Extract length-deciding function from package_raw_inbuf.

src/core/or/relay.c

@@ -2027,6 +2027,29 @@ uint64_t stats_n_data_cells_received = 0;
  * ever received were completely full of data. */
 uint64_t stats_n_data_bytes_received = 0;
 
+/**
+ * Helper. Return the number of bytes that should be put into a cell from a
+ * given edge connection on which <b>n_available</b> bytes are available.
+ */
+static size_t
+connection_edge_get_inbuf_bytes_to_package(size_t n_available,
+                                           int package_partial)
+{
+  if (!n_available)
+    return 0;
+
+  size_t length = RELAY_PAYLOAD_SIZE;
+
+  if (n_available < length) { /* not a full payload available */
+    if (package_partial)
+      length = n_available; /* just take whatever's available now */
+    else
+      return 0; /* nothing to do until we have a full payload */
+  }
+
+  return length;
+}
+
 /** If <b>conn</b> has an entire relay payload of bytes on its inbuf (or
  * <b>package_partial</b> is true), and the appropriate package windows aren't
  * empty, grab a cell and send it down the circuit.
@@ -2099,18 +2122,11 @@ connection_edge_package_raw_inbuf(edge_connection_t *conn, int package_partial,
     bytes_to_process = connection_get_inbuf_len(TO_CONN(conn));
   }
 
-  if (!bytes_to_process)
+  length = connection_edge_get_inbuf_bytes_to_package(bytes_to_process,
+                                                      package_partial);
+  if (!length)
     return 0;
 
-  length = RELAY_PAYLOAD_SIZE;
-
-  if (bytes_to_process < length) { /* not a full payload available */
-    if (package_partial)
-      length = bytes_to_process; /* just take whatever's available now */
-    else
-      return 0; /* nothing to do until we have a full payload */
-  }
-
   stats_n_data_bytes_packaged += length;
   stats_n_data_cells_packaged += 1;