more WIP and breakage

src/domain/BrawlViewModel.js

@@ -20,6 +20,7 @@ export default class BrawlViewModel extends EventEmitter {
         this._loading = false;
         this._error = null;
         this._sessionViewModel = null;
+        this._sessionSubscription = null;
         this._loginViewModel = null;
         this._sessionPickerViewModel = null;
     }
@@ -33,45 +34,35 @@ export default class BrawlViewModel extends EventEmitter {
     }
 
     async _showPicker() {
-        this._clearSections();
+        this._setSection(() => {
             this._sessionPickerViewModel = new SessionPickerViewModel({
                 sessionStore: this._sessionStore,
                 storageFactory: this._storageFactory,
                 sessionCallback: sessionInfo => this._onSessionPicked(sessionInfo)
             });
-        this.emit("change", "activeSection");
+        });
         try {
             await this._sessionPickerViewModel.load();
         } catch (err) {
-            this._clearSections();
-            this._error = err;
-            this.emit("change", "activeSection");
+            this._setSection(() => this._error = err);
         }
     }
 
     _showLogin() {
-        this._clearSections();
+        this._setSection(() => {
             this._loginViewModel = new LoginViewModel({
                 createHsApi: this._createHsApi,
                 defaultHomeServer: "https://matrix.org",
                 loginCallback: loginData => this._onLoginFinished(loginData)
             });
-        this.emit("change", "activeSection");
+        })
 
     }
 
     _showSession(session, sync) {
-        this._clearSections();
+        this._setSection(() => {
             this._sessionViewModel = new SessionViewModel({session, sync});
-        this.emit("change", "activeSection");
-    }
-
-    _clearSections() {
-        this._error = null;
-        this._loading = false;
-        this._sessionViewModel = null;
-        this._loginViewModel = null;
-        this._sessionPickerViewModel = null;
+        });
     }
 
     get activeSection() {
@@ -88,6 +79,25 @@ export default class BrawlViewModel extends EventEmitter {
         }
     }
 
+    _setSection(setter) {
+        const oldSection = this.activeSection;
+        // clear all members the activeSection depends on
+        this._error = null;
+        this._loading = false;
+        this._sessionViewModel = null;
+        this._loginViewModel = null;
+        this._sessionPickerViewModel = null;
+        // now set it again
+        setter();
+        const newSection = this.activeSection;
+        // remove session subscription when navigating away
+        if (oldSection === "session" && newSection !== oldSection) {
+            this._sessionSubscription();
+            this._sessionSubscription = null;
+        }
+        this.emit("change", "activeSection");
+    }
+
     get loadingText() { return this._loadingText; }
     get sessionViewModel() { return this._sessionViewModel; }
     get loginViewModel() { return this._loginViewModel; }
@@ -123,51 +133,12 @@ export default class BrawlViewModel extends EventEmitter {
     }
 
     async _loadSession(sessionInfo) {
-        try {
-            this._loading = true;
-            this._loadingText = "Loading your conversations…";
-            const reconnector = new Reconnector(
-                new ExponentialRetryDelay(2000, this._clock.createTimeout),
-                this._clock.createMeasure
-            );
-            const hsApi = this._createHsApi(sessionInfo.homeServer, sessionInfo.accessToken, reconnector);
-            const storage = await this._storageFactory.create(sessionInfo.id);
-            // no need to pass access token to session
-            const filteredSessionInfo = {
-                deviceId: sessionInfo.deviceId,
-                userId: sessionInfo.userId,
-                homeServer: sessionInfo.homeServer,
-            };
-            const session = new Session({storage, sessionInfo: filteredSessionInfo, hsApi});
-            // show spinner now, with title loading stored data?
-            this.emit("change", "activeSection");
-            await session.load();
-            const sync = new Sync({hsApi, storage, session});
-
-            reconnector.on("state", state => {
-                if (state === ConnectionState.Online) {
-                    sync.start();
-                    session.notifyNetworkAvailable(reconnector.lastVersionsResponse);
-                }
+        this._setSection(() => {
+            // TODO this is pseudo code-ish
+            const container = this._createSessionContainer();
+            this._sessionViewModel = new SessionViewModel({session, sync});
+            this._sessionSubscription = this._activeSessionContainer.subscribe(this._updateSessionState);
+            this._activeSessionContainer.start(sessionInfo);
         });
-            
-            const needsInitialSync = !session.syncToken;
-            if (!needsInitialSync) {
-                this._showSession(session, sync);
-            }
-            this._loadingText = "Getting your conversations from the server…";
-            this.emit("change", "loadingText");
-            // update spinner title to initial sync
-            await sync.start();
-            if (needsInitialSync) {
-                this._showSession(session, sync);
-            }
-            // start sending pending messages
-            session.notifyNetworkAvailable();
-        } catch (err) {
-            console.error(err);
-            this._error = err;
-        }
-        this.emit("change", "activeSection");
     }
 }

