Remove CFX_PtrList from renderer main loop.

Exposes an iterator over the object list, but not the object
holder, since pages and forms inherit from object holder, and
we don't want to imply that there's only one thing that might
be iterated over for those classes.

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/1700183002 .

19 files changed, 254 insertions, 332 deletions

diff --git a/core/include/fpdfapi/fpdf_page.h b/core/include/fpdfapi/fpdf_page.h
index fb951280a2..3d98e34578 100644
--- a/core/include/fpdfapi/fpdf_page.h
+++ b/core/include/fpdfapi/fpdf_page.h
@@ -7,6 +7,7 @@
 #ifndef CORE_INCLUDE_FPDFAPI_FPDF_PAGE_H_
 #define CORE_INCLUDE_FPDFAPI_FPDF_PAGE_H_
 
+#include <list>
 #include <memory>
 
 #include "core/include/fpdfapi/fpdf_parser.h"
@@ -27,33 +28,15 @@ class CPDF_StreamContentParser;
 #define PDFTRANS_ISOLATED 0x0200
 #define PDFTRANS_KNOCKOUT 0x0400
 
-class CPDF_PageObjectList : public CFX_PtrList {
+class CPDF_PageObjectList : public std::list<std::unique_ptr<CPDF_PageObject>> {
  public:
-  explicit CPDF_PageObjectList(int nBlockSize) : CFX_PtrList(nBlockSize) {}
-
-  CPDF_PageObject* GetNextObject(FX_POSITION& pos) const {
-    return static_cast<CPDF_PageObject*>(GetNext(pos));
-  }
-
-  CPDF_PageObject* GetPrevObject(FX_POSITION& pos) const {
-    return static_cast<CPDF_PageObject*>(GetPrev(pos));
-  }
-
-  CPDF_PageObject* GetObjectAt(FX_POSITION pos) const {
-    return static_cast<CPDF_PageObject*>(GetAt(pos));
-  }
-
   // Linear complexity, to be avoided except as needed by public APIs.
-  CPDF_PageObject* GetObjectByIndex(int index) const;
-
-  FX_POSITION InsertObject(FX_POSITION posInsertAfter,
-                           CPDF_PageObject* pNewObject);
+  CPDF_PageObject* GetPageObjectByIndex(int index);
 };
 
 class CPDF_PageObjectHolder {
  public:
   CPDF_PageObjectHolder();
-  ~CPDF_PageObjectHolder();
 
   void ContinueParse(IFX_Pause* pPause);
   FX_BOOL IsParsed() const { return m_ParseState == CONTENT_PARSED; }
@@ -165,8 +148,8 @@ class CPDF_Form : public CPDF_PageObjectHolder {
 };
 class CPDF_PageContentGenerator {
  public:
-  CPDF_PageContentGenerator(CPDF_Page* pPage);
-  ~CPDF_PageContentGenerator();
+  explicit CPDF_PageContentGenerator(CPDF_Page* pPage);
+
   FX_BOOL InsertPageObject(CPDF_PageObject* pPageObject);
   void GenerateContent();
   void TransformContent(CFX_Matrix& matrix);
diff --git a/core/include/fpdfapi/fpdf_render.h b/core/include/fpdfapi/fpdf_render.h
index fc0f68afe8..cc9b9413ea 100644
--- a/core/include/fpdfapi/fpdf_render.h
+++ b/core/include/fpdfapi/fpdf_render.h
@@ -151,7 +151,7 @@ class CPDF_ProgressiveRenderer {
   CFX_FloatRect m_ClipRect;
   FX_DWORD m_LayerIndex;
   CPDF_RenderContext::Layer* m_pCurrentLayer;
-  FX_POSITION m_LastObjectRendered;
+  CPDF_PageObjectList::iterator m_LastObjectRendered;
 };
 
 class CPDF_TextRenderer {
diff --git a/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp b/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp
index 82ab370564..ef0344cda0 100644
--- a/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp
+++ b/core/src/fpdfapi/fpdf_edit/fpdf_edit_content.cpp
@@ -14,25 +14,18 @@ CFX_ByteTextBuf& operator<<(CFX_ByteTextBuf& ar, CFX_Matrix& matrix) {
      << matrix.e << " " << matrix.f;
   return ar;
 }
+
 CPDF_PageContentGenerator::CPDF_PageContentGenerator(CPDF_Page* pPage)
-    : m_pPage(pPage) {
-  m_pDocument = NULL;
-  if (m_pPage) {
-    m_pDocument = m_pPage->m_pDocument;
-  }
-  FX_POSITION pos = pPage->GetPageObjectList()->GetHeadPosition();
-  while (pos) {
-    InsertPageObject(pPage->GetPageObjectList()->GetNextObject(pos));
-  }
+    : m_pPage(pPage), m_pDocument(m_pPage->m_pDocument) {
+  for (const auto& pObj : *pPage->GetPageObjectList())
+    InsertPageObject(pObj.get());
 }
-CPDF_PageContentGenerator::~CPDF_PageContentGenerator() {}
+
 FX_BOOL CPDF_PageContentGenerator::InsertPageObject(
     CPDF_PageObject* pPageObject) {
-  if (!pPageObject) {
-    return FALSE;
-  }
-  return m_pageObjects.Add(pPageObject);
+  return pPageObject && m_pageObjects.Add(pPageObject);
 }
+
 void CPDF_PageContentGenerator::GenerateContent() {
   CFX_ByteTextBuf buf;
   CPDF_Dictionary* pPageDict = m_pPage->m_pFormDict;
diff --git a/core/src/fpdfapi/fpdf_font/fpdf_font.cpp b/core/src/fpdfapi/fpdf_font/fpdf_font.cpp
index 52b79b0c1a..540f9a0731 100644
--- a/core/src/fpdfapi/fpdf_font/fpdf_font.cpp
+++ b/core/src/fpdfapi/fpdf_font/fpdf_font.cpp
@@ -1706,7 +1706,7 @@ CPDF_Type3Char* CPDF_Type3Font::LoadChar(FX_DWORD charcode, int level) {
   ASSERT(!pdfium::ContainsKey(m_CacheMap, charcode));
   CPDF_Type3Char* pCachedChar = pNewChar.release();
   m_CacheMap[charcode] = pCachedChar;
-  if (pCachedChar->m_pForm->GetPageObjectList()->GetCount() == 0) {
+  if (pCachedChar->m_pForm->GetPageObjectList()->empty()) {
     delete pCachedChar->m_pForm;
     pCachedChar->m_pForm = nullptr;
   }
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page.cpp
index 4194ff75eb..b1de6d6de2 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page.cpp
@@ -6,8 +6,11 @@
 
 #include "core/src/fpdfapi/fpdf_page/pageint.h"
 
+#include <algorithm>
+
 #include "core/include/fpdfapi/fpdf_module.h"
 #include "core/include/fpdfapi/fpdf_page.h"
+#include "third_party/base/stl_util.h"
 
 CPDF_PageObject* CPDF_PageObject::Create(int type) {
   switch (type) {
@@ -670,6 +673,19 @@ void CPDF_FormObject::CalcBoundingBox() {
   m_Right = form_rect.right;
   m_Top = form_rect.top;
 }
+
+CPDF_PageObject* CPDF_PageObjectList::GetPageObjectByIndex(int index) {
+  if (index < 0 || index >= pdfium::CollectionSize<int>(*this))
+    return nullptr;
+  int current = 0;
+  for (const auto& pObj : *this) {
+    if (index == current)
+      return pObj.get();
+    ++current;
+  }
+  return nullptr;
+}
+
 CPDF_PageObjectHolder::CPDF_PageObjectHolder()
     : m_pFormDict(nullptr),
       m_pFormStream(nullptr),
@@ -679,15 +695,8 @@ CPDF_PageObjectHolder::CPDF_PageObjectHolder()
       m_Transparency(0),
       m_bBackgroundAlphaNeeded(FALSE),
       m_bHasImageMask(FALSE),
-      m_ParseState(CONTENT_NOT_PARSED),
-      m_PageObjectList(128) {}
+      m_ParseState(CONTENT_NOT_PARSED) {}
 
