Add structure for widget messaging layer

src/stores/widgets/SdkWidgetDriver.ts

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2020 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 { Capability, Widget, WidgetDriver, WidgetKind } from "matrix-widget-api";
+import { iterableUnion } from "../../utils/iterables";
+
+export class SdkWidgetDriver extends WidgetDriver {
+    public constructor(
+        private widget: Widget,
+        private widgetKind: WidgetKind,
+        private locationEntityId: string,
+        private preapprovedCapabilities: Set<Capability> = new Set(),
+    ) {
+        super();
+    }
+
+    public async validateCapabilities(requested: Set<Capability>): Promise<Set<Capability>> {
+        // TODO: Prompt the user to accept capabilities
+        return iterableUnion(requested, this.preapprovedCapabilities);
+    }
+}

src/stores/widgets/WidgetMessagingStore.ts

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2020 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 { ClientWidgetApi, Widget, WidgetDriver, WidgetKind } from "matrix-widget-api";
+import { AsyncStoreWithClient } from "../AsyncStoreWithClient";
+import defaultDispatcher from "../../dispatcher/dispatcher";
+import { ActionPayload } from "../../dispatcher/payloads";
+import { Room } from "matrix-js-sdk/src/models/room";
+import { WidgetSurrogate } from "./WidgetSurrogate";
+import { SdkWidgetDriver } from "./SdkWidgetDriver";
+import { EnhancedMap } from "../../utils/maps";
+
+/**
+ * Temporary holding store for widget messaging instances. This is eventually
+ * going to be merged with a more complete WidgetStore, but for now it's
+ * easiest to split this into a single place.
+ */
+export class WidgetMessagingStore extends AsyncStoreWithClient<unknown> {
+    private static internalInstance = new WidgetMessagingStore();
+
+    // <room/user ID, <widget ID, Widget>>
+    private widgetMap = new EnhancedMap<string, EnhancedMap<string, WidgetSurrogate>>();
+
+    public constructor() {
+        super(defaultDispatcher);
+    }
+
+    public static get instance(): WidgetMessagingStore {
+        return WidgetMessagingStore.internalInstance;
+    }
+
+    protected async onAction(payload: ActionPayload): Promise<any> {
+        // nothing to do
+    }
+
+    protected async onReady(): Promise<any> {
+        // just in case
+        this.widgetMap.clear();
+    }
+
+    /**
+     * Gets the messaging instance for the widget. Returns a falsey value if none
+     * is present.
+     * @param {Room} room The room for which the widget lives within.
+     * @param {Widget} widget The widget to get messaging for.
+     * @returns {ClientWidgetApi} The messaging, or a falsey value.
+     */
+    public messagingForRoomWidget(room: Room, widget: Widget): ClientWidgetApi {
+        return this.widgetMap.get(room.roomId)?.get(widget.id)?.messaging;
+    }
+
+    /**
+     * Gets the messaging instance for the widget. Returns a falsey value if none
+     * is present.
+     * @param {Widget} widget The widget to get messaging for.
+     * @returns {ClientWidgetApi} The messaging, or a falsey value.
+     */
+    public messagingForAccountWidget(widget: Widget): ClientWidgetApi {
+        return this.widgetMap.get(this.matrixClient?.getUserId())?.get(widget.id)?.messaging;
+    }
+
+    private generateMessaging(locationId: string, widget: Widget, iframe: HTMLIFrameElement, driver: WidgetDriver) {
+        const messaging = new ClientWidgetApi(widget, iframe, driver);
+        this.widgetMap.getOrCreate(locationId, new EnhancedMap())
+            .getOrCreate(widget.id, new WidgetSurrogate(widget, messaging));
+        return messaging;
+    }
+
+    /**
+     * Generates a messaging instance for the widget. If an instance already exists, it
+     * will be returned instead.
+     * @param {Room} room The room in which the widget lives.
+     * @param {Widget} widget The widget to generate/get messaging for.
+     * @param {HTMLIFrameElement} iframe The widget's iframe.
+     * @returns {ClientWidgetApi} The generated/cached messaging.
+     */
+    public generateMessagingForRoomWidget(room: Room, widget: Widget, iframe: HTMLIFrameElement): ClientWidgetApi {
+        const existing = this.messagingForRoomWidget(room, widget);
+        if (existing) return existing;
+
+        const driver = new SdkWidgetDriver(widget, WidgetKind.Room, room.roomId);
+        return this.generateMessaging(room.roomId, widget, iframe, driver);
+    }
+
+    /**
+     * Generates a messaging instance for the widget. If an instance already exists, it
+     * will be returned instead.
+     * @param {Widget} widget The widget to generate/get messaging for.
+     * @param {HTMLIFrameElement} iframe The widget's iframe.
+     * @returns {ClientWidgetApi} The generated/cached messaging.
+     */
+    public generateMessagingForAccountWidget(widget: Widget, iframe: HTMLIFrameElement): ClientWidgetApi {
+        if (!this.matrixClient) {
+            throw new Error("No matrix client to create account widgets with");
+        }
+
+        const existing = this.messagingForAccountWidget(widget);
+        if (existing) return existing;
+
+        const userId = this.matrixClient.getUserId();
+        const driver = new SdkWidgetDriver(widget, WidgetKind.Account, userId);
+        return this.generateMessaging(userId, widget, iframe, driver);
+    }
+}

src/stores/widgets/WidgetSurrogate.ts

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2020 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 { ClientWidgetApi, Widget } from "matrix-widget-api";
+
+export class WidgetSurrogate {
+    public constructor(
+        public readonly definition: Widget,
+        public readonly messaging: ClientWidgetApi,
+    ) {
+    }
+}

src/utils/iterables.ts

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2020 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 { arrayUnion } from "./arrays";
+
+export function iterableUnion<C extends Iterable<T>, T>(a: C, b: C): Set<T> {
+    return new Set(arrayUnion(Array.from(a), Array.from(b)));
+}

src/utils/maps.ts

@@ -44,3 +44,20 @@ export function mapKeyChanges<K, V>(a: Map<K, V>, b: Map<K, V>): K[] {
     const diff = mapDiff(a, b);
     return arrayMerge(diff.removed, diff.added, diff.changed);
 }
+
+/**
+ * A Map<K, V> with added utility.
+ */
+export class EnhancedMap<K, V> extends Map<K, V> {
+    public constructor(entries?: Iterable<[K, V]>) {
+        super(entries);
+    }
+
+    public getOrCreate(key: K, def: V): V {
+        if (this.has(key)) {
+            return this.get(key);
+        }
+        this.set(key, def);
+        return def;
+    }
+}