feat(stream): add debug logging for SeekableStream operations and improve Reader handling

Author: cyk

internal/stream/stream.go

@@ -287,6 +287,7 @@ func NewSeekableStream(fs *FileStream, link *model.Link) (*SeekableStream, error
 	}
 
 	if fs.Reader != nil {
+		log.Debugf("[NewSeekableStream] FileStream already has Reader (type: %T), using it directly", fs.Reader)
 		fs.Add(link)
 		return &SeekableStream{FileStream: fs}, nil
 	}
@@ -300,15 +301,10 @@ func NewSeekableStream(fs *FileStream, link *model.Link) (*SeekableStream, error
 		if err != nil {
 			return nil, err
 		}
-		if _, ok := rr.(*model.FileRangeReader); ok {
-			var rc io.ReadCloser
-			rc, err = rr.RangeRead(fs.Ctx, http_range.Range{Length: -1})
-			if err != nil {
-				return nil, err
-			}
-			fs.Reader = rc
-			fs.Add(rc)
-		}
+		// IMPORTANT: Do NOT create Reader early for FileRangeReader!
+		// Let generateReader() create it on-demand when actually needed for reading
+		// This prevents the Reader from being consumed by intermediate operations like hash calculation
+		log.Debugf("[NewSeekableStream] Created RangeReader (type: %T), Reader will be generated on-demand", rr)
 		fs.size = size
 		fs.Add(link)
 		return &SeekableStream{FileStream: fs, rangeReader: rr}, nil
@@ -332,11 +328,13 @@ func (ss *SeekableStream) RangeRead(httpRange http_range.Range) (io.Reader, erro
 
 // only provide Reader as full stream when it's demanded. in rapid-upload, we can skip this to save memory
 func (ss *SeekableStream) Read(p []byte) (n int, err error) {
-	log.Debugf("[SeekableStream.Read] Called, will trigger generateReader if needed")
+	log.Debugf("[SeekableStream.Read] Called with buffer size: %d", len(p))
 	if err := ss.generateReader(); err != nil {
 		return 0, err
 	}
-	return ss.FileStream.Read(p)
+	n, err = ss.FileStream.Read(p)
+	log.Debugf("[SeekableStream.Read] Read %d bytes, err: %v", n, err)
+	return n, err
 }
 
 func (ss *SeekableStream) generateReader() error {
@@ -351,9 +349,9 @@ func (ss *SeekableStream) generateReader() error {
 		}
 		ss.Add(rc)
 		ss.Reader = rc
-		log.Warnf("[SeekableStream.generateReader] Reader has been set, stream is now consumed!")
+		log.Warnf("[SeekableStream.generateReader] Reader has been set, type: %T", rc)
 	} else {
-		log.Debugf("[SeekableStream.generateReader] Reader already exists, reusing")
+		log.Debugf("[SeekableStream.generateReader] Reader already exists (type: %T), reusing", ss.Reader)
 	}
 	return nil
 }