-CPDF_PageObjectHolder::~CPDF_PageObjectHolder() {
-  FX_POSITION pos = m_PageObjectList.GetHeadPosition();
-  while (pos) {
-    delete m_PageObjectList.GetNextObject(pos);
-  }
-}
 void CPDF_PageObjectHolder::ContinueParse(IFX_Pause* pPause) {
   if (!m_pParser) {
     return;
@@ -698,48 +707,29 @@ void CPDF_PageObjectHolder::ContinueParse(IFX_Pause* pPause) {
     m_pParser.reset();
   }
 }
-FX_POSITION CPDF_PageObjectList::InsertObject(FX_POSITION posInsertAfter,
-                                              CPDF_PageObject* pNewObject) {
-  if (!posInsertAfter) {
-    return AddHead(pNewObject);
-  }
-  return InsertAfter(posInsertAfter, pNewObject);
-}
-CPDF_PageObject* CPDF_PageObjectList::GetObjectByIndex(int index) const {
-  FX_POSITION pos = FindIndex(index);
-  return pos ? GetObjectAt(pos) : nullptr;
-}
+
 void CPDF_PageObjectHolder::Transform(const CFX_Matrix& matrix) {
-  FX_POSITION pos = m_PageObjectList.GetHeadPosition();
-  while (pos) {
-    m_PageObjectList.GetNextObject(pos)->Transform(matrix);
-  }
+  for (auto& pObj : m_PageObjectList)
+    pObj->Transform(matrix);
 }
+
 CFX_FloatRect CPDF_PageObjectHolder::CalcBoundingBox() const {
-  if (m_PageObjectList.GetCount() == 0) {
+  if (m_PageObjectList.empty())
     return CFX_FloatRect(0, 0, 0, 0);
-  }
-  FX_FLOAT left, right, top, bottom;
-  left = bottom = 1000000 * 1.0f;
-  right = top = -1000000 * 1.0f;
-  FX_POSITION pos = m_PageObjectList.GetHeadPosition();
-  while (pos) {
-    CPDF_PageObject* pObj = (CPDF_PageObject*)m_PageObjectList.GetNext(pos);
-    if (left > pObj->m_Left) {
-      left = pObj->m_Left;
-    }
-    if (right < pObj->m_Right) {
-      right = pObj->m_Right;
-    }
-    if (top < pObj->m_Top) {
-      top = pObj->m_Top;
-    }
-    if (bottom > pObj->m_Bottom) {
-      bottom = pObj->m_Bottom;
-    }
+
+  FX_FLOAT left = 1000000.0f;
+  FX_FLOAT right = -1000000.0f;
+  FX_FLOAT bottom = 1000000.0f;
+  FX_FLOAT top = -1000000.0f;
+  for (const auto& pObj : m_PageObjectList) {
+    left = std::min(left, pObj->m_Left);
+    right = std::max(right, pObj->m_Right);
+    bottom = std::min(bottom, pObj->m_Bottom);
+    top = std::max(top, pObj->m_Top);
   }
   return CFX_FloatRect(left, bottom, right, top);
 }
+
 void CPDF_PageObjectHolder::LoadTransInfo() {
   if (!m_pFormDict) {
     return;
@@ -889,7 +879,9 @@ CPDF_Form::CPDF_Form(CPDF_Document* pDoc,
   m_Transparency = 0;
   LoadTransInfo();
 }
+
 CPDF_Form::~CPDF_Form() {}
+
 void CPDF_Form::StartParse(CPDF_AllStates* pGraphicStates,
                            CFX_Matrix* pParentMatrix,
                            CPDF_Type3Char* pType3Char,
@@ -903,6 +895,7 @@ void CPDF_Form::StartParse(CPDF_AllStates* pGraphicStates,
                    level);
   m_ParseState = CONTENT_PARSING;
 }
+
 void CPDF_Form::ParseContent(CPDF_AllStates* pGraphicStates,
                              CFX_Matrix* pParentMatrix,
                              CPDF_Type3Char* pType3Char,
@@ -911,16 +904,16 @@ void CPDF_Form::ParseContent(CPDF_AllStates* pGraphicStates,
   StartParse(pGraphicStates, pParentMatrix, pType3Char, pOptions, level);
   ContinueParse(NULL);
 }
+
 CPDF_Form* CPDF_Form::Clone() const {
-  CPDF_Form* pClone =
+  CPDF_Form* pCloneForm =
       new CPDF_Form(m_pDocument, m_pPageResources, m_pFormStream, m_pResources);
-  FX_POSITION pos = m_PageObjectList.GetHeadPosition();
-  while (pos) {
-    CPDF_PageObject* pObj = (CPDF_PageObject*)m_PageObjectList.GetNext(pos);
-    pClone->m_PageObjectList.AddTail(pObj->Clone());
-  }
-  return pClone;
+  for (const auto& pObj : m_PageObjectList)
+    pCloneForm->m_PageObjectList.emplace_back(pObj->Clone());
+
+  return pCloneForm;
 }
+
 void CPDF_Page::GetDisplayMatrix(CFX_Matrix& matrix,
                                  int xPos,
                                  int yPos,
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
index 6e02cb11b4..d49186374f 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
@@ -780,7 +780,7 @@ void CPDF_StreamContentParser::AddForm(CPDF_Stream* pStream) {
     parser.Parse(stream.GetData(), stream.GetSize(), 0);
     return;
   }
-  CPDF_FormObject* pFormObj = new CPDF_FormObject;
+  std::unique_ptr<CPDF_FormObject> pFormObj(new CPDF_FormObject);
   pFormObj->m_pForm =
       new CPDF_Form(m_pDocument, m_pPageResources, pStream, m_pResources);
   pFormObj->m_FormMatrix = m_pCurStates->m_CTM;
@@ -796,8 +796,8 @@ void CPDF_StreamContentParser::AddForm(CPDF_Stream* pStream) {
     m_pObjectHolder->SetBackgroundAlphaNeeded(TRUE);
   }
   pFormObj->CalcBoundingBox();
-  SetGraphicStates(pFormObj, TRUE, TRUE, TRUE);
-  m_pObjectHolder->GetPageObjectList()->AddTail(pFormObj);
+  SetGraphicStates(pFormObj.get(), TRUE, TRUE, TRUE);
+  m_pObjectHolder->GetPageObjectList()->push_back(std::move(pFormObj));
 }
 
 CPDF_ImageObject* CPDF_StreamContentParser::AddImage(CPDF_Stream* pStream,
@@ -809,7 +809,8 @@ CPDF_ImageObject* CPDF_StreamContentParser::AddImage(CPDF_Stream* pStream,
   CFX_Matrix ImageMatrix;
   ImageMatrix.Copy(m_pCurStates->m_CTM);
   ImageMatrix.Concat(m_mtContentToUser);
-  CPDF_ImageObject* pImageObj = new CPDF_ImageObject;
+
+  std::unique_ptr<CPDF_ImageObject> pImageObj(new CPDF_ImageObject);
   if (pImage) {
     pImageObj->m_pImage =
         m_pDocument->GetPageData()->GetImage(pImage->GetStream());
@@ -819,11 +820,13 @@ CPDF_ImageObject* CPDF_StreamContentParser::AddImage(CPDF_Stream* pStream,
     pImageObj->m_pImage = new CPDF_Image(m_pDocument);
     pImageObj->m_pImage->LoadImageF(pStream, bInline);
   }
-  SetGraphicStates(pImageObj, pImageObj->m_pImage->IsMask(), FALSE, FALSE);
+  SetGraphicStates(pImageObj.get(), pImageObj->m_pImage->IsMask(), FALSE,
+                   FALSE);
   pImageObj->m_Matrix = ImageMatrix;
   pImageObj->CalcBoundingBox();
-  m_pObjectHolder->GetPageObjectList()->AddTail(pImageObj);
-  return pImageObj;
+  CPDF_ImageObject* pRet = pImageObj.get();
+  m_pObjectHolder->GetPageObjectList()->push_back(std::move(pImageObj));
+  return pRet;
 }
 
 void CPDF_StreamContentParser::Handle_MarkPlace_Dictionary() {}
@@ -1190,9 +1193,9 @@ void CPDF_StreamContentParser::Handle_ShadeFill() {
   if (!pShading->Load()) {
     return;
   }
-  CPDF_ShadingObject* pObj = new CPDF_ShadingObject;
+  std::unique_ptr<CPDF_ShadingObject> pObj(new CPDF_ShadingObject);
   pObj->m_pShading = pShading;
-  SetGraphicStates(pObj, FALSE, FALSE, FALSE);
+  SetGraphicStates(pObj.get(), FALSE, FALSE, FALSE);
   pObj->m_Matrix = m_pCurStates->m_CTM;
   pObj->m_Matrix.Concat(m_mtContentToUser);
   CFX_FloatRect bbox;
@@ -1211,7 +1214,7 @@ void CPDF_StreamContentParser::Handle_ShadeFill() {
   pObj->m_Right = bbox.right;
   pObj->m_Top = bbox.top;
   pObj->m_Bottom = bbox.bottom;
-  m_pObjectHolder->GetPageObjectList()->AddTail(pObj);
+  m_pObjectHolder->GetPageObjectList()->push_back(std::move(pObj));
 }
 
