[Gnash-dev] [patch] Get rid of warning in LineStyle.cpp

[Petter Reinholdtsen]

I had a look at these warnings during build:

  CXX    LineStyle.lo
FillStyle.h: In member function 'void gnash::LineStyle::read(gnash::SWFStream&, 
gnash::SWF::TagType, gnash::movie_definition&, const gnash::RunResources&)':
FillStyle.h:263: warning: dereferencing pointer '<anonymous>' does break 
strict-aliasing rules
/usr/include/boost/variant/detail/cast_storage.hpp:33: note: initialized from 
here
FillStyle.h: In member function 'void 
gnash::LineStyle::read_morph(gnash::SWFStream&, gnash::SWF::TagType, 
gnash::movie_definition&, const gnash::RunResources&, gnash::LineStyle*)':
FillStyle.h:263: warning: dereferencing pointer '<anonymous>' does break 
strict-aliasing rules
/usr/include/boost/variant/detail/cast_storage.hpp:33: note: initialized from 
here
FillStyle.h:263: warning: dereferencing pointer '<anonymous>' does break 
strict-aliasing rules
/usr/include/boost/variant/detail/cast_storage.hpp:33: note: initialized from 
here

I'm not sure I fully understand what is going on here, but I believe
it is related to implicit conversions and temp objects created when
returning the _color object.

This patch got rid of the warnings:

diff --git a/libcore/FillStyle.h b/libcore/FillStyle.h
index 927a3c7..3b39f85 100644
--- a/libcore/FillStyle.h
+++ b/libcore/FillStyle.h
@@ -259,7 +259,7 @@ public:
     }

     /// Get the color of the fill.
-    rgba color() const {
+    const rgba& color() const {
         return _color;
     }

diff --git a/libcore/LineStyle.cpp b/libcore/LineStyle.cpp
index 12365fa..1d3d210 100644
--- a/libcore/LineStyle.cpp
+++ b/libcore/LineStyle.cpp
@@ -40,7 +40,7 @@ namespace {
 class GetColor : public boost::static_visitor<rgba>
 {
 public:
-    rgba operator()(const SolidFill& f) const {
+    const rgba& operator()(const SolidFill& f) const {
         return f.color();
     }
     rgba operator()(const GradientFill&) const {

The change remove the need for some of the temporary objects that need
to be created and copied around when rgba.color() is used by GetColor,
and I believe it is good coding style to avoid forcing the compiler to
create more object that necessary.

Is this the correct fix?  Anyone understand why it is needed?

Happy hacking,
-- 
Petter Reinholdtsen