Merge to XFA: Introduce CPDF_DocumentFromFPDFDocument().

Manual merges everywhere.

Original Review URL: https://codereview.chromium.org/1395493007 .
(cherry picked from commit bb51c4fb6bc6095984c303c95e5336f83e66bc67)

Original Review URL: https://codereview.chromium.org/1396283006 .
(cherry picked from commit 86adb658843658969041a13bf6cf0cc950ffe8ed)

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/1395353004 .

7 files changed, 115 insertions, 128 deletions

diff --git a/fpdfsdk/src/fpdf_dataavail.cpp b/fpdfsdk/src/fpdf_dataavail.cpp
index d3b44160a8..f09b173208 100644
--- a/fpdfsdk/src/fpdf_dataavail.cpp
+++ b/fpdfsdk/src/fpdf_dataavail.cpp
@@ -119,10 +119,8 @@ FPDFAvail_GetDocument(FPDF_AVAIL avail, FPDF_BYTESTRING password) {
 }
 
 DLLEXPORT int STDCALL FPDFAvail_GetFirstPageNum(FPDF_DOCUMENT doc) {
-  if (doc == NULL)
-    return 0;
-  CPDF_Document* pDoc = ((CPDFXFA_Document*)doc)->GetPDFDoc();
-  return ((CPDF_Parser*)pDoc->GetParser())->GetFirstPageNo();
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(doc);
+  return pDoc ? pDoc->GetParser()->GetFirstPageNo() : 0;
 }
 
 DLLEXPORT int STDCALL FPDFAvail_IsPageAvail(FPDF_AVAIL avail,
diff --git a/fpdfsdk/src/fpdf_ext.cpp b/fpdfsdk/src/fpdf_ext.cpp
index f68a45f119..196ac99967 100644
--- a/fpdfsdk/src/fpdf_ext.cpp
+++ b/fpdfsdk/src/fpdf_ext.cpp
@@ -177,11 +177,11 @@ void CheckUnSupportError(CPDF_Document* pDoc, FX_DWORD err_code) {
 }
 
 DLLEXPORT int FPDFDoc_GetPageMode(FPDF_DOCUMENT document) {
-  if (!document)
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
     return PAGEMODE_UNKNOWN;
 
-  CPDF_Dictionary* pRoot =
-      (((CPDFXFA_Document*)document)->GetPDFDoc())->GetRoot();
+  CPDF_Dictionary* pRoot = pDoc->GetRoot();
   if (!pRoot)
     return PAGEMODE_UNKNOWN;
 
diff --git a/fpdfsdk/src/fpdfdoc.cpp b/fpdfsdk/src/fpdfdoc.cpp
index 568622b842..d4b6b08ff3 100644
--- a/fpdfsdk/src/fpdfdoc.cpp
+++ b/fpdfsdk/src/fpdfdoc.cpp
@@ -54,9 +54,9 @@ CPDF_LinkList* GetLinkList(CPDF_Page* page) {
 
 DLLEXPORT FPDF_BOOKMARK STDCALL
 FPDFBookmark_GetFirstChild(FPDF_DOCUMENT document, FPDF_BOOKMARK pDict) {
-  if (!document)
-    return NULL;
-  CPDF_Document* pDoc = ((CPDFXFA_Document*)document)->GetPDFDoc();
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
+    return nullptr;
   CPDF_BookmarkTree tree(pDoc);
   CPDF_Bookmark bookmark = CPDF_Bookmark((CPDF_Dictionary*)pDict);
   return tree.GetFirstChild(bookmark).GetDict();
@@ -64,9 +64,11 @@ FPDFBookmark_GetFirstChild(FPDF_DOCUMENT document, FPDF_BOOKMARK pDict) {
 
 DLLEXPORT FPDF_BOOKMARK STDCALL
 FPDFBookmark_GetNextSibling(FPDF_DOCUMENT document, FPDF_BOOKMARK pDict) {
-  if (!document || !pDict)
-    return NULL;
-  CPDF_Document* pDoc = ((CPDFXFA_Document*)document)->GetPDFDoc();
+  if (!pDict)
+    return nullptr;
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
+    return nullptr;
   CPDF_BookmarkTree tree(pDoc);
   CPDF_Bookmark bookmark = CPDF_Bookmark((CPDF_Dictionary*)pDict);
   return tree.GetNextSibling(bookmark).GetDict();
@@ -89,11 +91,11 @@ DLLEXPORT unsigned long STDCALL FPDFBookmark_GetTitle(FPDF_BOOKMARK pDict,
 