 void CPDF_StreamContentParser::Handle_SetCharSpace() {
@@ -1365,31 +1368,34 @@ void CPDF_StreamContentParser::AddTextObject(CFX_ByteString* pStrs,
   } else {
     textmode = m_pCurStates->m_TextState.GetObject()->m_TextMode;
   }
-  CPDF_TextObject* pText = new CPDF_TextObject;
-  m_pLastTextObject = pText;
-  SetGraphicStates(pText, TRUE, TRUE, TRUE);
-  if (textmode && textmode != 3 && textmode != 4 && textmode != 7) {
-    FX_FLOAT* pCTM = pText->m_TextState.GetModify()->m_CTM;
-    pCTM[0] = m_pCurStates->m_CTM.a;
-    pCTM[1] = m_pCurStates->m_CTM.c;
-    pCTM[2] = m_pCurStates->m_CTM.b;
-    pCTM[3] = m_pCurStates->m_CTM.d;
-  }
-  pText->SetSegments(pStrs, pKerning, nsegs);
-  pText->m_PosX = m_pCurStates->m_TextX;
-  pText->m_PosY = m_pCurStates->m_TextY + m_pCurStates->m_TextRise;
-  ConvertTextSpace(pText->m_PosX, pText->m_PosY);
-  FX_FLOAT x_advance, y_advance;
-  pText->CalcPositionData(&x_advance, &y_advance, m_pCurStates->m_TextHorzScale,
-                          m_Level);
-  m_pCurStates->m_TextX += x_advance;
-  m_pCurStates->m_TextY += y_advance;
-  if (textmode > 3) {
-    CPDF_TextObject* pCopy = new CPDF_TextObject;
-    pCopy->Copy(pText);
-    m_ClipTextList.Add(pCopy);
-  }
-  m_pObjectHolder->GetPageObjectList()->AddTail(pText);
+  {
+    std::unique_ptr<CPDF_TextObject> pText(new CPDF_TextObject);
+    m_pLastTextObject = pText.get();
+    SetGraphicStates(m_pLastTextObject, TRUE, TRUE, TRUE);
+    if (textmode && textmode != 3 && textmode != 4 && textmode != 7) {
+      FX_FLOAT* pCTM = pText->m_TextState.GetModify()->m_CTM;
+      pCTM[0] = m_pCurStates->m_CTM.a;
+      pCTM[1] = m_pCurStates->m_CTM.c;
+      pCTM[2] = m_pCurStates->m_CTM.b;
+      pCTM[3] = m_pCurStates->m_CTM.d;
+    }
+    pText->SetSegments(pStrs, pKerning, nsegs);
+    pText->m_PosX = m_pCurStates->m_TextX;
+    pText->m_PosY = m_pCurStates->m_TextY + m_pCurStates->m_TextRise;
+    ConvertTextSpace(pText->m_PosX, pText->m_PosY);
+    FX_FLOAT x_advance;
+    FX_FLOAT y_advance;
+    pText->CalcPositionData(&x_advance, &y_advance,
+                            m_pCurStates->m_TextHorzScale, m_Level);
+    m_pCurStates->m_TextX += x_advance;
+    m_pCurStates->m_TextY += y_advance;
+    if (textmode > 3) {
+      CPDF_TextObject* pCopy = new CPDF_TextObject;
+      pCopy->Copy(pText.get());
+      m_ClipTextList.Add(pCopy);
+    }
+    m_pObjectHolder->GetPageObjectList()->push_back(std::move(pText));
+  }
   if (pKerning && pKerning[nsegs - 1] != 0) {
     if (!pFont->IsVertWriting()) {
       m_pCurStates->m_TextX -=
@@ -1617,14 +1623,14 @@ void CPDF_StreamContentParser::AddPathObject(int FillType, FX_BOOL bStroke) {
   CFX_Matrix matrix = m_pCurStates->m_CTM;
   matrix.Concat(m_mtContentToUser);
   if (bStroke || FillType) {
-    CPDF_PathObject* pPathObj = new CPDF_PathObject;
+    std::unique_ptr<CPDF_PathObject> pPathObj(new CPDF_PathObject);
     pPathObj->m_bStroke = bStroke;
     pPathObj->m_FillType = FillType;
     pPathObj->m_Path = Path;
     pPathObj->m_Matrix = matrix;
-    SetGraphicStates(pPathObj, TRUE, FALSE, TRUE);
+    SetGraphicStates(pPathObj.get(), TRUE, FALSE, TRUE);
     pPathObj->CalcBoundingBox();
-    m_pObjectHolder->GetPageObjectList()->AddTail(pPathObj);
+    m_pObjectHolder->GetPageObjectList()->push_back(std::move(pPathObj));
   }
   if (PathClipType) {
     if (!matrix.IsIdentity()) {
@@ -1641,13 +1647,12 @@ FX_DWORD CPDF_StreamContentParser::Parse(const uint8_t* pData,
   if (m_Level > _FPDF_MAX_FORM_LEVEL_) {
     return dwSize;
   }
-  FX_DWORD InitObjCount = m_pObjectHolder->GetPageObjectList()->GetCount();
+  FX_DWORD InitObjCount = m_pObjectHolder->GetPageObjectList()->size();
   CPDF_StreamParser syntax(pData, dwSize);
   CPDF_StreamParserAutoClearer auto_clearer(&m_pSyntax, &syntax);
   m_CompatCount = 0;
   while (1) {
-    FX_DWORD cost =
-        m_pObjectHolder->GetPageObjectList()->GetCount() - InitObjCount;
+    FX_DWORD cost = m_pObjectHolder->GetPageObjectList()->size() - InitObjCount;
     if (max_cost && cost >= max_cost) {
       break;
     }
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
index 7fa3286e11..20f0c39c25 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
@@ -666,7 +666,7 @@ bool CPDF_StreamParser::PositionIsInBounds() const {
 CPDF_ContentParser::CPDF_ContentParser()
     : m_Status(Ready),
       m_InternalStage(STAGE_GETCONTENT),
-      m_pObjects(nullptr),
+      m_pObjectHolder(nullptr),
       m_bForm(false),
       m_pType3Char(nullptr),
       m_pData(nullptr),
@@ -684,7 +684,7 @@ void CPDF_ContentParser::Start(CPDF_Page* pPage, CPDF_ParseOptions* pOptions) {
     m_Status = Done;
     return;
   }
-  m_pObjects = pPage;
+  m_pObjectHolder = pPage;
   m_bForm = FALSE;
   if (pOptions) {
     m_Options = *pOptions;
@@ -720,7 +720,7 @@ void CPDF_ContentParser::Start(CPDF_Form* pForm,
                                CPDF_ParseOptions* pOptions,
                                int level) {
   m_pType3Char = pType3Char;
-  m_pObjects = pForm;
+  m_pObjectHolder = pForm;
   m_bForm = TRUE;
   CFX_Matrix form_matrix = pForm->m_pFormDict->GetMatrixBy("Matrix");
   if (pGraphicStates) {
@@ -803,7 +803,8 @@ void CPDF_ContentParser::Continue(IFX_Pause* pPause) {
         m_InternalStage = STAGE_PARSE;
         m_CurrentOffset = 0;
       } else {
-        CPDF_Array* pContent = m_pObjects->m_pFormDict->GetArrayBy("Contents");
+        CPDF_Array* pContent =
+            m_pObjectHolder->m_pFormDict->GetArrayBy("Contents");
         m_StreamArray[m_CurrentOffset].reset(new CPDF_StreamAcc);
         CPDF_Stream* pStreamObj = ToStream(
             pContent ? pContent->GetElementValue(m_CurrentOffset) : nullptr);
@@ -814,9 +815,9 @@ void CPDF_ContentParser::Continue(IFX_Pause* pPause) {
     if (m_InternalStage == STAGE_PARSE) {
       if (!m_pParser) {
         m_pParser.reset(new CPDF_StreamContentParser(
-            m_pObjects->m_pDocument, m_pObjects->m_pPageResources, nullptr,
-            nullptr, m_pObjects, m_pObjects->m_pResources, &m_pObjects->m_BBox,
-            &m_Options, nullptr, 0));
+            m_pObjectHolder->m_pDocument, m_pObjectHolder->m_pPageResources,
+            nullptr, nullptr, m_pObjectHolder, m_pObjectHolder->m_pResources,
+            &m_pObjectHolder->m_BBox, &m_Options, nullptr, 0));
         m_pParser->GetCurStates()->m_ColorState.GetModify()->Default();
       }
       if (m_CurrentOffset >= m_Size) {
@@ -841,10 +842,7 @@ void CPDF_ContentParser::Continue(IFX_Pause* pPause) {
         m_pType3Char->m_BBox.top =
             FXSYS_round(m_pParser->GetType3Data()[5] * 1000);
       }
-      FX_POSITION pos = m_pObjects->GetPageObjectList()->GetHeadPosition();
-      while (pos) {
-        CPDF_PageObject* pObj =
-            m_pObjects->GetPageObjectList()->GetNextObject(pos);
+      for (auto& pObj : *m_pObjectHolder->GetPageObjectList()) {
         if (pObj->m_ClipPath.IsNull()) {
           continue;
         }
diff --git a/core/src/fpdfapi/fpdf_page/pageint.h b/core/src/fpdfapi/fpdf_page/pageint.h
index 4df8d6aa9f..fb95b6b30d 100644
--- a/core/src/fpdfapi/fpdf_page/pageint.h
+++ b/core/src/fpdfapi/fpdf_page/pageint.h
@@ -94,7 +94,7 @@ class CPDF_StreamContentParser {
                            CPDF_Dictionary* pPageResources,
                            CPDF_Dictionary* pParentResources,
                            CFX_Matrix* pmtContentToUser,
-                           CPDF_PageObjectHolder* pObjHolder,
+                           CPDF_PageObjectHolder* pObjectHolder,
                            CPDF_Dictionary* pResources,
                            CFX_FloatRect* pBBox,
                            CPDF_ParseOptions* pOptions,
@@ -298,7 +298,7 @@ class CPDF_ContentParser {
 
