Traverse PDF page tree only once in CPDF_Document

core/fpdfapi/parser/cpdf_document.h

Index: core/fpdfapi/parser/cpdf_document.h
diff --git a/core/fpdfapi/parser/cpdf_document.h b/core/fpdfapi/parser/cpdf_document.h
index c557a56013f71da4dc7106ad5faa97eb154c56ae..e845ea8eeff7f24e755d3a17f978724311d596fb 100644
--- a/core/fpdfapi/parser/cpdf_document.h
+++ b/core/fpdfapi/parser/cpdf_document.h
@@ -9,6 +9,7 @@
 
 #include <functional>
 #include <memory>
+#include <stack>
 
 #include "core/fpdfapi/parser/cpdf_indirect_object_holder.h"
 #include "core/fpdfapi/parser/cpdf_object.h"
@@ -107,10 +108,7 @@ class CPDF_Document : public CPDF_IndirectObjectHolder {
 
   // Retrieve page count information by getting count value from the tree nodes
   int RetrievePageCount() const;
-  CPDF_Dictionary* FindPDFPage(CPDF_Dictionary* pPages,
-                               int iPage,
-                               int nPagesToGo,
-                               int level);
+  CPDF_Dictionary* TraversePDFPages(int iPage, int nPagesToGo);
   int FindPageIndex(CPDF_Dictionary* pNode,
                     uint32_t& skip_count,
                     uint32_t objnum,
@@ -126,10 +124,19 @@ class CPDF_Document : public CPDF_IndirectObjectHolder {
       FX_BOOL bVert,
       CFX_ByteString basefont,
       std::function<void(FX_WCHAR, FX_WCHAR, CPDF_Array*)> Insert);
-
+  int InsertDeletePDFPage(CPDF_Dictionary* pPages,
+                          int nPagesToGo,
+                          CPDF_Dictionary* pPage,
+                          FX_BOOL bInsert,
+                          std::set<CPDF_Dictionary*>* pVisited);
+  int InsertNewPage(int iPage,
+                    CPDF_Dictionary* pPageDict,
+                    CFX_ArrayTemplate<uint32_t>& pageList);
   std::unique_ptr<CPDF_Parser> m_pParser;
   CPDF_Dictionary* m_pRootDict;
   CPDF_Dictionary* m_pInfoDict;
+  std::stack<std::pair<CPDF_Dictionary*, int>> m_pTreeTraversal;
+  int m_iLastPageTraversed;
   bool m_bLinearized;
   int m_iFirstPageNo;
   uint32_t m_dwFirstPageObjNum;