special case luabridge for windows/MSVC

luabridge uses static fn addresses to identify classes.
Windows uses different addresses for *identical* static functions
in libardour.dll and ardour.exe

This solves the issue by moving the all functions from a
header-only implementation into libardour.

libs/ardour/luabindings.cc

@@ -38,6 +38,7 @@
 #include "ardour/interthread_info.h"
 #include "ardour/lua_api.h"
 #include "ardour/luabindings.h"
+#include "ardour/luaproc.h"
 #include "ardour/meter.h"
 #include "ardour/midi_track.h"
 #include "ardour/midi_port.h"
@@ -55,6 +56,96 @@
 
 #include "LuaBridge/LuaBridge.h"
 
+#ifdef PLATFORM_WINDOWS
+/* luabridge uses addresses of static functions/variables to identify classes.
+ *
+ * Static symbols on windows (even identical symbols) are not
+ * mapped to the same address when mixing .dll + .exe.
+ * So we need a single point to define those static functions.
+ * (normally they're header-only in libs/lua/LuaBridge/detail/ClassInfo.h)
+ *
+ * Really!! A static function with a static variable in a library header
+ * should never ever be replicated, even if it is a template.
+ * But then again this is windows... what else can go wrong.
+ */
+
+template <class T>
+void const*
+luabridge::ClassInfo<T>::getStaticKey ()
+{
+	static char value;
+	return &value;
+}
+
+template <class T>
+void const*
+luabridge::ClassInfo<T>::getClassKey ()
+{
+	static char value;
+	return &value;
+}
+
+template <class T>
+void const*
+luabridge::ClassInfo<T>::getConstKey ()
+{
+	static char value;
+	return &value;
+}
+
+void*
+luabridge::getIdentityKey ()
+{
+  static char value;
+  return &value;
+}
+
+/* ...and this is the ugly part of it.
+ *
+ * We need to foward declare classes from gtk2_ardour.
+ * This is needed because some of the classes use objects from libardour
+ * as function parameters and the .exe would re-create symbols for libardour
+ * objects.
+ *
+ * Classes which don't use libardour symbols could be moved to
+ * gtk2_ardour/luainstance.cc, but keeping this here reduces code
+ * duplication and does not give the compiler a chance to even think
+ * about replicating the symbols.
+ */
+
+#define CLASSKEYS(CLS) \
+	template void const* luabridge::ClassInfo< CLS >::getStaticKey(); \
+	template void const* luabridge::ClassInfo< CLS >::getClassKey();  \
+	template void const* luabridge::ClassInfo< CLS >::getConstKey();
+
+#define CLASSINFO(CLS) \
+	class CLS; \
+	template void const* luabridge::ClassInfo< CLS >::getStaticKey(); \
+	template void const* luabridge::ClassInfo< CLS >::getClassKey();  \
+	template void const* luabridge::ClassInfo< CLS >::getConstKey();
+
+CLASSINFO(MarkerSelection);
+CLASSINFO(TrackSelection);
+CLASSINFO(TrackViewList);
+CLASSINFO(TimeSelection);
+CLASSINFO(RegionSelection);
+CLASSINFO(PublicEditor);
+CLASSINFO(Selection);
+CLASSINFO(ArdourMarker);
+
+namespace Cairo {
+	class Context;
+}
+CLASSKEYS(Cairo::Context);
+CLASSKEYS(std::vector<double>);
+CLASSKEYS(std::list<ArdourMarker*>);
+CLASSKEYS(std::bitset<47ul>); // LuaSignal::LAST_SIGNAL
+CLASSKEYS(ArdourMarker*);
+CLASSKEYS(ARDOUR::RouteGroup);
+CLASSKEYS(ARDOUR::LuaProc);
+
+#endif // end windows special case
+
 /* Some notes on Lua bindings for libardour and friends
  *
  * - Prefer factory methods over Contructors whenever possible.
@@ -582,7 +673,6 @@ LuaBindings::common (lua_State* L)
 		.addFunction ("output_map", (ARDOUR::ChanMapping (PluginInsert::*)(uint32_t) const)&PluginInsert::output_map)
 		.addFunction ("set_input_map", &PluginInsert::set_input_map)
 		.addFunction ("set_output_map", &PluginInsert::set_output_map)
-
 		.endClass ()
 
 		.deriveWSPtrClass <AutomationControl, PBD::Controllable> ("AutomationControl")

libs/lua/LuaBridge/detail/ClassInfo.h

@@ -36,6 +36,15 @@ template <class T>
 class ClassInfo
 {
 public:
+#ifdef PLATFORM_WINDOWS
+	/* static symbols on windows (even identical symbols) are not
+	 * mapped to the same address when mixing .dll + .exe.
+	 * the implementation is moved to libardour/gtk2_ardour.
+	 */
+  static void const* getStaticKey ();
+  static void const* getClassKey ();
+  static void const* getConstKey ();
+#else
   /** Get the key for the static table.
 
       The static table holds the static data members, static properties, and
@@ -69,5 +78,6 @@ public:
     static char value;
     return &value;
   }
+#endif
 };
 

libs/lua/LuaBridge/detail/Userdata.h

@@ -51,11 +51,15 @@
     6. Our metatables have "__metatable" set to a boolean = false.
     7. Our lightuserdata is unique.
 */
+#ifdef PLATFORM_WINDOWS
+extern void* getIdentityKey ();
+#else
 inline void* getIdentityKey ()
 {
   static char value;
   return &value;
 }
+#endif
 
 /**
   Interface to a class pointer retrievable from a userdata.

tools/luadevel/wscript

@@ -33,13 +33,14 @@ def build(bld):
     if bld.is_defined('WINDOWS_VST_SUPPORT') and bld.env['build_target'] != 'mingw':
         return
 
+    if bld.env['build_target'] != 'mingw':
     # TEST/DEVEL TOOL #######################
-    obj = bld (features = 'cxx c cxxprogram')
-    obj.source       = 'devel.cc'
-    obj.target       = 'devel'
-    obj.uselib       = ['SIGCPP', 'READLINE']
-    obj.use          = ['liblua']
-    obj.install_path = None
+        obj = bld (features = 'cxx c cxxprogram')
+        obj.source       = 'devel.cc'
+        obj.target       = 'devel'
+        obj.uselib       = ['SIGCPP', 'READLINE']
+        obj.use          = ['liblua']
+        obj.install_path = None
     #########################################
 
     # commandline luasession wrapper