1 files changed, 290 insertions, 271 deletions

diff --git a/core/fpdfapi/parser/cpdf_data_avail.cpp b/core/fpdfapi/parser/cpdf_data_avail.cpp
index 457ae61c4..7db348a8d 100644
--- a/core/fpdfapi/parser/cpdf_data_avail.cpp
+++ b/core/fpdfapi/parser/cpdf_data_avail.cpp
@@ -1,4 +1,4 @@
-// Copyright 2016 PDFium Authors. All rights reserved.
+// Copyright 2016 The PDFium Authors
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -24,32 +24,31 @@
 #include "core/fpdfapi/parser/cpdf_stream.h"
 #include "core/fpdfapi/parser/cpdf_syntax_parser.h"
 #include "core/fpdfapi/parser/fpdf_parser_utility.h"
+#include "core/fxcrt/autorestorer.h"
 #include "core/fxcrt/fx_extension.h"
 #include "core/fxcrt/fx_safe_types.h"
-#include "third_party/base/compiler_specific.h"
+#include "core/fxcrt/stl_util.h"
+#include "third_party/base/check.h"
+#include "third_party/base/containers/contains.h"
+#include "third_party/base/notreached.h"
 #include "third_party/base/numerics/safe_conversions.h"
-#include "third_party/base/ptr_util.h"
-#include "third_party/base/stl_util.h"
 
 namespace {
 
-// static
-CPDF_Object* GetResourceObject(CPDF_Dictionary* pDict) {
+RetainPtr<CPDF_Object> GetResourceObject(RetainPtr<CPDF_Dictionary> pDict) {
   constexpr size_t kMaxHierarchyDepth = 64;
   size_t depth = 0;
 
-  CPDF_Dictionary* dictionary_to_check = pDict;
-  while (dictionary_to_check) {
-    CPDF_Object* result = dictionary_to_check->GetObjectFor("Resources");
+  while (pDict) {
+    RetainPtr<CPDF_Object> result = pDict->GetMutableObjectFor("Resources");
     if (result)
       return result;
-    CPDF_Object* parent = dictionary_to_check->GetObjectFor("Parent");
-    dictionary_to_check = parent ? parent->GetDict() : nullptr;
-
     if (++depth > kMaxHierarchyDepth) {
       // We have cycle in parents hierarchy.
       return nullptr;
     }
+    RetainPtr<CPDF_Object> parent = pDict->GetMutableObjectFor("Parent");
+    pDict = parent ? parent->GetMutableDict() : nullptr;
   }
   return nullptr;
 }
@@ -59,7 +58,7 @@ class HintsScope {
   HintsScope(RetainPtr<CPDF_ReadValidator> validator,
              CPDF_DataAvail::DownloadHints* hints)
       : validator_(std::move(validator)) {
-    ASSERT(validator_);
+    DCHECK(validator_);
     validator_->SetDownloadHints(hints);
   }
 
@@ -71,18 +70,15 @@ class HintsScope {
 
 }  // namespace
 
-CPDF_DataAvail::FileAvail::~FileAvail() {}
+CPDF_DataAvail::FileAvail::~FileAvail() = default;
 
-CPDF_DataAvail::DownloadHints::~DownloadHints() {}
+CPDF_DataAvail::DownloadHints::~DownloadHints() = default;
 
-CPDF_DataAvail::CPDF_DataAvail(
-    FileAvail* pFileAvail,
-    const RetainPtr<IFX_SeekableReadStream>& pFileRead,
-    bool bSupportHintTable)
-    : m_pFileRead(
-          pdfium::MakeRetain<CPDF_ReadValidator>(pFileRead, pFileAvail)),
-      m_dwFileLen(m_pFileRead->GetSize()),
-      m_bSupportHintTable(bSupportHintTable) {}
+CPDF_DataAvail::CPDF_DataAvail(FileAvail* pFileAvail,
+                               RetainPtr<IFX_SeekableReadStream> pFileRead)
+    : m_pFileRead(pdfium::MakeRetain<CPDF_ReadValidator>(std::move(pFileRead),
+                                                         pFileAvail)),
+      m_dwFileLen(m_pFileRead->GetSize()) {}
 
