Add document for uid of rewinder

src/items/network_item_manager.cpp

@@ -40,9 +40,14 @@ void NetworkItemManager::create()
 
 // ============================================================================
 /** Creates a new instance of the item manager. This is done at startup
- *  of each race. */
+ *  of each race.
+ *  We must save the item state first (so that it is restored first), otherwise
+ *  state updates for a kart could be overwritten by e.g. simulating the item
+ *  collection later (which resets bubblegum counter), so a rewinder uid of
+ *  "I" which is less than "Kx" (kart rewinder with id x)
+ */
 NetworkItemManager::NetworkItemManager()
-                  : Rewinder("N"), ItemManager()
+                  : Rewinder("I"), ItemManager()
 {
     m_confirmed_switch_ticks = -1;
     m_last_confirmed_item_ticks.clear();

src/network/rewind_manager.cpp

@@ -155,26 +155,8 @@ void RewindManager::saveState()
     m_overall_state_size = 0;
     std::vector<std::string> rewinder_using;
 
-    // We must save the item state first (so that it is restored first),
-    // otherwise state updates for a kart could be overwritten by
-    // e.g. simulating the item collection later (which resets bubblegum
-    // counter).
-    BareNetworkString* buffer = NULL;
-    if(auto r = m_all_rewinder["N"].lock())
-        buffer = r->saveState(&rewinder_using);
-    if (buffer)
-    {
-        m_overall_state_size += buffer->size();
-        gp->addState(buffer);
-    }
-    delete buffer;    // buffer can be freed
-
     for (auto& p : m_all_rewinder)
     {
-        // The Network ItemManager was saved first before this loop,
-        // so skip it here.
-        if(p.first=="N") continue;
-
         // TODO: check if it's worth passing in a sufficiently large buffer from
         // GameProtocol - this would save the copy operation.
         BareNetworkString* buffer = NULL;

src/network/rewinder.hpp

@@ -32,6 +32,15 @@ class Rewinder : public std::enable_shared_from_this<Rewinder>
 protected:
     void setUniqueIdentity(const std::string& uid)  { m_unique_identity = uid; }
 private:
+    /** Currently it has 2 usages:
+     *  1. Create the required flyable if the firing event missed using this
+     *     uid. (see RewindInfoState::restore)
+     *  2. Determine the order of restoring state for each rewinder, this is
+     *     used as a key in std::string, Rewinder map, which is less than.
+     *     So uid of "I" (item manager) is restored before "Kx" (which kart
+     *     id x) and TR / TB (the red / blue flag) is restored after karts,
+     *     because the restoreState in CTFFlag read kart transformation.
+     *  Otherwise it can be named whatever. */
     std::string m_unique_identity;
 
 public: