Add timestamp utilities with helpful names

ts/LibSignalStore.ts

@@ -5,6 +5,7 @@
 
 import { fromEncodedBinaryToArrayBuffer, constantTimeEqual } from './Crypto';
 import { isNotNil } from './util/isNotNil';
+import { isMoreRecentThan } from './util/timestamp';
 
 const TIMESTAMP_THRESHOLD = 5 * 1000; // 5 seconds
 const Direction = {
@@ -839,7 +840,7 @@ export class SignalProtocolStore extends EventsMixin {
   isNonBlockingApprovalRequired(identityRecord: IdentityKeyType): boolean {
     return (
       !identityRecord.firstUse &&
-      Date.now() - identityRecord.timestamp < TIMESTAMP_THRESHOLD &&
+      isMoreRecentThan(identityRecord.timestamp, TIMESTAMP_THRESHOLD) &&
       !identityRecord.nonblockingApproval
     );
   }
@@ -1138,7 +1139,7 @@ export class SignalProtocolStore extends EventsMixin {
     }
 
     if (
-      Date.now() - identityRecord.timestamp < TIMESTAMP_THRESHOLD &&
+      isMoreRecentThan(identityRecord.timestamp, TIMESTAMP_THRESHOLD) &&
       !identityRecord.nonblockingApproval &&
       !identityRecord.firstUse
     ) {

ts/background.ts

@@ -8,6 +8,9 @@ import { getTitleBarVisibility, TitleBarVisibility } from './types/Settings';
 import { isWindowDragElement } from './util/isWindowDragElement';
 import { assert } from './util/assert';
 import { routineProfileRefresh } from './routineProfileRefresh';
+import { isMoreRecentThan, isOlderThan } from './util/timestamp';
+
+const MAX_ATTACHMENT_DOWNLOAD_AGE = 3600 * 72 * 1000;
 
 export async function startApp(): Promise<void> {
   window.startupProcessingQueue = new window.Signal.Util.StartupQueue();
@@ -555,12 +558,11 @@ export async function startApp(): Promise<void> {
     };
 
     // How long since we were last running?
-    const now = Date.now();
     const lastHeartbeat = window.storage.get('lastHeartbeat');
     await window.storage.put('lastStartup', Date.now());
 
     const THIRTY_DAYS = 30 * 24 * 60 * 60 * 1000;
-    if (lastHeartbeat > 0 && now - lastHeartbeat > THIRTY_DAYS) {
+    if (lastHeartbeat > 0 && isOlderThan(lastHeartbeat, THIRTY_DAYS)) {
       await unlinkAndDisconnect();
     }
 
@@ -2097,12 +2099,14 @@ export async function startApp(): Promise<void> {
         // once we stop processing the queue.
         window.attachmentDownloadQueue = undefined;
 
-        const THREE_DAYS_AGO = Date.now() - 3600 * 72 * 1000;
         const MAX_ATTACHMENT_MSGS_TO_DOWNLOAD = 250;
         const attachmentsToDownload = attachmentDownloadQueue.filter(
           (message, index) =>
             index <= MAX_ATTACHMENT_MSGS_TO_DOWNLOAD ||
-            message.getReceivedAt() > THREE_DAYS_AGO ||
+            isMoreRecentThan(
+              message.getReceivedAt(),
+              MAX_ATTACHMENT_DOWNLOAD_AGE
+            ) ||
             // Stickers and long text attachments has to be downloaded for UI
             // to display the message properly.
             message.hasRequiredAttachmentDownloads()

ts/routineProfileRefresh.ts

@@ -8,12 +8,14 @@ import { assert } from './util/assert';
 import { missingCaseError } from './util/missingCaseError';
 import { isNormalNumber } from './util/isNormalNumber';
 import { map, take } from './util/iterables';
+import { isOlderThan } from './util/timestamp';
 import { ConversationModel } from './models/conversations';
 
 const STORAGE_KEY = 'lastAttemptedToRefreshProfilesAt';
 const MAX_AGE_TO_BE_CONSIDERED_ACTIVE = 30 * 24 * 60 * 60 * 1000;
 const MAX_AGE_TO_BE_CONSIDERED_RECENTLY_REFRESHED = 1 * 24 * 60 * 60 * 1000;
 const MAX_CONVERSATIONS_TO_REFRESH = 50;
+const MIN_ELAPSED_DURATION_TO_REFRESH_AGAIN = 12 * 3600 * 1000;
 
 // This type is a little stricter than what's on `window.storage`, and only requires what
 //   we need for easier testing.
@@ -81,8 +83,7 @@ function hasEnoughTimeElapsedSinceLastRefresh(storage: StorageType): boolean {
   }
 
   if (isNormalNumber(storedValue)) {
-    const twelveHoursAgo = Date.now() - 43200000;
-    return storedValue < twelveHoursAgo;
+    return isOlderThan(storedValue, MIN_ELAPSED_DURATION_TO_REFRESH_AGAIN);
   }
 
