From caceb94db8c21be58c38f5b5080c43a98ecb7521 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Wed, 22 Feb 2012 10:46:35 +0000
Subject: [PATCH] From Miha Ravsel, "While trying to create my custom
 serializer class, i created some dummy data which accidentally popped-up bug
 in InputStream readObjectFields function.

Bug description:
 Let's say we have class A
namespace Bug
{
class A : public osg::Object
{
public:
  //...
  typedef std::vector<osg::ref_ptr<A> > AList;

protected:
  AList _alist;
  //...
}
}

REGISTER_OBJECT_WRAPPER( A,
                        new Bug::A,
                        Bug::A,
                        "osg::Object Bug::A" )
{
       ADD_LIST_SERIALIZER(A,Bug::A::AList);
}


Bug:
We create say 3 instances of class A: A1,A2,A3 and then we add A2 and A3 and A1 as child instances of A1 so we get next structure:
A1
 |- A2,A3,A1

we call osgDB::writeObjectFile(A1,"/data/a.osgt") -> saved correctly( third element in list is saved as unique id that references parentClass

now we call
A1 = osgDB::readObjectFile("/data/a.osgt");

Everything is deserialized correctely except last element in list which should be same instance as parent A1.

The attached code resolves this issue by passing UniqueID in readObjectFields method and saving object in _identifierMap as soon as we have valid object instance so we can make reference to parent object from any child instance.
"
---
 include/osgDB/InputStream |  2 +-
 src/osgDB/InputStream.cpp | 11 ++++-------
 2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/include/osgDB/InputStream b/include/osgDB/InputStream
index af431f46c..cf0999815 100644
--- a/include/osgDB/InputStream
+++ b/include/osgDB/InputStream
@@ -138,7 +138,7 @@ public:
     osg::PrimitiveSet* readPrimitiveSet();
     osg::Image* readImage(bool readFromExternal=true);
     osg::Object* readObject( osg::Object* existingObj=0 );
-    osg::Object* readObjectFields( const std::string& className, osg::Object* existingObj=0);
+    osg::Object* readObjectFields( const std::string& className, unsigned int id, osg::Object* existingObj=0);
 
     /// set an input iterator, used directly when not using InputStream with a traditional file releated stream.
     void setInputIterator( InputIterator* ii ) { _in = ii; }
diff --git a/src/osgDB/InputStream.cpp b/src/osgDB/InputStream.cpp
index a86820bfe..47ed5ba64 100644
--- a/src/osgDB/InputStream.cpp
+++ b/src/osgDB/InputStream.cpp
@@ -599,9 +599,7 @@ osg::Image* InputStream::readImage(bool readFromExternal)
         image->setWriteHint( (osg::Image::WriteHint)writeHint );
     }
 
-    image = static_cast<osg::Image*>( readObjectFields(className, image.get()) );
-
-   _identifierMap[id] = image;
+    image = static_cast<osg::Image*>( readObjectFields(className, id, image.get()) );
 
    return image.release();
 }
@@ -620,16 +618,14 @@ osg::Object* InputStream::readObject( osg::Object* existingObj )
         return itr->second.get();
     }
 
-    osg::ref_ptr<osg::Object> obj = readObjectFields( className, existingObj );
-
-    _identifierMap[id] = obj;
+    osg::ref_ptr<osg::Object> obj = readObjectFields( className, id, existingObj );
 
     advanceToCurrentEndBracket();
 
     return obj.release();
 }
 
-osg::Object* InputStream::readObjectFields( const std::string& className, osg::Object* existingObj )
+osg::Object* InputStream::readObjectFields( const std::string& className, unsigned int id, osg::Object* existingObj )
 {
     ObjectWrapper* wrapper = Registry::instance()->getObjectWrapperManager()->findWrapper( className );
     if ( !wrapper )
@@ -641,6 +637,7 @@ osg::Object* InputStream::readObjectFields( const std::string& className, osg::O
     _fields.push_back( className );
     
     osg::ref_ptr<osg::Object> obj = existingObj ? existingObj : wrapper->getProto()->cloneType();
+    _identifierMap[id] = obj;
     if ( obj.valid() )
     {
         const StringList& associates = wrapper->getAssociates();