Migrate sessions table to BLOB column

Co-authored-by: Scott Nonnenberg <scott@signal.org>

ts/SignalProtocolStore.ts

@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 
 import PQueue from 'p-queue';
-import { isNumber, omit } from 'lodash';
+import { omit } from 'lodash';
 import { z } from 'zod';
 import { EventEmitter } from 'events';
 
@@ -27,10 +27,6 @@ import { isNotNil } from './util/isNotNil';
 import { drop } from './util/drop';
 import { Zone } from './util/Zone';
 import { isMoreRecentThan } from './util/timestamp';
-import {
-  sessionRecordToProtobuf,
-  sessionStructureToBytes,
-} from './util/sessionTranslation';
 import type {
   DeviceType,
   IdentityKeyType,
@@ -182,7 +178,7 @@ async function _fillCaches<ID, T extends HasIdType<ID>, HydratedType>(
 }
 
 export function hydrateSession(session: SessionType): SessionRecord {
-  return SessionRecord.deserialize(Buffer.from(session.record, 'base64'));
+  return SessionRecord.deserialize(Buffer.from(session.record));
 }
 export function hydratePublicKey(identityKey: IdentityKeyType): PublicKey {
   return PublicKey.deserialize(Buffer.from(identityKey.publicKey));
@@ -209,9 +205,6 @@ export function hydrateSignedPreKey(
   );
 }
 
-export function freezeSession(session: SessionRecord): string {
-  return session.serialize().toString('base64');
-}
 export function freezePublicKey(publicKey: PublicKey): Uint8Array {
   return publicKey.serialize();
 }
@@ -1333,9 +1326,14 @@ export class SignalProtocolStore extends EventEmitter {
           return entry.item;
         }
 
-        // We'll either just hydrate the item or we'll fully migrate the session
-        //   and save it to the database.
-        return await this._maybeMigrateSession(entry.fromDB, { zone });
+        const newItem = {
+          hydrated: true,
+          item: hydrateSession(entry.fromDB),
+          fromDB: entry.fromDB,
+        };
+        map.set(id, newItem);
+
+        return newItem.item;
       } catch (error) {
         const errorString = Errors.toLogFormat(error);
         log.error(`loadSession: failed to load session ${id}: ${errorString}`);
@@ -1359,68 +1357,6 @@ export class SignalProtocolStore extends EventEmitter {
     });
   }
 
-  private async _maybeMigrateSession(
-    session: SessionType,
-    { zone = GLOBAL_ZONE }: SessionTransactionOptions = {}
-  ): Promise<SessionRecord> {
-    if (!this.sessions) {
-      throw new Error('_maybeMigrateSession: this.sessions not yet cached!');
-    }
-
-    // Already migrated, hydrate and update cache
-    if (session.version === 2) {
-      const item = hydrateSession(session);
-
-      const map = this.pendingSessions.has(session.id)
-        ? this.pendingSessions
-        : this.sessions;
-      map.set(session.id, {
-        hydrated: true,
-        item,
-        fromDB: session,
-      });
-
-      return item;
-    }
-
-    // Not yet converted, need to translate to new format and save
-    if (session.version !== undefined) {
-      throw new Error('_maybeMigrateSession: Unknown session version type!');
-    }
-
-    const { ourServiceId } = session;
-
-    const keyPair = this.getIdentityKeyPair(ourServiceId);
-    if (!keyPair) {
-      throw new Error('_maybeMigrateSession: No identity key for ourself!');
-    }
-
-    const localRegistrationId = await this.getLocalRegistrationId(ourServiceId);
-    if (!isNumber(localRegistrationId)) {
-      throw new Error('_maybeMigrateSession: No registration id for ourself!');
-    }
-
-    const localUserData = {
-      identityKeyPublic: keyPair.pubKey,
-      registrationId: localRegistrationId,
-    };
-
-    log.info(`_maybeMigrateSession: Migrating session with id ${session.id}`);
-    const sessionProto = sessionRecordToProtobuf(
-      JSON.parse(session.record),
-      localUserData
-    );
-    const record = SessionRecord.deserialize(
-      Buffer.from(sessionStructureToBytes(sessionProto))
-    );
-
-    await this.storeSession(QualifiedAddress.parse(session.id), record, {
-      zone,
-    });
-
-    return record;
-  }
-
   async storeSession(
     qualifiedAddress: QualifiedAddress,
     record: SessionRecord,
@@ -1454,7 +1390,7 @@ export class SignalProtocolStore extends EventEmitter {
           conversationId: conversation.id,
           serviceId,
           deviceId,
-          record: record.serialize().toString('base64'),
+          record: record.serialize(),
         };
 
         const newSession = {
@@ -1533,9 +1469,7 @@ export class SignalProtocolStore extends EventEmitter {
               return undefined;
             }
 
-            const record = await this._maybeMigrateSession(entry.fromDB, {
-              zone,
-            });
+            const record = hydrateSession(entry.fromDB);
             if (record.hasCurrentState()) {
               return { record, entry };
             }
@@ -1688,9 +1622,7 @@ export class SignalProtocolStore extends EventEmitter {
       addr,
       `_archiveSession(${addr.toString()})`,
       async () => {
-        const item = entry.hydrated
-          ? entry.item
-          : await this._maybeMigrateSession(entry.fromDB, { zone });
+        const item = entry.hydrated ? entry.item : hydrateSession(entry.fromDB);
 
         if (!item.hasCurrentState()) {
           return;