src/domain/ViewModel.js

@@ -0,0 +1,19 @@
+export class ViewModel extends ObservableValue {
+    constructor(options) {
+        super();
+        this.disposables = new Disposables();
+        this._options = options;
+    }
+
+    childOptions(explicitOptions) {
+        return Object.assign({}, this._options, explicitOptions);
+    }
+
+    track(disposable) {
+        this.disposables.track(disposable);
+    }
+
+    dispose() {
+        this.disposables.dispose();
+    }
+}

src/domain/session/SessionLoadViewModel.js

@@ -0,0 +1,43 @@
+import EventEmitter from "../../EventEmitter.js";
+import RoomTileViewModel from "./roomlist/RoomTileViewModel.js";
+import RoomViewModel from "./room/RoomViewModel.js";
+import SyncStatusViewModel from "./SyncStatusViewModel.js";
+
+export default class SessionLoadViewModel extends ViewModel {
+    constructor(options) {
+        super(options);
+        this._sessionContainer = options.sessionContainer;
+        this._updateState();
+    }
+
+    onSubscribeFirst() {
+        this.track(this._sessionContainer.subscribe(this._updateState));
+    }
+
+    _updateState(previousState) {
+        const state = this._sessionContainer.state;
+        if (previousState !== LoadState.Ready && state === LoadState.Ready) {
+            this._sessionViewModel = new SessionViewModel(this.childOptions({
+                sessionContainer: this._sessionContainer
+            }));
+            this.track(this._sessionViewModel);
+        } else if (previousState === LoadState.Ready && state !== LoadState.Ready) {
+            this.disposables.disposeTracked(this._sessionViewModel);
+            this._sessionViewModel = null;
+        }
+        this.emit();
+    }
+
+    get isLoading() {
+        const state = this._sessionContainer.state;
+        return state === LoadState.Loading || state === LoadState.InitialSync;
+    }
+
+    get loadingLabel() {
+        switch (this._sessionContainer.state) {
+            case LoadState.Loading: return "Loading your conversations…";
+            case LoadState.InitialSync: return "Getting your conversations from the server…";
+            default: return null;
+        }
+    }
+}

src/domain/session/SessionViewModel.js

@@ -31,6 +31,13 @@ export default class SessionViewModel extends EventEmitter {
         return this._currentRoomViewModel;
     }
 
+    dispose() {
+        if (this._currentRoomViewModel) {
+            this._currentRoomViewModel.dispose();
+            this._currentRoomViewModel = null;
+        }
+    }
+
     _closeCurrentRoom() {
         if (this._currentRoomViewModel) {
             this._currentRoomViewModel.dispose();

src/matrix/Reconnector.js

@@ -1,13 +1,3 @@
-// need to prevent memory leaks here!
-export class DomOnlineDetected {
-    constructor(reconnector) {
-        // window.addEventListener('offline', () => appendOnlineStatus(false));
-        // window.addEventListener('online', () => appendOnlineStatus(true));
-        // appendOnlineStatus(navigator.onLine);
-        // on online, reconnector.tryNow()
-    }
-}
-
 export class ExponentialRetryDelay {
     constructor(start = 2000, createTimeout) {
         this._start = start;
@@ -76,7 +66,7 @@ export const ConnectionState = createEnum(
     "Online"
 );
 
