Get rid of NULLs in core/

Review-Url: https://codereview.chromium.org/2032613003

11 files changed, 120 insertions, 127 deletions

diff --git a/core/fpdfdoc/cpdf_variabletext.cpp b/core/fpdfdoc/cpdf_variabletext.cpp
index a8b9c3c778..1d5fde289d 100644
--- a/core/fpdfdoc/cpdf_variabletext.cpp
+++ b/core/fpdfdoc/cpdf_variabletext.cpp
@@ -310,7 +310,7 @@ CPVT_WordPlace CPDF_VariableText::InsertWord(const CPVT_WordPlace& place,
   int32_t nFontIndex =
       GetSubWord() > 0 ? GetDefaultFontIndex()
                        : GetWordFontIndex(word, charset, GetDefaultFontIndex());
-  return AddWord(newplace, CPVT_WordInfo(word, charset, nFontIndex, NULL));
+  return AddWord(newplace, CPVT_WordInfo(word, charset, nFontIndex, nullptr));
 }
 
 CPVT_WordPlace CPDF_VariableText::InsertSection(
diff --git a/core/fpdfdoc/doc_action.cpp b/core/fpdfdoc/doc_action.cpp
index e646df2b4c..c512d1afa9 100644
--- a/core/fpdfdoc/doc_action.cpp
+++ b/core/fpdfdoc/doc_action.cpp
@@ -109,7 +109,7 @@ size_t CPDF_ActionFields::GetFieldsCount() const {
     return 0;
   }
   CFX_ByteString csType = pDict->GetStringBy("S");
-  CPDF_Object* pFields = NULL;
+  CPDF_Object* pFields = nullptr;
   if (csType == "Hide") {
     pFields = pDict->GetDirectObjectBy("T");
   } else {
@@ -159,23 +159,23 @@ std::vector<CPDF_Object*> CPDF_ActionFields::GetAllFields() const {
 
 CPDF_Object* CPDF_ActionFields::GetField(size_t iIndex) const {
   if (!m_pAction) {
-    return NULL;
+    return nullptr;
   }
   CPDF_Dictionary* pDict = m_pAction->GetDict();
   if (!pDict) {
-    return NULL;
+    return nullptr;
   }
   CFX_ByteString csType = pDict->GetStringBy("S");
-  CPDF_Object* pFields = NULL;
+  CPDF_Object* pFields = nullptr;
   if (csType == "Hide") {
     pFields = pDict->GetDirectObjectBy("T");
   } else {
     pFields = pDict->GetArrayBy("Fields");
   }
   if (!pFields) {
-    return NULL;
+    return nullptr;
   }
-  CPDF_Object* pFindObj = NULL;
+  CPDF_Object* pFindObj = nullptr;
   if (pFields->IsDictionary() || pFields->IsString()) {
     if (iIndex == 0)
       pFindObj = pFields;
diff --git a/core/fpdfdoc/doc_annot.cpp b/core/fpdfdoc/doc_annot.cpp
index f8bad07ceb..9b2f9e505f 100644
--- a/core/fpdfdoc/doc_annot.cpp
+++ b/core/fpdfdoc/doc_annot.cpp
@@ -158,7 +158,7 @@ CPDF_Stream* FPDFDOC_GetAnnotAP(CPDF_Dictionary* pAnnotDict,
                                 CPDF_Annot::AppearanceMode mode) {
   CPDF_Dictionary* pAP = pAnnotDict->GetDictBy("AP");
   if (!pAP) {
-    return NULL;
+    return nullptr;
   }
   const FX_CHAR* ap_entry = "N";
   if (mode == CPDF_Annot::Down)
@@ -215,7 +215,7 @@ static CPDF_Form* FPDFDOC_Annot_GetMatrix(const CPDF_Page* pPage,
                                           CFX_Matrix& matrix) {
   CPDF_Form* pForm = pAnnot->GetAPForm(pPage, mode);
   if (!pForm) {
-    return NULL;
+    return nullptr;
   }
   CFX_FloatRect form_bbox = pForm->m_pFormDict->GetRectBy("BBox");
   CFX_Matrix form_matrix = pForm->m_pFormDict->GetMatrixBy("Matrix");
@@ -276,7 +276,7 @@ void CPDF_Annot::DrawBorder(CFX_RenderDevice* pDevice,
   CPDF_Dictionary* pBS = m_pAnnotDict->GetDictBy("BS");
   char style_char;
   FX_FLOAT width;
-  CPDF_Array* pDashArray = NULL;
+  CPDF_Array* pDashArray = nullptr;
   if (!pBS) {
     CPDF_Array* pBorderArray = m_pAnnotDict->GetArrayBy("Border");
     style_char = 'S';
diff --git a/core/fpdfdoc/doc_basic.cpp b/core/fpdfdoc/doc_basic.cpp
index ab99cff772..72f2985cef 100644
--- a/core/fpdfdoc/doc_basic.cpp
+++ b/core/fpdfdoc/doc_basic.cpp
@@ -92,7 +92,7 @@ static CPDF_Object* SearchNameNode(CPDF_Dictionary* pNode,
                                    CPDF_Array** ppFind,
                                    int nLevel = 0) {
   if (nLevel > nMaxRecursion) {
-    return NULL;
+    return nullptr;
   }
   CPDF_Array* pLimits = pNode->GetArrayBy("Limits");
   if (pLimits) {
@@ -105,7 +105,7 @@ static CPDF_Object* SearchNameNode(CPDF_Dictionary* pNode,
     }
     if (csName.Compare(csLeft.AsStringC()) < 0 ||
         csName.Compare(csRight.AsStringC()) > 0) {
-      return NULL;
+      return nullptr;
     }
   }
   CPDF_Array* pNames = pNode->GetArrayBy("Names");
@@ -128,11 +128,11 @@ static CPDF_Object* SearchNameNode(CPDF_Dictionary* pNode,
       return pNames->GetDirectObjectAt(i * 2 + 1);
     }
     nIndex += dwCount;
-    return NULL;
+    return nullptr;
   }
   CPDF_Array* pKids = pNode->GetArrayBy("Kids");
   if (!pKids) {
-    return NULL;
+    return nullptr;
   }
   for (size_t i = 0; i < pKids->GetCount(); i++) {
     CPDF_Dictionary* pKid = pKids->GetDictAt(i);
@@ -145,7 +145,7 @@ static CPDF_Object* SearchNameNode(CPDF_Dictionary* pNode,
       return pFound;
     }
   }
-  return NULL;
+  return nullptr;
 }
 