   ParseStatus m_Status;
   InternalStage m_InternalStage;
-  CPDF_PageObjectHolder* m_pObjects;
+  CPDF_PageObjectHolder* m_pObjectHolder;
   FX_BOOL m_bForm;
   CPDF_ParseOptions m_Options;
   CPDF_Type3Char* m_pType3Char;
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render.cpp
index 0023ee92de..147de51f4d 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render.cpp
@@ -244,29 +244,24 @@ void CPDF_RenderStatus::RenderObjectList(
   CFX_Matrix device2object;
   device2object.SetReverse(*pObj2Device);
   device2object.TransformRect(clip_rect);
-  int index = 0;
-  FX_POSITION pos = pObjectHolder->GetPageObjectList()->GetHeadPosition();
-  while (pos) {
-    index++;
-    CPDF_PageObject* pCurObj =
-        pObjectHolder->GetPageObjectList()->GetNextObject(pos);
-    if (pCurObj == m_pStopObj) {
+
+  for (const auto& pCurObj : *pObjectHolder->GetPageObjectList()) {
+    if (pCurObj.get() == m_pStopObj) {
       m_bStopped = TRUE;
       return;
     }
-    if (!pCurObj) {
+    if (!pCurObj)
       continue;
-    }
-    if (!pCurObj || pCurObj->m_Left > clip_rect.right ||
+
+    if (pCurObj->m_Left > clip_rect.right ||
         pCurObj->m_Right < clip_rect.left ||
         pCurObj->m_Bottom > clip_rect.top ||
         pCurObj->m_Top < clip_rect.bottom) {
       continue;
     }
-    RenderSingleObject(pCurObj, pObj2Device);
-    if (m_bStopped) {
+    RenderSingleObject(pCurObj.get(), pObj2Device);
+    if (m_bStopped)
       return;
-    }
   }
 }
 void CPDF_RenderStatus::RenderSingleObject(const CPDF_PageObject* pObj,
@@ -1037,8 +1032,7 @@ CPDF_ProgressiveRenderer::CPDF_ProgressiveRenderer(
       m_pDevice(pDevice),
       m_pOptions(pOptions),
       m_LayerIndex(0),
-      m_pCurrentLayer(nullptr),
-      m_LastObjectRendered(nullptr) {}
+      m_pCurrentLayer(nullptr) {}
 
