Fix concurrent edit, tests

1 files changed, 7 insertions, 5 deletions

diff --git a/whiteboard.cpp b/whiteboard.cpp
index fcfdca8..8736726 100644
--- a/whiteboard.cpp
+++ b/whiteboard.cpp
@@ -167,12 +167,14 @@ std::string Whiteboard::handle_request(Whiteboard::connection& c, const std::str
    pt::ptree ptree;
    ptree.put_child("diff", xml.get_child("request.diff"));
    Diff d{ptree};
-   std::string data {m_storage->getDocument(id)};
-   data = d.apply(data);
+   if (!d.empty()) {
+    std::string data {m_storage->getDocument(id)};
+    data = d.apply(data);
 
-   m_storage->setDocument(id, data);
-   m_registry.setId(c, id);
-   notify_other_connections_diff(c, id, d);
+    m_storage->setDocument(id, data);
+    m_registry.setId(c, id);
+    notify_other_connections_diff(c, id, d);
+   }
    
    int pos {xml.get<int>("request.pos")};
    if (m_storage->getCursorPos(id) != pos) {