomEncryption?.dispose();
+        super.dispose();
-        this._timeline?.dispose();
         this._sendQueue.dispose();
     }
 }
-
-class DecryptionRequest {
-    constructor(decryptFn, log) {
-        this._cancelled = false;
-        this.preparation = null;
-        this._promise = log.wrap("decryptEntries", log => decryptFn(this, log));
-    }
-
-    complete() {
-        return this._promise;
-    }
-
-    get cancelled() {
-        return this._cancelled;
-    }
-
-    dispose() {
-        this._cancelled = true;
-        if (this.preparation) {
-            this.preparation.dispose();
-        }
-    }
-}

src/matrix/room/RoomStatus.js

@@ -0,0 +1,51 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+export class RoomStatus {
+    constructor(joined, invited, archived) {
+        this.joined = joined;
+        this.invited = invited;
+        this.archived = archived;
+    }
+
+    withInvited() {
+        if (this.invited) {
+            return this;
+        } else if (this.archived) {
+            return RoomStatus.invitedAndArchived;
+        } else {
+            return RoomStatus.invited;
+        }
+    }
+
+    withoutInvited() {
+        if (!this.invited) {
+            return this;
+        } else if (this.joined) {
+            return RoomStatus.joined;
+        } else if (this.archived) {
+            return RoomStatus.archived;
+        } else {
+            return RoomStatus.none;
+        }
+    }
+}
+
+RoomStatus.joined = new RoomStatus(true, false, false);
+RoomStatus.archived = new RoomStatus(false, false, true);
+RoomStatus.invited = new RoomStatus(false, true, false);
+RoomStatus.invitedAndArchived = new RoomStatus(false, true, true);
+RoomStatus.none = new RoomStatus(false, false, false);

src/matrix/room/RoomSummary.js

@@ -27,6 +27,24 @@ function applyTimelineEntries(data, timelineEntries, isInitialSync, canMarkUnrea
     return data;
 }
 
+export function reduceStateEvents(roomResponse, callback, value) {
+    const stateEvents = roomResponse?.state?.events;
+    // state comes before timeline
+    if (Array.isArray(stateEvents)) {
+        value = stateEvents.reduce(callback, value);
+    }
+    const timelineEvents = roomResponse?.timeline?.events;
+    // and after that state events in the timeline
+    if (Array.isArray(timelineEvents)) {
+        value = timelineEvents.reduce((data, event) => {
+            if (typeof event.state_key === "string") {
+                value = callback(value, event);
+            }
+            return value;
+        }, value);
+    }
+    return value;
+}
 
 function applySyncResponse(data, roomResponse, membership) {
     if (roomResponse.summary) {
@@ -39,40 +57,32 @@ function applySyncResponse(data, roomResponse, membership) {
     if (roomResponse.account_data) {
         data = roomResponse.account_data.events.reduce(processRoomAccountData, data);
     }
-    const stateEvents = roomResponse?.state?.events;
+    // process state events in state and in timeline.
-    // state comes before timeline
-    if (Array.isArray(stateEvents)) {
-        data = stateEvents.reduce(processStateEvent, data);
-    }
-    const timelineEvents = roomResponse?.timeline?.events;
-    // process state events in timeline
     // non-state events are handled by applyTimelineEntries
     // so decryption is handled properly
-    if (Array.isArray(timelineEvents)) {
+    data = reduceStateEvents(roomResponse, processStateEvent, data);
-        data = timelineEvents.reduce((data, event) => {
-            if (typeof event.state_key === "string") {
-                return processStateEvent(data, event);
-            }
-            return data;
-        }, data);
-    }
     const unreadNotifications = roomResponse.unread_notifications;
     if (unreadNotifications) {
-        const highlightCount = unreadNotifications.highlight_count || 0;
+        data = processNotificationCounts(data, unreadNotifications);
-        if (highlightCount !== data.highlightCount) {
-            data = data.cloneIfNeeded();
-            data.highlightCount = highlightCount;
-        }
-        const notificationCount = unreadNotifications.notification_count;
-        if (notificationCount !== data.notificationCount) {
-            data = data.cloneIfNeeded();
-            data.notificationCount = notificationCount;
-        }
     }
 
