[#1418] writecache: Do not use pointers as parameters

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>

pkg/local_object_storage/shard/dump.go

@@ -81,7 +81,10 @@ func (s *Shard) Dump(prm *DumpPrm) (*DumpRes, error) {
 	var count int
 
 	if s.hasWriteCache() {
-		err := s.writeCache.Iterate(new(writecache.IterationPrm).WithHandler(func(data []byte) error {
+		var iterPrm writecache.IterationPrm
+
+		iterPrm.WithIgnoreErrors(prm.ignoreErrors)
+		iterPrm.WithHandler(func(data []byte) error {
 			var size [4]byte
 			binary.LittleEndian.PutUint32(size[:], uint32(len(data)))
 			if _, err := w.Write(size[:]); err != nil {
@@ -94,7 +97,9 @@ func (s *Shard) Dump(prm *DumpPrm) (*DumpRes, error) {
 
 			count++
 			return nil
-		}).WithIgnoreErrors(prm.ignoreErrors))
+		})
+
+		err := s.writeCache.Iterate(iterPrm)
 		if err != nil {
 			return nil, err
 		}

pkg/local_object_storage/writecache/iterate.go

@@ -19,21 +19,19 @@ type IterationPrm struct {
 }
 
 // WithHandler sets a callback to be executed on every object.
-func (p *IterationPrm) WithHandler(f func([]byte) error) *IterationPrm {
+func (p *IterationPrm) WithHandler(f func([]byte) error) {
 	p.handler = f
-	return p
 }
 
 // WithIgnoreErrors sets a flag indicating that errors should be ignored.
-func (p *IterationPrm) WithIgnoreErrors(ignore bool) *IterationPrm {
+func (p *IterationPrm) WithIgnoreErrors(ignore bool) {
 	p.ignoreErrors = ignore
-	return p
 }
 
 // Iterate iterates over all objects present in write cache.
 // This is very difficult to do correctly unless write-cache is put in read-only mode.
 // Thus we silently fail if shard is not in read-only mode to avoid reporting misleading results.
-func (c *cache) Iterate(prm *IterationPrm) error {
+func (c *cache) Iterate(prm IterationPrm) error {
 	c.modeMtx.RLock()
 	defer c.modeMtx.RUnlock()
 	if !c.readOnly() {

pkg/local_object_storage/writecache/writecache.go

@@ -20,7 +20,7 @@ type Cache interface {
 	Get(address oid.Address) (*object.Object, error)
 	Head(oid.Address) (*object.Object, error)
 	Delete(oid.Address) error
-	Iterate(*IterationPrm) error
+	Iterate(IterationPrm) error
 	Put(*object.Object) error
 	SetMode(Mode)
 	DumpInfo() Info