-export class Reconnector {
+export class Reconnector extends ObservableValue {
     constructor({retryDelay, createTimeMeasure}) {
         this._online 
         this._retryDelay = retryDelay;
@@ -124,7 +114,7 @@ export class Reconnector {
             } else {
                 this._stateSince = null;
             }
-            this.emit("change", state);
+            this.emit(state);
         }
     }
     

src/matrix/SessionContainer.js

@@ -0,0 +1,95 @@
+const factory = {
+    Clock: () => new DOMClock(),
+    Request: () => fetchRequest,
+    Online: () => new DOMOnline(),
+    HomeServerApi: ()
+}
+
+export const LoadState = createEnum(
+    "Loading",
+    "InitialSync",
+    "Migrating",    //not used atm, but would fit here
+    "Error",
+    "Ready",
+);
+
+class SessionContainer extends ObservableValue {
+    constructor({clock, random, isOnline, request, storageFactory, factory}) {
+        this.disposables = new Disposables();
+    }
+
+    dispose() {
+        this.disposables.dispose();
+    }
+
+    get state() {
+        return this._state;
+    }
+
+    _setState(state) {
+        if (state !== this._state) {
+            const previousState = this._state;
+            this._state = state;
+            this.emit(previousState);
+        }
+    }
+
+    get sync() {
+        return this._sync;
+    }
+
+    get session() {
+        return this._session;
+    }
+
+    _createReconnector() {
+        const reconnector = new Reconnector(
+            new ExponentialRetryDelay(2000, this._clock.createTimeout),
+            this._clock.createMeasure
+        );
+        // retry connection immediatly when online is detected
+        this.disposables.track(isOnline.subscribe(online => {
+            if(online) {
+                reconnector.tryNow();
+            }
+        }));
+        return reconnector;
+    }
+
+    async start(sessionInfo) {
+        try {
+            this._setState(LoadState.Loading);
+            this._reconnector = this._createReconnector();
+            const hsApi = this._createHsApi(sessionInfo.homeServer, sessionInfo.accessToken, this._reconnector);
+            const storage = await this._storageFactory.create(sessionInfo.id);
+            // no need to pass access token to session
+            const filteredSessionInfo = {
+                deviceId: sessionInfo.deviceId,
+                userId: sessionInfo.userId,
+                homeServer: sessionInfo.homeServer,
+            };
+            this._session = new Session({storage, sessionInfo: filteredSessionInfo, hsApi});
+            await this._session.load();
+            this._sync = new Sync({hsApi, storage, this._session});
+
+            // notify sync and session when back online
+            this.disposables.track(reconnector.subscribe(state => {
+                this._sync.start();
+                session.notifyNetworkAvailable(reconnector.lastVersionsResponse);
+            }));
+            
+            const needsInitialSync = !this._session.syncToken;
+            if (!needsInitialSync) {
+                this._setState(LoadState.Ready);
+            } else {
+                this._setState(LoadState.InitialSync);
+            }
+            await this._sync.start();
+            this._setState(LoadState.Ready);
+            this._session.notifyNetworkAvailable();
+        } catch (err) {
+            this._error = err;
+            this._setState(LoadState.Error);
+        }
+    }
+}

src/observable/BaseObservableCollection.js

@@ -31,6 +31,15 @@ export default class BaseObservableCollection {
     // Add iterator over handlers here
 }
 
