but what about the memory leak ( due to pointer creation with in function
body ) ??
-----Original Message-----
From: Adams, David [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, June 12, 2001 2:12 PM
To: '[EMAIL PROTECTED]'
Subject: RE: wrapping Xerces API in my code !!
Similar to how your getParentNode() method worked.
Xml_DOM_Node Xml_DOM_Node::getFirstChild() const
{
DOM_Node node = pdomnodeimpl->domnode.getFirstChild();
Xml_DOM_Node_Impl* p = new Xml_DOM_Node_Impl;
p->domnode = node;
// I didn't notice this before, but it could be a problem.
// You're returning a stack value here. Look at 'main()'
below.
return Xml_DOM_Node(p);
// You might want to do this instead:
Xml_DOM_Node* pXmlDOMNode = new Xml_DOM_Node(p);
return pXmlDOMNode; // change the return type on your method
declaration to return a pointer
}
void main(void)
{
.
.
.
DOM_Node n; // again, some valid node
Xml_DOM_Node_Impl* impl = new Xml_DOM_Node_Impl;
Xml_DOM_Node xmlnode1(impl);
// DISASTER. Pointer to a return stack value that no longer
exists.
//Xml_DOM_Node* xmlnode2 = xmlnode1.getFirstChild();
// This is better. Uses the assignment operator.
// You may need to add one to your wrapper class.
Xml_DOM_Node xmlnode2 = xmlnode1.getFirstChild();
}
> -----Original Message-----
> From: Awasthi, Anand [SMTP:[EMAIL PROTECTED]]
> Sent: Tuesday, June 12, 2001 1:47 PM
> To: '[EMAIL PROTECTED]'
> Subject: RE: wrapping Xerces API in my code !!
>
> Hi ,
>
> I am calling getFirstChild() method on my xml_DOM_Node() , but this method
>
> modifies my Xml_DOM_Node but i dont want them to modify it.
> how do i do this ??
>
>
>
>
> Xml_DOM_Node Xml_DOM_Node::getFirstChild() const
> {
> DOM_Node node = pdomnodeimpl->domnode.getFirstChild();
> pdomnodeimpl->domnode = node;
> return Xml_DOM_Node(pdomnodeimpl);
> }
>
> -----Original Message-----
> From: Adams, David [mailto:[EMAIL PROTECTED]]
> Sent: Tuesday, June 12, 2001 11:02 AM
> To: '[EMAIL PROTECTED]'
> Subject: RE: wrapping Xerces API in my code !!
>
>
> Has your DOM_Node object within your struct been initialized to a valid
> DOM
> tree node? If not, when you call your 'DOMString
> Xml_DOM_Node::getNodeName() const' and 'Xml_DOM_Node
> Xml_DOM_Node::getParentNode() const' methods, you will get an Access
> Violation. Outside of that, I can only suggest you run it through the
> debugger and look at the variables that are getting the violation and see
> if
> they appear valid. If they aren't, trace your stack backwards and see
> where
> the failed to get set to a valid value.
>
> p.s.
> void main(void)
> {
> // assume this is some valid DOM_Node object
> DOM_Node n;
>
> // ERROR! your destructor will try to delete this stack variable. Be
> careful here.
> //Xml_DOM_Node_Impl impl;
> //impl.domnode = n;
> //Xml_DOM_Node xml_domnode(&impl);
>
> // use this instead
> Xml_DOM_Node_Impl* impl = new Xml_DOM_Node_Impl;
> impl->domnode = n;
> Xml_DOM_Node xml_domnode(impl);
> DOMString domstring = xml_domnode.getNodeName();
> }
>
> > -----Original Message-----
> > From: Awasthi, Anand [SMTP:[EMAIL PROTECTED]]
> > Sent: Tuesday, June 12, 2001 10:22 AM
> > To: '[EMAIL PROTECTED]'
> > Subject: RE: wrapping Xerces API in my code !!
> >
> > thanks for quick repsonse Adams.
> >
> > Answer to your queries:
> >
> > 1. I dont want my clients to know about third party classes like
> DOM_Node
> > when they construct Xml_DOM_Node. thats why i
> > hidden them beneath my struct Xml_DOM_Node_Impl
> >
> > 2. and since i am constrcuting like Xml_DOM_Node(Xml_DOM_Node_Impl*)
> > i cant pass DOM_Node in constructor.
> >
> >
> >
> > this code complies but I am getting Access violation all the time when i
> > run
> > this code.
