1 files changed, 117 insertions, 0 deletions
diff --git a/format/packfile/ingest/record_resolve.go b/format/packfile/ingest/record_resolve.go
new file mode 100644
index 00000000..1ccc427b
--- /dev/null
+++ b/format/packfile/ingest/record_resolve.go
@@ -0,0 +1,117 @@
+package ingest
+
+import (
+	"fmt"
+
+	objecttype "codeberg.org/lindenii/furgit/object/type"
+	packfmt "codeberg.org/lindenii/furgit/format/packfile"
+)
+
+// resolveRecord resolves one record and returns canonical type/content.
+func resolveRecord(state *ingestState, idx int, visiting map[int]struct{}) (objecttype.Type, []byte, error) {
+	if idx < 0 || idx >= len(state.records) {
+		return objecttype.TypeInvalid, nil, fmt.Errorf("packfile/ingest: record index out of bounds")
+	}
+
+	if _, ok := visiting[idx]; ok {
+		return objecttype.TypeInvalid, nil, &DeltaCycleError{Offset: state.records[idx].offset}
+	}
+
+	visiting[idx] = struct{}{}
+	defer delete(visiting, idx)
+
+	record := &state.records[idx]
+	if ty, content, ok := state.baseCache.get(idx); ok {
+		return ty, content, nil
+	}
+
+	if packfmt.IsBaseObjectType(record.packedType) {
+		ty, content, err := readBaseRecordContent(state, idx)
+		if err != nil {
+			return objecttype.TypeInvalid, nil, err
+		}
+
+		if record.resolved {
+			state.baseCache.add(idx, record.realType, content)
+
+			return record.realType, content, nil
+		}
+
+		id, err := hashCanonicalObject(state.algo, ty, content)
+		if err != nil {
+			return objecttype.TypeInvalid, nil, err
+		}
+
+		record.objectID = id
+		record.realType = ty
+		record.resolved = true
+		state.objectToRecord[id] = idx
+		state.baseCache.add(idx, ty, content)
+
+		return ty, content, nil
+	}
+
+	var (
+		baseType    objecttype.Type
+		baseContent []byte
+		err         error
+	)
+	switch record.packedType {
+	case objecttype.TypeOfsDelta:
+		baseIdx, ok := state.offsetToRecord[record.baseOffset]
+		if !ok {
+			return objecttype.TypeInvalid, nil, &MalformedPackEntryError{
+				Offset: record.offset,
+				Reason: "missing ofs-delta base entry",
+			}
+		}
+
+		baseType, baseContent, err = resolveRecord(state, baseIdx, visiting)
+		if err != nil {
+			return objecttype.TypeInvalid, nil, err
+		}
+	case objecttype.TypeRefDelta:
+		baseIdx, ok := state.objectToRecord[record.baseObject]
+		if ok {
+			baseType, baseContent, err = resolveRecord(state, baseIdx, visiting)
+			if err != nil {
+				return objecttype.TypeInvalid, nil, err
+			}
+		} else {
+			return objecttype.TypeInvalid, nil, errExternalThinBase
+		}
+	case objecttype.TypeInvalid,
+		objecttype.TypeCommit,
+		objecttype.TypeTree,
+		objecttype.TypeBlob,
+		objecttype.TypeTag,
+		objecttype.TypeFuture:
+		return objecttype.TypeInvalid, nil, &MalformedPackEntryError{
+			Offset: record.offset,
+			Reason: "unsupported delta type",
+		}
+	default:
+		return objecttype.TypeInvalid, nil, &MalformedPackEntryError{
+			Offset: record.offset,
+			Reason: "unsupported delta type",
+		}
+	}
+
+	ty, content, err := applyDeltaRecord(state, idx, baseType, baseContent)
+	if err != nil {
+		return objecttype.TypeInvalid, nil, err
+	}
+
+	id, err := hashCanonicalObject(state.algo, ty, content)
+	if err != nil {
+		return objecttype.TypeInvalid, nil, err
+	}
+
+	record.objectID = id
+	record.realType = ty
+	record.resolved = true
+	state.objectToRecord[id] = idx
+	state.baseCache.add(idx, ty, content)
+
+	return ty, content, nil
+}