nursery_store: adds graduating state and proper finalization

nursery_store.go

@@ -52,13 +52,15 @@ type NurseryStore interface {
 	// TODO: make this handle one output at a time?
 	AwardDiplomas(...kidOutput) ([]wire.OutPoint, error)
 
-	// FinalizeClass accepts a block height as a parameter and purges its
+	IsMatureChannel(*wire.OutPoint) (bool, error)
+
+	// TryFinalizeClass accepts a block height as a parameter and purges its
 	// persistent state for all outputs at that height. During a restart,
 	// the utxo nursery will begin it's recovery procedure from the next
 	// height that has yet to be finalized. This block height should lag
 	// beyond the best height for this chain as a measure of reorg
 	// protection.
-	FinalizeClass(height uint32) error
+	TryFinalizeClass(height uint32) error
 
 	// State Bucket Enumeration.
 
@@ -83,6 +85,8 @@ type NurseryStore interface {
 	// whose type should be inferred from the key's prefix.
 	ForChanOutputs(*wire.OutPoint, func([]byte, []byte) error) error
 
+	RemoveChannel(*wire.OutPoint) error
+
 	// The Point of No Return.
 
 	// LastFinalizedHeight returns the last block height for which the
@@ -164,6 +168,8 @@ var (
 	// and will be swept into the wallet after waiting out the relative
 	// timelock.
 	kndrPrefix = []byte("kndr")
+
+	gradPrefix = []byte("grad")
 )
 
 //	              Overview of Nursery Store Storage Hierarchy
@@ -563,62 +569,71 @@ func (ns *nurseryStore) AwardDiplomas(
 	// proceed to mark the channels as closed.
 	// TODO(conner): write list of closed channels to separate bucket so
 	// that they can be replayed on restart?
-	var closedChannelSet = make(map[wire.OutPoint]struct{})
+	var possibleCloseSet = make(map[wire.OutPoint]struct{})
 	if err := ns.db.Update(func(tx *bolt.Tx) error {
 		for _, kid := range kids {
-			// Attempt to prune the height bucket matching the kid
-			// output's confirmation height if it contains no active
-			// outputs.
-			err := ns.pruneHeight(tx, kid.ConfHeight())
-			switch err {
-			case ErrBucketNotEmpty:
-				// Bucket still has active outputs, proceed to
-				// prune channel bucket.
 
-			case ErrBucketDoesNotExist:
-				// Bucket was previously pruned by another
-				// graduating output.
-
-			case nil:
-				// Bucket was pruned successfully and no errors
-				// were encounter.
-				utxnLog.Infof("Height bucket %d pruned",
-					kid.ConfHeight())
-
-			default:
-				// Unexpected database error.
-				return err
-			}
+			confHeight := kid.ConfHeight()
 
 			outpoint := kid.OutPoint()
 			chanPoint := kid.OriginChanPoint()
 
-			// Remove the outpoint belonging to the kid output from
-			// it's channel bucket, then attempt to prune the
-			// channel bucket if it is now empty.
-			err = ns.deleteAndPruneChannel(tx, chanPoint, outpoint)
-			switch err {
-			case ErrBucketNotEmpty:
-				// Bucket still has active outputs, continue to
-				// next kid to avoid adding this channel point
-				// to the set of channels to be closed.
-				continue
+			// Remove output from kindergarten bucket.
 
-			case ErrBucketDoesNotExist:
-				// Bucket may have been removed previously,
-				// allow this to fall through and ensure the
-				// channel point is added to the set channels to
-				// be closed.
+			pfxOutputKey, err := prefixOutputKey(kndrPrefix, outpoint)
+			if err != nil {
+				return err
+			}
 
-			case nil:
-				// Channel bucket was successfully pruned,
-				// proceed to add to set of channels to be
-				// closed.
-				utxnLog.Infof("Height bucket %d pruned",
-					kid.ConfHeight())
+			hghtChanBucket := ns.getHeightChanBucket(tx, confHeight, chanPoint)
+			if hghtChanBucket != nil {
+				if err := hghtChanBucket.DeleteBucket(pfxOutputKey); err != nil {
+					return err
+				}
 
