channeldb+invoices: move invoice cancel logic into registry

This commit is a continuation of the centralization of invoice state
transition logic in the invoice registry.

channeldb/invoices.go

@@ -753,37 +753,6 @@ func (d *DB) UpdateInvoice(paymentHash lntypes.Hash,
 	return updatedInvoice, err
 }
 
-// CancelInvoice attempts to cancel the invoice corresponding to the passed
-// payment hash.
-func (d *DB) CancelInvoice(paymentHash lntypes.Hash) (*Invoice, error) {
-	var canceledInvoice *Invoice
-	err := d.Update(func(tx *bbolt.Tx) error {
-		invoices, err := tx.CreateBucketIfNotExists(invoiceBucket)
-		if err != nil {
-			return err
-		}
-		invoiceIndex, err := invoices.CreateBucketIfNotExists(
-			invoiceIndexBucket,
-		)
-		if err != nil {
-			return err
-		}
-
-		// Check the invoice index to see if an invoice paying to this
-		// hash exists within the DB.
-		invoiceNum := invoiceIndex.Get(paymentHash[:])
-		if invoiceNum == nil {
-			return ErrInvoiceNotFound
-		}
-
-		canceledInvoice, err = cancelInvoice(invoices, invoiceNum)
-
-		return err
-	})
-
-	return canceledInvoice, err
-}
-
 // InvoicesSettledSince can be used by callers to catch up any settled invoices
 // they missed within the settled invoice time series. We'll return all known
 // settled invoice that have a settle index higher than the passed
@@ -1282,35 +1251,3 @@ func setSettleFields(settleIndex *bbolt.Bucket, invoiceNum []byte,
 
 	return nil
 }
-
-func cancelInvoice(invoices *bbolt.Bucket, invoiceNum []byte) (
-	*Invoice, error) {
-
-	invoice, err := fetchInvoice(invoiceNum, invoices)
-	if err != nil {
-		return nil, err
-	}
-
-	switch invoice.Terms.State {
-	case ContractSettled:
-		return &invoice, ErrInvoiceAlreadySettled
-	case ContractCanceled:
-		return &invoice, ErrInvoiceAlreadyCanceled
-	}
-
-	invoice.Terms.State = ContractCanceled
-
-	// Set AmtPaid back to 0, in case the invoice was already accepted.
-	invoice.AmtPaid = 0
-
-	var buf bytes.Buffer
-	if err := serializeInvoice(&buf, &invoice); err != nil {
-		return nil, err
-	}
-
-	if err := invoices.Put(invoiceNum[:], buf.Bytes()); err != nil {
-		return nil, err
-	}
-
-	return &invoice, nil
-}

invoices/invoiceregistry.go

@@ -634,7 +634,24 @@ func (i *InvoiceRegistry) CancelInvoice(payHash lntypes.Hash) error {
 
 	log.Debugf("Invoice(%v): canceling invoice", payHash)
 
-	invoice, err := i.cdb.CancelInvoice(payHash)
+	updateInvoice := func(invoice *channeldb.Invoice) (
+		*channeldb.InvoiceUpdateDesc, error) {
+
+		switch invoice.Terms.State {
+		case channeldb.ContractSettled:
+			return nil, channeldb.ErrInvoiceAlreadySettled
+		case channeldb.ContractCanceled:
+			return nil, channeldb.ErrInvoiceAlreadyCanceled
+		}
+
+		// Move invoice to the canceled state.
+		return &channeldb.InvoiceUpdateDesc{
+			AmtPaid: 0,
+			State:   channeldb.ContractCanceled,
+		}, nil
+	}
+
+	invoice, err := i.cdb.UpdateInvoice(payHash, updateInvoice)
 
 	// Implement idempotency by returning success if the invoice was already
 	// canceled.