From 777882ff52e38200f0754ea43191ab0cbf5b35db Mon Sep 17 00:00:00 2001
From: b00ris <b00ris@mail.ru>
Date: Tue, 18 May 2021 21:32:04 +0300
Subject: [PATCH] Fix corner case for KV_Snapshot.Next (#1957)
* fix next
* comment test
---
ethdb/kv_snapshot.go | 67 +++++++++++++++++++++++++++-----------------
1 file changed, 41 insertions(+), 26 deletions(-)
diff --git a/ethdb/kv_snapshot.go b/ethdb/kv_snapshot.go
index 4fa7f12c4f..ec55f58afc 100644
--- a/ethdb/kv_snapshot.go
+++ b/ethdb/kv_snapshot.go
@@ -515,6 +515,7 @@ func (s *snCursor) SeekExact(key []byte) ([]byte, []byte, error) {
func (s *snCursor) iteration(dbNextElement func() ([]byte, []byte, error), sndbNextElement func() ([]byte, []byte, error), cmpFunc func(kdb, ksndb []byte) (int, bool)) ([]byte, []byte, error) {
var err error
+ var noDBNext, noSnDBNext bool
//current returns error on empty bucket
lastDBKey, lastDBVal, err := s.dbCursor.Current()
if err != nil {
@@ -523,11 +524,17 @@ func (s *snCursor) iteration(dbNextElement func() ([]byte, []byte, error), sndbN
if innerErr != nil {
return nil, nil, fmt.Errorf("get current from db %w inner %v", err, innerErr)
}
+ noDBNext = true
}
lastSNDBKey, lastSNDBVal, err := s.snCursor.Current()
if err != nil {
- return nil, nil, err
+ var innerErr error
+ lastSNDBKey, lastSNDBVal, innerErr = sndbNextElement()
+ if innerErr != nil {
+ return nil, nil, fmt.Errorf("get current from snapshot %w inner %v", err, innerErr)
+ }
+ noSnDBNext = true
}
cmp, br := cmpFunc(lastDBKey, lastSNDBKey)
@@ -537,40 +544,48 @@ func (s *snCursor) iteration(dbNextElement func() ([]byte, []byte, error), sndbN
//todo Seek fastpath
if cmp > 0 {
- lastSNDBKey, lastSNDBVal, err = sndbNextElement()
- if err != nil {
- return nil, nil, err
- }
- //todo
- if currentKeyCmp, _ := common.KeyCmp(s.currentKey, lastDBKey); len(lastSNDBKey) == 0 && currentKeyCmp >= 0 && len(s.currentKey) > 0 {
- lastDBKey, lastDBVal, err = dbNextElement()
- }
- if err != nil {
- return nil, nil, err
+ if !noSnDBNext {
+ lastSNDBKey, lastSNDBVal, err = sndbNextElement()
+ if err != nil {
+ return nil, nil, err
+ }
+
+ if currentKeyCmp, _ := common.KeyCmp(s.currentKey, lastDBKey); len(lastSNDBKey) == 0 && currentKeyCmp >= 0 && len(s.currentKey) > 0 {
+ lastDBKey, lastDBVal, err = dbNextElement()
+ }
+ if err != nil {
+ return nil, nil, err
+ }
}
}
//current receives last acceptable key. If it is empty
if cmp < 0 {
- lastDBKey, lastDBVal, err = dbNextElement()
- if err != nil {
- return nil, nil, err
- }
- if currentKeyCmp, _ := common.KeyCmp(s.currentKey, lastSNDBKey); len(lastDBKey) == 0 && currentKeyCmp >= 0 && len(s.currentKey) > 0 {
- lastSNDBKey, lastSNDBVal, err = sndbNextElement()
- }
- if err != nil {
- return nil, nil, err
+ if !noDBNext {
+ lastDBKey, lastDBVal, err = dbNextElement()
+ if err != nil {
+ return nil, nil, err
+ }
+ if currentKeyCmp, _ := common.KeyCmp(s.currentKey, lastSNDBKey); len(lastDBKey) == 0 && currentKeyCmp >= 0 && len(s.currentKey) > 0 {
+ lastSNDBKey, lastSNDBVal, err = sndbNextElement()
+ }
+ if err != nil {
+ return nil, nil, err
+ }
}
}
if cmp == 0 {
- lastDBKey, lastDBVal, err = dbNextElement()
- if err != nil {
- return nil, nil, err
+ if !noDBNext {
+ lastDBKey, lastDBVal, err = dbNextElement()
+ if err != nil {
+ return nil, nil, err
+ }
}
- lastSNDBKey, lastSNDBVal, err = sndbNextElement()
- if err != nil {
- return nil, nil, err
+ if !noSnDBNext {
+ lastSNDBKey, lastSNDBVal, err = sndbNextElement()
+ if err != nil {
+ return nil, nil, err
+ }
}
}
--
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