refactor: use "DB" instead of "backend" in names

triedb/database.go

@@ -37,7 +37,7 @@ type Config struct {
 	HashDB    *hashdb.Config // Configs for hash-based scheme
 	PathDB    *pathdb.Config // Configs for experimental path-based scheme
 
-	DBOverride BackendConstructor // Injects an arbitrary backend implementation
+	DBOverride DBConstructor // Injects an arbitrary backend-database implementation
 }
 
 // HashDefaults represents a config for using hash-based scheme with
@@ -228,7 +228,7 @@ func (db *Database) InsertPreimage(preimages map[common.Hash][]byte) {
 //
 // It's only supported by hash-based database and will return an error for others.
 func (db *Database) Cap(limit common.StorageSize) error {
-	hdb, ok := db.backend.(HashBackend)
+	hdb, ok := db.backend.(HashDB)
 	if !ok {
 		return errors.New("not supported")
 	}
@@ -244,7 +244,7 @@ func (db *Database) Cap(limit common.StorageSize) error {
 //
 // It's only supported by hash-based database and will return an error for others.
 func (db *Database) Reference(root common.Hash, parent common.Hash) error {
-	hdb, ok := db.backend.(HashBackend)
+	hdb, ok := db.backend.(HashDB)
 	if !ok {
 		return errors.New("not supported")
 	}
@@ -255,7 +255,7 @@ func (db *Database) Reference(root common.Hash, parent common.Hash) error {
 // Dereference removes an existing reference from a root node. It's only
 // supported by hash-based database and will return an error for others.
 func (db *Database) Dereference(root common.Hash) error {
-	hdb, ok := db.backend.(HashBackend)
+	hdb, ok := db.backend.(HashDB)
 	if !ok {
 		return errors.New("not supported")
 	}
@@ -268,7 +268,7 @@ func (db *Database) Dereference(root common.Hash) error {
 // corresponding trie histories are existent. It's only supported by path-based
 // database and will return an error for others.
 func (db *Database) Recover(target common.Hash) error {
-	pdb, ok := db.backend.(PathBackend)
+	pdb, ok := db.backend.(PathDB)
 	if !ok {
 		return errors.New("not supported")
 	}
@@ -286,7 +286,7 @@ func (db *Database) Recover(target common.Hash) error {
 // recovered. It's only supported by path-based database and will return an
 // error for others.
 func (db *Database) Recoverable(root common.Hash) (bool, error) {
-	pdb, ok := db.backend.(PathBackend)
+	pdb, ok := db.backend.(PathDB)
 	if !ok {
 		return false, errors.New("not supported")
 	}
@@ -299,7 +299,7 @@ func (db *Database) Recoverable(root common.Hash) (bool, error) {
 //
 // It's only supported by path-based database and will return an error for others.
 func (db *Database) Disable() error {
-	pdb, ok := db.backend.(PathBackend)
+	pdb, ok := db.backend.(PathDB)
 	if !ok {
 		return errors.New("not supported")
 	}
@@ -309,7 +309,7 @@ func (db *Database) Disable() error {
 // Enable activates database and resets the state tree with the provided persistent
 // state root once the state sync is finished.
 func (db *Database) Enable(root common.Hash) error {
-	pdb, ok := db.backend.(PathBackend)
+	pdb, ok := db.backend.(PathDB)
 	if !ok {
 		return errors.New("not supported")
 	}
@@ -321,7 +321,7 @@ func (db *Database) Enable(root common.Hash) error {
 // flattening everything down (bad for reorgs). It's only supported by path-based
 // database and will return an error for others.
 func (db *Database) Journal(root common.Hash) error {
-	pdb, ok := db.backend.(PathBackend)
+	pdb, ok := db.backend.(PathDB)
 	if !ok {
 		return errors.New("not supported")
 	}
@@ -332,7 +332,7 @@ func (db *Database) Journal(root common.Hash) error {
 // It's only supported by path-based database and will return an error for
 // others.
 func (db *Database) SetBufferSize(size int) error {
-	pdb, ok := db.backend.(PathBackend)
+	pdb, ok := db.backend.(PathDB)
 	if !ok {
 		return errors.New("not supported")
 	}

triedb/database.libevm.go

@@ -26,27 +26,28 @@ import (
 	"github.com/ava-labs/libevm/triedb/pathdb"
 )
 