     return data;
 }
 
+function processNotificationCounts(data, unreadNotifications) {
+    const highlightCount = unreadNotifications.highlight_count || 0;
+    if (highlightCount !== data.highlightCount) {
+        data = data.cloneIfNeeded();
+        data.highlightCount = highlightCount;
+    }
+    const notificationCount = unreadNotifications.notification_count;
+    if (notificationCount !== data.notificationCount) {
+        data = data.cloneIfNeeded();
+        data.notificationCount = notificationCount;
+    }
+    return data;
+} 
+
 function processRoomAccountData(data, event) {
     if (event?.type === "m.tag") {
         let tags = event?.content?.tags;
@@ -152,10 +162,11 @@ function applyInvite(data, invite) {
     if (data.isDirectMessage !== invite.isDirectMessage) {
         data = data.cloneIfNeeded();
         data.isDirectMessage = invite.isDirectMessage;
-    }
+        if (invite.isDirectMessage) {
-    if (data.dmUserId !== invite.inviter?.userId) {
+            data.dmUserId = invite.inviter?.userId;
-        data = data.cloneIfNeeded();
+        } else {
-        data.dmUserId = invite.inviter?.userId;
+            data.dmUserId = null;
+        }
     }
     return data;
 }
@@ -204,8 +215,12 @@ export class SummaryData {
     }
 
     serialize() {
-        const {cloned, ...serializedProps} = this;
+        return Object.entries(this).reduce((obj, [key, value]) => {
-        return serializedProps;
+            if (key !== "cloned" && value !== null) {
+                obj[key] = value;
+            }
+            return obj;
+        }, {});
     }
 
     applyTimelineEntries(timelineEntries, isInitialSync, canMarkUnread, ownUserId) {
@@ -223,6 +238,10 @@ export class SummaryData {
     get needsHeroes() {
         return !this.name && !this.canonicalAlias && this.heroes && this.heroes.length > 0;
     }
+
+    isNewJoin(oldData) {
+        return this.membership === "join" && oldData.membership !== "join";
+    }
 }
 
 export class RoomSummary {
@@ -265,6 +284,14 @@ export class RoomSummary {
 		}
 	}
 
+    /** move summary to archived store when leaving the room */
+    writeArchivedData(data, txn) {
+        if (data !== this._data) {
+            txn.archivedRoomSummary.set(data.serialize());
+            return data;
+        }
+    }
+
     async writeAndApplyData(data, storage) {
         if (data === this._data) {
             return false;
@@ -297,15 +324,15 @@ export class RoomSummary {
 
 export function tests() {
     return {
-        "membership trigger change": function(assert) {
+        "serialize doesn't include null fields or cloned": assert => {
-            const summary = new RoomSummary("id");
+            const roomId = "!123:hs.tld";
-            let written = false;
+            const data = new SummaryData(null, roomId);
-            let changes = summary.data.applySyncResponse({}, "join");
+            const clone = data.cloneIfNeeded();
-            const txn = {roomSummary: {set: () => { written = true; }}};
+            const serialized = clone.serialize();
-            changes = summary.writeData(changes, txn);
+            assert.strictEqual(serialized.cloned, undefined);
-            assert(changes);
+            assert.equal(serialized.roomId, roomId);
-            assert(written);
+            const nullCount = Object.values(serialized).reduce((count, value) => count + value === null ? 1 : 0, 0);
-            assert.equal(changes.membership, "join");
+            assert.strictEqual(nullCount, 0);
         }
     }
 }

src/matrix/room/members/MemberList.js

@@ -15,15 +15,15 @@ limitations under the License.
 */
 
 import {ObservableMap} from "../../../observable/map/ObservableMap.js";
+import {RetainedValue} from "../../../utils/RetainedValue.js";
 