 DLLEXPORT FPDF_BOOKMARK STDCALL FPDFBookmark_Find(FPDF_DOCUMENT document,
                                                   FPDF_WIDESTRING title) {
-  if (!document)
-    return NULL;
   if (!title || title[0] == 0)
-    return NULL;
-  CPDF_Document* pDoc = ((CPDFXFA_Document*)document)->GetPDFDoc();
+    return nullptr;
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
+    return nullptr;
   CPDF_BookmarkTree tree(pDoc);
   FX_STRSIZE len = CFX_WideString::WStringLength(title);
   CFX_WideString encodedTitle = CFX_WideString::FromUTF16LE(title, len);
@@ -102,12 +104,12 @@ DLLEXPORT FPDF_BOOKMARK STDCALL FPDFBookmark_Find(FPDF_DOCUMENT document,
 
 DLLEXPORT FPDF_DEST STDCALL FPDFBookmark_GetDest(FPDF_DOCUMENT document,
                                                  FPDF_BOOKMARK pDict) {
-  if (!document)
-    return NULL;
   if (!pDict)
-    return NULL;
+    return nullptr;
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
+    return nullptr;
   CPDF_Bookmark bookmark((CPDF_Dictionary*)pDict);
-  CPDF_Document* pDoc = (CPDF_Document*)document;
   CPDF_Dest dest = bookmark.GetDest(pDoc);
   if (dest)
     return dest.GetObject();
@@ -115,7 +117,7 @@ DLLEXPORT FPDF_DEST STDCALL FPDFBookmark_GetDest(FPDF_DOCUMENT document,
   // action
   CPDF_Action action = bookmark.GetAction();
   if (!action)
-    return NULL;
+    return nullptr;
   return action.GetDest(pDoc).GetObject();
 }
 
@@ -148,10 +150,11 @@ DLLEXPORT unsigned long STDCALL FPDFAction_GetType(FPDF_ACTION pDict) {
 
 DLLEXPORT FPDF_DEST STDCALL FPDFAction_GetDest(FPDF_DOCUMENT document,
                                                FPDF_ACTION pDict) {
-  if (!document || !pDict)
+  if (!pDict)
+    return nullptr;
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
     return nullptr;
-
-  CPDF_Document* pDoc = ((CPDFXFA_Document*)document)->GetPDFDoc();
   CPDF_Action action((CPDF_Dictionary*)pDict);
   return action.GetDest(pDoc).GetObject();
 }
@@ -174,10 +177,11 @@ DLLEXPORT unsigned long STDCALL FPDFAction_GetURIPath(FPDF_DOCUMENT document,
                                                       FPDF_ACTION pDict,
                                                       void* buffer,
                                                       unsigned long buflen) {
-  if (!document || !pDict)
+  if (!pDict)
+    return 0;
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
     return 0;
-
-  CPDF_Document* pDoc = ((CPDFXFA_Document*)document)->GetPDFDoc();
   CPDF_Action action((CPDF_Dictionary*)pDict);
   CFX_ByteString path = action.GetURI(pDoc);
   unsigned long len = path.GetLength() + 1;
@@ -188,10 +192,11 @@ DLLEXPORT unsigned long STDCALL FPDFAction_GetURIPath(FPDF_DOCUMENT document,
 
 DLLEXPORT unsigned long STDCALL FPDFDest_GetPageIndex(FPDF_DOCUMENT document,
                                                       FPDF_DEST pDict) {
-  if (!document || !pDict)
+  if (!pDict)
+    return 0;
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
     return 0;
-
-  CPDF_Document* pDoc = ((CPDFXFA_Document*)document)->GetPDFDoc();
   CPDF_Dest dest((CPDF_Array*)pDict);
   return dest.GetPageIndex(pDoc);
 }
@@ -229,10 +234,11 @@ FPDFLink_GetLinkZOrderAtPoint(FPDF_PAGE page, double x, double y) {
 