+// like an EventEmitter, but doesn't have an event type
+export class ObservableValue extends BaseObservableCollection {
+    emit(argument) {
+        for (const h of this._handlers) {
+            h(argument);
+        }
+    }
+}
+
 export function tests() {
     class Collection extends BaseObservableCollection {
         constructor() {

src/ui/web/dom/Clock.js

@@ -1,6 +1,6 @@
-import {AbortError} from "./error.js";
+import {AbortError} from "../utils/error.js";
 
-class DOMTimeout {
+class Timeout {
     constructor(ms) {
         this._reject = null;
         this._handle = null;
@@ -27,7 +27,7 @@ class DOMTimeout {
     }
 }
 
-class DOMTimeMeasure {
+class TimeMeasure {
     constructor() {
         this._start = window.performance.now();
     }
@@ -37,13 +37,13 @@ class DOMTimeMeasure {
     }
 }
 
-export class DOMClock {
+export class Clock {
     createMeasure() {
-        return new DOMTimeMeasure();
+        return new TimeMeasure();
     }
 
     createTimeout(ms) {
-        return new DOMTimeout(ms);
+        return new Timeout(ms);
     }
 
     now() {

src/ui/web/dom/Online.js

@@ -0,0 +1,29 @@
+export class Online extends ObservableValue {
+    constructor() {
+        super();
+        this._onOffline = this._onOffline.bind(this);
+        this._onOnline = this._onOnline.bind(this);
+    }
+
+    _onOffline() {
+        this.emit(false);
+    }
+
+    _onOnline() {
+        this.emit(true);
+    }
+
+    get value() {
+        return navigator.onLine;
+    }
+
+    onSubscribeFirst() {
+        window.addEventListener('offline', this._onOffline);
+        window.addEventListener('online', this._onOnline);
+    }
+
+    onUnsubscribeLast() {
+        window.removeEventListener('offline', this._onOffline);
+        window.removeEventListener('online', this._onOnline);
+    }
+}

src/ui/web/general/SwitchView.js

@@ -34,3 +34,38 @@ export default class SwitchView {
         return this._childView;
     }
 }
+
+// SessionLoadView
+// should this be the new switch view?
+// and the other one be the BasicSwitchView?
+new BoundSwitchView(vm, vm => vm.isLoading, (loading, vm) => {
+    if (loading) {
+        return new InlineTemplateView(vm, t => {
+            return t.div({className: "loading"}, [
+                t.span({className: "spinner"}),
+                t.span(vm => vm.loadingText)
+            ]);
+        });
+    } else {
+        return new SessionView(vm.sessionViewModel);
+    }
+});
+
+class BoundSwitchView extends SwitchView {
+    constructor(value, mapper, viewCreator) {
+        super(viewCreator(mapper(value), value));
+        this._mapper = mapper;
+        this._viewCreator = viewCreator;
+        this._mappedValue = mapper(value);
+    }
+
+    update(value) {
+        const mappedValue = this._mapper(value);
+        if (mappedValue !== this._mappedValue) {
+            this._mappedValue = mappedValue;
+            this.switch(this._viewCreator(this._mappedValue, value));
+        } else {
+            super.update(value);
+        }
+    }
+}

src/utils/Disposables.js

@@ -0,0 +1,37 @@
+function disposeValue(value) {
+    if (typeof d === "function") {
+        value();
+    } else {
+        value.dispose();
+    }
+}
+
+export class Disposables {
+    constructor() {
+        this._disposables = [];
+    }
+
+    track(disposable) {
+        this._disposables.push(disposable);
+    }
+
+    dispose() {
+        if (this._disposables) {
+            for (const d of this._disposables) {
+                disposeValue(d);
+            }
+            this._disposables = null;
+        }
+    }
+
+
+    disposeTracked(value) {
+        const idx = this._disposables.indexOf(value);
+        if (idx !== -1) {
+            const [foundValue] = this._disposables.splice(idx, 1);
+            disposeValue(foundValue);
+            return true;
+        }
+        return false;
+    }
+}