[cppia] Fix haxe overridden scriptable methods (#1273)

* [cppia] Add flag for scriptable overridden methods

This allows overridden methods to be marked so that they do not add an
addtional slot to the vtable, which has previously caused bugs due to
incorrect vtable indices.

* [cppia] Infer overrides from matching method name

For haxe versions that do not tag overridden methods in
__scriptableFunctions tables, we can infer overrides at runtime by
comparing method names.

* [cppia] Swap scriptable func argument order

This way is a bit more backwards compatible. An overridden method will
always have a super version provided.

Author: tobil4sk

include/hx/Scriptable.h

@@ -19,11 +19,19 @@ struct ScriptNamedFunction : public ScriptFunction
 {
    ScriptNamedFunction(const ScriptFunction &s) : ScriptFunction(s), name(0), isStatic(false), superExecute(0) { }
 
+#if (HXCPP_API_LEVEL >= 500)
+   ScriptNamedFunction(const char *inName=0,StackExecute inExe=0,const char *inSig=0, bool inIsStatic=false, StackExecute superExecute=0, bool inIsOverride=false)
+      : ScriptFunction(inExe, inSig), name(inName), isStatic(inIsStatic), isOverride(inIsOverride), superExecute(superExecute)  { }
+#else
    ScriptNamedFunction(const char *inName=0,StackExecute inExe=0,const char *inSig=0, bool inIsStatic=false, StackExecute superExecute=0)
       : ScriptFunction(inExe, inSig), name(inName), isStatic(inIsStatic), superExecute(superExecute)  { }
+#endif
 
    const char *name;
    bool isStatic;
+#if (HXCPP_API_LEVEL >= 500)
+   bool isOverride;
+#endif
    StackExecute superExecute;
 };
 

src/hx/cppia/Cppia.h

@@ -575,6 +575,9 @@ struct CppiaVar
 
 
 
+#if (HXCPP_API_LEVEL >= 500)
+# define NATIVE_CLASS_OVERRIDES_MARKED
+#endif
 
 class HaxeNativeClass
 {
@@ -596,6 +599,10 @@ class HaxeNativeClass
    static HaxeNativeClass *findClass(const std::string &inName);
    static HaxeNativeClass *hxObject();
    static void link();
+#ifndef NATIVE_CLASS_OVERRIDES_MARKED
+private:
+   void addVtableEntries( std::vector<std::string> &outVtable, hx::UnorderedSet<std::string> &outMethodsSet);
+#endif
 };
 
 class HaxeNativeInterface

src/hx/cppia/HaxeNative.cpp

@@ -30,16 +30,36 @@ HaxeNativeClass::HaxeNativeClass(const std::string &inName, int inDataOffset, Sc
    haxeSuper = 0;
 }
 
+#ifdef NATIVE_CLASS_OVERRIDES_MARKED
 void HaxeNativeClass::addVtableEntries( std::vector<std::string> &outVtable)
 {
    if (haxeSuper)
       haxeSuper->addVtableEntries(outVtable);
 
    if (functions)
       for(ScriptNamedFunction *func = functions; func->name; func++)
-         if (!func->isStatic)
+         if (!func->isStatic && !func->isOverride)
             outVtable.push_back( func->name );
 }
+#else
+void HaxeNativeClass::addVtableEntries(std::vector<std::string>& outVtable) {
+   hx::UnorderedSet<std::string> methodsSet;
+   addVtableEntries(outVtable, methodsSet);
+}
+
+void HaxeNativeClass::addVtableEntries( std::vector<std::string> &outVtable,  hx::UnorderedSet<std::string>& outMethodsSet)
+{
+   if (haxeSuper)
+      haxeSuper->addVtableEntries(outVtable, outMethodsSet);
+
+   if (functions)
+      for (ScriptNamedFunction* func = functions; func->name; func++)
+         if (!func->isStatic && outMethodsSet.find(func->name) == outMethodsSet.end()) {
+            outVtable.push_back(func->name);
+            outMethodsSet.emplace(func->name);
+         }
+}
+#endif
 
 void HaxeNativeClass::dump()
 {