 DLLEXPORT FPDF_DEST STDCALL FPDFLink_GetDest(FPDF_DOCUMENT document,
                                              FPDF_LINK pDict) {
-  if (!document || !pDict)
+  if (!pDict)
+    return nullptr;
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
     return nullptr;
-
-  CPDF_Document* pDoc = ((CPDFXFA_Document*)document)->GetPDFDoc();
   CPDF_Link link((CPDF_Dictionary*)pDict);
   FPDF_DEST dest = link.GetDest(pDoc).GetObject();
   if (dest)
@@ -327,10 +333,11 @@ DLLEXPORT unsigned long STDCALL FPDF_GetMetaText(FPDF_DOCUMENT doc,
                                                  FPDF_BYTESTRING tag,
                                                  void* buffer,
                                                  unsigned long buflen) {
-  if (!doc || !tag)
+  if (!tag)
+    return 0;
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(doc);
+  if (!pDoc)
     return 0;
-  CPDF_Document* pDoc = ((CPDFXFA_Document*)doc)->GetPDFDoc();
-  // Get info dictionary
   CPDF_Dictionary* pInfo = pDoc->GetInfo();
   if (!pInfo)
     return 0;
diff --git a/fpdfsdk/src/fpdfeditimg.cpp b/fpdfsdk/src/fpdfeditimg.cpp
index 269b382d89..09295aa3c4 100644
--- a/fpdfsdk/src/fpdfeditimg.cpp
+++ b/fpdfsdk/src/fpdfeditimg.cpp
@@ -11,10 +11,11 @@
 
 DLLEXPORT FPDF_PAGEOBJECT STDCALL
 FPDFPageObj_NewImgeObj(FPDF_DOCUMENT document) {
-  if (!document)
-    return NULL;
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
+    return nullptr;
   CPDF_ImageObject* pImageObj = new CPDF_ImageObject;
-  CPDF_Image* pImg = new CPDF_Image(((CPDFXFA_Document*)document)->GetPDFDoc());
+  CPDF_Image* pImg = new CPDF_Image(pDoc);
   pImageObj->m_pImage = pImg;
   return pImageObj;
 }
diff --git a/fpdfsdk/src/fpdfeditpage.cpp b/fpdfsdk/src/fpdfeditpage.cpp
index 145d8ca5c3..e7bbf05f4a 100644
--- a/fpdfsdk/src/fpdfeditpage.cpp
+++ b/fpdfsdk/src/fpdfeditpage.cpp
@@ -48,10 +48,8 @@ DLLEXPORT FPDF_DOCUMENT STDCALL FPDF_CreateNewDocument() {
 }
 
 DLLEXPORT void STDCALL FPDFPage_Delete(FPDF_DOCUMENT document, int page_index) {
-  CPDF_Document* pDoc = ((CPDFXFA_Document*)document)->GetPDFDoc();
-  if (pDoc == NULL)
-    return;
-  if (page_index < 0 || page_index >= pDoc->GetPageCount())
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc || page_index < 0 || page_index >= pDoc->GetPageCount())
     return;
 
   pDoc->DeletePage(page_index);
@@ -61,17 +59,14 @@ DLLEXPORT FPDF_PAGE STDCALL FPDFPage_New(FPDF_DOCUMENT document,
                                          int page_index,
                                          double width,
                                          double height) {
-  if (!document)
-    return NULL;
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
+    return nullptr;
 
-  //	CPDF_Parser* pParser = (CPDF_Parser*)document;
-  CPDF_Document* pDoc = ((CPDFXFA_Document*)document)->GetPDFDoc();
   if (page_index < 0)
     page_index = 0;
   if (pDoc->GetPageCount() < page_index)
     page_index = pDoc->GetPageCount();
-  //	if (page_index < 0 || page_index >= pDoc->GetPageCount())
-  //		return NULL;
 
