incrementUserUSN increment the given user's max_usn by 1 and returns the new, incremented max_usn
(tx *gorm.DB, userID int)
| 26 | // incrementUserUSN increment the given user's max_usn by 1 |
| 27 | // and returns the new, incremented max_usn |
| 28 | func incrementUserUSN(tx *gorm.DB, userID int) (int, error) { |
| 29 | // First, get the current max_usn to detect transition from empty server |
| 30 | var user database.User |
| 31 | if err := tx.Select("max_usn, full_sync_before").Where("id = ?", userID).First(&user).Error; err != nil { |
| 32 | return 0, errors.Wrap(err, "getting current user state") |
| 33 | } |
| 34 | |
| 35 | // If transitioning from empty server (MaxUSN=0) to non-empty (MaxUSN=1), |
| 36 | // set full_sync_before to current timestamp to force all other clients to full sync |
| 37 | if user.MaxUSN == 0 && user.FullSyncBefore == 0 { |
| 38 | currentTime := time.Now().Unix() |
| 39 | if err := tx.Table("users").Where("id = ?", userID).Update("full_sync_before", currentTime).Error; err != nil { |
| 40 | return 0, errors.Wrap(err, "setting full_sync_before on empty server transition") |
| 41 | } |
| 42 | } |
| 43 | |
| 44 | if err := tx.Table("users").Where("id = ?", userID).Update("max_usn", gorm.Expr("max_usn + 1")).Error; err != nil { |
| 45 | return 0, errors.Wrap(err, "incrementing user max_usn") |
| 46 | } |
| 47 | |
| 48 | if err := tx.Select("max_usn").Where("id = ?", userID).First(&user).Error; err != nil { |
| 49 | return 0, errors.Wrap(err, "getting the updated user max_usn") |
| 50 | } |
| 51 | |
| 52 | return user.MaxUSN, nil |
| 53 | } |