 static CPDF_Object* SearchNameNode(CPDF_Dictionary* pNode,
@@ -155,14 +155,14 @@ static CPDF_Object* SearchNameNode(CPDF_Dictionary* pNode,
                                    CPDF_Array** ppFind,
                                    int nLevel = 0) {
   if (nLevel > nMaxRecursion)
-    return NULL;
+    return nullptr;
 
   CPDF_Array* pNames = pNode->GetArrayBy("Names");
   if (pNames) {
     size_t nCount = pNames->GetCount() / 2;
     if (nIndex >= nCurIndex + nCount) {
       nCurIndex += nCount;
-      return NULL;
+      return nullptr;
     }
     if (ppFind)
       *ppFind = pNames;
@@ -171,7 +171,7 @@ static CPDF_Object* SearchNameNode(CPDF_Dictionary* pNode,
   }
   CPDF_Array* pKids = pNode->GetArrayBy("Kids");
   if (!pKids)
-    return NULL;
+    return nullptr;
   for (size_t i = 0; i < pKids->GetCount(); i++) {
     CPDF_Dictionary* pKid = pKids->GetDictAt(i);
     if (!pKid)
@@ -181,7 +181,7 @@ static CPDF_Object* SearchNameNode(CPDF_Dictionary* pNode,
     if (pFound)
       return pFound;
   }
-  return NULL;
+  return nullptr;
 }
 