 CPDF_ProgressiveRenderer::~CPDF_ProgressiveRenderer() {
   if (m_pRenderStatus)
@@ -1062,7 +1056,8 @@ void CPDF_ProgressiveRenderer::Continue(IFX_Pause* pPause) {
         return;
       }
       m_pCurrentLayer = m_pContext->GetLayer(m_LayerIndex);
-      m_LastObjectRendered = nullptr;
+      m_LastObjectRendered =
+          m_pCurrentLayer->m_pObjectHolder->GetPageObjectList()->end();
       m_pRenderStatus.reset(new CPDF_RenderStatus());
       m_pRenderStatus->Initialize(
           m_pContext, m_pDevice, NULL, NULL, NULL, NULL, m_pOptions,
@@ -1073,19 +1068,18 @@ void CPDF_ProgressiveRenderer::Continue(IFX_Pause* pPause) {
       device2object.SetReverse(m_pCurrentLayer->m_Matrix);
       device2object.TransformRect(m_ClipRect);
     }
-    FX_POSITION pos;
-    if (m_LastObjectRendered) {
-      pos = m_LastObjectRendered;
-      m_pCurrentLayer->m_pObjectHolder->GetPageObjectList()->GetNextObject(pos);
+    CPDF_PageObjectList::iterator iter;
+    CPDF_PageObjectList::iterator iterEnd =
+        m_pCurrentLayer->m_pObjectHolder->GetPageObjectList()->end();
+    if (m_LastObjectRendered != iterEnd) {
+      iter = m_LastObjectRendered;
+      ++iter;
     } else {
-      pos = m_pCurrentLayer->m_pObjectHolder->GetPageObjectList()
-                ->GetHeadPosition();
+      iter = m_pCurrentLayer->m_pObjectHolder->GetPageObjectList()->begin();
     }
     int nObjsToGo = kStepLimit;
-    while (pos) {
-      CPDF_PageObject* pCurObj =
-          m_pCurrentLayer->m_pObjectHolder->GetPageObjectList()->GetObjectAt(
-              pos);
+    while (iter != iterEnd) {
+      CPDF_PageObject* pCurObj = iter->get();
       if (pCurObj && pCurObj->m_Left <= m_ClipRect.right &&
           pCurObj->m_Right >= m_ClipRect.left &&
           pCurObj->m_Bottom <= m_ClipRect.top &&
@@ -1106,19 +1100,18 @@ void CPDF_ProgressiveRenderer::Continue(IFX_Pause* pPause) {
           --nObjsToGo;
         }
       }
-      m_LastObjectRendered = pos;
+      m_LastObjectRendered = iter;
       if (nObjsToGo == 0) {
         if (pPause && pPause->NeedToPauseNow())
           return;
         nObjsToGo = kStepLimit;
       }
-      m_pCurrentLayer->m_pObjectHolder->GetPageObjectList()->GetNextObject(pos);
+      ++iter;
     }
     if (m_pCurrentLayer->m_pObjectHolder->IsParsed()) {
       m_pRenderStatus.reset();
       m_pDevice->RestoreState();
       m_pCurrentLayer = nullptr;
-      m_LastObjectRendered = nullptr;
       m_LayerIndex++;
       if (pPause && pPause->NeedToPauseNow()) {
         return;
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render_text.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render_text.cpp
index f19e6f8258..d2faac3b7e 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render_text.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render_text.cpp
@@ -316,11 +316,10 @@ FX_BOOL CPDF_Type3Char::LoadBitmap(CPDF_RenderContext* pContext) {
   if (m_pBitmap || !m_pForm) {
     return TRUE;
   }
-  if (m_pForm->GetPageObjectList()->GetCount() == 1 && !m_bColored) {
-    CPDF_PageObject* pPageObj = m_pForm->GetPageObjectList()->GetObjectAt(
-        m_pForm->GetPageObjectList()->GetHeadPosition());
+  if (m_pForm->GetPageObjectList()->size() == 1 && !m_bColored) {
+    auto& pPageObj = m_pForm->GetPageObjectList()->front();
     if (pPageObj->m_Type == CPDF_PageObject::IMAGE) {
-      CPDF_ImageObject* pImage = (CPDF_ImageObject*)pPageObj;
+      CPDF_ImageObject* pImage = static_cast<CPDF_ImageObject*>(pPageObj.get());
       m_ImageMatrix = pImage->m_Matrix;
       const CFX_DIBSource* pSource = pImage->m_pImage->LoadDIBSource();
       if (pSource) {
diff --git a/core/src/fpdftext/fpdf_text_int.cpp b/core/src/fpdftext/fpdf_text_int.cpp
index aa13acee8a..8972f84d7c 100644
--- a/core/src/fpdftext/fpdf_text_int.cpp
+++ b/core/src/fpdftext/fpdf_text_int.cpp
@@ -761,20 +761,13 @@ int32_t CPDF_TextPage::FindTextlineFlowDirection() {
   uint8_t* pDataV = nVerticalMask.data();
   int32_t index = 0;
   FX_FLOAT fLineHeight = 0.0f;
-  CPDF_PageObject* pPageObj = NULL;
-  FX_POSITION pos = NULL;
-  pos = m_pPage->GetPageObjectList()->GetHeadPosition();
-  if (!pos) {
+  if (m_pPage->GetPageObjectList()->empty())
     return -1;
-  }
-  while (pos) {
-    pPageObj = m_pPage->GetPageObjectList()->GetNextObject(pos);
-    if (!pPageObj) {
-      continue;
-    }
-    if (CPDF_PageObject::TEXT != pPageObj->m_Type) {
+
+  for (auto& pPageObj : *m_pPage->GetPageObjectList()) {
+    if (!pPageObj || pPageObj->m_Type != CPDF_PageObject::TEXT)
       continue;
-    }
+
     int32_t minH =
         (int32_t)pPageObj->m_Left < 0 ? 0 : (int32_t)pPageObj->m_Left;
     int32_t maxH = (int32_t)pPageObj->m_Right > nPageWidth
@@ -785,28 +778,26 @@ int32_t CPDF_TextPage::FindTextlineFlowDirection() {
     int32_t maxV = (int32_t)pPageObj->m_Top > nPageHeight
                        ? nPageHeight
                        : (int32_t)pPageObj->m_Top;
-    if (minH >= maxH || minV >= maxV) {
+    if (minH >= maxH || minV >= maxV)
       continue;
-    }
+
     FXSYS_memset(pDataH + minH, 1, maxH - minH);
     FXSYS_memset(pDataV + minV, 1, maxV - minV);
-    if (fLineHeight <= 0.0f) {
+    if (fLineHeight <= 0.0f)
       fLineHeight = pPageObj->m_Top - pPageObj->m_Bottom;
-    }
-    pPageObj = NULL;
   }
   int32_t nStartH = 0;
   int32_t nEndH = 0;
   FX_FLOAT nSumH = 0.0f;
-  for (index = 0; index < nPageWidth; index++)
-    if (1 == nHorizontalMask[index]) {
+  for (index = 0; index < nPageWidth; index++) {
+    if (1 == nHorizontalMask[index])
       break;
-    }
+  }
   nStartH = index;
-  for (index = nPageWidth; index > 0; index--)
-    if (1 == nHorizontalMask[index - 1]) {
+  for (index = nPageWidth; index > 0; index--) {
+    if (1 == nHorizontalMask[index - 1])
       break;
-    }
+  }
   nEndH = index;
   for (index = nStartH; index < nEndH; index++) {
     nSumH += nHorizontalMask[index];
@@ -815,15 +806,15 @@ int32_t CPDF_TextPage::FindTextlineFlowDirection() {
   int32_t nStartV = 0;
   int32_t nEndV = 0;
   FX_FLOAT nSumV = 0.0f;
-  for (index = 0; index < nPageHeight; index++)
-    if (1 == nVerticalMask[index]) {
+  for (index = 0; index < nPageHeight; index++) {
+    if (1 == nVerticalMask[index])
       break;
-    }
+  }
   nStartV = index;
-  for (index = nPageHeight; index > 0; index--)
-    if (1 == nVerticalMask[index - 1]) {
+  for (index = nPageHeight; index > 0; index--) {
+    if (1 == nVerticalMask[index - 1])
       break;
-    }
+  }
   nEndV = index;
   for (index = nStartV; index < nEndV; index++) {
     nSumV += nVerticalMask[index];
@@ -848,58 +839,50 @@ int32_t CPDF_TextPage::FindTextlineFlowDirection() {
 }
 
 void CPDF_TextPage::ProcessObject() {
-  FX_POSITION pos = m_pPage->GetPageObjectList()->GetHeadPosition();
-  if (!pos) {
+  if (m_pPage->GetPageObjectList()->empty())
     return;
-  }
+
   m_TextlineDir = FindTextlineFlowDirection();
-  int nCount = 0;
-  while (pos) {
-    CPDF_PageObject* pPageObj =
-        m_pPage->GetPageObjectList()->GetNextObject(pos);
-    if (pPageObj) {
-      if (pPageObj->m_Type == CPDF_PageObject::TEXT) {
+  const CPDF_PageObjectList* pObjList = m_pPage->GetPageObjectList();
+  for (auto it = pObjList->begin(); it != pObjList->end(); ++it) {
+    if (CPDF_PageObject* pObj = it->get()) {
+      if (pObj->m_Type == CPDF_PageObject::TEXT) {
         CFX_Matrix matrix;
-        ProcessTextObject((CPDF_TextObject*)pPageObj, matrix, pos);
-        nCount++;
-      } else if (pPageObj->m_Type == CPDF_PageObject::FORM) {
+        ProcessTextObject(static_cast<CPDF_TextObject*>(pObj), matrix, pObjList,
+                          it);
+      } else if (pObj->m_Type == CPDF_PageObject::FORM) {
         CFX_Matrix formMatrix(1, 0, 0, 1, 0, 0);
-        ProcessFormObject((CPDF_FormObject*)pPageObj, formMatrix);
+        ProcessFormObject(static_cast<CPDF_FormObject*>(pObj), formMatrix);
       }
     }
   }
-  int count = m_LineObj.GetSize();
-  for (int i = 0; i < count; i++) {
+  for (int i = 0; i < m_LineObj.GetSize(); i++)
     ProcessTextObject(m_LineObj.GetAt(i));
-  }
+
   m_LineObj.RemoveAll();
   CloseTempLine();
 }
 
 void CPDF_TextPage::ProcessFormObject(CPDF_FormObject* pFormObj,
                                       const CFX_Matrix& formMatrix) {
-  CPDF_PageObject* pPageObj = NULL;
-  FX_POSITION pos;
-  if (!pFormObj) {
+  CPDF_PageObjectList* pObjectList = pFormObj->m_pForm->GetPageObjectList();
+  if (pObjectList->empty())
     return;
-  }
-  pos = pFormObj->m_pForm->GetPageObjectList()->GetHeadPosition();
-  if (!pos) {
-    return;
-  }
+
   CFX_Matrix curFormMatrix;
   curFormMatrix.Copy(pFormObj->m_FormMatrix);
   curFormMatrix.Concat(formMatrix);
-  while (pos) {
-    pPageObj = pFormObj->m_pForm->GetPageObjectList()->GetNextObject(pos);
-    if (pPageObj) {
+
+  for (auto it = pObjectList->begin(); it != pObjectList->end(); ++it) {
+    if (CPDF_PageObject* pPageObj = it->get()) {
       if (pPageObj->m_Type == CPDF_PageObject::TEXT) {
-        ProcessTextObject((CPDF_TextObject*)pPageObj, curFormMatrix, pos);
+        ProcessTextObject(static_cast<CPDF_TextObject*>(pPageObj),
+                          curFormMatrix, pObjectList, it);
       } else if (pPageObj->m_Type == CPDF_PageObject::FORM) {
-        ProcessFormObject((CPDF_FormObject*)pPageObj, curFormMatrix);
+        ProcessFormObject(static_cast<CPDF_FormObject*>(pPageObj),
+                          curFormMatrix);
       }
     }
-    pPageObj = NULL;
   }
 }
 