-export class MemberList {
+export class MemberList extends RetainedValue {
     constructor({members, closeCallback}) {
+        super(closeCallback);
         this._members = new ObservableMap();
         for (const member of members) {
             this._members.add(member.userId, member);
         }
-        this._closeCallback = closeCallback;
-        this._retentionCount = 1;
     }
 
     afterSync(memberChanges) {
@@ -35,15 +35,4 @@ export class MemberList {
     get members() {
         return this._members;
     }
-
-    retain() {
-        this._retentionCount += 1;
-    }
-
-    release() {
-        this._retentionCount -= 1;
-        if (this._retentionCount === 0) {
-            this._closeCallback();
-        }
-    }
 }

src/matrix/room/timeline/Timeline.js

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import {SortedArray, MappedList, ConcatList} from "../../../observable/index.js";
+import {SortedArray, MappedList, ConcatList, ObservableArray} from "../../../observable/index.js";
 import {Disposables} from "../../../utils/Disposables.js";
 import {Direction} from "./Direction.js";
 import {TimelineReader} from "./persistence/TimelineReader.js";
@@ -36,11 +36,16 @@ export class Timeline {
             fragmentIdComparer: this._fragmentIdComparer
         });
         this._readerRequest = null;
-        const localEntries = new MappedList(pendingEvents, pe => {
+        let localEntries;
-            return new PendingEventEntry({pendingEvent: pe, member: this._ownMember, clock});
+        if (pendingEvents) {
-        }, (pee, params) => {
+            localEntries = new MappedList(pendingEvents, pe => {
-            pee.notifyUpdate(params);
+                return new PendingEventEntry({pendingEvent: pe, member: this._ownMember, clock});
-        });
+            }, (pee, params) => {
+                pee.notifyUpdate(params);
+            });
+        } else {
+            localEntries = new ObservableArray();
+        }
         this._allEntries = new ConcatList(this._remoteEntries, localEntries);
     }
 

src/matrix/room/timeline/persistence/SyncWriter.js

@@ -200,13 +200,17 @@ export class SyncWriter {
                 const index = events.findIndex(event => event.event_id === lastEventId);
                 if (index !== -1) {
                     log.set("overlap_event_id", lastEventId);
-                    return {
+                    return Object.assign({}, timeline, {
                         limited: false,
-                        events: events.slice(index + 1)
+                        events: events.slice(index + 1),
-                    };
+                    });
                 }
             }
         }
+        if (!timeline.limited) {
+            log.set("force_limited_without_overlap", true);
+            return Object.assign({}, timeline, {limited: true});
+        }
         return timeline;
     }
 

src/matrix/storage/common.js

@@ -18,6 +18,7 @@ export const STORE_NAMES = Object.freeze([
     "session",
     "roomState",
     "roomSummary",
+    "archivedRoomSummary",
     "invites",
     "roomMembers",
     "timelineEvents",

src/matrix/storage/idb/Transaction.js

@@ -64,6 +64,10 @@ export class Transaction {
     get roomSummary() {
         return this._store("roomSummary", idbStore => new RoomSummaryStore(idbStore));
     }
+    
+    get archivedRoomSummary() {
+        return this._store("archivedRoomSummary", idbStore => new RoomSummaryStore(idbStore));
+    }
 
     get invites() {
         return this._store("invites", idbStore => new InviteStore(idbStore));

src/matrix/storage/idb/error.js

@@ -42,7 +42,7 @@ export class IDBError extends StorageError {
 
 export class IDBRequestError extends IDBError {
     constructor(request, message = "IDBRequest failed") {
-        const source = request?.source;
+        const source = request.source;
         const cause = request.error;
         super(message, source, cause);
     }

src/matrix/storage/idb/schema.js

@@ -12,7 +12,8 @@ export const schema = [
     createE2EEStores,
     migrateEncryptionFlag,
     createAccountDataStore,
-    createInviteStore
+    createInviteStore,
+    createArchivedRoomSummaryStore,
 ];
 // TODO: how to deal with git merge conflicts of this array?
 
@@ -109,3 +110,8 @@ function createAccountDataStore(db) {
 function createInviteStore(db) {
     db.createObjectStore("invites", {keyPath: "roomId"});
 }
+
+// v8
+function createArchivedRoomSummaryStore(db) {
+    db.createObjectStore("archivedRoomSummary", {keyPath: "summary.roomId"});
+}

src/matrix/storage/idb/stores/DeviceIdentityStore.js

@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import {MAX_UNICODE, MIN_UNICODE} from "./common.js";
+
 function encodeKey(userId, deviceId) {
     return `${userId}|${deviceId}`;
 }
@@ -66,4 +68,11 @@ export class DeviceIdentityStore {
     remove(userId, deviceId) {
         this._store.delete(encodeKey(userId, deviceId));
     }
+
+    removeAllForUser(userId) {
+        // exclude both keys as they are theoretical min and max,
+        // but we should't have a match for just the room id, or room id with max
+        const range = IDBKeyRange.bound(encodeKey(userId, MIN_UNICODE), encodeKey(userId, MAX_UNICODE), true, true);
+        this._store.delete(range);
+    }
 }

