[#1616] getsvc: Move range assembling to a separate file

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

pkg/services/object/get/assembler.go

@@ -59,15 +59,23 @@ func (a *assembler) Assemble(ctx context.Context, writer ObjectWriter) (*objectS
 	if previousID == nil && len(childrenIDs) == 0 {
 		return nil, objectSDK.NewSplitInfoError(a.splitInfo)
 	}
+
 	if len(childrenIDs) > 0 {
-		if err := a.assembleObjectByChildrenList(ctx, childrenIDs, writer); err != nil {
+		if a.rng != nil {
-			return nil, err
+			err = a.assembleObjectByChildrenListRange(ctx, childrenIDs, writer)
+		} else {
+			err = a.assembleObjectByChildrenList(ctx, childrenIDs, writer)
 		}
 	} else {
-		if err := a.assemleObjectByPreviousIDInReverse(ctx, *previousID, writer); err != nil {
+		if a.rng != nil {
-			return nil, err
+			err = a.assemleObjectByPreviousIDInReverseRange(ctx, *previousID, writer)
+		} else {
+			err = a.assemleObjectByPreviousIDInReverse(ctx, *previousID, writer)
 		}
 	}
+	if err != nil {
+		return nil, err
+	}
 	return a.parentObject, nil
 }
 
@@ -153,26 +161,16 @@ func (a *assembler) getChildObject(ctx context.Context, id oid.ID, rng *objectSD
 }
 
 func (a *assembler) assembleObjectByChildrenList(ctx context.Context, childrenIDs []oid.ID, writer ObjectWriter) error {
-	if a.rng == nil {
 	if err := writer.WriteHeader(ctx, a.parentObject.CutPayload()); err != nil {
 		return err
 	}
-		return a.assemblePayloadByObjectIDs(ctx, writer, childrenIDs, nil, true)
+	return a.assemblePayloadByObjectIDs(ctx, writer, childrenIDs, true)
-	}
-
-	if err := a.assemblePayloadInReverse(ctx, writer, childrenIDs[len(childrenIDs)-1]); err != nil {
-		return err
-	}
-	return writer.WriteChunk(ctx, a.parentObject.Payload())
 }
 
 func (a *assembler) assemleObjectByPreviousIDInReverse(ctx context.Context, prevID oid.ID, writer ObjectWriter) error {
-	if a.rng == nil {
 	if err := writer.WriteHeader(ctx, a.parentObject.CutPayload()); err != nil {
 		return err
 	}
-	}
-
 	if err := a.assemblePayloadInReverse(ctx, writer, prevID); err != nil {
 		return err
 	}
@@ -182,16 +180,9 @@ func (a *assembler) assemleObjectByPreviousIDInReverse(ctx context.Context, prev
 	return nil
 }
 
-func (a *assembler) assemblePayloadByObjectIDs(ctx context.Context, writer ObjectWriter, partIDs []oid.ID, partRanges []objectSDK.Range, verifyIsChild bool) error {
+func (a *assembler) assemblePayloadByObjectIDs(ctx context.Context, writer ObjectWriter, partIDs []oid.ID, verifyIsChild bool) error {
-	withRng := len(partRanges) > 0 && a.rng != nil
-
 	for i := range partIDs {
-		var r *objectSDK.Range
+		_, err := a.getChildObject(ctx, partIDs[i], nil, verifyIsChild, writer)
-		if withRng {
-			r = &partRanges[i]
-		}
-
-		_, err := a.getChildObject(ctx, partIDs[i], r, verifyIsChild, writer)
 		if err != nil {
 			return err
 		}
@@ -200,22 +191,16 @@ func (a *assembler) assemblePayloadByObjectIDs(ctx context.Context, writer Objec
 }
 
 func (a *assembler) assemblePayloadInReverse(ctx context.Context, writer ObjectWriter, prevID oid.ID) error {
-	chain, rngs, err := a.buildChain(ctx, prevID)
+	chain, err := a.buildChain(ctx, prevID)
 	if err != nil {
 		return err
 	}
 
-	reverseRngs := len(rngs) > 0
-
 	for left, right := 0, len(chain)-1; left < right; left, right = left+1, right-1 {
 		chain[left], chain[right] = chain[right], chain[left]
-
-		if reverseRngs {
-			rngs[left], rngs[right] = rngs[right], rngs[left]
-		}
 	}
 
-	return a.assemblePayloadByObjectIDs(ctx, writer, chain, rngs, false)
+	return a.assemblePayloadByObjectIDs(ctx, writer, chain, false)
 }
 
 func (a *assembler) isChild(obj *objectSDK.Object) bool {
@@ -223,63 +208,28 @@ func (a *assembler) isChild(obj *objectSDK.Object) bool {
 	return parent == nil || equalAddresses(a.addr, object.AddressOf(parent))
 }
 