@@ -1032,9 +1015,11 @@ void CPDF_TextPage::CloseTempLine() {
   m_TempTextBuf.Delete(0, m_TempTextBuf.GetLength());
 }
 
-void CPDF_TextPage::ProcessTextObject(CPDF_TextObject* pTextObj,
-                                      const CFX_Matrix& formMatrix,
-                                      FX_POSITION ObjPos) {
+void CPDF_TextPage::ProcessTextObject(
+    CPDF_TextObject* pTextObj,
+    const CFX_Matrix& formMatrix,
+    const CPDF_PageObjectList* pObjList,
+    CPDF_PageObjectList::const_iterator ObjPos) {
   CFX_FloatRect re(pTextObj->m_Left, pTextObj->m_Bottom, pTextObj->m_Right,
                    pTextObj->m_Top);
   if (FXSYS_fabs(pTextObj->m_Right - pTextObj->m_Left) < 0.01f) {
@@ -1048,7 +1033,7 @@ void CPDF_TextPage::ProcessTextObject(CPDF_TextObject* pTextObj,
     m_LineObj.Add(Obj);
     return;
   }
-  if (IsSameAsPreTextObject(pTextObj, ObjPos)) {
+  if (IsSameAsPreTextObject(pTextObj, pObjList, ObjPos)) {
     return;
   }
   PDFTEXT_Obj prev_Obj = m_LineObj.GetAt(count - 1);
@@ -1832,29 +1817,19 @@ FX_BOOL CPDF_TextPage::IsSameTextObject(CPDF_TextObject* pTextObj1,
   }
   return TRUE;
 }
-
-FX_BOOL CPDF_TextPage::IsSameAsPreTextObject(CPDF_TextObject* pTextObj,
-                                             FX_POSITION ObjPos) {
-  if (!pTextObj) {
-    return FALSE;
-  }
+FX_BOOL CPDF_TextPage::IsSameAsPreTextObject(
+    CPDF_TextObject* pTextObj,
+    const CPDF_PageObjectList* pObjList,
+    CPDF_PageObjectList::const_iterator iter) {
   int i = 0;
-  if (!ObjPos) {
-    ObjPos = m_pPage->GetPageObjectList()->GetTailPosition();
-  }
-  CPDF_PageObject* pObj = m_pPage->GetPageObjectList()->GetPrevObject(ObjPos);
-  while (i < 5 && ObjPos) {
-    pObj = m_pPage->GetPageObjectList()->GetPrevObject(ObjPos);
-    if (pObj == pTextObj) {
+  while (i < 5 && iter != pObjList->begin()) {
+    --iter;
+    CPDF_PageObject* pOtherObj = iter->get();
+    if (pOtherObj == pTextObj || pOtherObj->m_Type != CPDF_PageObject::TEXT)
       continue;
-    }
-    if (pObj->m_Type != CPDF_PageObject::TEXT) {
-      continue;
-    }
-    if (IsSameTextObject((CPDF_TextObject*)pObj, pTextObj)) {
+    if (IsSameTextObject(static_cast<CPDF_TextObject*>(pOtherObj), pTextObj))
       return TRUE;
-    }
-    i++;
+    ++i;
   }
   return FALSE;
 }
diff --git a/core/src/fpdftext/text_int.h b/core/src/fpdftext/text_int.h
index 9b7d654930..113e1d1ac8 100644
--- a/core/src/fpdftext/text_int.h
+++ b/core/src/fpdftext/text_int.h
@@ -10,6 +10,7 @@
 #include <deque>
 #include <vector>
 
+#include "core/include/fpdfapi/fpdf_page.h"
 #include "core/include/fpdftext/fpdf_text.h"
 #include "core/include/fxcrt/fx_basic.h"
 
@@ -107,11 +108,14 @@ class CPDF_TextPage : public IPDF_TextPage {
   void ProcessTextObject(PDFTEXT_Obj pObj);
   void ProcessTextObject(CPDF_TextObject* pTextObj,
                          const CFX_Matrix& formMatrix,
-                         FX_POSITION ObjPos);
+                         const CPDF_PageObjectList* pObjList,
+                         CPDF_PageObjectList::const_iterator ObjPos);
   int ProcessInsertObject(const CPDF_TextObject* pObj,
                           const CFX_Matrix& formMatrix);
   FX_BOOL GenerateCharInfo(FX_WCHAR unicode, PAGECHAR_INFO& info);
-  FX_BOOL IsSameAsPreTextObject(CPDF_TextObject* pTextObj, FX_POSITION ObjPos);
+  FX_BOOL IsSameAsPreTextObject(CPDF_TextObject* pTextObj,
+                                const CPDF_PageObjectList* pObjList,
+                                CPDF_PageObjectList::const_iterator ObjPos);
   FX_BOOL IsSameTextObject(CPDF_TextObject* pTextObj1,
                            CPDF_TextObject* pTextObj2);
   int GetCharWidth(FX_DWORD charCode, CPDF_Font* pFont) const;
diff --git a/fpdfsdk/include/fxedit/fx_edit.h b/fpdfsdk/include/fxedit/fx_edit.h
index 359f7d85e1..5e1ac0f390 100644
--- a/fpdfsdk/include/fxedit/fx_edit.h
+++ b/fpdfsdk/include/fxedit/fx_edit.h
@@ -458,19 +458,19 @@ class IFX_Edit {
                            const CPDF_Point& ptOffset,
                            const CPVT_WordRange* pRange);
   static void GeneratePageObjects(
-      CPDF_PageObjectHolder* pPageObjects,
+      CPDF_PageObjectHolder* pObjectHolder,
       IFX_Edit* pEdit,
       const CPDF_Point& ptOffset,
       const CPVT_WordRange* pRange,
       FX_COLORREF crText,
       CFX_ArrayTemplate<CPDF_TextObject*>& ObjArray);
   static void GenerateRichPageObjects(
-      CPDF_PageObjectHolder* pPageObjects,
+      CPDF_PageObjectHolder* pObjectHolder,
       IFX_Edit* pEdit,
       const CPDF_Point& ptOffset,
       const CPVT_WordRange* pRange,
       CFX_ArrayTemplate<CPDF_TextObject*>& ObjArray);
-  static void GenerateUnderlineObjects(CPDF_PageObjectHolder* pPageObjects,
+  static void GenerateUnderlineObjects(CPDF_PageObjectHolder* pObjectHolder,
                                        IFX_Edit* pEdit,
                                        const CPDF_Point& ptOffset,
                                        const CPVT_WordRange* pRange,
diff --git a/fpdfsdk/include/pdfwindow/PWL_Edit.h b/fpdfsdk/include/pdfwindow/PWL_Edit.h
index 4b3411b772..73528180d9 100644
--- a/fpdfsdk/include/pdfwindow/PWL_Edit.h
+++ b/fpdfsdk/include/pdfwindow/PWL_Edit.h
@@ -110,10 +110,10 @@ class CPWL_Edit : public CPWL_EditCtrl, public IFX_Edit_OprNotify {
     m_pFillerNotify = pNotify;
   }
 
-  void GeneratePageObjects(CPDF_PageObjectHolder* pPageObjects,
+  void GeneratePageObjects(CPDF_PageObjectHolder* pObjectHolder,
                            const CPDF_Point& ptOffset,
                            CFX_ArrayTemplate<CPDF_TextObject*>& ObjArray);
-  void GeneratePageObjects(CPDF_PageObjectHolder* pPageObjects,
+  void GeneratePageObjects(CPDF_PageObjectHolder* pObjectHolder,
                            const CPDF_Point& ptOffset);
 
  protected:
diff --git a/fpdfsdk/src/fpdf_flatten.cpp b/fpdfsdk/src/fpdf_flatten.cpp
index 36b8319dca..9aee35f760 100644
--- a/fpdfsdk/src/fpdf_flatten.cpp
+++ b/fpdfsdk/src/fpdf_flatten.cpp
@@ -35,17 +35,14 @@ FX_BOOL IsValiableRect(CPDF_Rect rect, CPDF_Rect rcPage) {
   return TRUE;
 }
 
-FX_BOOL GetContentsRect(CPDF_Document* pDoc,
-                        CPDF_Dictionary* pDict,
-                        CPDF_RectArray* pRectArray) {
-  CPDF_Page* pPDFPage = new CPDF_Page;
+void GetContentsRect(CPDF_Document* pDoc,
+                     CPDF_Dictionary* pDict,
+                     CPDF_RectArray* pRectArray) {
+  std::unique_ptr<CPDF_Page> pPDFPage(new CPDF_Page);
   pPDFPage->Load(pDoc, pDict, FALSE);
   pPDFPage->ParseContent(nullptr);
 
