Use Option<usize> for content_length

Signed-off-by: Alexander Onnikov <Alexander.Onnikov@xored.com>

server/src/handlers.rs

@@ -378,10 +378,13 @@ pub async fn head(request: HttpRequest) -> HandlerResult<HttpResponse> {
 
         // see https://github.com/actix/examples/blob/master/forms/multipart-s3/src/main.rs#L67-L79
         let content_length = merge::content_length(parts);
-        response.body(SizedStream::new(
-            content_length as u64,
-            stream::empty::<Result<_, io::Error>>().boxed_local(),
-        ))
+        match content_length {
+            Some(content_length) => response.body(SizedStream::new(
+                content_length as u64,
+                stream::empty::<Result<_, io::Error>>().boxed_local(),
+            )),
+            None => response.finish(),
+        }
     } else {
         HttpResponse::NotFound().finish()
     };

server/src/merge.rs

@@ -156,22 +156,23 @@ pub async fn stream(
     }
 }
 
-pub fn content_length(parts: Vec<ObjectPart<PartData>>) -> usize {
+pub fn content_length(parts: Vec<ObjectPart<PartData>>) -> Option<usize> {
     let first = parts.first().unwrap();
     let merge_strategy = first.data.merge_strategy.unwrap();
 
-    let mut content_length: usize = 0;
     match merge_strategy {
         MergeStrategy::Concatenate => {
+            let mut content_length = 0;
+
             for part in parts {
                 content_length += part.data.size;
             }
+
+            Some(content_length)
         }
 
-        MergeStrategy::JsonPatch => return 0,
+        MergeStrategy::JsonPatch => None,
     }
-
-    content_length
 }
 
 async fn part_data(s3: &S3Client, part: ObjectPart<PartData>) -> anyhow::Result<Vec<u8>> {