Add "Copy matrix.to permalink" message action

src/domain/session/room/timeline/tiles/BaseMessageTile.js

@@ -17,6 +17,8 @@ limitations under the License.
 import {SimpleTile} from "./SimpleTile.js";
 import {ReactionsViewModel} from "../ReactionsViewModel.js";
 import {getIdentifierColorNumber, avatarInitials, getAvatarHttpUrl} from "../../../../avatar";
+import {copyPlaintext} from "../../../../../platform/web/dom/utils";
+
 
 export class BaseMessageTile extends SimpleTile {
     constructor(entry, options) {
@@ -45,6 +47,10 @@ export class BaseMessageTile extends SimpleTile {
         return `https://matrix.to/#/${encodeURIComponent(this._room.id)}/${encodeURIComponent(this._entry.id)}`;
     }
 
+    copyPermalink() {
+        copyPlaintext(this.permaLink);
+    }
+
     get senderProfileLink() {
         return `https://matrix.to/#/${encodeURIComponent(this.sender)}`;
     }

src/matrix/room/PowerLevels.js

@@ -66,10 +66,11 @@ export class PowerLevels {
 
     /** @param {string} action either "invite", "kick", "ban" or "redact". */
     _getActionLevel(action) {
-        const level = this._plEvent?.content[action];
+        const level = this._plEvent?.content?.[action];
         if (typeof level === "number") {
             return level;
         } else {
+            // TODO: Why does this default to 50?
             return 50;
         }
     }

src/platform/web/dom/ImageHandle.js

@@ -15,7 +15,7 @@ limitations under the License.
 */
 
 import {BlobHandle} from "./BlobHandle.js";
-import {domEventAsPromise} from "./utils.js";
+import {domEventAsPromise} from "./utils";
 
 export class ImageHandle {
     static async fromBlob(blob) {

src/platform/web/dom/utils.ts

@@ -0,0 +1,79 @@
+/*
+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.
+*/
+
+export function domEventAsPromise(element, successEvent): Promise<void> {
+    return new Promise((resolve, reject) => {
+        let detach;
+        const handleError = evt => {
+            detach();
+            reject(evt.target.error);
+        };
+        const handleSuccess = () => {
+            detach();
+            resolve();
+        };
+        detach = () => {
+            element.removeEventListener(successEvent, handleSuccess);
+            element.removeEventListener("error", handleError);
+        };
+        element.addEventListener(successEvent, handleSuccess);
+        element.addEventListener("error", handleError);
+    });
+}
+
+// Copies the given text to clipboard and returns a boolean of whether the action was
+// successful
+export async function copyPlaintext(text: string): Promise<boolean> {
+    try {
+        if (navigator?.clipboard?.writeText) {
+            await navigator.clipboard.writeText(text);
+            return true;
+        } else {
+            const textArea = document.createElement("textarea");
+            textArea.value = text;
+
+            // Avoid scrolling to bottom
+            textArea.style.top = "0";
+            textArea.style.left = "0";
+            textArea.style.position = "fixed";
+
+            document.body.appendChild(textArea);
+
+            const selection = document.getSelection();
+            if (!selection) {
+                console.error('copyPlaintext: Unable to copy text to clipboard in fallback mode because `selection` was null/undefined');
+                return false;
+            }
+
+            const range = document.createRange();
+            // range.selectNodeContents(textArea);
+            range.selectNode(textArea);
+            selection.removeAllRanges();
+            selection.addRange(range);
+
+            const successful = document.execCommand("copy");
+            selection.removeAllRanges();
+            document.body.removeChild(textArea);
+            if(!successful) {
+                console.error('copyPlaintext: Unable to copy text to clipboard in fallback mode because the `copy` command is unsupported or disabled');
+            }
+            return successful;
+        }
+    } catch (err) {
+        console.error("copyPlaintext: Ran into an error", err);
+    }
+    return false;
+}

src/platform/web/ui/session/room/timeline/BaseMessageView.js

@@ -120,6 +120,8 @@ export class BaseMessageView extends TemplateView {
         } else if (vm.canRedact) {
             options.push(Menu.option(vm.i18n`Delete`, () => vm.redact()).setDestructive());
         }
+
+        options.push(Menu.option(vm.i18n`Copy permalink`, () => vm.copyPermalink()));
         return options;
     }
 

src/platform/web/ui/session/room/timeline/VideoView.js

@@ -15,7 +15,7 @@ limitations under the License.
 */
 
 import {BaseMediaView} from "./BaseMediaView.js";
-import {domEventAsPromise} from "../../../../dom/utils.js";
+import {domEventAsPromise} from "../../../../dom/utils";
 
 export class VideoView extends BaseMediaView {
     renderMedia(t) {