Perform crypto store operations directly after transaction

src/client.js

@@ -685,6 +685,9 @@ MatrixClient.prototype.initCrypto = async function() {
         throw new Error(`Cannot enable encryption: no cryptoStore provided`);
     }
 
+    logger.log("Crypto: Starting up crypto store...");
+    await this._cryptoStore.startup();
+
     // initialise the list of encrypted rooms (whether or not crypto is enabled)
     logger.log("Crypto: initialising roomlist...");
     await this._roomList.init();

src/crypto/DeviceList.js

@@ -197,16 +197,16 @@ export class DeviceList extends EventEmitter {
             const resolveSavePromise = this._resolveSavePromise;
             this._savePromiseTime = targetTime;
             this._saveTimer = setTimeout(() => {
-                logger.log('Saving device tracking data at token ' + this._syncToken);
+                logger.log('Saving device tracking data', this._syncToken);
+
                 // null out savePromise now (after the delay but before the write),
                 // otherwise we could return the existing promise when the save has
-                // actually already happened. Likewise for the dirty flag.
+                // actually already happened.
                 this._savePromiseTime = null;
                 this._saveTimer = null;
                 this._savePromise = null;
                 this._resolveSavePromise = null;
 
-                this._dirty = false;
                 this._cryptoStore.doTxn(
                     'readwrite', [IndexedDBCryptoStore.STORE_DEVICE_DATA], (txn) => {
                         this._cryptoStore.storeEndToEndDeviceData({
@@ -217,7 +217,13 @@ export class DeviceList extends EventEmitter {
                         }, txn);
                     },
                 ).then(() => {
+                    // The device list is considered dirty until the write
+                    // completes.
+                    this._dirty = false;
                     resolveSavePromise();
+                }, err => {
+                    logger.error('Failed to save device tracking data', this._syncToken);
+                    logger.error(err);
                 });
             }, delay);
         }

src/crypto/store/indexeddb-crypto-store-backend.js

@@ -352,7 +352,11 @@ export class Backend {
         const objectStore = txn.objectStore("sessions");
         const countReq = objectStore.count();
         countReq.onsuccess = function() {
-            func(countReq.result);
+            try {
+                func(countReq.result);
+            } catch (e) {
+                abortWithException(txn, e);
+            }
         };
     }
 
@@ -402,16 +406,16 @@ export class Backend {
         const objectStore = txn.objectStore("sessions");
         const getReq = objectStore.openCursor();
         getReq.onsuccess = function() {
-            const cursor = getReq.result;
-            if (cursor) {
-                func(cursor.value);
-                cursor.continue();
-            } else {
-                try {
+            try {
+                const cursor = getReq.result;
+                if (cursor) {
+                    func(cursor.value);
+                    cursor.continue();
+                } else {
                     func(null);
-                } catch (e) {
-                    abortWithException(txn, e);
                 }
+            } catch (e) {
+                abortWithException(txn, e);
             }
         };
     }