Show a progress bar while migrating from legacy crypto (matrix-org#12104)

* Show a progress bar during migration of crypto data

* playwright: add new `pageWithCredentials` fixture

* Add a playwright test for migration progress

* Add documentation for `idbSave`

Author: richvdh

.prettierignore

@@ -17,3 +17,6 @@ yarn.lock
 
 # This file is owned, parsed, and generated by allchange, which doesn't comply with prettier
 /CHANGELOG.md
+
+# This file is also machine-generated
+/playwright/e2e/crypto/test_indexeddb_cryptostore_dump/dump.json

playwright/e2e/crypto/migration.spec.ts

@@ -0,0 +1,72 @@
+/*
+Copyright 2023-2024 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 path from "path";
+import { readFile } from "node:fs/promises";
+
+import { expect, test as base } from "../../element-web-test";
+
+const test = base.extend({
+    // Replace the `user` fixture with one which populates the indexeddb data before starting the app.
+    user: async ({ context, pageWithCredentials: page, credentials }, use) => {
+        await page.route(`/test_indexeddb_cryptostore_dump/*`, async (route, request) => {
+            const resourcePath = path.join(__dirname, new URL(request.url()).pathname);
+            const body = await readFile(resourcePath, { encoding: "utf-8" });
+            await route.fulfill({ body });
+        });
+        await page.goto("/test_indexeddb_cryptostore_dump/index.html");
+
+        await use(credentials);
+    },
+});
+
+test.describe("migration", function () {
+    test.use({ displayName: "Alice" });
+
+    test("Should support migration from legacy crypto", async ({ context, user, page }, workerInfo) => {
+        test.skip(workerInfo.project.name === "Legacy Crypto", "This test only works with Rust crypto.");
+        test.slow();
+
+        // We should see a migration progress bar
+        await page.getByText("Hang tight.").waitFor({ timeout: 60000 });
+
+        // When the progress bar first loads, it should have a high max (one per megolm session to import), and
+        // a relatively low value.
+        const progressBar = page.getByRole("progressbar");
+        const initialProgress = parseFloat(await progressBar.getAttribute("value"));
+        const initialMax = parseFloat(await progressBar.getAttribute("max"));
+        expect(initialMax).toBeGreaterThan(4000);
+        expect(initialProgress).toBeGreaterThanOrEqual(0);
+        expect(initialProgress).toBeLessThanOrEqual(500);
+
+        // Later, the progress should pass 50%
+        await expect
+            .poll(
+                async () => {
+                    const progressBar = page.getByRole("progressbar");
+                    return (
+                        (parseFloat(await progressBar.getAttribute("value")) * 100.0) /
+                        parseFloat(await progressBar.getAttribute("max"))
+                    );
+                },
+                { timeout: 60000 },
+            )
+            .toBeGreaterThan(50);
+
+        // Eventually, we should get a normal matrix chat
+        await page.waitForSelector(".mx_MatrixChat", { timeout: 120000 });
+    });
+});

playwright/e2e/crypto/test_indexeddb_cryptostore_dump/README.md

@@ -0,0 +1,60 @@
+# Dump of libolm indexeddb cryptostore
+
+This directory contains, in `dump.json`, a dump of a real indexeddb store from a session using
+libolm crypto.
+
+The corresponding pickle key is `+1k2Ppd7HIisUY824v7JtV3/oEE4yX0TqtmNPyhaD7o`.
+
+This directory also contains, in `index.html` and `load.js`, a page which will populate indexeddb with the data
+(and the pickle key). This can be served via a Playwright [Route](https://playwright.dev/docs/api/class-route) so as to
+populate the indexeddb before the main application loads. Note that encrypting the pickle key requires the test User ID
+and Device ID, so they must be stored in `localstorage` before loading `index.html`.
+
+## Creation of the dump file
+
+The dump was created by pasting the following into the browser console:
+
+```javascript
+async function exportIndexedDb(name) {
+    const db = await new Promise((resolve, reject) => {
+        const dbReq = indexedDB.open(name);
+        dbReq.onerror = reject;
+        dbReq.onsuccess = () => resolve(dbReq.result);
+    });
+
+    const storeNames = db.objectStoreNames;
+    const exports = {};
+    for (const store of storeNames) {
+        exports[store] = [];
+        const txn = db.transaction(store, "readonly");
+        const objectStore = txn.objectStore(store);
+        await new Promise((resolve, reject) => {
+            const cursorReq = objectStore.openCursor();
+            cursorReq.onerror = reject;
+            cursorReq.onsuccess = (event) => {
+                const cursor = event.target.result;
+                if (cursor) {
+                    const entry = { value: cursor.value };
+                    if (!objectStore.keyPath) {
+                        entry.key = cursor.key;
+                    }
+                    exports[store].push(entry);
+                    cursor.continue();
+                } else {
+                    resolve();
+                }
+            };
+        });
+    }
+    return exports;
+}
+
+window.saveAs(
+    new Blob([JSON.stringify(await exportIndexedDb("matrix-js-sdk:crypto"), null, 2)], {
+        type: "application/json;charset=utf-8",
+    }),
+    "dump.json",
+);
+```
+
+The pickle key is extracted via `mxMatrixClientPeg.get().crypto.olmDevice.pickleKey`.