From 93eba19a8ee619bf9716cbd9fd26ef6adc87e693 Mon Sep 17 00:00:00 2001
From: Dmitrii Stepanov <d.stepanov@yadro.com>
Date: Thu, 6 Apr 2023 16:03:00 +0300
Subject: [PATCH] [#223] objectsvc: Refactor split-tree traverse

Resolve funlen & gocognit linters for traverseSplitChain method.

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>
---
 pkg/services/object/util/chain.go | 141 ++++++++++++++++--------------
 1 file changed, 75 insertions(+), 66 deletions(-)

diff --git a/pkg/services/object/util/chain.go b/pkg/services/object/util/chain.go
index e6ec93630..96dafd10e 100644
--- a/pkg/services/object/util/chain.go
+++ b/pkg/services/object/util/chain.go
@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 
+	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
 	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
 	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
 )
@@ -72,7 +73,6 @@ func TraverseSplitChain(r HeadReceiver, addr oid.Address, h SplitMemberHandler)
 	return err
 }
 
-// nolint: funlen, gocognit
 func traverseSplitChain(r HeadReceiver, addr oid.Address, h SplitMemberHandler) (bool, error) {
 	v, err := r.Head(addr)
 	if err != nil {
@@ -94,80 +94,89 @@ func traverseSplitChain(r HeadReceiver, addr oid.Address, h SplitMemberHandler)
 		default:
 			return false, errors.New("lack of split information")
 		case withLink:
-			var addr oid.Address
-			addr.SetContainer(cnr)
-			addr.SetObject(link)
-
-			chain := make([]oid.ID, 0)
-
-			if _, err := traverseSplitChain(r, addr, func(member *object.Object, reverseDirection bool) (stop bool) {
-				children := member.Children()
-
-				if reverseDirection {
-					chain = append(children, chain...)
-				} else {
-					chain = append(chain, children...)
-				}
-
-				return false
-			}); err != nil {
-				return false, err
-			}
-
-			var reverseChain []*object.Object
-
-			for i := range chain {
-				addr.SetObject(chain[i])
-
-				if stop, err := traverseSplitChain(r, addr, func(member *object.Object, reverseDirection bool) (stop bool) {
-					if !reverseDirection {
-						return h(member, false)
-					}
-
-					reverseChain = append(reverseChain, member)
-					return false
-				}); err != nil || stop {
-					return stop, err
-				}
-			}
-
-			for i := len(reverseChain) - 1; i >= 0; i-- {
-				if h(reverseChain[i], false) {
-					return true, nil
-				}
-			}
+			return traverseByLink(cnr, link, r, h)
 		case withLast:
-			var addr oid.Address
-			addr.SetContainer(cnr)
+			return traverseByLast(cnr, last, withLast, res, r, h)
+		}
+	}
+}
 
-			for last, withLast = res.LastPart(); withLast; {
-				addr.SetObject(last)
+func traverseByLink(cnr cid.ID, link oid.ID, r HeadReceiver, h SplitMemberHandler) (bool, error) {
+	var addr oid.Address
+	addr.SetContainer(cnr)
+	addr.SetObject(link)
 
-				var directChain []*object.Object
+	chain := make([]oid.ID, 0)
 
-				if _, err := traverseSplitChain(r, addr, func(member *object.Object, reverseDirection bool) (stop bool) {
-					if reverseDirection {
-						last, withLast = member.PreviousID()
-						return h(member, true)
-					}
+	if _, err := traverseSplitChain(r, addr, func(member *object.Object, reverseDirection bool) (stop bool) {
+		children := member.Children()
 
-					directChain = append(directChain, member)
+		if reverseDirection {
+			chain = append(children, chain...)
+		} else {
+			chain = append(chain, children...)
+		}
 
-					return false
-				}); err != nil {
-					return false, err
-				}
+		return false
+	}); err != nil {
+		return false, err
+	}
 
-				for i := len(directChain) - 1; i >= 0; i-- {
-					if h(directChain[i], true) {
-						return true, nil
-					}
-				}
+	var reverseChain []*object.Object
 
-				if len(directChain) > 0 {
-					last, withLast = directChain[len(directChain)-1].PreviousID()
-				}
+	for i := range chain {
+		addr.SetObject(chain[i])
+
+		if stop, err := traverseSplitChain(r, addr, func(member *object.Object, reverseDirection bool) (stop bool) {
+			if !reverseDirection {
+				return h(member, false)
 			}
+
+			reverseChain = append(reverseChain, member)
+			return false
+		}); err != nil || stop {
+			return stop, err
+		}
+	}
+
+	for i := len(reverseChain) - 1; i >= 0; i-- {
+		if h(reverseChain[i], false) {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
+func traverseByLast(cnr cid.ID, last oid.ID, withLast bool, res *object.SplitInfo, r HeadReceiver, h SplitMemberHandler) (bool, error) {
+	var addr oid.Address
+	addr.SetContainer(cnr)
+
+	for last, withLast = res.LastPart(); withLast; {
+		addr.SetObject(last)
+
+		var directChain []*object.Object
+
+		if _, err := traverseSplitChain(r, addr, func(member *object.Object, reverseDirection bool) (stop bool) {
+			if reverseDirection {
+				last, withLast = member.PreviousID()
+				return h(member, true)
+			}
+
+			directChain = append(directChain, member)
+
+			return false
+		}); err != nil {
+			return false, err
+		}
+
+		for i := len(directChain) - 1; i >= 0; i-- {
+			if h(directChain[i], true) {
+				return true, nil
+			}
+		}
+
+		if len(directChain) > 0 {
+			last, withLast = directChain[len(directChain)-1].PreviousID()
 		}
 	}