Bug 1181297 - Add debug descriptor to nsINode. r=smaug

--HG--
extra : rebase_source : bd60af0462be0c276e5732aa42cd1bc524541152

dom/base/nsINode.cpp

@@ -422,6 +422,36 @@ nsINode::IsInAnonymousSubtree() const
   return AsContent()->IsInAnonymousSubtree();
 }
 
+std::ostream&
+operator<<(std::ostream& aStream, const nsINode& aNode)
+{
+  nsAutoString elemDesc;
+  const nsINode* curr = &aNode;
+  while (curr) {
+    const nsString& localName = curr->LocalName();
+    nsString id;
+    if (curr->IsElement()) {
+      curr->AsElement()->GetId(id);
+    }
+
+    if (!elemDesc.IsEmpty()) {
+      elemDesc = elemDesc + NS_LITERAL_STRING(".");
+    }
+
+    elemDesc = elemDesc + localName;
+
+    if (!id.IsEmpty()) {
+      elemDesc = elemDesc + NS_LITERAL_STRING("['") + id +
+                 NS_LITERAL_STRING("']");
+    }
+
+    curr = curr->GetParentNode();
+  }
+
+  NS_ConvertUTF16toUTF8 str(elemDesc);
+  return aStream << str.get();
+}
+
 bool
 nsINode::IsAnonymousContentInSVGUseSubtree() const
 {

dom/base/nsINode.h

@@ -22,6 +22,7 @@
 #include "js/TypeDecls.h"     // for Handle, Value, JSObject, JSContext
 #include "mozilla/dom/DOMString.h"
 #include "mozilla/dom/BindingDeclarations.h"
+#include <iosfwd>
 
 // Including 'windows.h' will #define GetClassInfo to something else.
 #ifdef XP_WIN
@@ -582,6 +583,12 @@ public:
     return mNodeInfo->NamespaceID() == aNamespace;
   }
 
+  /**
+   * Print a debugger friendly descriptor of this element. This will describe
+   * the position of this element in the document.
+   */
+  friend std::ostream& operator<<(std::ostream& aStream, const nsINode& aNode);
+
 protected:
   // These 2 methods are useful for the recursive templates IsHTMLElement,
   // IsSVGElement, etc.
@@ -1722,7 +1729,7 @@ public:
     mNodeInfo->GetPrefix(aPrefix);
   }
 #endif
-  void GetLocalName(mozilla::dom::DOMString& aLocalName)
+  void GetLocalName(mozilla::dom::DOMString& aLocalName) const
   {
     const nsString& localName = LocalName();
     if (localName.IsVoid()) {