> > could you pls tell how to debug access violations ??
> >
> >
> > thanks a lot
> > Anand
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > -----Original Message-----
> > From: Adams, David [mailto:[EMAIL PROTECTED]]
> > Sent: Tuesday, June 12, 2001 10:09 AM
> > To: '[EMAIL PROTECTED]'
> > Subject: RE: wrapping Xerces API in my code !!
> >
> >
> > It compiles and it does run, but I don't understand what you are trying
> to
> > do in a couple of spots.
> >
> > 1) unless you are deliberately trying to hide DOM_Node in that struct,
> or
> > unless you deliberately left some additional stuff out of that struct
> for
> > the sake of simplifying your email, I don't see why you don't just put
> the
> > 'DOM_Node' directly in your class. You have a class that wraps a struct
> > that
> > wraps a DOM_Node. Why not just have a class that wraps DOM_Node ?
> >
> > class Xml_DOM_Node
> > {
> > public:
> > Xml_DOM_Node(DOM_Node); // Xerces Referencing counting makes
> > this essentially the same as 'DOM_Node&'
> > ~Xml_DOM_Node();
> > DOMString getNodeName() const;
> > Xml_DOM_Node getParentNode() const;
> > private:
> > DOM_Node domnode;
> > };
> >
> > 2) I don't understand why you are reassiging your DOM_Node value in this
> > routine, but I don't know what you attend to do with your application.
> You
> > will be pointing your wrapper class to some other node on the tree;
> maybe
> > that's what you intended.
> > Xml_DOM_Node Xml_DOM_Node::getParentNode() const
> > {
> > DOM_Node node =
> > pdomnodeimpl->domnode.getParentNode();
> > pdomnodeimpl->domnode = node;
> > return Xml_DOM_Node(pdomnodeimpl);
> > }
> >
> > /*
> > // could this be what you really wanted?
> > Xml_DOM_Node Xml_DOM_Node::getParentNode() const
> > {
> > DOM_Node node =
> > pdomnodeimpl->domnode.getParentNode();
> > return Xml_DOM_Node(node);
> > }
> > */
> >
> >
> > > -----Original Message-----
> > > From: anand awasthi [SMTP:[EMAIL PROTECTED]]
> > > Sent: Tuesday, June 12, 2001 9:28 AM
> > > To: [EMAIL PROTECTED]
> > > Subject: wrapping Xerces API in my code !!
> > >
> > > Hi,
> > >
> > > I am trying to wrap Xerces API in my code in following
> > > manner :
> > >
> > >
> > > oni.h
> > > ----------
> > >
> > > struct Xml_DOM_Node_Impl;
> > > struct Xml_DOM_Node_Impl
> > > {
> > > DOM_Node domnode;
> > > };
> > >
> > > class Xml_DOM_Node
> > > {
> > > public:
> > > Xml_DOM_Node(Xml_DOM_Node_Impl*);
> > > ~Xml_DOM_Node();
> > > DOMString getNodeName() const;
> > > Xml_DOM_Node getParentNode() const;
> > > private:
> > > Xml_DOM_Node_Impl* pdomnodeimpl;
> > > };
> > >
> > >
> > > -------------------------------------------
> > >
> > > oni.cpp
> > > ---------
> > >
> > > #include "oni.h"
> > > #include <xercesheaders>
> > >
> > >
> > > Xml_DOM_Node::Xml_DOM_Node(Xml_DOM_Node_Impl* impl) :
> > > pdomnodeimpl(impl)
> > > {
> > > }
> > >
> > > DOMString Xml_DOM_Node::getNodeName() const
> > > {
> > > return (pdomnodeimpl->domnode.getNodeName());
> > > }
> > >
> > > Xml_DOM_Node Xml_DOM_Node::getParentNode() const
> > > {
> > > DOM_Node node =
> > > pdomnodeimpl->domnode.getParentNode();
> > > pdomnodeimpl->domnode = node;
> > > return Xml_DOM_Node(pdomnodeimpl);
> > > }
> > >
> > > Xml_DOM_Node::~Xml_DOM_Node()
> > > {
> > > delete pdomnodeimpl;
> > > }
> > >
> > > could C++/Xerces gurus pls tell me that above code is
> > > correct or not ?? if notr then pls suggest me better
> > > ways.
> > >
> > > i would really appreciate that.
> > >
> > > thanks
> > >
> > > __________________________________________________
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