-			default:
-				// Uh oh, database error.
+				// Attempt to prune the height bucket matching the kid
+				// output's confirmation height if it contains no active
+				// outputs.
+				err := ns.pruneHeight(tx, confHeight)
+				switch err {
+				case ErrBucketNotEmpty:
+					// Bucket still has active outputs, proceed to
+					// prune channel bucket.
+
+				case ErrBucketDoesNotExist:
+					// Bucket was previously pruned by another
+					// graduating output.
+
+				case nil:
+					// Bucket was pruned successfully and no errors
+					// were encounter.
+					utxnLog.Infof("Height bucket %d pruned", confHeight)
+
+				default:
+					// Unexpected database error.
+					return err
+				}
+			}
+
+			chanBucket, err := ns.createChannelBucket(tx, chanPoint)
+			if err != nil {
+				return err
+			}
+
+			if err := chanBucket.Delete(pfxOutputKey); err != nil {
+				return err
+			}
+
+			// Convert kindergarten key to graduate key.
+			copy(pfxOutputKey, gradPrefix)
+
+			var gradBuffer bytes.Buffer
+			if err := kid.Encode(&gradBuffer); err != nil {
+				return err
+			}
+
+			err = chanBucket.Put(pfxOutputKey, gradBuffer.Bytes())
+			if err != nil {
 				return err
 			}
 
@@ -628,7 +643,7 @@ func (ns *nurseryStore) AwardDiplomas(
 			// to our set of closed channels to be closed, since
 			// these may need to be replayed to ensure the channel
 			// database is aware that incubation has completed.
-			closedChannelSet[*chanPoint] = struct{}{}
+			possibleCloseSet[*chanPoint] = struct{}{}
 		}
 
 		return nil
@@ -637,25 +652,31 @@ func (ns *nurseryStore) AwardDiplomas(
 	}
 
 	// Convert our set of channels to be closed into a list.
-	channelsToBeClosed := make([]wire.OutPoint, 0, len(closedChannelSet))
-	for chanPoint := range closedChannelSet {
-		channelsToBeClosed = append(channelsToBeClosed, chanPoint)
+	possibleCloses := make([]wire.OutPoint, 0, len(possibleCloseSet))
+	for chanPoint := range possibleCloseSet {
+		possibleCloses = append(possibleCloses, chanPoint)
 	}
 
-	utxnLog.Infof("Channels to be marked fully closed: %x",
-		channelsToBeClosed)
+	utxnLog.Infof("Possible channels to be marked fully closed: %v",
+		possibleCloses)
 
-	return channelsToBeClosed, nil
+	return possibleCloses, nil
 }
 
-// FinalizeClass accepts a block height as a parameter and purges its
+// TryFinalizeClass accepts a block height as a parameter and purges its
 // persistent state for all outputs at that height. During a restart, the utxo
 // nursery will begin it's recovery procedure from the next height that has
 // yet to be finalized.
-func (ns *nurseryStore) FinalizeClass(height uint32) error {
-	utxnLog.Infof("Finalizing class at height %v", height)
+func (ns *nurseryStore) TryFinalizeClass(height uint32) error {
 	return ns.db.Update(func(tx *bolt.Tx) error {
-		return ns.putLastFinalizedHeight(tx, height)
+		utxnLog.Infof("Attempting to finalize class at height %v", height)
+		lastHeight, err := ns.getNextLastFinalizedHeight(tx, height)
+		if err != nil {
+			return err
+		}
+		utxnLog.Infof("Finalizing class at height %v", lastHeight)
+
+		return ns.putLastFinalizedHeight(tx, lastHeight)
 	})
 }
 
@@ -697,9 +718,11 @@ func (ns *nurseryStore) FetchCribs(height uint32) ([]babyOutput, error) {
 func (ns *nurseryStore) FetchKindergartens(height uint32) ([]kidOutput, error) {
 	// Construct a list of all kidOutputs that mature at the provided block
 	// height.
+	utxnLog.Infof("Fetching kinders")
 	var kids []kidOutput
 	if err := ns.forEachHeightPrefix(kndrPrefix, height,
 		func(buf []byte) error {
+			utxnLog.Infof("Inside kinder")
 
 			// We will attempt to deserialize all outputs stored
 			// with the kindergarten prefix into kidOutputs, since
@@ -719,6 +742,7 @@ func (ns *nurseryStore) FetchKindergartens(height uint32) ([]kidOutput, error) {
 		}); err != nil {
 		return nil, err
 	}
+	utxnLog.Infof("Returning kinders")
 
 	return kids, nil
 }
@@ -816,13 +840,49 @@ func (ns *nurseryStore) ForChanOutputs(chanPoint *wire.OutPoint,
 	callback func([]byte, []byte) error) error {
 