 static size_t CountNames(CPDF_Dictionary* pNode, int nLevel = 0) {
@@ -219,7 +219,7 @@ int CPDF_NameTree::GetIndex(const CFX_ByteString& csName) const {
     return -1;
   }
   size_t nIndex = 0;
-  if (!SearchNameNode(m_pRoot, csName, nIndex, NULL)) {
+  if (!SearchNameNode(m_pRoot, csName, nIndex, nullptr)) {
     return -1;
   }
   return nIndex;
@@ -227,17 +227,17 @@ int CPDF_NameTree::GetIndex(const CFX_ByteString& csName) const {
 CPDF_Object* CPDF_NameTree::LookupValue(int nIndex,
                                         CFX_ByteString& csName) const {
   if (!m_pRoot) {
-    return NULL;
+    return nullptr;
   }
   size_t nCurIndex = 0;
-  return SearchNameNode(m_pRoot, nIndex, nCurIndex, csName, NULL);
+  return SearchNameNode(m_pRoot, nIndex, nCurIndex, csName, nullptr);
 }
 CPDF_Object* CPDF_NameTree::LookupValue(const CFX_ByteString& csName) const {
   if (!m_pRoot) {
-    return NULL;
+    return nullptr;
   }
   size_t nIndex = 0;
-  return SearchNameNode(m_pRoot, csName, nIndex, NULL);
+  return SearchNameNode(m_pRoot, csName, nIndex, nullptr);
 }
 CPDF_Array* CPDF_NameTree::LookupNamedDest(CPDF_Document* pDoc,
                                            const CFX_ByteString& sName) {
@@ -474,7 +474,7 @@ CFX_WideString CPDF_PageLabel::GetLabel(int nPage) const {
   }
   CPDF_Dictionary* pLabels = pPDFRoot->GetDictBy("PageLabels");
   CPDF_NumberTree numberTree(pLabels);
-  CPDF_Object* pValue = NULL;
+  CPDF_Object* pValue = nullptr;
   int n = nPage;
   while (n >= 0) {
     pValue = numberTree.LookupValue(n);
@@ -489,7 +489,7 @@ CFX_WideString CPDF_PageLabel::GetLabel(int nPage) const {
       if (pLabel->KeyExist("P")) {
         wsLabel += pLabel->GetUnicodeTextBy("P");
       }
-      CFX_ByteString bsNumberingStyle = pLabel->GetStringBy("S", nullptr);
+      CFX_ByteString bsNumberingStyle = pLabel->GetStringBy("S", "");
       int nLabelNum = nPage - n + pLabel->GetIntegerBy("St", 1);
       CFX_WideString wsNumPortion =
           _GetLabelNumPortion(nLabelNum, bsNumberingStyle);
diff --git a/core/fpdfdoc/doc_form.cpp b/core/fpdfdoc/doc_form.cpp
index 1570a6800c..7ecf35de37 100644
--- a/core/fpdfdoc/doc_form.cpp
+++ b/core/fpdfdoc/doc_form.cpp
@@ -97,13 +97,13 @@ class CFieldTree {
           return field_ptr;
         }
         --*fields_to_go;
-        return NULL;
+        return nullptr;
       }
       for (int i = 0; i < children.GetSize(); i++) {
         if (CPDF_FormField* pField = children.GetAt(i)->GetField(fields_to_go))
           return pField;
       }
-      return NULL;
+      return nullptr;
     }
     CPDF_FormField* GetField(int index) {
       int fields_to_go = index;
@@ -125,8 +125,8 @@ class CFieldTree {
   _Node m_Root;
 };
 CFieldTree::CFieldTree() {
-  m_Root.parent = NULL;
-  m_Root.field_ptr = NULL;
+  m_Root.parent = nullptr;
+  m_Root.field_ptr = nullptr;
 }
 CFieldTree::~CFieldTree() {
   RemoveAll();
@@ -135,7 +135,7 @@ CFieldTree::_Node* CFieldTree::AddChild(_Node* pParent,
                                         const CFX_WideString& short_name,
                                         CPDF_FormField* field_ptr) {
   if (!pParent) {
-    return NULL;
+    return nullptr;
   }
   _Node* pNode = new _Node;
   pNode->parent = pParent;
