layout/base/nsChildIterator.cpp

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  38
  39 /*
  40  * used by nsCSSFrameConstructor to determine and iterate the child list
  41  * used to construct frames (normal children or something from XBL)
  42  */
  43
  44 #include "nsChildIterator.h"
  45 #include "nsIDocument.h"
  46 #include "nsBindingManager.h"
  47
  48 nsresult
  49 ChildIterator::Init(nsIContent*    aContent,
  50                     ChildIterator* aFirst,
  51                     ChildIterator* aLast)
  52 {
  53   // Initialize out parameters to be equal, in case of failure.
  54   aFirst->mContent = aLast->mContent = nsnull;
  55   aFirst->mChild   = aLast->mChild   = nsnull;
  56
  57   NS_PRECONDITION(aContent != nsnull, "no content");
  58   if (! aContent)
  59     return NS_ERROR_NULL_POINTER;
  60
  61   nsIDocument* doc = aContent->GetOwnerDoc();
  62   NS_ASSERTION(doc, "element not in the document");
  63   if (! doc)
  64     return NS_ERROR_FAILURE;
  65
  66   // If this node has XBL children, then use them. Otherwise, just use
  67   // the vanilla content APIs.
  68   nsINodeList* nodes = doc->BindingManager()->GetXBLChildNodesFor(aContent);
  69
  70   aFirst->mContent = aContent;
  71   aLast->mContent  = aContent;
  72   aFirst->mNodes   = nodes;
  73   aLast->mNodes    = nodes;
  74
  75   if (nodes) {
  76     PRUint32 length;
  77     nodes->GetLength(&length);
  78     aFirst->mIndex = 0;
  79     aLast->mIndex = length;
  80   } else {
  81     aFirst->mChild = aContent->GetFirstChild();
  82     aLast->mChild = nsnull;
  83   }
  84
  85   return NS_OK;
  86 }