Fix initialization order problem

C++ standart doesn't guarantee the order of initialization for static members in different modules. So, some modules may try to use non-initialized data in the non-initialized module and get an error.
Let's fix this problem using nifty-counter technique.

Author: FreeZoneMods

src/utils/xrSE_Factory/ai_space.cpp

@@ -11,11 +11,35 @@
 #include "xrScriptEngine/script_engine.hpp"
 #include "xrServerEntities/object_factory.h"
 
-static CAI_Space g_ai_space;
+// Nifty counter required to solve initilization order problem
+// Please, do NOT initialize this static members directly, it breaks the initialization logic
+// And yes, according to the standard ($3.6.2/1): "Objects with static storage duration (3.7.1) shall be
+// zero-initialized (8.5) before any other initialization takes place" So, it must be automatically
+// initialized with zeros before executing the constructor
+static CAI_Space* s_ai_space;
+static u32 s_nifty_counter;
+
+SAI_Space_Initializer::SAI_Space_Initializer()
+{
+    if (s_nifty_counter++ == 0)
+    {
+        s_ai_space = new CAI_Space();
+    }
+}
+
+SAI_Space_Initializer::~SAI_Space_Initializer()
+{
+    if (--s_nifty_counter == 0)
+    {
+        xr_delete(s_ai_space);
+    }
+}
 
 CAI_Space& CAI_Space::GetInstance()
 {
-    auto& instance = g_ai_space;
+    VERIFY(s_ai_space);
+
+    auto& instance = *s_ai_space;
     if (!instance.m_inited)
     {
         instance.init();

src/utils/xrSE_Factory/ai_space.h

@@ -44,6 +44,14 @@ class CAI_Space
     bool Unsubscribe(CEventNotifierCallback::CID cid, EEventID event_id) { return true; }
 };
 
+// Static initializer for every translation unit
+// Need to avoid static initilization order problem
+static struct SAI_Space_Initializer
+{
+    SAI_Space_Initializer();
+    ~SAI_Space_Initializer();
+} s_AISpaceInitializer;
+
 IC CAI_Space& ai();
 
 #include "ai_space_inline.h"

src/xrGame/ai_space.cpp

@@ -22,11 +22,35 @@
 #include "moving_objects.h"
 #include "doors_manager.h"
 
-static CAI_Space g_ai_space;
+// Nifty counter required to solve initilization order problem
+// Please, do NOT initialize this static members directly, it breaks the initialization logic
+// And yes, according to the standard ($3.6.2/1): "Objects with static storage duration (3.7.1) shall be
+// zero-initialized (8.5) before any other initialization takes place" So, it must be automatically
+// initialized with zeros before executing the constructor
+static CAI_Space* s_ai_space;
+static u32 s_nifty_counter;
+
+SAI_Space_Initializer::SAI_Space_Initializer()
+{
+    if (s_nifty_counter++ == 0)
+    {
+        s_ai_space = new CAI_Space();
+    }
+}
+
+SAI_Space_Initializer::~SAI_Space_Initializer()
+{
+    if (--s_nifty_counter == 0)
+    {
+        xr_delete(s_ai_space);
+    }
+}
 
 CAI_Space& CAI_Space::GetInstance()
 {
-    auto& instance = g_ai_space;
+    VERIFY(s_ai_space);
+
+    auto& instance = *s_ai_space;
     if (!instance.m_inited)
     {
         instance.init();

src/xrGame/ai_space.h

@@ -91,6 +91,14 @@ class CAI_Space : public AISpaceBase
     IC doors::manager& doors() const;
 };
 
+// Static initializer for every translation unit
+// Need to avoid static initilization order problem
+static struct SAI_Space_Initializer
+{
+    SAI_Space_Initializer();
+    ~SAI_Space_Initializer();
+} s_AISpaceInitializer;
+
 IC CAI_Space& ai();
 
 #include "ai_space_inline.h"