From 286242cad0cea9eb1977be23191be9e469765b3c Mon Sep 17 00:00:00 2001
From: Dmitrii Stepanov <d.stepanov@yadro.com>
Date: Mon, 24 Jul 2023 13:40:47 +0300
Subject: [PATCH] [#539] getsvc: Use buffer to assemble object

To reduce memory consumption.

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>
---
 pkg/services/object/get/assemble.go  |  3 ++-
 pkg/services/object/get/assembler.go | 13 ++++++++-----
 pkg/services/object/get/get_test.go  |  1 +
 pkg/services/object/get/writer.go    | 10 +++++++++-
 4 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/pkg/services/object/get/assemble.go b/pkg/services/object/get/assemble.go
index 777822ac3..43f2c470b 100644
--- a/pkg/services/object/get/assemble.go
+++ b/pkg/services/object/get/assemble.go
@@ -113,8 +113,9 @@ func (r *request) HeadObject(ctx context.Context, id oid.ID) (*objectSDK.Object,
 	return w.Object(), nil
 }
 
-func (r *request) GetObject(ctx context.Context, id oid.ID, rng *objectSDK.Range) (*objectSDK.Object, error) {
+func (r *request) GetObject(ctx context.Context, id oid.ID, rng *objectSDK.Range, payloadBuffer []byte) (*objectSDK.Object, error) {
 	w := NewSimpleObjectWriter()
+	w.SetPayloadBuffer(payloadBuffer)
 
 	p := r.prm
 	p.common = p.common.WithLocalOnly(false)
diff --git a/pkg/services/object/get/assembler.go b/pkg/services/object/get/assembler.go
index 321d4b16d..2299751e1 100644
--- a/pkg/services/object/get/assembler.go
+++ b/pkg/services/object/get/assembler.go
@@ -10,7 +10,7 @@ import (
 )
 
 type objectGetter interface {
-	GetObject(ctx context.Context, id oid.ID, rng *objectSDK.Range) (*objectSDK.Object, error)
+	GetObject(ctx context.Context, id oid.ID, rng *objectSDK.Range, buffer []byte) (*objectSDK.Object, error)
 	HeadObject(ctx context.Context, id oid.ID) (*objectSDK.Object, error)
 }
 
@@ -77,7 +77,7 @@ func (a *assembler) getLastPartOrLinkObjectID() (oid.ID, bool) {
 }
 
 func (a *assembler) initializeFromSourceObjectID(ctx context.Context, id oid.ID) (*oid.ID, []oid.ID, error) {
-	sourceObject, err := a.getChildObject(ctx, id, nil, true)
+	sourceObject, err := a.getChildObject(ctx, id, nil, true, nil)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -131,8 +131,8 @@ func (a *assembler) initializeFromSourceObjectID(ctx context.Context, id oid.ID)
 	return nil, sourceObject.Children(), nil
 }
 
-func (a *assembler) getChildObject(ctx context.Context, id oid.ID, rng *objectSDK.Range, verifyIsChild bool) (*objectSDK.Object, error) {
-	obj, err := a.objGetter.GetObject(ctx, id, rng)
+func (a *assembler) getChildObject(ctx context.Context, id oid.ID, rng *objectSDK.Range, verifyIsChild bool, payloadBuffer []byte) (*objectSDK.Object, error) {
+	obj, err := a.objGetter.GetObject(ctx, id, rng, payloadBuffer)
 	if err != nil {
 		return nil, err
 	}
@@ -176,13 +176,14 @@ func (a *assembler) assemleObjectByPreviousIDInReverse(ctx context.Context, prev
 func (a *assembler) assemblePayloadByObjectIDs(ctx context.Context, writer ObjectWriter, partIDs []oid.ID, partRanges []objectSDK.Range, verifyIsChild bool) error {
 	withRng := len(partRanges) > 0 && a.rng != nil
 
+	var buffer []byte
 	for i := range partIDs {
 		var r *objectSDK.Range
 		if withRng {
 			r = &partRanges[i]
 		}
 
-		child, err := a.getChildObject(ctx, partIDs[i], r, verifyIsChild)
+		child, err := a.getChildObject(ctx, partIDs[i], r, verifyIsChild, buffer)
 		if err != nil {
 			return err
 		}
@@ -190,6 +191,8 @@ func (a *assembler) assemblePayloadByObjectIDs(ctx context.Context, writer Objec
 		if err := writer.WriteChunk(ctx, child.Payload()); err != nil {
 			return err
 		}
+
+		buffer = child.Payload()
 	}
 	return nil
 }
diff --git a/pkg/services/object/get/get_test.go b/pkg/services/object/get/get_test.go
index 9c5506064..b6b77506e 100644
--- a/pkg/services/object/get/get_test.go
+++ b/pkg/services/object/get/get_test.go
@@ -629,6 +629,7 @@ func TestGetRemoteSmall(t *testing.T) {
 
 		*c1, *c2 = *c2, *c1
 
+		w.SetPayloadBuffer(make([]byte, 0))
 		err = svc.Get(ctx, p)
 		require.NoError(t, err)
 		require.Equal(t, obj, w.Object())
diff --git a/pkg/services/object/get/writer.go b/pkg/services/object/get/writer.go
index 1b842adeb..0f8c71f7b 100644
--- a/pkg/services/object/get/writer.go
+++ b/pkg/services/object/get/writer.go
@@ -49,10 +49,18 @@ func NewSimpleObjectWriter() *SimpleObjectWriter {
 	}
 }
 
+func (s *SimpleObjectWriter) SetPayloadBuffer(buffer []byte) {
+	if buffer != nil {
+		s.pld = buffer[:0]
+	}
+}
+
 func (s *SimpleObjectWriter) WriteHeader(_ context.Context, obj *objectSDK.Object) error {
 	s.obj = obj
 
-	s.pld = make([]byte, 0, obj.PayloadSize())
+	if s.pld == nil {
+		s.pld = make([]byte, 0, obj.PayloadSize())
+	}
 
 	return nil
 }