   CPDF_Dictionary* pPageDict = pDoc->CreateNewPage(page_index);
   if (!pPageDict)
diff --git a/fpdfsdk/src/fpdfppo.cpp b/fpdfsdk/src/fpdfppo.cpp
index d3899156a2..ed2446471e 100644
--- a/fpdfsdk/src/fpdfppo.cpp
+++ b/fpdfsdk/src/fpdfppo.cpp
@@ -380,12 +380,15 @@ DLLEXPORT FPDF_BOOL STDCALL FPDF_ImportPages(FPDF_DOCUMENT dest_doc,
                                              FPDF_DOCUMENT src_doc,
                                              FPDF_BYTESTRING pagerange,
                                              int index) {
-  if (dest_doc == NULL || src_doc == NULL)
+  CPDF_Document* pDestDoc = CPDFDocumentFromFPDFDocument(dest_doc);
+  if (!dest_doc)
+    return FALSE;
+
+  CPDF_Document* pSrcDoc = CPDFDocumentFromFPDFDocument(src_doc);
+  if (!pSrcDoc)
     return FALSE;
   CFX_WordArray pageArray;
-  CPDFXFA_Document* pSrcDoc = (CPDFXFA_Document*)src_doc;
-  CPDF_Document* pSrcPDFDoc = pSrcDoc->GetPDFDoc();
-  int nCount = pSrcPDFDoc->GetPageCount();
+  int nCount = pSrcDoc->GetPageCount();
   if (pagerange) {
     if (ParserPageRangeString(pagerange, &pageArray, nCount) == FALSE)
       return FALSE;
@@ -395,32 +398,30 @@ DLLEXPORT FPDF_BOOL STDCALL FPDF_ImportPages(FPDF_DOCUMENT dest_doc,
     }
   }
 
-  CPDFXFA_Document* pDestDoc = (CPDFXFA_Document*)dest_doc;
-  CPDF_Document* pDestPDFDoc = pDestDoc->GetPDFDoc();
   CPDF_PageOrganizer pageOrg;
-
-  pageOrg.PDFDocInit(pDestPDFDoc, pSrcPDFDoc);
-
-  if (pageOrg.ExportPage(pSrcPDFDoc, &pageArray, pDestPDFDoc, index))
-    return TRUE;
-  return FALSE;
+  pageOrg.PDFDocInit(pDestDoc, pSrcDoc);
+  return pageOrg.ExportPage(pSrcDoc, &pageArray, pDestDoc, index);
 }
 
 DLLEXPORT FPDF_BOOL STDCALL FPDF_CopyViewerPreferences(FPDF_DOCUMENT dest_doc,
                                                        FPDF_DOCUMENT src_doc) {
-  if (src_doc == NULL || dest_doc == NULL)
-    return false;
-  CPDFXFA_Document* pSrcDoc = (CPDFXFA_Document*)src_doc;
-  CPDF_Document* pSrcPDFDoc = pSrcDoc->GetPDFDoc();
-  CPDF_Dictionary* pSrcDict = pSrcPDFDoc->GetRoot();
+  CPDF_Document* pDstDoc = CPDFDocumentFromFPDFDocument(dest_doc);
+  if (!pDstDoc)
+    return FALSE;
+
+  CPDF_Document* pSrcDoc = CPDFDocumentFromFPDFDocument(src_doc);
+  if (!pSrcDoc)
+    return FALSE;
+
+  CPDF_Dictionary* pSrcDict = pSrcDoc->GetRoot();
   pSrcDict = pSrcDict->GetDict(FX_BSTRC("ViewerPreferences"));
   if (!pSrcDict)
     return FALSE;
-  CPDFXFA_Document* pDstDoc = (CPDFXFA_Document*)dest_doc;
-  CPDF_Document* pDstPDFDoc = pDstDoc->GetPDFDoc();
-  CPDF_Dictionary* pDstDict = pDstPDFDoc->GetRoot();
+
+  CPDF_Dictionary* pDstDict = pDstDoc->GetRoot();
   if (!pDstDict)
     return FALSE;
+
   pDstDict->SetAt(FX_BSTRC("ViewerPreferences"), pSrcDict->Clone(TRUE));
   return TRUE;
 }
diff --git a/fpdfsdk/src/fpdfview.cpp b/fpdfsdk/src/fpdfview.cpp
index fc16147cfa..5d9bf4b252 100644
--- a/fpdfsdk/src/fpdfview.cpp
+++ b/fpdfsdk/src/fpdfview.cpp
@@ -22,6 +22,10 @@
 #include "../include/fpdfxfa/fpdfxfa_util.h"
 #include "../include/javascript/IJavaScript.h"
 
+CPDF_Document* CPDFDocumentFromFPDFDocument(FPDF_DOCUMENT doc) {
+  return doc ? static_cast<CPDFXFA_Document*>(doc)->GetPDFDoc() : nullptr;
+}
+
 CFPDF_FileStream::CFPDF_FileStream(FPDF_FILEHANDLER* pFS) {
   m_pFS = pFS;
   m_nCurPos = 0;
@@ -375,17 +379,18 @@ FPDF_LoadCustomDocument(FPDF_FILEACCESS* pFileAccess,
 