@@ -158,7 +158,7 @@ void CFieldTree::RemoveNode(_Node* pNode, int nLevel) {
 CFieldTree::_Node* CFieldTree::_Lookup(_Node* pParent,
                                        const CFX_WideString& short_name) {
   if (!pParent) {
-    return NULL;
+    return nullptr;
   }
   for (int i = 0; i < pParent->children.GetSize(); i++) {
     _Node* pNode = pParent->children[i];
@@ -168,7 +168,7 @@ CFieldTree::_Node* CFieldTree::_Lookup(_Node* pParent,
       return pNode;
     }
   }
-  return NULL;
+  return nullptr;
 }
 void CFieldTree::RemoveAll() {
   for (int i = 0; i < m_Root.children.GetSize(); i++) {
@@ -184,13 +184,13 @@ void CFieldTree::SetField(const CFX_WideString& full_name,
   const FX_WCHAR* pName;
   FX_STRSIZE nLength;
   name_extractor.GetNext(pName, nLength);
-  _Node *pNode = &m_Root, *pLast = NULL;
+  _Node *pNode = &m_Root, *pLast = nullptr;
   while (nLength > 0) {
     pLast = pNode;
     CFX_WideString name = CFX_WideString(pName, nLength);
     pNode = _Lookup(pLast, name);
     if (!pNode) {
-      pNode = AddChild(pLast, name, NULL);
+      pNode = AddChild(pLast, name, nullptr);
     }
     name_extractor.GetNext(pName, nLength);
   }
@@ -200,30 +200,31 @@ void CFieldTree::SetField(const CFX_WideString& full_name,
 }
 CPDF_FormField* CFieldTree::GetField(const CFX_WideString& full_name) {
   if (full_name == L"") {
-    return NULL;
+    return nullptr;
   }
   CFieldNameExtractor name_extractor(full_name);
   const FX_WCHAR* pName;
   FX_STRSIZE nLength;
   name_extractor.GetNext(pName, nLength);
-  _Node *pNode = &m_Root, *pLast = NULL;
+  _Node *pNode = &m_Root, *pLast = nullptr;
   while (nLength > 0 && pNode) {
     pLast = pNode;
     CFX_WideString name = CFX_WideString(pName, nLength);
     pNode = _Lookup(pLast, name);
     name_extractor.GetNext(pName, nLength);
   }
-  return pNode ? pNode->field_ptr : NULL;
+  return pNode ? pNode->field_ptr : nullptr;
 }
 CPDF_FormField* CFieldTree::RemoveField(const CFX_WideString& full_name) {
   if (full_name == L"") {
-    return NULL;
+    return nullptr;
   }
   CFieldNameExtractor name_extractor(full_name);
   const FX_WCHAR* pName;
   FX_STRSIZE nLength;
   name_extractor.GetNext(pName, nLength);
-  _Node *pNode = &m_Root, *pLast = NULL;
+  _Node* pNode = &m_Root;
+  _Node* pLast = nullptr;
   while (nLength > 0 && pNode) {
     pLast = pNode;
     CFX_WideString name = CFX_WideString(pName, nLength);
@@ -241,17 +242,17 @@ CPDF_FormField* CFieldTree::RemoveField(const CFX_WideString& full_name) {
     RemoveNode(pNode);
     return pField;
   }
-  return NULL;
+  return nullptr;
 }
 CFieldTree::_Node* CFieldTree::FindNode(const CFX_WideString& full_name) {
   if (full_name == L"") {
-    return NULL;
+    return nullptr;
   }
   CFieldNameExtractor name_extractor(full_name);
   const FX_WCHAR* pName;
   FX_STRSIZE nLength;
   name_extractor.GetNext(pName, nLength);
-  _Node *pNode = &m_Root, *pLast = NULL;
+  _Node *pNode = &m_Root, *pLast = nullptr;
   while (nLength > 0 && pNode) {
     pLast = pNode;
     CFX_WideString name = CFX_WideString(pName, nLength);
@@ -375,10 +376,10 @@ static int CALLBACK EnumFontFamExProc(ENUMLOGFONTEXA* lpelfe,
 static FX_BOOL RetrieveSpecificFont(LOGFONTA& lf) {
   PDF_FONTDATA fd;