-  FX_POSITION pos = pPDFPage->GetPageObjectList()->GetHeadPosition();
-  while (pos) {
-    CPDF_PageObject* pPageObject =
-        pPDFPage->GetPageObjectList()->GetNextObject(pos);
+  for (auto& pPageObject : *pPDFPage->GetPageObjectList()) {
     if (!pPageObject)
       continue;
 
@@ -54,14 +51,9 @@ FX_BOOL GetContentsRect(CPDF_Document* pDoc,
     rc.right = pPageObject->m_Right;
     rc.bottom = pPageObject->m_Bottom;
     rc.top = pPageObject->m_Top;
-
-    if (IsValiableRect(rc, pDict->GetRectBy("MediaBox"))) {
+    if (IsValiableRect(rc, pDict->GetRectBy("MediaBox")))
       pRectArray->Add(rc);
-    }
   }
-
-  delete pPDFPage;
-  return TRUE;
 }
 
 void ParserStream(CPDF_Dictionary* pPageDic,
diff --git a/fpdfsdk/src/fpdfeditpage.cpp b/fpdfsdk/src/fpdfeditpage.cpp
index 6d39cb100f..6c14079131 100644
--- a/fpdfsdk/src/fpdfeditpage.cpp
+++ b/fpdfsdk/src/fpdfeditpage.cpp
@@ -8,6 +8,7 @@
 
 #include "fpdfsdk/include/fsdk_define.h"
 #include "public/fpdf_formfill.h"
+#include "third_party/base/stl_util.h"
 
 #ifdef PDF_ENABLE_XFA
 #include "fpdfsdk/include/fpdfxfa/fpdfxfa_app.h"
@@ -135,9 +136,10 @@ DLLEXPORT void STDCALL FPDFPage_InsertObject(FPDF_PAGE page,
   CPDF_PageObject* pPageObj = (CPDF_PageObject*)page_obj;
   if (!pPageObj)
     return;
-  FX_POSITION LastPersition = pPage->GetPageObjectList()->GetTailPosition();
 
-  pPage->GetPageObjectList()->InsertObject(LastPersition, pPageObj);
+  pPage->GetPageObjectList()->push_back(
+      std::unique_ptr<CPDF_PageObject>(pPageObj));
+
   switch (pPageObj->m_Type) {
     case FPDF_PAGEOBJ_PATH: {
       CPDF_PathObject* pPathObj = (CPDF_PathObject*)pPageObj;
@@ -145,8 +147,6 @@ DLLEXPORT void STDCALL FPDFPage_InsertObject(FPDF_PAGE page,
       break;
     }
     case FPDF_PAGEOBJ_TEXT: {
-      //	CPDF_PathObject* pPathObj = (CPDF_PathObject*)pPageObj;
-      //	pPathObj->CalcBoundingBox();
       break;
     }
     case FPDF_PAGEOBJ_IMAGE: {
@@ -177,7 +177,7 @@ DLLEXPORT int STDCALL FPDFPage_CountObject(FPDF_PAGE page) {
           "Page")) {
     return -1;
   }
-  return pPage->GetPageObjectList()->GetCount();
+  return pdfium::CollectionSize<int>(*pPage->GetPageObjectList());
 }
 
 DLLEXPORT FPDF_PAGEOBJECT STDCALL FPDFPage_GetObject(FPDF_PAGE page,
@@ -186,9 +186,9 @@ DLLEXPORT FPDF_PAGEOBJECT STDCALL FPDFPage_GetObject(FPDF_PAGE page,
   if (!pPage || !pPage->m_pFormDict || !pPage->m_pFormDict->KeyExist("Type") ||
       pPage->m_pFormDict->GetElement("Type")->GetDirect()->GetString().Compare(
           "Page")) {
-    return NULL;
+    return nullptr;
   }
-  return pPage->GetPageObjectList()->GetObjectByIndex(index);
+  return pPage->GetPageObjectList()->GetPageObjectByIndex(index);
 }
 
 DLLEXPORT FPDF_BOOL STDCALL FPDFPage_HasTransparency(FPDF_PAGE page) {
diff --git a/fpdfsdk/src/fxedit/fxet_pageobjs.cpp b/fpdfsdk/src/fxedit/fxet_pageobjs.cpp
index d54e4649db..c3bd79759b 100644
--- a/fpdfsdk/src/fxedit/fxet_pageobjs.cpp
+++ b/fpdfsdk/src/fxedit/fxet_pageobjs.cpp
@@ -409,10 +409,10 @@ void IFX_Edit::DrawRichEdit(CFX_RenderDevice* pDevice,
   pDevice->RestoreState();
 }
 
-static void AddRectToPageObjects(CPDF_PageObjectHolder* pPageObjs,
+static void AddRectToPageObjects(CPDF_PageObjectHolder* pObjectHolder,
                                  FX_COLORREF crFill,
                                  const CPDF_Rect& rcFill) {
-  CPDF_PathObject* pPathObj = new CPDF_PathObject;
+  std::unique_ptr<CPDF_PathObject> pPathObj(new CPDF_PathObject);
   CPDF_PathData* pPathData = pPathObj->m_Path.GetModify();
   pPathData->AppendRect(rcFill.left, rcFill.bottom, rcFill.right, rcFill.top);
 
@@ -425,12 +425,11 @@ static void AddRectToPageObjects(CPDF_PageObjectHolder* pPageObjs,
 
   pPathObj->m_FillType = FXFILL_ALTERNATE;
   pPathObj->m_bStroke = FALSE;
-  pPageObjs->GetPageObjectList()->InsertObject(
-      pPageObjs->GetPageObjectList()->GetTailPosition(), pPathObj);
+  pObjectHolder->GetPageObjectList()->push_back(std::move(pPathObj));
 }
 
 static CPDF_TextObject* AddTextObjToPageObjects(
-    CPDF_PageObjectHolder* pPageObjs,
+    CPDF_PageObjectHolder* pObjectHolder,
     FX_COLORREF crText,
     CPDF_Font* pFont,
     FX_FLOAT fFontSize,
@@ -438,8 +437,7 @@ static CPDF_TextObject* AddTextObjToPageObjects(
     int32_t nHorzScale,
     const CPDF_Point& point,
     const CFX_ByteString& text) {
-  CPDF_TextObject* pTxtObj = new CPDF_TextObject;
-
+  std::unique_ptr<CPDF_TextObject> pTxtObj(new CPDF_TextObject);
   CPDF_TextStateData* pTextStateData = pTxtObj->m_TextState.GetModify();
   pTextStateData->m_pFont = pFont;
   pTextStateData->m_FontSize = fFontSize;
@@ -462,14 +460,14 @@ static CPDF_TextObject* AddTextObjToPageObjects(
 
   pTxtObj->SetPosition(point.x, point.y);
   pTxtObj->SetText(text);
-  pPageObjs->GetPageObjectList()->InsertObject(
-      pPageObjs->GetPageObjectList()->GetTailPosition(), pTxtObj);
 
