extract olm/Session into own file

src/matrix/e2ee/olm/Decryption.js

@@ -16,6 +16,7 @@ limitations under the License.
 
 import {DecryptionError} from "../common.js";
 import {groupBy} from "../../../utils/groupBy.js";
+import {Session} from "./Session.js";
 
 const SESSION_LIMIT_PER_SENDER_KEY = 4;
 
@@ -169,44 +170,6 @@ export class Decryption {
     }
 }
 
-class Session {
-    constructor(data, pickleKey, olm, isNew = false) {
-        this.data = data;
-        this._olm = olm;
-        this._pickleKey = pickleKey;
-        this.isNew = isNew;
-        this.isModified = isNew;
-    }
-
-    static create(senderKey, olmSession, olm, pickleKey, timestamp) {
-        return new Session({
-            session: olmSession.pickle(pickleKey),
-            sessionId: olmSession.session_id(),
-            senderKey,
-            lastUsed: timestamp,
-        }, pickleKey, olm, true);
-    }
-
-    get id() {
-        return this.data.sessionId;
-    }
-
-    load() {
-        const session = new this._olm.Session();
-        session.unpickle(this._pickleKey, this.data.session);
-        return session;
-    }
-
-    unload(olmSession) {
-        olmSession.free();
-    }
-
-    save(olmSession) {
-        this.data.session = olmSession.pickle(this._pickleKey);
-        this.isModified = true;
-    }
-}
-
 // decryption helper for a single senderKey
 class SenderKeyDecryption {
     constructor(senderKey, sessions, olm, timestamp) {

src/matrix/e2ee/olm/Session.js

@@ -0,0 +1,58 @@
+/*
+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 createSessionEntry(olmSession, senderKey, timestamp, pickleKey) {
+    return {
+        session: olmSession.pickle(pickleKey),
+        sessionId: olmSession.session_id(),
+        senderKey,
+        lastUsed: timestamp,
+    };
+}
+
+export class Session {
+    constructor(data, pickleKey, olm, isNew = false) {
+        this.data = data;
+        this._olm = olm;
+        this._pickleKey = pickleKey;
+        this.isNew = isNew;
+        this.isModified = isNew;
+    }
+
+    static create(senderKey, olmSession, olm, pickleKey, timestamp) {
+        const data = createSessionEntry(olmSession, senderKey, timestamp, pickleKey);
+        return new Session(data, pickleKey, olm, true);
+    }
+
+    get id() {
+        return this.data.sessionId;
+    }
+
+    load() {
+        const session = new this._olm.Session();
+        session.unpickle(this._pickleKey, this.data.session);
+        return session;
+    }
+
+    unload(olmSession) {
+        olmSession.free();
+    }
+
+    save(olmSession) {
+        this.data.session = olmSession.pickle(this._pickleKey);
+        this.isModified = true;
+    }
+}