| 1 | package rootparticipation |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "sync/atomic" |
| 6 | ) |
| 7 | |
| 8 | type transactionKey struct{} |
| 9 | type heldTransaction struct { |
| 10 | ledger Ledger |
| 11 | active atomic.Bool |
| 12 | } |
| 13 | |
| 14 | func TransactionLedger(ctx context.Context) (Ledger, bool, error) { |
| 15 | held, ok := ctx.Value(transactionKey{}).(*heldTransaction) |
| 16 | if !ok { |
| 17 | return Ledger{}, false, nil |
| 18 | } |
| 19 | if !held.active.Load() { |
| 20 | return Ledger{}, true, ErrUnavailable |
| 21 | } |
| 22 | if err := ctx.Err(); err != nil { |
| 23 | return Ledger{}, true, err |
| 24 | } |
| 25 | return held.ledger, true, nil |
| 26 | } |
| 27 | |
| 28 | func (l Ledger) lockTransaction(ctx context.Context) (func(), error) { |
| 29 | held, ok, err := TransactionLedger(ctx) |
| 30 | if err != nil { |
| 31 | return nil, err |
| 32 | } |
| 33 | if ok { |
| 34 | if held.State != l.State { |
| 35 | return nil, ErrUnavailable |
| 36 | } |
| 37 | return func() {}, nil |
| 38 | } |
| 39 | return l.State.Lock(ctx, "transaction.lock") |
| 40 | } |
| 41 | |
| 42 | func (l Ledger) WithTransaction(ctx context.Context, fn func(context.Context) error) error { |
| 43 | if l.State == nil || fn == nil { |
| 44 | return ErrUnavailable |
| 45 | } |
| 46 | unlock, err := l.lockTransaction(ctx) |
| 47 | if err != nil { |
| 48 | return err |
| 49 | } |
| 50 | defer unlock() |
| 51 | held := &heldTransaction{ledger: l} |
| 52 | held.active.Store(true) |
| 53 | defer held.active.Store(false) |
| 54 | return fn(context.WithValue(ctx, transactionKey{}, held)) |
| 55 | } |
| 56 | |
amadan