   assert(

ts/test-both/util/timestamp_test.ts

@@ -0,0 +1,37 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { assert } from 'chai';
+
+import { isOlderThan, isMoreRecentThan } from '../../util/timestamp';
+
+const ONE_HOUR = 3600 * 1000;
+const ONE_DAY = 24 * ONE_HOUR;
+
+describe('timestamp', () => {
+  describe('isOlderThan', () => {
+    it('returns false on recent and future timestamps', () => {
+      assert.isFalse(isOlderThan(Date.now(), ONE_DAY));
+      assert.isFalse(isOlderThan(Date.now() + ONE_DAY, ONE_DAY));
+    });
+
+    it('returns true on old enough timestamps', () => {
+      assert.isFalse(isOlderThan(Date.now() - ONE_DAY + ONE_HOUR, ONE_DAY));
+      assert.isTrue(isOlderThan(Date.now() - ONE_DAY - ONE_HOUR, ONE_DAY));
+    });
+  });
+
+  describe('isMoreRecentThan', () => {
+    it('returns true on recent and future timestamps', () => {
+      assert.isTrue(isMoreRecentThan(Date.now(), ONE_DAY));
+      assert.isTrue(isMoreRecentThan(Date.now() + ONE_DAY, ONE_DAY));
+    });
+
+    it('returns false on old enough timestamps', () => {
+      assert.isTrue(isMoreRecentThan(Date.now() - ONE_DAY + ONE_HOUR, ONE_DAY));
+      assert.isFalse(
+        isMoreRecentThan(Date.now() - ONE_DAY - ONE_HOUR, ONE_DAY)
+      );
+    });
+  });
+});

ts/textsecure/AccountManager.ts

@@ -17,8 +17,10 @@ import ProvisioningCipher from './ProvisioningCipher';
 import WebSocketResource, {
   IncomingWebSocketRequest,
 } from './WebsocketResources';
+import { isMoreRecentThan, isOlderThan } from '../util/timestamp';
 
 const ARCHIVE_AGE = 30 * 24 * 60 * 60 * 1000;
+const PREKEY_ROTATION_AGE = 24 * 60 * 60 * 1000;
 
 function getIdentifier(id: string) {
   if (!id || !id.length) {
@@ -321,10 +323,9 @@ export default class AccountManager extends EventTarget {
       existingKeys.sort((a, b) => (b.created_at || 0) - (a.created_at || 0));
       const confirmedKeys = existingKeys.filter(key => key.confirmed);
 
-      const ONE_DAY_AGO = Date.now() - 24 * 60 * 60 * 1000;
       if (
         confirmedKeys.length >= 3 &&
-        confirmedKeys[0].created_at > ONE_DAY_AGO
+        isMoreRecentThan(confirmedKeys[0].created_at, PREKEY_ROTATION_AGE)
       ) {
         window.log.warn(
           'rotateSignedPreKey: 3+ confirmed keys, most recent is less than a day old. Cancelling rotation.'
@@ -437,9 +438,8 @@ export default class AccountManager extends EventTarget {
             return;
           }
           const createdAt = key.created_at || 0;
-          const age = Date.now() - createdAt;
 
-          if (age > ARCHIVE_AGE) {
+          if (isOlderThan(createdAt, ARCHIVE_AGE)) {
             window.log.info(
               'Removing confirmed signed prekey:',
               key.keyId,
@@ -463,8 +463,7 @@ export default class AccountManager extends EventTarget {
           }
 
           const createdAt = key.created_at || 0;
-          const age = Date.now() - createdAt;
-          if (age > ARCHIVE_AGE) {
+          if (isOlderThan(createdAt, ARCHIVE_AGE)) {
             window.log.info(
               'Removing unconfirmed signed prekey:',
               key.keyId,

ts/util/isConversationUnregistered.ts

@@ -1,6 +1,8 @@
 // Copyright 2021 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
 
+import { isMoreRecentThan } from './timestamp';
+
 const SIX_HOURS = 1000 * 60 * 60 * 6;
 
 export function isConversationUnregistered({
@@ -8,6 +10,6 @@ export function isConversationUnregistered({
 }: Readonly<{ discoveredUnregisteredAt?: number }>): boolean {
   return Boolean(
     discoveredUnregisteredAt &&
-      discoveredUnregisteredAt > Date.now() - SIX_HOURS
+      isMoreRecentThan(discoveredUnregisteredAt, SIX_HOURS)
   );
 }

ts/util/lint/exceptions.json

@@ -14026,7 +14026,7 @@
     "rule": "jQuery-load(",
     "path": "ts/LibSignalStore.js",
     "line": "        await window.ConversationController.load();",
-    "lineNumber": 810,
+    "lineNumber": 811,
     "reasonCategory": "falseMatch",
     "updated": "2021-02-27T00:48:49.313Z"
   },
@@ -14034,7 +14034,7 @@
     "rule": "jQuery-load(",
     "path": "ts/LibSignalStore.ts",
     "line": "    await window.ConversationController.load();",
-    "lineNumber": 1221,
+    "lineNumber": 1222,
     "reasonCategory": "falseMatch",
     "updated": "2021-02-27T00:48:49.313Z"
   },

ts/util/timestamp.ts

@@ -0,0 +1,10 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+export function isMoreRecentThan(timestamp: number, delta: number): boolean {
+  return timestamp > Date.now() - delta;
+}
+
+export function isOlderThan(timestamp: number, delta: number): boolean {
+  return timestamp <= Date.now() - delta;
+}