src/matrix/storage/idb/stores/RoomMemberStore.js

@@ -1,6 +1,6 @@
 /*
 Copyright 2020 Bruno Windels <bruno@windels.cloud>
-Copyright 2020 The Matrix.org Foundation C.I.C.
+Copyright 2020, 2021 The Matrix.org Foundation C.I.C.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -15,6 +15,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import {MAX_UNICODE} from "./common.js";
+
 function encodeKey(roomId, userId) {
     return `${roomId}|${userId}`;
 }
@@ -60,4 +62,11 @@ export class RoomMemberStore {
         });
         return userIds;
     }
+
+    removeAllForRoom(roomId) {
+        // exclude both keys as they are theoretical min and max,
+        // but we should't have a match for just the room id, or room id with max
+        const range = IDBKeyRange.bound(roomId, `${roomId}|${MAX_UNICODE}`, true, true);
+        this._roomMembersStore.delete(range);
+    }
 }

src/matrix/storage/idb/stores/RoomStateStore.js

@@ -1,5 +1,6 @@
 /*
 Copyright 2020 Bruno Windels <bruno@windels.cloud>
+Copyright 2021 The Matrix.org Foundation C.I.C.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -14,17 +15,19 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import {MAX_UNICODE} from "./common.js";
+
 export class RoomStateStore {
 	constructor(idbStore) {
 		this._roomStateStore = idbStore;
 	}
 
 	async getAllForType(type) {
-
+		throw new Error("unimplemented");
 	}
 
 	async get(type, stateKey) {
-        
+        throw new Error("unimplemented");
 	}
 
 	async set(roomId, event) {
@@ -32,4 +35,11 @@ export class RoomStateStore {
         const entry = {roomId, event, key};
 		return this._roomStateStore.put(entry);
 	}
+
+	removeAllForRoom(roomId) {
+		// exclude both keys as they are theoretical min and max,
+		// but we should't have a match for just the room id, or room id with max
+		const range = IDBKeyRange.bound(roomId, `${roomId}|${MAX_UNICODE}`, true, true);
+		this._roomStateStore.delete(range);
+	}
 }

src/matrix/storage/idb/stores/RoomSummaryStore.js

@@ -27,6 +27,8 @@ store contains:
 	inviteCount
 	joinCount
 */
+
+/** Used for both roomSummary and archivedRoomSummary stores */
 export class RoomSummaryStore {
 	constructor(summaryStore) {
 		this._summaryStore = summaryStore;
@@ -39,4 +41,17 @@ export class RoomSummaryStore {
 	set(summary) {
 		return this._summaryStore.put(summary);
 	}
+
+	get(roomId) {
+		return this._summaryStore.get(roomId);
+	}
+
+	async has(roomId) {
+        const fetchedKey = await this._summaryStore.getKey(roomId);
+        return roomId === fetchedKey;
+	}
+
+	remove(roomId) {
+		return this._summaryStore.delete(roomId);
+	}
 }

src/matrix/storage/idb/stores/common.js

@@ -0,0 +1,18 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+export const MIN_UNICODE = "\u{0}";
+export const MAX_UNICODE = "\u{10FFFF}";

src/matrix/storage/idb/utils.js

@@ -81,21 +81,37 @@ export function reqAsPromise(req) {
             resolve(event.target.result);
             needsSyncPromise && Promise._flush && Promise._flush();
         });
-        req.addEventListener("error", () => {
+        req.addEventListener("error", event => {
-            reject(new IDBRequestError(req));
+            const error = new IDBRequestError(event.target);
+            reject(error);
             needsSyncPromise && Promise._flush && Promise._flush();
         });
     });
 }
 