 DLLEXPORT FPDF_BOOL STDCALL FPDF_GetFileVersion(FPDF_DOCUMENT doc,
                                                 int* fileVersion) {
-  if (!doc || !fileVersion)
+  if (!fileVersion)
     return FALSE;
+
   *fileVersion = 0;
-  CPDFXFA_Document* pDoc = (CPDFXFA_Document*)doc;
-  CPDF_Document* pPDFDoc = pDoc->GetPDFDoc();
-  if (!pPDFDoc)
-    return (FX_DWORD)-1;
-  CPDF_Parser* pParser = (CPDF_Parser*)pPDFDoc->GetParser();
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(doc);
+  if (!pDoc)
+    return FALSE;
 
+  CPDF_Parser* pParser = pDoc->GetParser();
   if (!pParser)
     return FALSE;
+
   *fileVersion = pParser->GetFileVersion();
   return TRUE;
 }
@@ -393,48 +398,37 @@ DLLEXPORT FPDF_BOOL STDCALL FPDF_GetFileVersion(FPDF_DOCUMENT doc,
 // jabdelmalek: changed return type from FX_DWORD to build on Linux (and match
 // header).
 DLLEXPORT unsigned long STDCALL FPDF_GetDocPermissions(FPDF_DOCUMENT document) {
-  if (document == NULL)
-    return 0;
-  CPDFXFA_Document* pDoc = (CPDFXFA_Document*)document;
-  CPDF_Document* pPDFDoc = pDoc->GetPDFDoc();
-  if (!pPDFDoc)
-    return (FX_DWORD)-1;
-  CPDF_Parser* pParser = (CPDF_Parser*)pPDFDoc->GetParser();
-  CPDF_Dictionary* pDict = pParser->GetEncryptDict();
-  if (pDict == NULL)
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
     return (FX_DWORD)-1;
 
-  return pDict->GetInteger("P");
+  CPDF_Dictionary* pDict = pDoc->GetParser()->GetEncryptDict();
+  return pDict ? pDict->GetInteger("P") : (FX_DWORD)-1;
 }
 
 DLLEXPORT int STDCALL FPDF_GetSecurityHandlerRevision(FPDF_DOCUMENT document) {
-  if (document == NULL)
-    return -1;
-  CPDF_Document* pDoc = ((CPDFXFA_Document*)document)->GetPDFDoc();
-  CPDF_Parser* pParser = (CPDF_Parser*)pDoc->GetParser();
-  CPDF_Dictionary* pDict = pParser->GetEncryptDict();
-  if (pDict == NULL)
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
     return -1;
 
-  return pDict->GetInteger("R");
+  CPDF_Dictionary* pDict = pDoc->GetParser()->GetEncryptDict();
+  return pDict ? pDict->GetInteger("R") : -1;
 }
 
 DLLEXPORT int STDCALL FPDF_GetPageCount(FPDF_DOCUMENT document) {
-  if (document == NULL)
-    return 0;
-  CPDFXFA_Document* pDoc = (CPDFXFA_Document*)document;
-  return pDoc->GetPageCount();
-  //	return ((CPDF_Document*)document)->GetPageCount();
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  return pDoc ? pDoc->GetPageCount() : 0;
 }
 
 DLLEXPORT FPDF_PAGE STDCALL FPDF_LoadPage(FPDF_DOCUMENT document,
                                           int page_index) {
-  if (document == NULL)
-    return NULL;
-  CPDFXFA_Document* pDoc = (CPDFXFA_Document*)document;
-  if (page_index < 0 || page_index >= pDoc->GetPageCount())
-    return NULL;
-  //	CPDF_Parser* pParser = (CPDF_Parser*)document;
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
+    return nullptr;
+
+  if (page_index < 0 || page_index >= FPDF_GetPageCount(document))
+    return nullptr;
+
   return pDoc->GetPage(page_index);
 }
 
