better separation between filters; comments

blockchain/indexers/cfindex.go

@@ -5,15 +5,11 @@
 package indexers
 
 import (
-	"fmt"
-
 	"github.com/btcsuite/btcd/blockchain"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/database"
 	"github.com/btcsuite/btcutil"
 	"github.com/btcsuite/btcutil/gcs/builder"
-
-	"os"
 )
 
 const (
@@ -21,67 +17,86 @@ const (
 	cfIndexName = "committed filter index"
 )
 
+// Committed filters come in two flavours: basic and extended. They are
+// generated and dropped in pairs, and both are indexed by a block's hash.
+// Besides holding different content, they also live in different buckets.
 var (
 	// cfBasicIndexKey is the name of the db bucket used to house the
-	// block hash -> Basic CF index (CF #0).
+	// block hash -> Basic cf index (cf#0).
 	cfBasicIndexKey = []byte("cf0byhashidx")
 	// cfExtendedIndexKey is the name of the db bucket used to house the
-	// block hash -> Extended CF index (CF #1).
+	// block hash -> Extended cf index (cf#1).
 	cfExtendedIndexKey = []byte("cf1byhashidx")
 )
 
-func dbFetchCFIndexEntry(dbTx database.Tx, blockHash *chainhash.Hash) ([]byte,
+// dbFetchBasicEntry() retrieves a block's basic filter. An entry's absence is
-    error) {
+// not considered an error. The filter is returned serialized.
-	// Load the record from the database and return now if it doesn't exist.
+func dbFetchBasicEntry(dbTx database.Tx, h *chainhash.Hash) ([]byte, error) {
-	index := dbTx.Metadata().Bucket(cfBasicIndexKey)
+	idx := dbTx.Metadata().Bucket(cfBasicIndexKey)
-	serializedFilter := index.Get(blockHash[:])
+	return idx.Get(h[:]), nil
-	if len(serializedFilter) == 0 {
-		return nil, nil
 }
 
-	return serializedFilter, nil
+// dbFetchExtendedEntry() retrieves a block's extended filter. An entry's
+// absence is not considered an error. The filter is returned serialized.
+func dbFetchExtendedEntry(dbTx database.Tx, h *chainhash.Hash) ([]byte, error) {
+	idx := dbTx.Metadata().Bucket(cfExtendedIndexKey)
+	return idx.Get(h[:]), nil
 }
 
-// The serialized format for keys and values in the block hash to CF bucket is:
+// dbStoreBasicEntry() stores a block's basic filter.
-//   <hash> = <CF>
+func dbStoreBasicEntry(dbTx database.Tx, h *chainhash.Hash, f []byte) error {
-//
+	idx := dbTx.Metadata().Bucket(cfBasicIndexKey)
-//   Field           Type              Size
+	return idx.Put(h[:], f)
-//   hash            chainhash.Hash    32 bytes
+}
-//   CF              []byte            variable
-//   -----
-//   Total: > 32 bytes
 
-// CFIndex implements a CF by hash index.
+// dbStoreBasicEntry() stores a block's extended filter.
-type CFIndex struct {
+func dbStoreExtendedEntry(dbTx database.Tx, h *chainhash.Hash, f []byte) error {
+	idx := dbTx.Metadata().Bucket(cfExtendedIndexKey)
+	return idx.Put(h[:], f)
+}
+
+// dbDeleteBasicEntry() deletes a block's basic filter.
+func dbDeleteBasicEntry(dbTx database.Tx, h *chainhash.Hash) error {
+	idx := dbTx.Metadata().Bucket(cfBasicIndexKey)
+	return idx.Delete(h[:])
+}
+
+// dbDeleteExtendedEntry() deletes a block's extended filter.
+func dbDeleteExtendedEntry(dbTx database.Tx, h *chainhash.Hash) error {
+	idx := dbTx.Metadata().Bucket(cfExtendedIndexKey)
+	return idx.Delete(h[:])
+}
+
+// CfIndex implements a committed filter (cf) by hash index.
+type CfIndex struct {
 	db database.DB
 }
 
-// Ensure the CFIndex type implements the Indexer interface.
+// Ensure the CfIndex type implements the Indexer interface.
-var _ Indexer = (*CFIndex)(nil)
+var _ Indexer = (*CfIndex)(nil)
 
-// Init initializes the hash-based CF index.
+// Init initializes the hash-based cf index. This is part of the Indexer
-//
+// interface.
-// This is part of the Indexer interface.
+func (idx *CfIndex) Init() error {
-func (idx *CFIndex) Init() error {
+	return nil // Nothing to do.
-	return nil
 }
 
-// Key returns the database key to use for the index as a byte slice.
+// Key returns the database key to use for the index as a byte slice. This is
-func (idx *CFIndex) Key() []byte {
+// part of the Indexer interface.
+func (idx *CfIndex) Key() []byte {
 	return cfBasicIndexKey
 }
 
-// Name returns the human-readable name of the index.
+// Name returns the human-readable name of the index. This is part of the
-//
+// Indexer interface.
-// This is part of the Indexer interface.
+func (idx *CfIndex) Name() string {
-func (idx *CFIndex) Name() string {
 	return cfIndexName
 }
 
