ruby: use rtti info to cast Item/etc subclasses

plugins/ruby/codegen.pl

@@ -128,6 +128,20 @@ sub render_global_class {
     $seen_class{$name}++;
     %seen_enum_name = ();
 
+    my $rtti_name = $type->getAttribute('original-name') ||
+                    $type->getAttribute('type-name');
+
+    my $has_rtti = $parent;
+    if (!$parent and $type->getAttribute('ld:meta') eq 'class-type') {
+        for my $anytypename (keys %global_types) {
+            my $anytype = $global_types{$anytypename};
+            if ($anytype->getAttribute('ld:meta') eq 'class-type') {
+                my $anyparent = $anytype->getAttribute('inherits-from');
+                $has_rtti = 1 if ($anyparent and $anyparent eq $name);
+            }
+        }
+    }
+
     my $rbparent = ($parent ? rb_ucase($parent) : 'Compound');
 
     my $cppvar = "v_$cpp_var_counter";
@@ -139,6 +153,7 @@ sub render_global_class {
 
     push @lines_rb, "class $rbname < $rbparent";
     indent_rb {
+        push @lines_rb, "rtti_classname '$rtti_name'" if $has_rtti;
         render_struct_fields($type, "(*$cppvar)");
     };
     push @lines_rb, "end\n";

plugins/ruby/ruby-memstruct.rb

@@ -74,6 +74,10 @@ class Compound < MemStruct
 			m.instance_eval(&b)
 			m.new
 		end
+		def rtti_classname(n)
+			# TODO store total size for allocate() ? what about non-virtual ones ?
+			DFHack.rtti_register(n, self)
+		end
 	end
 	def _set(h) ; h.each { |k, v| send("_#{k}=", v) } ; end
 end
@@ -348,8 +352,34 @@ class Global < MemStruct
 	def initialize(glob)
 		@_glob = glob
 	end
-	def _at(addr) ; g = DFHack::MemHack.const_get(@_glob) ; g.new._at(addr) ; end
+	def _at(addr)
+		g = DFHack::MemHack.const_get(@_glob)
+		g = DFHack.rtti_getclass(g, addr)
+		g.new._at(addr)
+	end
 end
 
+module ::DFHack
+	def self.rtti_register(cname, cls)
+		@rtti_n2c ||= {}
+		@rtti_class ||= {}
+		@rtti_n2c[cname] = cls
+		@rtti_class[cls] = true
+	end
 
+	# return the ruby class to use for a given address if rtti info is available
+	def self.rtti_getclass(cls, addr)
+		@rtti_n2c ||= {}
+		@rtti_class ||= {}
+		if addr != 0 and @rtti_class[cls]
+			@rtti_n2c[rtti_readclassname(get_vtable_ptr(addr))] || cls
+		else
+			cls
+		end
+	end
 
+	def self.rtti_readclassname(vptr)
+		@rtti_v2n ||= {}
+		@rtti_v2n[vptr] ||= get_rtti_classname(vptr)
+	end
+end

plugins/ruby/ruby.cpp

@@ -380,10 +380,29 @@ static VALUE rb_dfget_vtable(VALUE self, VALUE name)
     return rb_uint2inum(addr);
 }
 
-static VALUE rb_dfget_rtti_classname(VALUE self, VALUE objptr)
+// read the c++ class name from a vtable pointer, inspired from doReadClassName
+// XXX virtual classes only! dark pointer arithmetic, use with caution !
+static VALUE rb_dfget_rtti_classname(VALUE self, VALUE vptr)
 {
-    void **ptr = (void**)rb_num2ulong(objptr);
+    char *ptr = (char*)rb_num2ulong(vptr);
-    return rb_str_new2(typeid(*ptr).name());
+#ifdef WIN32
+    char *rtti = *(char**)(ptr - 0x4);
+    char *typeinfo = *(char**)(rtti + 0xC);
+    // skip the .?AV, trim @@ from end
+    return rb_str_new(typeinfo+0xc, strlen(typeinfo+0xc)-2);
+#else
+    char *typeinfo = *(char**)(ptr - 0x4);
+    char *typestring = *(char**)(typeinfo + 0x4);
+    while (*typestring >= '0' && *typestring <= '9')
+        typestring++;
+    return rb_str_new2(typestring);
+#endif
+}
+
+static VALUE rb_dfget_vtable_ptr(VALUE self, VALUE objptr)
+{
+    // actually, rb_dfmemory_read_int32
+    return rb_uint2inum(*(uint32_t*)rb_num2ulong(objptr));
 }
 
 
@@ -391,7 +410,7 @@ static VALUE rb_dfget_rtti_classname(VALUE self, VALUE objptr)
 
 // raw memory access
 // used by the ruby class definitions
-// WARNING: may cause game crash ! double-check your addresses !
+// XXX may cause game crash ! double-check your addresses !
 
 static VALUE rb_dfmalloc(VALUE self, VALUE len)
 {
@@ -583,6 +602,7 @@ static void ruby_bind_dfhack(void) {
     rb_define_singleton_method(rb_cDFHack, "get_global_address", RUBY_METHOD_FUNC(rb_dfget_global_address), 1);
     rb_define_singleton_method(rb_cDFHack, "get_vtable", RUBY_METHOD_FUNC(rb_dfget_vtable), 1);
     rb_define_singleton_method(rb_cDFHack, "get_rtti_classname", RUBY_METHOD_FUNC(rb_dfget_rtti_classname), 1);
+    rb_define_singleton_method(rb_cDFHack, "get_vtable_ptr", RUBY_METHOD_FUNC(rb_dfget_vtable_ptr), 1);
     rb_define_singleton_method(rb_cDFHack, "register_dfcommand", RUBY_METHOD_FUNC(rb_dfregister), 2);
     rb_define_singleton_method(rb_cDFHack, "print_str", RUBY_METHOD_FUNC(rb_dfprint_str), 1);
     rb_define_singleton_method(rb_cDFHack, "print_err", RUBY_METHOD_FUNC(rb_dfprint_err), 1);