   memset(&fd, 0, sizeof(PDF_FONTDATA));
-  HDC hDC = ::GetDC(NULL);
+  HDC hDC = ::GetDC(nullptr);
   EnumFontFamiliesExA(hDC, &lf, (FONTENUMPROCA)EnumFontFamExProc, (LPARAM)&fd,
                       0);
-  ::ReleaseDC(NULL, hDC);
+  ::ReleaseDC(nullptr, hDC);
   if (fd.bFind) {
     memcpy(&lf, &fd.lf, sizeof(LOGFONTA));
   }
@@ -440,7 +441,8 @@ CFX_ByteString CPDF_InterForm::GetNativeFont(uint8_t charSet, void* pLogFont) {
                                 "Microsoft Sans Serif", lf);
   }
   if (!bRet) {
-    bRet = RetrieveSpecificFont(charSet, DEFAULT_PITCH | FF_DONTCARE, NULL, lf);
+    bRet =
+        RetrieveSpecificFont(charSet, DEFAULT_PITCH | FF_DONTCARE, nullptr, lf);
   }
   if (bRet) {
     if (pLogFont) {
@@ -613,14 +615,14 @@ FX_BOOL CPDF_InterForm::ValidateFieldName(
 }
 FX_BOOL CPDF_InterForm::ValidateFieldName(CFX_WideString& csNewFieldName,
                                           int iType) {
-  return ValidateFieldName(csNewFieldName, iType, NULL, NULL);
+  return ValidateFieldName(csNewFieldName, iType, nullptr, nullptr);
 }
 FX_BOOL CPDF_InterForm::ValidateFieldName(const CPDF_FormField* pField,
                                           CFX_WideString& csNewFieldName) {
   return pField && !csNewFieldName.IsEmpty() &&
          ValidateFieldName(csNewFieldName,
                            ((CPDF_FormField*)pField)->GetFieldType(), pField,
-                           NULL);
+                           nullptr);
 }
 FX_BOOL CPDF_InterForm::ValidateFieldName(const CPDF_FormControl* pControl,
                                           CFX_WideString& csNewFieldName) {
@@ -688,7 +690,7 @@ CPDF_FormField* CPDF_InterForm::GetField(uint32_t index,
 CPDF_FormField* CPDF_InterForm::GetFieldByDict(
     CPDF_Dictionary* pFieldDict) const {
   if (!pFieldDict) {
-    return NULL;
+    return nullptr;
   }
   CFX_WideString csWName = GetFullName(pFieldDict);
   return m_pFieldTree->GetField(csWName);
@@ -926,14 +928,14 @@ void CPDF_InterForm::FixPageFields(const CPDF_Page* pPage) {
 }
 CPDF_FormField* CPDF_InterForm::AddTerminalField(CPDF_Dictionary* pFieldDict) {
   if (!pFieldDict->KeyExist("T")) {
-    return NULL;
+    return nullptr;
   }
   CPDF_Dictionary* pDict = pFieldDict;
   CFX_WideString csWName = GetFullName(pFieldDict);
   if (csWName.IsEmpty()) {
-    return NULL;
+    return nullptr;
   }
-  CPDF_FormField* pField = NULL;
+  CPDF_FormField* pField = nullptr;
   pField = m_pFieldTree->GetField(csWName);
   if (!pField) {
     CPDF_Dictionary* pParent = pFieldDict;
@@ -1049,7 +1051,7 @@ CFDF_Document* CPDF_InterForm::ExportToFDF(
     bool bSimpleFileSpec) const {
   CFDF_Document* pDoc = CFDF_Document::CreateNewDoc();
   if (!pDoc) {
-    return NULL;
+    return nullptr;
   }
   CPDF_Dictionary* pMainDict = pDoc->GetRoot()->GetDictBy("FDF");
   if (!pdf_path.IsEmpty()) {
diff --git a/core/fpdfdoc/doc_tagged.cpp b/core/fpdfdoc/doc_tagged.cpp
index b5b89a017e..05109bb747 100644
--- a/core/fpdfdoc/doc_tagged.cpp
+++ b/core/fpdfdoc/doc_tagged.cpp
@@ -132,14 +132,14 @@ CPDF_StructElementImpl* CPDF_StructTreeImpl::AddPageNode(
     std::map<CPDF_Dictionary*, CPDF_StructElementImpl*>& map,
     int nLevel) {
   if (nLevel > nMaxRecursion)
-    return NULL;
+    return nullptr;
 