 	return ns.db.View(func(tx *bolt.Tx) error {
-		chanBucket := ns.getChannelBucket(tx, chanPoint)
-		if chanBucket == nil {
-			return ErrContractNotFound
+		return ns.forChanOutputs(tx, chanPoint, callback)
+	})
+}
+func (ns *nurseryStore) forChanOutputs(tx *bolt.Tx, chanPoint *wire.OutPoint,
+	callback func([]byte, []byte) error) error {
+
+	chanBucket := ns.getChannelBucket(tx, chanPoint)
+	if chanBucket == nil {
+		return ErrContractNotFound
+	}
+
+	return chanBucket.ForEach(callback)
+}
+
+func (ns *nurseryStore) IsMatureChannel(chanPoint *wire.OutPoint) (bool, error) {
+	var isMature bool
+	if err := ns.db.View(func(tx *bolt.Tx) error {
+		var nOutputs, nGrads int
+		if err := ns.forChanOutputs(tx, chanPoint, func(pfxKey, _ []byte) error {
+			// Count total and number of grad outputs
+			if string(pfxKey[:4]) == string(gradPrefix) {
+				nGrads++
+			}
+			nOutputs++
+
+			return nil
+
+		}); err != nil {
+			return err
 		}
 
-		return chanBucket.ForEach(callback)
-	})
+		utxnLog.Infof("Found %d graduated outputs out of %d", nGrads, nOutputs)
+		// Channel is mature if all outputs are graduated.
+		if nGrads == nOutputs {
+			isMature = true
+		}
+
+		return nil
+	}); err != nil {
+		return false, err
+	}
+
+	return isMature, nil
 }
 
 // The Point of No Return.
@@ -867,6 +927,49 @@ func (ns *nurseryStore) getLastFinalizedHeight(tx *bolt.Tx) (uint32, error) {
 	return byteOrder.Uint32(heightBytes), nil
 }
 
+func (ns *nurseryStore) getNextLastFinalizedHeight(tx *bolt.Tx, height uint32) (uint32, error) {
+	// Retrieve the previous last finalized height.
+	lastHeight, err := ns.getLastFinalizedHeight(tx)
+	if err != nil {
+		return 0, err
+	}
+
+	// TODO(conner): add lower bound after which all state is purged.
+
+	// Retrieve the existing chain bucket for this nursery store.
+	chainBucket := tx.Bucket(ns.pfxChainKey)
+	if chainBucket == nil {
+		return lastHeight, nil
+	}
+
+	// Retrieve the existing height index.
+	hghtIndex := chainBucket.Bucket(heightIndexKey)
+	if hghtIndex == nil {
+		return lastHeight, nil
+	}
+
+	for curHeight := lastHeight + 1; curHeight <= height; curHeight++ {
+		var curHeightBytes [4]byte
+		byteOrder.PutUint32(curHeightBytes[:], curHeight)
+
+		hghtBucket := hghtIndex.Bucket(curHeightBytes[:])
+		if hghtBucket == nil {
+			continue
+		}
+
+		nChildren, err := ns.numChildrenInBucket(hghtBucket)
+		if err != nil {
+			return 0, err
+		}
+
+		if nChildren > 0 {
+			return curHeight - 1, nil
+		}
+	}
+
+	return height, nil
+}
+
 // pubLastFinalizedHeight is a helper method that writes the provided height
 // under the last finalized height key.
 func (ns *nurseryStore) putLastFinalizedHeight(tx *bolt.Tx,
@@ -1135,6 +1238,7 @@ func (ns *nurseryStore) forEachHeightPrefix(prefix []byte, height uint32,
 				// the appropriate channel bucket.
 				outputBytes := chanBucket.Get(pfxOutputKey)
 				if outputBytes == nil {
+					pfxOutputKey, _ = c.Next()
 					continue
 				}
 
@@ -1228,6 +1332,31 @@ func (ns *nurseryStore) deleteAndPruneChannel(tx *bolt.Tx,
 	return ns.removeBucketIfEmpty(chanIndex, chanBytes)
 }
 
+func (ns *nurseryStore) RemoveChannel(chanPoint *wire.OutPoint) error {
+	return ns.db.Update(func(tx *bolt.Tx) error {
+		// Retrieve the existing chain bucket for this nursery store.
+		chainBucket := tx.Bucket(ns.pfxChainKey)
+		if chainBucket == nil {
+			return nil
+		}
+
+		// Retrieve the channel index stored in the chain bucket.
+		chanIndex := chainBucket.Bucket(channelIndexKey)
+		if chanIndex == nil {
+			return nil
+		}
+
+		// Serialize the provided channel point, such that we can delete
+		// the mature channel bucket.
+		var chanBuffer bytes.Buffer
+		if err := writeOutpoint(&chanBuffer, chanPoint); err != nil {
+			return err
+		}
+
+		return chanIndex.DeleteBucket(chanBuffer.Bytes())
+	})
+}
+
 // pruneHeight
 // NOTE: This method returns two concrete errors apart from those returned by
 // the underlying database: ErrBucketDoesNotExist and ErrBucketNotEmpty. These