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package database
import (
"database/sql"
"errors"
"fmt"
"slices"
)
// returns true in case of successful deletion
func (db *DB) DeleteState(name string) (bool, error) {
result, err := db.Exec(`DELETE FROM states WHERE name = ?;`, name)
if err != nil {
return false, err
}
n, err := result.RowsAffected()
if err != nil {
return false, err
}
return n == 1, nil
}
func (db *DB) GetState(name string) ([]byte, error) {
var encryptedData []byte
err := db.QueryRow(
`SELECT versions.data
FROM versions
JOIN states ON states.id = versions.state_id
WHERE states.name = ?
ORDER BY versions.id DESC
LIMIT 1;`,
name).Scan(&encryptedData)
if err != nil {
if errors.Is(err, sql.ErrNoRows) {
return []byte{}, nil
}
return nil, err
}
if encryptedData == nil {
return []byte{}, nil
}
return db.dataEncryptionKey.DecryptAES256(encryptedData)
}
// returns true in case of id mismatch
func (db *DB) SetState(name string, data []byte, lockID string) (bool, error) {
encryptedData, err := db.dataEncryptionKey.EncryptAES256(data)
if err != nil {
return false, err
}
tx, err := db.Begin()
if err != nil {
return false, err
}
defer func() {
if err != nil {
_ = tx.Rollback()
}
}()
var (
stateID int64
lockData []byte
)
if err = tx.QueryRowContext(db.ctx, `SELECT id, lock->>'ID' FROM states WHERE name = ?;`, name).Scan(&stateID, &lockData); err != nil {
if errors.Is(err, sql.ErrNoRows) {
var result sql.Result
result, err = tx.ExecContext(db.ctx, `INSERT INTO states(name) VALUES (?)`, name)
if err != nil {
return false, err
}
stateID, err = result.LastInsertId()
if err != nil {
return false, err
}
} else {
return false, err
}
}
if lockID != "" && slices.Compare([]byte(lockID), lockData) != 0 {
err = fmt.Errorf("failed to update state, lock ID does not match")
return true, err
}
_, err = tx.ExecContext(db.ctx,
`INSERT INTO versions(state_id, data, lock)
SELECT :stateID, :data, lock
FROM states
WHERE states.id = :stateID;`,
sql.Named("stateID", stateID),
sql.Named("data", encryptedData))
if err != nil {
return false, err
}
_, err = tx.ExecContext(db.ctx,
`DELETE FROM versions
WHERE state_id = (SELECT id
FROM states
WHERE name = :name)
AND id < (SELECT MIN(id)
FROM(SELECT versions.id
FROM versions
JOIN states ON states.id = versions.state_id
WHERE states.name = :name
ORDER BY versions.id DESC
LIMIT 64));`,
sql.Named("name", name),
)
if err != nil {
return false, err
}
err = tx.Commit()
return false, err
}
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