objectstore/packed: Improve delta base caching

1 files changed, 29 insertions, 29 deletions

diff --git a/objectstore/packed/delta_plan.go b/objectstore/packed/delta_plan.go
index 07dd5c77..f1a3b9b0 100644
--- a/objectstore/packed/delta_plan.go
+++ b/objectstore/packed/delta_plan.go
@@ -8,76 +8,76 @@ import (
 	"codeberg.org/lindenii/furgit/objecttype"
 )
 
-// deltaFrame describes one delta payload to apply during reconstruction.
-type deltaFrame struct {
-	// packName identifies where the delta payload lives.
-	packName string
+// deltaNode describes one delta object in a reconstruction chain.
+type deltaNode struct {
+	// loc identifies the delta object's pack location.
+	loc location
 	// dataOffset points to the start of the delta zlib payload in pack.
 	dataOffset int
 }
 
-// deltaPlan describes how to reconstruct one requested object.
-type deltaPlan struct {
+// deltaChain describes how to reconstruct one requested object.
+type deltaChain struct {
 	// declaredSize is the target object's declared content size.
 	declaredSize int64
 	// baseLoc points to the innermost base object.
 	baseLoc location
 	// baseType is the canonical object type resolved from baseLoc.
 	baseType objecttype.Type
-	// frames contains deltas from target down toward base.
-	frames []deltaFrame
+	// deltas contains delta objects from target down toward base.
+	deltas []deltaNode
 }
 
-// deltaPlanFor walks one object's chain and builds a delta reconstruction plan.
-func (store *Store) deltaPlanFor(start location) (deltaPlan, error) {
+// deltaBuildChain walks one object's chain and builds a reconstruction chain.
+func (store *Store) deltaBuildChain(start location) (deltaChain, error) {
 	visited := make(map[location]struct{})
 	current := start
 
-	var plan deltaPlan
-	plan.declaredSize = -1
+	var chain deltaChain
+	chain.declaredSize = -1
 
 	for {
 		if _, ok := visited[current]; ok {
-			return deltaPlan{}, fmt.Errorf("objectstore/packed: delta cycle while resolving object")
+			return deltaChain{}, fmt.Errorf("objectstore/packed: delta cycle while resolving object")
 		}
 		visited[current] = struct{}{}
 
 		pack, meta, err := store.entryMetaAt(current)
 		if err != nil {
-			return deltaPlan{}, err
+			return deltaChain{}, err
 		}
-		if plan.declaredSize < 0 {
+		if chain.declaredSize < 0 {
 			if packfmt.IsBaseObjectType(meta.ty) {
-				plan.declaredSize = meta.size
+				chain.declaredSize = meta.size
 			} else {
 				declaredSize, err := deltaDeclaredSizeAt(pack, meta.dataOffset)
 				if err != nil {
-					return deltaPlan{}, err
+					return deltaChain{}, err
 				}
-				plan.declaredSize = declaredSize
+				chain.declaredSize = declaredSize
 			}
 		}
 
 		if packfmt.IsBaseObjectType(meta.ty) {
-			plan.baseLoc = current
-			plan.baseType = meta.ty
-			return plan, nil
+			chain.baseLoc = current
+			chain.baseType = meta.ty
+			return chain, nil
 		}
 
 		switch meta.ty {
 		case objecttype.TypeRefDelta:
-			plan.frames = append(plan.frames, deltaFrame{
-				packName:   current.packName,
+			chain.deltas = append(chain.deltas, deltaNode{
+				loc:        current,
 				dataOffset: meta.dataOffset,
 			})
 			next, err := store.lookup(meta.baseRefID)
 			if err != nil {
-				return deltaPlan{}, err
+				return deltaChain{}, err
 			}
 			current = next
 		case objecttype.TypeOfsDelta:
-			plan.frames = append(plan.frames, deltaFrame{
-				packName:   current.packName,
+			chain.deltas = append(chain.deltas, deltaNode{
+				loc:        current,
 				dataOffset: meta.dataOffset,
 			})
 			current = location{
@@ -85,11 +85,11 @@ func (store *Store) deltaPlanFor(start location) (deltaPlan, error) {
 				offset:   meta.baseOfs,
 			}
 		case objecttype.TypeCommit, objecttype.TypeTree, objecttype.TypeBlob, objecttype.TypeTag:
-			return deltaPlan{}, fmt.Errorf("objectstore/packed: internal invariant violation for base type %d", meta.ty)
+			return deltaChain{}, fmt.Errorf("objectstore/packed: internal invariant violation for base type %d", meta.ty)
 		case objecttype.TypeInvalid, objecttype.TypeFuture:
-			return deltaPlan{}, fmt.Errorf("objectstore/packed: unsupported pack type %d", meta.ty)
+			return deltaChain{}, fmt.Errorf("objectstore/packed: unsupported pack type %d", meta.ty)
 		default:
-			return deltaPlan{}, fmt.Errorf("objectstore/packed: unsupported pack type %d", meta.ty)
+			return deltaChain{}, fmt.Errorf("objectstore/packed: unsupported pack type %d", meta.ty)
 		}
 	}
 }