#5555: Avoid double-entering the think() method from external trigger…

…s (wxTimer).

The lock cannot be placed within the GameConnection::think() body, since think is recursively calling itself by design.

plugins/dm.gameconnection/GameConnection.cpp

@@ -16,6 +16,7 @@
 
 #include "scene/Traverse.h"
 #include "wxutil/Bitmap.h"
+#include "util/ScopedBoolLock.h"
 
 #include <sigc++/signal.h>
 #include <sigc++/connection.h>
@@ -51,6 +52,10 @@ namespace
 #endif
 }
 
+GameConnection::GameConnection() :
+    _timerInProgress(false)
+{}
+
 std::size_t GameConnection::generateNewSequenceNumber() {
     return ++_seqno;
 }
@@ -103,6 +108,15 @@ void GameConnection::think() {
     }
 }
 
+void GameConnection::onTimerEvent(wxTimerEvent& ev)
+{ 
+    if (_timerInProgress) return; // avoid double-entering
+
+    util::ScopedBoolLock guard(_timerInProgress);
+
+    think();
+}
+
 void GameConnection::waitAction() {
     while (_seqnoInProgress)
         think();

plugins/dm.gameconnection/GameConnection.h

@@ -25,6 +25,7 @@ class GameConnection :
     public RegisterableModule
 {
 public:
+    GameConnection();
     ~GameConnection();
 
     //connect to TDM instance if not connected yet
@@ -103,8 +104,9 @@ class GameConnection :
     std::unique_ptr<MessageTcp> _connection;
     //when connected, this timer calls Think periodically
     std::unique_ptr<wxTimer> _thinkTimer;
+    bool _timerInProgress;
 
-    void onTimerEvent(wxTimerEvent& ev) { think(); }
+    void onTimerEvent(wxTimerEvent& ev);
 
     //signal listener for when map is saved, loaded, unloaded, etc.
     sigc::connection _mapEventListener;