 // Create is invoked when the indexer manager determines the index needs to be
-// created for the first time. It creates buckets for the two hash-based CF
+// created for the first time. It creates buckets for the two hash-based cf
 // indexes (simple, extended).
-func (idx *CFIndex) Create(dbTx database.Tx) error {
+func (idx *CfIndex) Create(dbTx database.Tx) error {
 	meta := dbTx.Metadata()
 	_, err := meta.CreateBucket(cfBasicIndexKey)
 	if err != nil {
@@ -91,7 +106,9 @@ func (idx *CFIndex) Create(dbTx database.Tx) error {
 	return err
 }
 
-func generateFilterForBlock(block *btcutil.Block) ([]byte, error) {
+// makeBasicFilter() builds a block's basic filter, which consists of all
+// outpoints referenced by transactions within the block.
+func makeBasicFilterForBlock(block *btcutil.Block) ([]byte, error) {
 	b := builder.WithKeyHash(block.Hash())
 	_, err := b.Key()
 	if err != nil {
@@ -110,67 +127,47 @@ func generateFilterForBlock(block *btcutil.Block) ([]byte, error) {
 }
 
 // ConnectBlock is invoked by the index manager when a new block has been
-// connected to the main chain.  This indexer adds a hash-to-CF mapping for
+// connected to the main chain. This indexer adds a hash-to-cf mapping for
-// every passed block.
+// every passed block. This is part of the Indexer interface.
-//
+func (idx *CfIndex) ConnectBlock(dbTx database.Tx, block *btcutil.Block,
-// This is part of the Indexer interface.
-func (idx *CFIndex) ConnectBlock(dbTx database.Tx, block *btcutil.Block,
     view *blockchain.UtxoViewpoint) error {
-	filterBytes, err := generateFilterForBlock(block)
+	f, err := makeBasicFilterForBlock(block)
 	if err != nil {
 		return err
 	}
-
+	return dbStoreBasicEntry(dbTx, block.Hash(), f)
-	meta := dbTx.Metadata()
-	index := meta.Bucket(cfBasicIndexKey)
-	err = index.Put(block.Hash()[:], filterBytes)
-	if err != nil {
-		return err
-	}
-
-	fmt.Fprintf(os.Stderr, "Stored CF for block %v", block.Hash())
-
-	return nil
 }
 
 // DisconnectBlock is invoked by the index manager when a block has been
-// disconnected from the main chain.  This indexer removes the hash-to-CF
+// disconnected from the main chain.  This indexer removes the hash-to-cf
-// mapping for every passed block.
+// mapping for every passed block. This is part of the Indexer interface.
-//
+func (idx *CfIndex) DisconnectBlock(dbTx database.Tx, block *btcutil.Block,
-// This is part of the Indexer interface.
-func (idx *CFIndex) DisconnectBlock(dbTx database.Tx, block *btcutil.Block,
     view *blockchain.UtxoViewpoint) error {
-	index := dbTx.Metadata().Bucket(cfBasicIndexKey)
+	return dbDeleteBasicEntry(dbTx, block.Hash())
-	filterBytes := index.Get(block.Hash()[:])
-	if len(filterBytes) == 0 {
-		return fmt.Errorf("can't remove non-existent filter %s from " +
-		    "the cfilter index", block.Hash())
-	}
-	return index.Delete(block.Hash()[:])
 }
 
-func (idx *CFIndex) FilterByBlockHash(hash *chainhash.Hash) ([]byte, error) {
+func (idx *CfIndex) FilterByBlockHash(hash *chainhash.Hash) ([]byte, error) {
 	var filterBytes []byte
 	err := idx.db.View(func(dbTx database.Tx) error {
 		var err error
-		filterBytes, err = dbFetchCFIndexEntry(dbTx, hash)
+		filterBytes, err = dbFetchBasicEntry(dbTx, hash)
 		return err
 	})
 	return filterBytes, err
 }
 
-// NewCFIndex returns a new instance of an indexer that is used to create a
+// NewCfIndex returns a new instance of an indexer that is used to create a
 // mapping of the hashes of all blocks in the blockchain to their respective
-// committed bloom filters.
+// committed filters.
 //
 // It implements the Indexer interface which plugs into the IndexManager that in
 // turn is used by the blockchain package. This allows the index to be
 // seamlessly maintained along with the chain.
-func NewCFIndex(db database.DB) *CFIndex {
+func NewCfIndex(db database.DB) *CfIndex {
-	return &CFIndex{db: db}
+	return &CfIndex{db: db}
 }
 
-// DropCFIndex drops the CF index from the provided database if exists.
+// DropCfIndex drops the CF index from the provided database if exists.
-func DropCFIndex(db database.DB) error {
+func DropCfIndex(db database.DB) error {
 	return dropIndex(db, cfBasicIndexKey, cfIndexName)
 }

server.go

@@ -229,7 +229,7 @@ type server struct {
 	// do not need to be protected for concurrent access.
 	txIndex   *indexers.TxIndex
 	addrIndex *indexers.AddrIndex
-	cfIndex   *indexers.CFIndex
+	cfIndex   *indexers.CfIndex
 }
 
 // serverPeer extends the peer to maintain state shared by the server and
@@ -2244,8 +2244,8 @@ func newServer(listenAddrs []string, db database.DB, chainParams *chaincfg.Param
 		indexes = append(indexes, s.addrIndex)
 	}
 	if !cfg.NoCFilters {
-		indxLog.Info("CF index is enabled")
+		indxLog.Info("cf index is enabled")
-		s.cfIndex = indexers.NewCFIndex(db)
+		s.cfIndex = indexers.NewCfIndex(db)
 		indexes = append(indexes, s.cfIndex)
 	}