-func (a *assembler) buildChain(ctx context.Context, prevID oid.ID) ([]oid.ID, []objectSDK.Range, error) {
+func (a *assembler) buildChain(ctx context.Context, prevID oid.ID) ([]oid.ID, error) {
 	var (
 		chain []oid.ID
-		rngs  []objectSDK.Range
-		from  = a.rng.GetOffset()
-		to    = from + a.rng.GetLength()
 
 		hasPrev = true
 	)
 
 	// fill the chain end-to-start
 	for hasPrev {
-		// check that only for "range" requests,
-		// for `GET` it stops via the false `withPrev`
-		if a.rng != nil && a.currentOffset <= from {
-			break
-		}
-
 		head, err := a.objGetter.HeadObject(ctx, prevID)
 		if err != nil {
-			return nil, nil, err
+			return nil, err
 		}
 		if !a.isChild(head) {
-			return nil, nil, errParentAddressDiffers
+			return nil, errParentAddressDiffers
 		}
 
-		if a.rng != nil {
-			sz := head.PayloadSize()
-
-			a.currentOffset -= sz
-
-			if a.currentOffset < to {
-				off := uint64(0)
-				if from > a.currentOffset {
-					off = from - a.currentOffset
-					sz -= from - a.currentOffset
-				}
-
-				if to < a.currentOffset+off+sz {
-					sz = to - off - a.currentOffset
-				}
-
-				index := len(rngs)
-				rngs = append(rngs, objectSDK.Range{})
-				rngs[index].SetOffset(off)
-				rngs[index].SetLength(sz)
-
 		id, _ := head.ID()
 		chain = append(chain, id)
-			}
-		} else {
-			id, _ := head.ID()
-			chain = append(chain, id)
-		}
 
 		prevID, hasPrev = head.PreviousID()
 	}
 
-	return chain, rngs, nil
+	return chain, nil
 }

pkg/services/object/get/assembler_range.go

@@ -0,0 +1,103 @@
+package getsvc
+
+import (
+	"context"
+
+	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
+)
+
+func (a *assembler) assembleObjectByChildrenListRange(ctx context.Context, childrenIDs []oid.ID, writer ObjectWriter) error {
+	if err := a.assemblePayloadInReverseRange(ctx, writer, childrenIDs[len(childrenIDs)-1]); err != nil {
+		return err
+	}
+	return writer.WriteChunk(ctx, a.parentObject.Payload())
+}
+
+func (a *assembler) assemleObjectByPreviousIDInReverseRange(ctx context.Context, prevID oid.ID, writer ObjectWriter) error {
+	if err := a.assemblePayloadInReverseRange(ctx, writer, prevID); err != nil {
+		return err
+	}
+	if err := writer.WriteChunk(ctx, a.parentObject.Payload()); err != nil { // last part
+		return err
+	}
+	return nil
+}
+
+func (a *assembler) assemblePayloadByObjectIDsRange(ctx context.Context, writer ObjectWriter, partIDs []oid.ID, partRanges []objectSDK.Range) error {
+	for i := range partIDs {
+		_, err := a.getChildObject(ctx, partIDs[i], &partRanges[i], false, writer)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (a *assembler) assemblePayloadInReverseRange(ctx context.Context, writer ObjectWriter, prevID oid.ID) error {
+	chain, rngs, err := a.buildChainRange(ctx, prevID)
+	if err != nil {
+		return err
+	}
+
+	for left, right := 0, len(chain)-1; left < right; left, right = left+1, right-1 {
+		chain[left], chain[right] = chain[right], chain[left]
+		rngs[left], rngs[right] = rngs[right], rngs[left]
+	}
+
+	return a.assemblePayloadByObjectIDsRange(ctx, writer, chain, rngs)
+}
+
+func (a *assembler) buildChainRange(ctx context.Context, prevID oid.ID) ([]oid.ID, []objectSDK.Range, error) {
+	var (
+		chain []oid.ID
+		rngs  []objectSDK.Range
+		from  = a.rng.GetOffset()
+		to    = from + a.rng.GetLength()
+
+		hasPrev = true
+	)
+
+	// fill the chain end-to-start
+	for hasPrev {
+		if a.currentOffset <= from {
+			break
+		}
+
+		head, err := a.objGetter.HeadObject(ctx, prevID)
+		if err != nil {
+			return nil, nil, err
+		}
+		if !a.isChild(head) {
+			return nil, nil, errParentAddressDiffers
+		}
+
+		sz := head.PayloadSize()
+
+		a.currentOffset -= sz
+
+		if a.currentOffset < to {
+			off := uint64(0)
+			if from > a.currentOffset {
+				off = from - a.currentOffset
+				sz -= from - a.currentOffset
+			}
+
+			if to < a.currentOffset+off+sz {
+				sz = to - off - a.currentOffset
+			}
+
+			index := len(rngs)
+			rngs = append(rngs, objectSDK.Range{})
+			rngs[index].SetOffset(off)
+			rngs[index].SetLength(sz)
+
+			id, _ := head.ID()
+			chain = append(chain, id)
+		}
+
+		prevID, hasPrev = head.PreviousID()
+	}
+
+	return chain, rngs, nil
+}