session-desktop/ts/session/disappearing_messages/legacy.ts

import { ProtobufUtils, SignalService } from '../../protobuf';
import { ReleasedFeatures } from '../../util/releaseFeature';
import { DisappearingMessageConversationModeType } from './types';

// TODO legacy messages support will be removed in a future release
export function isLegacyDisappearingModeEnabled(
  expirationMode: DisappearingMessageConversationModeType | undefined
): boolean {
  return Boolean(
    expirationMode &&
      expirationMode !== 'off' &&
      !ReleasedFeatures.isDisappearMessageV2FeatureReleasedCached()
  );
}

export function checkIsLegacyDisappearingDataMessage(
  couldBeLegacyContent: boolean,
  dataMessage: SignalService.DataMessage
): boolean {
  return (
    couldBeLegacyContent &&
    ProtobufUtils.hasDefinedProperty(dataMessage, 'expireTimer') &&
    dataMessage.expireTimer > -1
  );
}

// TODO legacy messages support will be removed in a future release
// NOTE We need this to check for legacy disappearing messages where the expirationType and expireTimer should be undefined on the ContentMessage
export function couldBeLegacyDisappearingMessageContent(
  contentMessage: SignalService.Content
): boolean {
  return (
    (contentMessage.expirationType === SignalService.Content.ExpirationType.UNKNOWN ||
      (ReleasedFeatures.isDisappearMessageV2FeatureReleasedCached() &&
        !ProtobufUtils.hasDefinedProperty(contentMessage, 'expirationType'))) &&
    !ProtobufUtils.hasDefinedProperty(contentMessage, 'expirationTimer')
  );
}