Method beginRWTx

db.go:839–872

()

}

func (db *DB) beginRWTx() (*Tx, error) {
	// If the database was opened with Options.ReadOnly, return an error.
	if db.readOnly {
		return nil, berrors.ErrDatabaseReadOnly
	}

	// Obtain writer lock. This is released by the transaction when it closes.
	// This enforces only one writer transaction at a time.
	db.rwlock.Lock()

	// Once we have the writer lock then we can lock the meta pages so that
	// we can set up the transaction.
	db.metalock.Lock()
	defer db.metalock.Unlock()

	// Exit if the database is not open yet.
	if !db.opened {
		db.rwlock.Unlock()
		return nil, berrors.ErrDatabaseNotOpen
	}

	// Exit if the database is not correctly mapped.
	if db.data == nil {
		db.rwlock.Unlock()
		return nil, berrors.ErrInvalidMapping
	}

	// Create a transaction associated with the database.
	t := &Tx{writable: true}
	t.init(db)
	db.rwtx = t
	db.freelist.ReleasePendingPages()
	return t, nil
}

// removeTx removes a transaction from the database.
func (db *DB) removeTx(tx *Tx) {