 export function txnAsPromise(txn) {
+    let error;
     return new Promise((resolve, reject) => {
         txn.addEventListener("complete", () => {
             resolve();
             needsSyncPromise && Promise._flush && Promise._flush();
         });
-        txn.addEventListener("abort", () => {
+        txn.addEventListener("error", event => {
-            reject(new IDBRequestError(txn));
+            const request = event.target;
+            // catch first error here, but don't reject yet,
+            // as we don't have access to the failed request in the abort event handler
+            if (!error && request) {
+                error = new IDBRequestError(request);
+            }
+        });
+        txn.addEventListener("abort", event => {
+            if (!error) {
+                const txn = event.target;
+                const dbName = txn.db.name;
+                const storeNames = Array.from(txn.objectStoreNames).join(", ")
+                error = new StorageError(`Transaction on ${dbName} with stores ${storeNames} was aborted.`);
+            }
+            reject(error);
             needsSyncPromise && Promise._flush && Promise._flush();
         });
     });

src/observable/BaseObservable.js

@@ -48,6 +48,13 @@ export class BaseObservable {
         return null;
     }
 
+    unsubscribeAll() {
+        if (this._handlers.size !== 0) {
+            this._handlers.clear();
+            this.onUnsubscribeLast();
+        }
+    }
+
     get hasSubscriptions() {
         return this._handlers.size !== 0;
     }

src/observable/ObservableValue.js

@@ -94,6 +94,18 @@ export class ObservableValue extends BaseObservableValue {
     }
 }
 
+export class RetainedObservableValue extends ObservableValue {
+    constructor(initialValue, freeCallback) {
+        super(initialValue);
+        this._freeCallback = freeCallback;
+    }
+
+    onUnsubscribeLast() {
+        super.onUnsubscribeLast();
+        this._freeCallback();
+    }
+}
+
 export function tests() {
     return {
         "set emits an update": assert => {

src/platform/web/ui/css/themes/element/theme.css

@@ -897,3 +897,12 @@ button.link {
     display: block;
     width: 100%;
 }
+
+.RoomArchivedView {
+    padding: 12px;
+    background-color: rgba(245, 245, 245, 0.90);
+}
+
+.RoomArchivedView h3 {
+    margin: 0;
+}

src/platform/web/ui/session/room/RoomArchivedView.js

@@ -0,0 +1,23 @@
+/*
+Copyright 2020 Bruno Windels <bruno@windels.cloud>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {TemplateView} from "../../general/TemplateView.js";
+
+export class RoomArchivedView extends TemplateView {
+    render(t, vm) {
+        return t.div({className: "RoomArchivedView"}, t.h3(vm => vm.description));
+    }
+}

src/platform/web/ui/session/room/RoomView.js

@@ -19,10 +19,17 @@ import {TemplateView} from "../../general/TemplateView.js";
 import {TimelineList} from "./TimelineList.js";
 import {TimelineLoadingView} from "./TimelineLoadingView.js";
 import {MessageComposer} from "./MessageComposer.js";
+import {RoomArchivedView} from "./RoomArchivedView.js";
 import {AvatarView} from "../../avatar.js";
 
 export class RoomView extends TemplateView {
     render(t, vm) {
+        let bottomView;
+        if (vm.composerViewModel.kind === "composer") {
+            bottomView = new MessageComposer(vm.composerViewModel);
+        } else if (vm.composerViewModel.kind === "archived") {
+            bottomView = new RoomArchivedView(vm.composerViewModel);
+        }
         return t.main({className: "RoomView middle"}, [
             t.div({className: "RoomHeader middle-header"}, [
                 t.a({className: "button-utility close-middle", href: vm.closeUrl, title: vm.i18n`Close room`}),
@@ -38,7 +45,7 @@ export class RoomView extends TemplateView {
                         new TimelineList(timelineViewModel) :
                         new TimelineLoadingView(vm);    // vm is just needed for i18n
                 }),
-                t.view(new MessageComposer(vm.composerViewModel)),
+                t.view(bottomView),
             ])
         ]);
     }

src/utils/RetainedValue.js

@@ -0,0 +1,33 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+export class RetainedValue {
+    constructor(freeCallback) {
+        this._freeCallback = freeCallback;
+        this._retentionCount = 1;
+    }
+
+    retain() {
+        this._retentionCount += 1;
+    }
+
+    release() {
+        this._retentionCount -= 1;
+        if (this._retentionCount === 0) {
+            this._freeCallback();
+        }
+    }
+}