1 files changed, 21 insertions, 13 deletions

diff --git a/whiteboard.cpp b/whiteboard.cpp
index b84f7cc..059571d 100644
--- a/whiteboard.cpp
+++ b/whiteboard.cpp
@@ -39,6 +39,7 @@
 #include "libreichwein/xml.h"
 
 #include "config.h"
+#include "diff.h"
 #include "qrcode.h"
 #include "storage.h"
 
@@ -151,20 +152,27 @@ std::string Whiteboard::handle_request(Whiteboard::connection& c, const std::str
 
   if (command == "modify") {
    std::string id {xml.get<std::string>("request.id")};
-   std::string data {xml.get<std::string>("request.data")};
-   if (m_storage->getDocument(id) != data) {
-    m_storage->setDocument(id, data);
-    m_registry.setId(c, id);
-    notify_other_connections_file(c, id);
-    
-    int pos {xml.get<int>("request.pos")};
-    if (m_storage->getCursorPos(id) != pos) {
-     m_storage->setCursorPos(id, pos);
-     notify_other_connections_pos(c, id);
-    }
-    return make_xml({{"type", "modify"}, {"revision", std::to_string(m_storage->getRevision(id)) }});
+   
+   int baserev {xml.get<int>("request.baserev")};
+   if (baserev != m_storage->getRevision(id))
+    return make_xml({{"type", "error"}, {"message", "Bad base revision ("s + std::to_string(baserev) + "). Current: "s + std::to_string(m_storage->getRevision(id)) }});
+
+   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);
+
+   m_storage->setDocument(id, data);
+   m_registry.setId(c, id);
+   notify_other_connections_file(c, id);
+   
+   int pos {xml.get<int>("request.pos")};
+   if (m_storage->getCursorPos(id) != pos) {
+    m_storage->setCursorPos(id, pos);
+    notify_other_connections_pos(c, id);
    }
-   return {};
+   return make_xml({{"type", "modify"}, {"revision", std::to_string(m_storage->getRevision(id)) }});
   } else if (command == "cursorpos") {
    std::string id {xml.get<std::string>("request.id")};
    int pos {xml.get<int>("request.pos")};