gecko-dev/layout/base/nsChildIterator.cpp

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#include "nsChildIterator.h"
#include "nsIDocument.h"
#include "nsIBindingManager.h"

nsresult
ChildIterator::Init(nsIContent*    aContent,
                    ChildIterator* aFirst,
                    ChildIterator* aLast)
{
  // Initialize out parameters to be equal, in case of failure.
  aFirst->mContent = aLast->mContent = nsnull;
  aFirst->mIndex   = aLast->mIndex   = 0;
  
  NS_PRECONDITION(aContent != nsnull, "no content");
  if (! aContent)
    return NS_ERROR_NULL_POINTER;

  nsCOMPtr<nsIDocument> doc;
  aContent->GetDocument(*getter_AddRefs(doc));
  NS_ASSERTION(doc != nsnull, "element not in the document");
  if (! doc)
    return NS_ERROR_FAILURE;

  nsCOMPtr<nsIBindingManager> mgr;
  doc->GetBindingManager(getter_AddRefs(mgr));
  if (! mgr)
    return NS_ERROR_FAILURE;

  // If this node has XBL children, then use them. Otherwise, just use
  // the vanilla content APIs.
  nsCOMPtr<nsIDOMNodeList> nodes;
  mgr->GetXBLChildNodesFor(aContent, getter_AddRefs(nodes));

  PRUint32 length;
  if (nodes)
    nodes->GetLength(&length);
  else
    aContent->ChildCount((PRInt32&) length);

  aFirst->mContent = aContent;
  aLast->mContent  = aContent;
  aFirst->mIndex   = 0;
  aLast->mIndex    = length;
  aFirst->mNodes   = nodes;
  aLast->mNodes    = nodes;

  return NS_OK;
}