core/rawdb: improve table database (#20703)

This PR fixes issues in TableDatabase.

TableDatabase is a wrapper of underlying ethdb.Database with an additional prefix.
The prefix is applied to all entries it maintains. However when we try to retrieve entries
from it we don't handle the key properly. In theory the prefix should be truncated and
only user key is returned. But we don't do it in some cases, e.g. the iterator and batch
replayer created from it. So this PR is the fix to these issues.

core/rawdb/table.go

@@ -113,13 +113,21 @@ func (t *table) NewIterator() ethdb.Iterator {
 // database content starting at a particular initial key (or after, if it does
 // not exist).
 func (t *table) NewIteratorWithStart(start []byte) ethdb.Iterator {
-	return t.db.NewIteratorWithStart(start)
+	iter := t.db.NewIteratorWithStart(append([]byte(t.prefix), start...))
+	return &tableIterator{
+		iter:   iter,
+		prefix: t.prefix,
+	}
 }
 
 // NewIteratorWithPrefix creates a binary-alphabetical iterator over a subset
 // of database content with a particular key prefix.
 func (t *table) NewIteratorWithPrefix(prefix []byte) ethdb.Iterator {
-	return t.db.NewIteratorWithPrefix(append([]byte(t.prefix), prefix...))
+	iter := t.db.NewIteratorWithPrefix(append([]byte(t.prefix), prefix...))
+	return &tableIterator{
+		iter:   iter,
+		prefix: t.prefix,
+	}
 }
 
 // Stat returns a particular internal stat of the database.
@@ -198,7 +206,69 @@ func (b *tableBatch) Reset() {
 	b.batch.Reset()
 }
 
+// tableReplayer is a wrapper around a batch replayer which truncates
+// the added prefix.
+type tableReplayer struct {
+	w      ethdb.KeyValueWriter
+	prefix string
+}
+
+// Put implements the interface KeyValueWriter.
+func (r *tableReplayer) Put(key []byte, value []byte) error {
+	trimmed := key[len(r.prefix):]
+	return r.w.Put(trimmed, value)
+}
+
+// Delete implements the interface KeyValueWriter.
+func (r *tableReplayer) Delete(key []byte) error {
+	trimmed := key[len(r.prefix):]
+	return r.w.Delete(trimmed)
+}
+
 // Replay replays the batch contents.
 func (b *tableBatch) Replay(w ethdb.KeyValueWriter) error {
-	return b.batch.Replay(w)
+	return b.batch.Replay(&tableReplayer{w: w, prefix: b.prefix})
+}
+
+// tableIterator is a wrapper around a database iterator that prefixes each key access
+// with a pre-configured string.
+type tableIterator struct {
+	iter   ethdb.Iterator
+	prefix string
+}
+
+// Next moves the iterator to the next key/value pair. It returns whether the
+// iterator is exhausted.
+func (iter *tableIterator) Next() bool {
+	return iter.iter.Next()
+}
+
+// Error returns any accumulated error. Exhausting all the key/value pairs
+// is not considered to be an error.
+func (iter *tableIterator) Error() error {
+	return iter.iter.Error()
+}
+
+// Key returns the key of the current key/value pair, or nil if done. The caller
+// should not modify the contents of the returned slice, and its contents may
+// change on the next call to Next.
+func (iter *tableIterator) Key() []byte {
+	key := iter.iter.Key()
+	if key == nil {
+		return nil
+	}
+	return key[len(iter.prefix):]
+}
+
+// Value returns the value of the current key/value pair, or nil if done. The
+// caller should not modify the contents of the returned slice, and its contents
+// may change on the next call to Next.
+func (iter *tableIterator) Value() []byte {
+	return iter.iter.Value()
+}
+
+// Release releases associated resources. Release should always succeed and can
+// be called multiple times without causing error.
+func (iter *tableIterator) Release() {
+	iter.iter.Release()
 }