-// Backend defines the intersection of methods shared by [hashdb.Database] and
-// [pathdb.Database].
-type Backend backend
+// BackendDB defines the intersection of methods shared by [hashdb.Database] and
+// [pathdb.Database]. It is defined to export an otherwise internal type used by
+// the non-libevm geth implementation.
+type BackendDB backend
 
 // A ReaderProvider exposes its underlying Reader as an interface. Both
 // [hashdb.Database] and [pathdb.Database] return concrete types so Go's lack of
 // support for [covariant types] means that this method can't be defined on
-// [Backend].
+// [BackendDB].
 //
 // [covariant types]: https://go.dev/doc/faq#covariant_types
 type ReaderProvider interface {
 	Reader(common.Hash) (database.Reader, error)
 }
 
-// A BackendConstructor constructs alternative backend implementations.
-type BackendConstructor func(ethdb.Database, *Config) BackendOverride
+// A DBConstructor constructs alternative backend-database implementations.
+type DBConstructor func(ethdb.Database, *Config) DBOverride
 
-// A BackendOverride is an arbitrary implementation of a [Database] backend. It
-// MUST be either a [HashBackend] or a [PathBackend].
-type BackendOverride interface {
-	Backend
+// A DBOverride is an arbitrary implementation of a [Database] backend. It MUST
+// be either a [HashDB] or a [PathDB].
+type DBOverride interface {
+	BackendDB
 	ReaderProvider
 }
 
@@ -60,8 +61,8 @@ func (db *Database) overrideBackend(diskdb ethdb.Database, config *Config) bool
 
 	db.backend = config.DBOverride(diskdb, config)
 	switch db.backend.(type) {
-	case HashBackend:
-	case PathBackend:
+	case HashDB:
+	case PathDB:
 	default:
 		log.Crit("Database override is neither hash- nor path-based")
 	}
@@ -70,22 +71,22 @@ func (db *Database) overrideBackend(diskdb ethdb.Database, config *Config) bool
 
 var (
 	// If either of these break then the respective interface SHOULD be updated.
-	_ HashBackend = (*hashdb.Database)(nil)
-	_ PathBackend = (*pathdb.Database)(nil)
+	_ HashDB = (*hashdb.Database)(nil)
+	_ PathDB = (*pathdb.Database)(nil)
 )
 
-// A HashBackend mirrors the functionality of a [hashdb.Database].
-type HashBackend interface {
-	Backend
+// A HashDB mirrors the functionality of a [hashdb.Database].
+type HashDB interface {
+	BackendDB
 
 	Cap(limit common.StorageSize) error
 	Reference(root common.Hash, parent common.Hash)
 	Dereference(root common.Hash)
 }
 
-// A PathBackend mirrors the functionality of a [pathdb.Database].
-type PathBackend interface {
-	Backend
+// A PathDB mirrors the functionality of a [pathdb.Database].
+type PathDB interface {
+	BackendDB
 
 	Recover(root common.Hash, loader triestate.TrieLoader) error
 	Recoverable(root common.Hash) bool

triedb/database.libevm_test.go

@@ -28,7 +28,7 @@ import (
 
 func TestDBOverride(t *testing.T) {
 	config := &Config{
-		DBOverride: func(d ethdb.Database, c *Config) BackendOverride {
+		DBOverride: func(d ethdb.Database, c *Config) DBOverride {
 			return override{}
 		},
 	}
@@ -42,7 +42,7 @@ func TestDBOverride(t *testing.T) {
 }
 
 type override struct {
-	PathBackend
+	PathDB
 }
 
 type reader struct {