   auto it = map.find(pDict);
   if (it != map.end())
     return it->second;
 
   CPDF_StructElementImpl* pElement =
-      new CPDF_StructElementImpl(this, NULL, pDict);
+      new CPDF_StructElementImpl(this, nullptr, pDict);
   map[pDict] = pElement;
   CPDF_Dictionary* pParent = pDict->GetDictBy("P");
   if (!pParent || pParent->GetStringBy("Type") == "StructTreeRoot") {
@@ -301,7 +301,7 @@ void CPDF_StructElementImpl::LoadKid(uint32_t PageObjNum,
       pKid->m_Element.m_pElement =
           new CPDF_StructElementImpl(m_pTree, this, pKidDict);
     } else {
-      pKid->m_Element.m_pElement = NULL;
+      pKid->m_Element.m_pElement = nullptr;
     }
   }
 }
@@ -335,7 +335,7 @@ CPDF_Object* CPDF_StructElementImpl::GetAttr(const CFX_ByteStringC& owner,
                                              FX_BOOL bInheritable,
                                              FX_FLOAT fLevel) {
   if (fLevel > nMaxRecursion) {
-    return NULL;
+    return nullptr;
   }
   if (bInheritable) {
     CPDF_Object* pAttr = GetAttr(owner, name, FALSE);
@@ -343,7 +343,7 @@ CPDF_Object* CPDF_StructElementImpl::GetAttr(const CFX_ByteStringC& owner,
       return pAttr;
     }
     if (!m_pParent) {
-      return NULL;
+      return nullptr;
     }
     return m_pParent->GetAttr(owner, name, TRUE, fLevel + 1);
   }
diff --git a/core/fpdfdoc/doc_utils.cpp b/core/fpdfdoc/doc_utils.cpp
index 6c61c3d75e..05197380a6 100644
--- a/core/fpdfdoc/doc_utils.cpp
+++ b/core/fpdfdoc/doc_utils.cpp
@@ -23,7 +23,7 @@ CPDF_Object* SearchNumberNode(const CPDF_Dictionary* pNode, int num) {
   CPDF_Array* pLimits = pNode->GetArrayBy("Limits");
   if (pLimits &&
       (num < pLimits->GetIntegerAt(0) || num > pLimits->GetIntegerAt(1))) {
-    return NULL;
+    return nullptr;
   }
   CPDF_Array* pNumbers = pNode->GetArrayBy("Nums");
   if (pNumbers) {
@@ -36,11 +36,11 @@ CPDF_Object* SearchNumberNode(const CPDF_Dictionary* pNode, int num) {
         break;
       }
     }
-    return NULL;
+    return nullptr;
   }
   CPDF_Array* pKids = pNode->GetArrayBy("Kids");
   if (!pKids) {
-    return NULL;
+    return nullptr;
   }
   for (size_t i = 0; i < pKids->GetCount(); i++) {
     CPDF_Dictionary* pKid = pKids->GetDictAt(i);
@@ -52,7 +52,7 @@ CPDF_Object* SearchNumberNode(const CPDF_Dictionary* pNode, int num) {
       return pFound;
     }
   }
-  return NULL;
+  return nullptr;
 }
 