-  return pTxtObj;
+  CPDF_TextObject* pRet = pTxtObj.get();
+  pObjectHolder->GetPageObjectList()->push_back(std::move(pTxtObj));
+  return pRet;
 }
 
 void IFX_Edit::GeneratePageObjects(
-    CPDF_PageObjectHolder* pPageObjects,
+    CPDF_PageObjectHolder* pObjectHolder,
     IFX_Edit* pEdit,
     const CPDF_Point& ptOffset,
     const CPVT_WordRange* pRange,
@@ -504,7 +502,7 @@ void IFX_Edit::GeneratePageObjects(
               nOldFontIndex != word.nFontIndex) {
             if (sTextBuf.GetLength() > 0) {
               ObjArray.Add(AddTextObjToPageObjects(
-                  pPageObjects, crText, pFontMap->GetPDFFont(nOldFontIndex),
+                  pObjectHolder, crText, pFontMap->GetPDFFont(nOldFontIndex),
                   fFontSize, 0.0f, 100,
                   CPDF_Point(ptBT.x + ptOffset.x, ptBT.y + ptOffset.y),
                   sTextBuf.GetByteString()));
@@ -523,7 +521,7 @@ void IFX_Edit::GeneratePageObjects(
 
       if (sTextBuf.GetLength() > 0) {
         ObjArray.Add(AddTextObjToPageObjects(
-            pPageObjects, crText, pFontMap->GetPDFFont(nOldFontIndex),
+            pObjectHolder, crText, pFontMap->GetPDFFont(nOldFontIndex),
             fFontSize, 0.0f, 100,
             CPDF_Point(ptBT.x + ptOffset.x, ptBT.y + ptOffset.y),
             sTextBuf.GetByteString()));
@@ -533,7 +531,7 @@ void IFX_Edit::GeneratePageObjects(
 }
 
 void IFX_Edit::GenerateRichPageObjects(
-    CPDF_PageObjectHolder* pPageObjects,
+    CPDF_PageObjectHolder* pObjectHolder,
     IFX_Edit* pEdit,
     const CPDF_Point& ptOffset,
     const CPVT_WordRange* pRange,
@@ -574,7 +572,7 @@ void IFX_Edit::GenerateRichPageObjects(
               crOld != crCurText) {
             if (sTextBuf.GetLength() > 0) {
               ObjArray.Add(AddTextObjToPageObjects(
-                  pPageObjects, crOld, pFontMap->GetPDFFont(wp.nFontIndex),
+                  pObjectHolder, crOld, pFontMap->GetPDFFont(wp.nFontIndex),
                   wp.fFontSize, wp.fCharSpace, wp.nHorzScale,
                   CPDF_Point(ptBT.x + ptOffset.x, ptBT.y + ptOffset.y),
                   sTextBuf.GetByteString()));
@@ -597,7 +595,7 @@ void IFX_Edit::GenerateRichPageObjects(
             rcUnderline.top += ptOffset.y;
             rcUnderline.bottom += ptOffset.y;
 
-            AddRectToPageObjects(pPageObjects, crCurText, rcUnderline);
+            AddRectToPageObjects(pObjectHolder, crCurText, rcUnderline);
           }
 
           if (word.WordProps.nWordStyle & PVTWORD_STYLE_CROSSOUT) {
@@ -607,7 +605,7 @@ void IFX_Edit::GenerateRichPageObjects(
             rcCrossout.top += ptOffset.y;
             rcCrossout.bottom += ptOffset.y;
 
-            AddRectToPageObjects(pPageObjects, crCurText, rcCrossout);
+            AddRectToPageObjects(pObjectHolder, crCurText, rcCrossout);
           }
 
           oldplace = place;
@@ -616,7 +614,7 @@ void IFX_Edit::GenerateRichPageObjects(
 
       if (sTextBuf.GetLength() > 0) {
         ObjArray.Add(AddTextObjToPageObjects(
-            pPageObjects, crOld, pFontMap->GetPDFFont(wp.nFontIndex),
+            pObjectHolder, crOld, pFontMap->GetPDFFont(wp.nFontIndex),
             wp.fFontSize, wp.fCharSpace, wp.nHorzScale,
             CPDF_Point(ptBT.x + ptOffset.x, ptBT.y + ptOffset.y),
             sTextBuf.GetByteString()));
@@ -625,7 +623,7 @@ void IFX_Edit::GenerateRichPageObjects(
   }
 }
 
-void IFX_Edit::GenerateUnderlineObjects(CPDF_PageObjectHolder* pPageObjects,
+void IFX_Edit::GenerateUnderlineObjects(CPDF_PageObjectHolder* pObjectHolder,
                                         IFX_Edit* pEdit,
                                         const CPDF_Point& ptOffset,
                                         const CPVT_WordRange* pRange,
@@ -651,7 +649,7 @@ void IFX_Edit::GenerateUnderlineObjects(CPDF_PageObjectHolder* pPageObjects,
           rcUnderline.right += ptOffset.x;
           rcUnderline.top += ptOffset.y;
           rcUnderline.bottom += ptOffset.y;
-          AddRectToPageObjects(pPageObjects, color, rcUnderline);
+          AddRectToPageObjects(pObjectHolder, color, rcUnderline);
         }
       }
     }
diff --git a/fpdfsdk/src/javascript/Document.cpp b/fpdfsdk/src/javascript/Document.cpp
index c2638d012d..733384a154 100644
--- a/fpdfsdk/src/javascript/Document.cpp
+++ b/fpdfsdk/src/javascript/Document.cpp
@@ -1382,20 +1382,15 @@ FX_BOOL Document::getPageNthWord(IJS_Context* cc,
 
   int nWords = 0;
   CFX_WideString swRet;
-  FX_POSITION pos = page.GetPageObjectList()->GetHeadPosition();
-  while (pos) {
-    if (CPDF_PageObject* pPageObj =
-            page.GetPageObjectList()->GetNextObject(pos)) {
-      if (pPageObj->m_Type == CPDF_PageObject::TEXT) {
-        int nObjWords = CountWords((CPDF_TextObject*)pPageObj);
-
-        if (nWords + nObjWords >= nWordNo) {
-          swRet = GetObjWordStr((CPDF_TextObject*)pPageObj, nWordNo - nWords);
-          break;
-        }
-
-        nWords += nObjWords;
+  for (auto& pPageObj : *page.GetPageObjectList()) {
+    if (pPageObj->m_Type == CPDF_PageObject::TEXT) {
+      CPDF_TextObject* pTextObj = static_cast<CPDF_TextObject*>(pPageObj.get());
+      int nObjWords = CountWords(pTextObj);
+      if (nWords + nObjWords >= nWordNo) {
+        swRet = GetObjWordStr(pTextObj, nWordNo - nWords);
+        break;
       }
+      nWords += nObjWords;
     }
   }
 
@@ -1442,15 +1437,9 @@ FX_BOOL Document::getPageNumWords(IJS_Context* cc,
   page.ParseContent(nullptr);
 
   int nWords = 0;
-  FX_POSITION pos = page.GetPageObjectList()->GetHeadPosition();
-  while (pos) {
-    if (CPDF_PageObject* pPageObj =
-            page.GetPageObjectList()->GetNextObject(pos)) {
-      if (pPageObj->m_Type == CPDF_PageObject::TEXT) {
-        CPDF_TextObject* pTextObj = (CPDF_TextObject*)pPageObj;
-        nWords += CountWords(pTextObj);
-      }
-    }
+  for (auto& pPageObj : *page.GetPageObjectList()) {
+    if (pPageObj->m_Type == CPDF_PageObject::TEXT)
+      nWords += CountWords(static_cast<CPDF_TextObject*>(pPageObj.get()));
   }
 
   vRet = nWords;
diff --git a/fpdfsdk/src/pdfwindow/PWL_Edit.cpp b/fpdfsdk/src/pdfwindow/PWL_Edit.cpp
index 4b3886a11d..ce9274aeb9 100644
--- a/fpdfsdk/src/pdfwindow/PWL_Edit.cpp
+++ b/fpdfsdk/src/pdfwindow/PWL_Edit.cpp
@@ -1166,20 +1166,20 @@ CPVT_WordRange CPWL_Edit::GetSameWordsRange(const CPVT_WordPlace& place,
 }
 
 void CPWL_Edit::GeneratePageObjects(
-    CPDF_PageObjectHolder* pPageObjects,
+    CPDF_PageObjectHolder* pObjectHolder,
     const CPDF_Point& ptOffset,
     CFX_ArrayTemplate<CPDF_TextObject*>& ObjArray) {
   IFX_Edit::GeneratePageObjects(
-      pPageObjects, m_pEdit, ptOffset, NULL,
+      pObjectHolder, m_pEdit, ptOffset, NULL,
       CPWL_Utils::PWLColorToFXColor(GetTextColor(), GetTransparency()),
       ObjArray);
 }
 
-void CPWL_Edit::GeneratePageObjects(CPDF_PageObjectHolder* pPageObjects,
+void CPWL_Edit::GeneratePageObjects(CPDF_PageObjectHolder* pObjectHolder,
                                     const CPDF_Point& ptOffset) {
   CFX_ArrayTemplate<CPDF_TextObject*> ObjArray;
   IFX_Edit::GeneratePageObjects(
-      pPageObjects, m_pEdit, ptOffset, NULL,
+      pObjectHolder, m_pEdit, ptOffset, NULL,
       CPWL_Utils::PWLColorToFXColor(GetTextColor(), GetTransparency()),
       ObjArray);
 }