@@ -673,11 +667,7 @@ DLLEXPORT void STDCALL FPDF_ClosePage(FPDF_PAGE page) {
 }
 
 DLLEXPORT void STDCALL FPDF_CloseDocument(FPDF_DOCUMENT document) {
-  if (!document)
-    return;
-
-  CPDFXFA_Document* pDoc = (CPDFXFA_Document*)document;
-  delete pDoc;
+  delete CPDFDocumentFromFPDFDocument(document);
 }
 
 DLLEXPORT unsigned long STDCALL FPDF_GetLastError() {
@@ -899,18 +889,15 @@ DLLEXPORT int STDCALL FPDF_GetPageSizeByIndex(FPDF_DOCUMENT document,
 
 DLLEXPORT FPDF_BOOL STDCALL
 FPDF_VIEWERREF_GetPrintScaling(FPDF_DOCUMENT document) {
-  CPDFXFA_Document* pDoc = (CPDFXFA_Document*)document;
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
   if (!pDoc)
     return TRUE;
-  CPDF_Document* pPDFDoc = pDoc->GetPDFDoc();
-  if (!pPDFDoc)
-    return TRUE;
-  CPDF_ViewerPreferences viewRef(pPDFDoc);
+  CPDF_ViewerPreferences viewRef(pDoc);
   return viewRef.PrintScaling();
 }
 
 DLLEXPORT int STDCALL FPDF_VIEWERREF_GetNumCopies(FPDF_DOCUMENT document) {
-  CPDF_Document* pDoc = ((CPDFXFA_Document*)document)->GetPDFDoc();
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
   if (!pDoc)
     return 1;
   CPDF_ViewerPreferences viewRef(pDoc);
@@ -919,7 +906,7 @@ DLLEXPORT int STDCALL FPDF_VIEWERREF_GetNumCopies(FPDF_DOCUMENT document) {
 
 DLLEXPORT FPDF_PAGERANGE STDCALL
 FPDF_VIEWERREF_GetPrintPageRange(FPDF_DOCUMENT document) {
-  CPDF_Document* pDoc = ((CPDFXFA_Document*)document)->GetPDFDoc();
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
   if (!pDoc)
     return NULL;
   CPDF_ViewerPreferences viewRef(pDoc);
@@ -928,7 +915,7 @@ FPDF_VIEWERREF_GetPrintPageRange(FPDF_DOCUMENT document) {
 
 DLLEXPORT FPDF_DUPLEXTYPE STDCALL
 FPDF_VIEWERREF_GetDuplex(FPDF_DOCUMENT document) {
-  CPDF_Document* pDoc = ((CPDFXFA_Document*)document)->GetPDFDoc();
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
   if (!pDoc)
     return DuplexUndefined;
   CPDF_ViewerPreferences viewRef(pDoc);
@@ -943,9 +930,9 @@ FPDF_VIEWERREF_GetDuplex(FPDF_DOCUMENT document) {
 }
 
 DLLEXPORT FPDF_DWORD STDCALL FPDF_CountNamedDests(FPDF_DOCUMENT document) {
-  if (!document)
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
     return 0;
-  CPDF_Document* pDoc = ((CPDFXFA_Document*)document)->GetPDFDoc();
 
   CPDF_Dictionary* pRoot = pDoc->GetRoot();
   if (!pRoot)
@@ -961,17 +948,15 @@ DLLEXPORT FPDF_DWORD STDCALL FPDF_CountNamedDests(FPDF_DOCUMENT document) {
 
 DLLEXPORT FPDF_DEST STDCALL FPDF_GetNamedDestByName(FPDF_DOCUMENT document,
                                                     FPDF_BYTESTRING name) {
-  if (!document)
-    return NULL;
   if (!name || name[0] == 0)
-    return NULL;
+    return nullptr;
 
-  CPDFXFA_Document* pDoc = (CPDFXFA_Document*)document;
-  CPDF_Document* pPDFDoc = pDoc->GetPDFDoc();
-  if (!pPDFDoc)
-    return NULL;
-  CPDF_NameTree name_tree(pPDFDoc, FX_BSTRC("Dests"));
-  return name_tree.LookupNamedDest(pPDFDoc, name);
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
+    return nullptr;
+
+  CPDF_NameTree name_tree(pDoc, FX_BSTRC("Dests"));
+  return name_tree.LookupNamedDest(pDoc, name);
 }
 
 FPDF_RESULT FPDF_BStr_Init(FPDF_BSTR* str) {