 }  // namespace
@@ -279,16 +279,17 @@ void InitInterFormDict(CPDF_Dictionary*& pFormDict, CPDF_Document* pDocument) {
   }
   CFX_ByteString csDA;
   if (!pFormDict->KeyExist("DR")) {
-    CPDF_Font* pFont = NULL;
-    CFX_ByteString csBaseName, csDefault;
+    CFX_ByteString csBaseName;
+    CFX_ByteString csDefault;
     uint8_t charSet = CPDF_InterForm::GetNativeCharSet();
-    pFont = CPDF_InterForm::AddStandardFont(pDocument, "Helvetica");
+    CPDF_Font* pFont = CPDF_InterForm::AddStandardFont(pDocument, "Helvetica");
     if (pFont) {
       AddInterFormFont(pFormDict, pDocument, pFont, csBaseName);
       csDefault = csBaseName;
     }
     if (charSet != 0) {
-      CFX_ByteString csFontName = CPDF_InterForm::GetNativeFont(charSet, NULL);
+      CFX_ByteString csFontName =
+          CPDF_InterForm::GetNativeFont(charSet, nullptr);
       if (!pFont || csFontName != "Helvetica") {
         pFont = CPDF_InterForm::AddNativeFont(pDocument);
         if (pFont) {
@@ -341,15 +342,15 @@ CPDF_Font* GetInterFormFont(CPDF_Dictionary* pFormDict,
                             uint32_t index,
                             CFX_ByteString& csNameTag) {
   if (!pFormDict) {
-    return NULL;
+    return nullptr;
   }
   CPDF_Dictionary* pDR = pFormDict->GetDictBy("DR");
   if (!pDR) {
-    return NULL;
+    return nullptr;
   }
   CPDF_Dictionary* pFonts = pDR->GetDictBy("Font");
   if (!pFonts) {
-    return NULL;
+    return nullptr;
   }
   uint32_t dwCount = 0;
   for (const auto& it : *pFonts) {
@@ -369,46 +370,46 @@ CPDF_Font* GetInterFormFont(CPDF_Dictionary* pFormDict,
     }
     dwCount++;
   }
-  return NULL;
+  return nullptr;
 }
 CPDF_Font* GetInterFormFont(CPDF_Dictionary* pFormDict,
                             CPDF_Document* pDocument,
                             CFX_ByteString csNameTag) {
   CFX_ByteString csAlias = PDF_NameDecode(csNameTag);
   if (!pFormDict || csAlias.IsEmpty()) {
-    return NULL;
+    return nullptr;
   }
   CPDF_Dictionary* pDR = pFormDict->GetDictBy("DR");
   if (!pDR) {
-    return NULL;
+    return nullptr;
   }
   CPDF_Dictionary* pFonts = pDR->GetDictBy("Font");
   if (!pFonts) {
-    return NULL;
+    return nullptr;
   }
   CPDF_Dictionary* pElement = pFonts->GetDictBy(csAlias);
   if (!pElement) {
-    return NULL;
+    return nullptr;
   }
   if (pElement->GetStringBy("Type") == "Font") {
     return pDocument->LoadFont(pElement);
   }
-  return NULL;
+  return nullptr;
 }
 CPDF_Font* GetInterFormFont(CPDF_Dictionary* pFormDict,
                             CPDF_Document* pDocument,
                             CFX_ByteString csFontName,
                             CFX_ByteString& csNameTag) {
   if (!pFormDict || csFontName.IsEmpty()) {
-    return NULL;
+    return nullptr;
   }
   CPDF_Dictionary* pDR = pFormDict->GetDictBy("DR");
   if (!pDR) {
-    return NULL;
+    return nullptr;
   }
   CPDF_Dictionary* pFonts = pDR->GetDictBy("Font");
   if (!pFonts) {
-    return NULL;
+    return nullptr;
   }
   for (const auto& it : *pFonts) {
     const CFX_ByteString& csKey = it.first;
@@ -434,22 +435,22 @@ CPDF_Font* GetInterFormFont(CPDF_Dictionary* pFormDict,
       return pFind;
     }
   }
-  return NULL;
+  return nullptr;
 }
 CPDF_Font* GetNativeInterFormFont(CPDF_Dictionary* pFormDict,
                                   CPDF_Document* pDocument,
                                   uint8_t charSet,
                                   CFX_ByteString& csNameTag) {
   if (!pFormDict) {
-    return NULL;
+    return nullptr;
   }
   CPDF_Dictionary* pDR = pFormDict->GetDictBy("DR");
   if (!pDR) {
-    return NULL;
+    return nullptr;
   }
   CPDF_Dictionary* pFonts = pDR->GetDictBy("Font");
   if (!pFonts) {
-    return NULL;
+    return nullptr;
   }
   for (const auto& it : *pFonts) {
     const CFX_ByteString& csKey = it.first;
@@ -475,7 +476,7 @@ CPDF_Font* GetNativeInterFormFont(CPDF_Dictionary* pFormDict,
       return pFind;
     }
   }
-  return NULL;
+  return nullptr;
 }
 CPDF_Font* GetNativeInterFormFont(CPDF_Dictionary* pFormDict,
                                   CPDF_Document* pDocument,
@@ -669,7 +670,7 @@ void RemoveInterFormFont(CPDF_Dictionary* pFormDict, CFX_ByteString csNameTag) {
 CPDF_Font* GetDefaultInterFormFont(CPDF_Dictionary* pFormDict,
                                    CPDF_Document* pDocument) {
   if (!pFormDict) {
-    return NULL;
+    return nullptr;
   }
   CPDF_DefaultAppearance cDA(pFormDict->GetStringBy("DA"));
   CFX_ByteString csFontNameTag;
@@ -735,10 +736,10 @@ CPDF_Object* FPDF_GetFieldAttr(CPDF_Dictionary* pFieldDict,
                                const FX_CHAR* name,
                                int nLevel) {
   if (nLevel > FPDFDOC_UTILS_MAXRECURSION) {
-    return NULL;
+    return nullptr;
   }
   if (!pFieldDict) {
-    return NULL;
+    return nullptr;
   }
   CPDF_Object* pAttr = pFieldDict->GetDirectObjectBy(name);
   if (pAttr) {
@@ -746,7 +747,7 @@ CPDF_Object* FPDF_GetFieldAttr(CPDF_Dictionary* pFieldDict,
   }
   CPDF_Dictionary* pParent = pFieldDict->GetDictBy("Parent");
   if (!pParent) {
-    return NULL;
+    return nullptr;
   }
   return FPDF_GetFieldAttr(pParent, name, nLevel + 1);
 }
diff --git a/core/fpdfdoc/doc_viewerPreferences.cpp b/core/fpdfdoc/doc_viewerPreferences.cpp
index a355635bf0..1de8c92614 100644
--- a/core/fpdfdoc/doc_viewerPreferences.cpp
+++ b/core/fpdfdoc/doc_viewerPreferences.cpp
@@ -9,46 +9,35 @@
 
