Add tool to migrate logins between origins

App checks at startup for an existing session, if there isn't one,
it will start the tool to check for a login in the file:// origin.
If there is one, it will copy the login over to the vector://vector
origin.

In principle this could also be used to migrate logins between
other origins on the web if this were ever required.

This includes a minified copy of the browserified js-sdk with
a getAllEndToEndSessions() function added to the crypto store
(https://github.com/matrix-org/matrix-js-sdk/pull/812). This is
not great, but for a short-lived tool this seems better than
introducing more entry points into webpack only used for the
electron app.

origin_migrator/source.js

@@ -0,0 +1,210 @@
+/*
+Copyright 2018 New Vector Ltd
+
+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.
+*/
+
+const TARGET_ORIGIN = 'vector://vector';
+const BATCH_SIZE = 500;
+let destFrame;
+
+let initResolver = null;
+let getSummaryResolver = null;
+
+function onMessage(e) {
+    if (e.origin !== TARGET_ORIGIN) return;
+
+    if (e.data.cmd === 'initOK' && initResolver) {
+        initResolver();
+        initResolver = null;
+    } else if (e.data.cmd === 'summary' && getSummaryResolver) {
+        getSummaryResolver(e.data.data);
+        getSummaryResolver = null;
+    }
+}
+
+async function initDestFrame() {
+    return new Promise(resolve => {
+        initResolver = resolve;
+        destFrame.postMessage({
+            cmd: 'init', 
+        }, TARGET_ORIGIN);
+    });
+}
+
+async function getSummary() {
+    return new Promise(resolve => {
+        getSummaryResolver = resolve;
+        destFrame.postMessage({
+            cmd: 'getSummary', 
+        }, TARGET_ORIGIN);
+    });
+}
+
+async function doMigrate() {
+    let accountSent = 0;
+    let sessionsSent = 0;
+    let inboundGroupSessionsSent = 0;
+    let deviceDataSent = 0;
+    let roomsSent = 0;
+    let localStorageKeysSent = 0;
+
+    if (!window.ipcRenderer) {
+        console.error("ipcRenderer not found");
+        return;
+    }
+
+    if (window.localStorage.getItem('mx_user_id') === null) {
+        window.ipcRenderer.send("origin_migration_nodata");
+        return;
+    }
+
+    destFrame = window.parent.frames.dest;
+
+    await initDestFrame();
+
+    const IndexedDBCryptoStore = window.matrixcs.IndexedDBCryptoStore;
+
+    const cryptoStore = new IndexedDBCryptoStore(window.indexedDB, 'matrix-js-sdk:crypto');
+
+    await cryptoStore.doTxn(
+        'readonly', [IndexedDBCryptoStore.STORE_ACCOUNT],
+        (txn) => {
+            cryptoStore.getAccount(txn, (account) => {
+                destFrame.postMessage({
+                    cmd: 'storeAccount',
+                    data: account,
+                }, TARGET_ORIGIN);
+                ++accountSent;
+            });
+        },
+    );
+
+    await cryptoStore.doTxn(
+        'readonly', [IndexedDBCryptoStore.STORE_SESSIONS],
+        (txn) => {
+            let sessBatch = [];
+            cryptoStore.getAllEndToEndSessions(txn, (sessInfo) => {
+                if (sessInfo) {
+                    ++sessionsSent;
+                    sessBatch.push(sessInfo);
+                }
+                if (sessBatch.length >= BATCH_SIZE || sessInfo === null) {
+                    destFrame.postMessage({
+                        cmd: 'storeSessions',
+                        data: sessBatch,
+                    }, TARGET_ORIGIN);
+                    sessBatch = [];
+                }
+            });
+        },
+    );
+
+    await cryptoStore.doTxn(
+        'readonly', [IndexedDBCryptoStore.STORE_INBOUND_GROUP_SESSIONS],
+        (txn) => {
+            let sessBatch = [];
+            cryptoStore.getAllEndToEndInboundGroupSessions(txn, (sessInfo) => {
+                if (sessInfo) {
+                    ++inboundGroupSessionsSent;
+                    sessBatch.push(sessInfo);
+                }
+                if (sessBatch.length >= BATCH_SIZE || sessInfo === null) {
+                    destFrame.postMessage({
+                        cmd: 'storeInboundGroupSessions',
+                        data: sessBatch,
+                    }, TARGET_ORIGIN);
+                    sessBatch = [];
+                }
+            });
+        },
+    );
+
+    await cryptoStore.doTxn(
+        'readonly', [IndexedDBCryptoStore.STORE_DEVICE_DATA],
+        (txn) => {
+            cryptoStore.getEndToEndDeviceData(txn, (deviceData) => {
+                destFrame.postMessage({
+                    cmd: 'storeDeviceData',
+                    data: deviceData,
+                }, TARGET_ORIGIN);
+                ++deviceDataSent;
+            });
+        },
+    );
+
+    await cryptoStore.doTxn(
+        'readonly', [IndexedDBCryptoStore.STORE_ROOMS],
+        (txn) => {
+            cryptoStore.getEndToEndRooms(txn, (rooms) => {
+                destFrame.postMessage({
+                    cmd: 'storeRooms',
+                    data: rooms,
+                }, TARGET_ORIGIN);
+                ++roomsSent;
+            });
+        },
+    );
+
+    // we don't bother migrating;
+    // * sync data (we can just initialsync again)
+    // * logs
+    // * key requests (worst case they'll just be re-sent)
+    // * sessions needing backup (feature isn't available on Electron)
+
+    for (let i = 0; i < window.localStorage.length; ++i) {
+        const key = window.localStorage.key(i);
+        const val = window.localStorage.getItem(key);
+        
+        destFrame.postMessage({
+            cmd: 'storeLocalStorage',
+            data: { key, val },
+        }, TARGET_ORIGIN);
+        ++localStorageKeysSent;
+    }
+
+    const summary = await getSummary();
+    let success = false;
+    if (
+        summary.accountStored === accountSent &&
+        summary.sessionsStored === sessionsSent &&
+        summary.inboundGroupSessionsStored === inboundGroupSessionsSent &&
+        summary.deviceDataStored === deviceDataSent &&
+        summary.roomsStored === roomsSent &&
+        summary.localStorageKeysStored === localStorageKeysSent
+    ) {
+        success = true;
+        window.localStorage.clear();
+        await cryptoStore.deleteAllData();
+
+        // we don't bother migrating them, but also blow away the sync & logs db,
+        // otherwise they'll just hang about taking up space
+        await new Promise(resolve => {
+            const req = window.indexedDB.deleteDatabase('matrix-js-sdk:riot-web-sync');
+            req.onsuccess = resolve;
+            req.onerror = resolve;
+        });
+        await new Promise(resolve => {
+            const req = window.indexedDB.deleteDatabase('logs');
+            req.onsuccess = resolve;
+            req.onerror = resolve;
+        });
+    }
+
+    window.ipcRenderer.send("origin_migration_complete", success, {
+        accountSent, sessionsSent, inboundGroupSessionsSent,
+        deviceDataSent, roomsSent, localStorageKeysSent,
+    }, summary);
+}
+
+window.addEventListener('message', onMessage);