 CPDF_ViewerPreferences::CPDF_ViewerPreferences(CPDF_Document* pDoc)
     : m_pDoc(pDoc) {}
+
 CPDF_ViewerPreferences::~CPDF_ViewerPreferences() {}
+
 FX_BOOL CPDF_ViewerPreferences::IsDirectionR2L() const {
-  CPDF_Dictionary* pDict = m_pDoc->GetRoot();
-  pDict = pDict->GetDictBy("ViewerPreferences");
-  if (!pDict) {
-    return FALSE;
-  }
-  return "R2L" == pDict->GetStringBy("Direction");
+  CPDF_Dictionary* pDict = GetViewerPreferences();
+  return pDict ? pDict->GetStringBy("Direction") == "R2L" : FALSE;
 }
+
 FX_BOOL CPDF_ViewerPreferences::PrintScaling() const {
-  CPDF_Dictionary* pDict = m_pDoc->GetRoot();
-  pDict = pDict->GetDictBy("ViewerPreferences");
-  if (!pDict) {
-    return TRUE;
-  }
-  return "None" != pDict->GetStringBy("PrintScaling");
+  CPDF_Dictionary* pDict = GetViewerPreferences();
+  return pDict ? pDict->GetStringBy("PrintScaling") != "None" : TRUE;
 }
+
 int32_t CPDF_ViewerPreferences::NumCopies() const {
-  CPDF_Dictionary* pDict = m_pDoc->GetRoot();
-  pDict = pDict->GetDictBy("ViewerPreferences");
-  if (!pDict) {
-    return 1;
-  }
-  return pDict->GetIntegerBy("NumCopies");
+  CPDF_Dictionary* pDict = GetViewerPreferences();
+  return pDict ? pDict->GetIntegerBy("NumCopies") : 1;
 }
+
 CPDF_Array* CPDF_ViewerPreferences::PrintPageRange() const {
-  CPDF_Dictionary* pDict = m_pDoc->GetRoot();
-  CPDF_Array* pRange = NULL;
-  pDict = pDict->GetDictBy("ViewerPreferences");
-  if (!pDict) {
-    return pRange;
-  }
-  pRange = pDict->GetArrayBy("PrintPageRange");
-  return pRange;
+  CPDF_Dictionary* pDict = GetViewerPreferences();
+  return pDict ? pDict->GetArrayBy("PrintPageRange") : nullptr;
 }
+
 CFX_ByteString CPDF_ViewerPreferences::Duplex() const {
+  CPDF_Dictionary* pDict = GetViewerPreferences();
+  return pDict ? pDict->GetStringBy("Duplex") : CFX_ByteString("None");
+}
+
+CPDF_Dictionary* CPDF_ViewerPreferences::GetViewerPreferences() const {
   CPDF_Dictionary* pDict = m_pDoc->GetRoot();
-  pDict = pDict->GetDictBy("ViewerPreferences");
-  if (!pDict) {
-    return "None";
-  }
-  return pDict->GetStringBy("Duplex");
+  return pDict ? pDict->GetDictBy("ViewerPreferences") : nullptr;
 }
diff --git a/core/fpdfdoc/include/cpdf_variabletext.h b/core/fpdfdoc/include/cpdf_variabletext.h
index faa5036469..06b41f186c 100644
--- a/core/fpdfdoc/include/cpdf_variabletext.h
+++ b/core/fpdfdoc/include/cpdf_variabletext.h
@@ -115,20 +115,20 @@ class CPDF_VariableText : private CPDF_EditContainer {
   void ResetAll();
   void SetText(const FX_WCHAR* text,
                int32_t charset = 1,
-               const CPVT_SecProps* pSecProps = NULL,
-               const CPVT_WordProps* pWordProps = NULL);
+               const CPVT_SecProps* pSecProps = nullptr,
+               const CPVT_WordProps* pWordProps = nullptr);
   CPVT_WordPlace InsertWord(const CPVT_WordPlace& place,
                             uint16_t word,
                             int32_t charset = 1,
-                            const CPVT_WordProps* pWordProps = NULL);
+                            const CPVT_WordProps* pWordProps = nullptr);
   CPVT_WordPlace InsertSection(const CPVT_WordPlace& place,
-                               const CPVT_SecProps* pSecProps = NULL,
-                               const CPVT_WordProps* pWordProps = NULL);
+                               const CPVT_SecProps* pSecProps = nullptr,
+                               const CPVT_WordProps* pWordProps = nullptr);
   CPVT_WordPlace InsertText(const CPVT_WordPlace& place,
                             const FX_WCHAR* text,
                             int32_t charset = 1,
-                            const CPVT_SecProps* pSecProps = NULL,
-                            const CPVT_WordProps* pWordProps = NULL);
+                            const CPVT_SecProps* pSecProps = nullptr,
+                            const CPVT_WordProps* pWordProps = nullptr);
   CPVT_WordPlace DeleteWords(const CPVT_WordRange& PlaceRange);
   CPVT_WordPlace DeleteWord(const CPVT_WordPlace& place);
   CPVT_WordPlace BackSpaceWord(const CPVT_WordPlace& place);
diff --git a/core/fpdfdoc/include/fpdf_doc.h b/core/fpdfdoc/include/fpdf_doc.h
index 339182c19b..a70a24c1e3 100644
--- a/core/fpdfdoc/include/fpdf_doc.h
+++ b/core/fpdfdoc/include/fpdf_doc.h
@@ -44,7 +44,6 @@ class CPDF_Page;
 class CPDF_PageObject;
 class CPDF_RenderContext;
 class CPDF_RenderOptions;
-class CPDF_ViewerPreferences;
 class CXML_Element;
 class IPDF_FormNotify;
 
@@ -899,6 +898,8 @@ class CPDF_ViewerPreferences {
   CFX_ByteString Duplex() const;
 
  protected:
+  CPDF_Dictionary* GetViewerPreferences() const;
+
   CPDF_Document* const m_pDoc;
 };
 
diff --git a/core/fpdfdoc/pdf_vt.h b/core/fpdfdoc/pdf_vt.h
index 9026eeee9e..3f06f7d6d6 100644
--- a/core/fpdfdoc/pdf_vt.h
+++ b/core/fpdfdoc/pdf_vt.h
@@ -28,7 +28,7 @@ class CPVT_ArrayTemplate : public CFX_ArrayTemplate<TYPE> {
     if (nIndex >= 0 && nIndex < CFX_ArrayTemplate<TYPE>::GetSize()) {
       return CFX_ArrayTemplate<TYPE>::GetAt(nIndex);
     }
-    return NULL;
+    return nullptr;
   }
   void RemoveAt(int nIndex) {
     if (nIndex >= 0 && nIndex < CFX_ArrayTemplate<TYPE>::GetSize()) {