 CPDF_DataAvail::~CPDF_DataAvail() {
   m_pHintTables.reset();
@@ -101,47 +97,49 @@ void CPDF_DataAvail::OnObservableDestroyed() {
 CPDF_DataAvail::DocAvailStatus CPDF_DataAvail::IsDocAvail(
     DownloadHints* pHints) {
   if (!m_dwFileLen)
-    return DataError;
+    return kDataError;
 
+  DCHECK(m_SeenPageObjList.empty());
+  AutoRestorer<std::set<uint32_t>> seen_objects_restorer(&m_SeenPageObjList);
   const HintsScope hints_scope(GetValidator(), pHints);
   while (!m_bDocAvail) {
     if (!CheckDocStatus())
-      return DataNotAvailable;
+      return kDataNotAvailable;
   }
 
-  return DataAvailable;
+  return kDataAvailable;
 }
 
 bool CPDF_DataAvail::CheckDocStatus() {
-  switch (m_docStatus) {
-    case PDF_DATAAVAIL_HEADER:
+  switch (m_internalStatus) {
+    case InternalStatus::kHeader:
       return CheckHeader();
-    case PDF_DATAAVAIL_FIRSTPAGE:
+    case InternalStatus::kFirstPage:
       return CheckFirstPage();
-    case PDF_DATAAVAIL_HINTTABLE:
+    case InternalStatus::kHintTable:
       return CheckHintTables();
-    case PDF_DATAAVAIL_LOADALLCROSSREF:
+    case InternalStatus::kLoadAllCrossRef:
       return CheckAndLoadAllXref();
-    case PDF_DATAAVAIL_LOADALLFILE:
+    case InternalStatus::kLoadAllFile:
       return LoadAllFile();
-    case PDF_DATAAVAIL_ROOT:
+    case InternalStatus::kRoot:
       return CheckRoot();
-    case PDF_DATAAVAIL_INFO:
+    case InternalStatus::kInfo:
       return CheckInfo();
-    case PDF_DATAAVAIL_PAGETREE:
+    case InternalStatus::kPageTree:
       if (m_bTotalLoadPageTree)
         return CheckPages();
       return LoadDocPages();
-    case PDF_DATAAVAIL_PAGE:
+    case InternalStatus::kPage:
       if (m_bTotalLoadPageTree)
         return CheckPage();
-      m_docStatus = PDF_DATAAVAIL_PAGE_LATERLOAD;
+      m_internalStatus = InternalStatus::kPageLaterLoad;
       return true;
-    case PDF_DATAAVAIL_ERROR:
+    case InternalStatus::kError:
       return LoadAllFile();
-    case PDF_DATAAVAIL_PAGE_LATERLOAD:
-      m_docStatus = PDF_DATAAVAIL_PAGE;
-      FALLTHROUGH;
+    case InternalStatus::kPageLaterLoad:
+      m_internalStatus = InternalStatus::kPage;
+      [[fallthrough]];
     default:
       m_bDocAvail = true;
       return true;
@@ -149,12 +147,12 @@ bool CPDF_DataAvail::CheckDocStatus() {
 }
 
 bool CPDF_DataAvail::CheckPageStatus() {
-  switch (m_docStatus) {
-    case PDF_DATAAVAIL_PAGETREE:
+  switch (m_internalStatus) {
+    case InternalStatus::kPageTree:
       return CheckPages();
-    case PDF_DATAAVAIL_PAGE:
+    case InternalStatus::kPage:
       return CheckPage();
-    case PDF_DATAAVAIL_ERROR:
+    case InternalStatus::kError:
       return LoadAllFile();
     default:
       m_bPagesTreeLoad = true;
@@ -165,7 +163,7 @@ bool CPDF_DataAvail::CheckPageStatus() {
 
 bool CPDF_DataAvail::LoadAllFile() {
   if (GetValidator()->CheckWholeFileAndRequestIfUnavailable()) {
-    m_docStatus = PDF_DATAAVAIL_DONE;
+    m_internalStatus = InternalStatus::kDone;
     return true;
   }
   return false;
@@ -173,27 +171,27 @@ bool CPDF_DataAvail::LoadAllFile() {
 
 bool CPDF_DataAvail::CheckAndLoadAllXref() {
   if (!m_pCrossRefAvail) {
-    const CPDF_ReadValidator::Session read_session(GetValidator());
+    CPDF_ReadValidator::ScopedSession read_session(GetValidator());
     const FX_FILESIZE last_xref_offset = m_parser.ParseStartXRef();
     if (GetValidator()->has_read_problems())
       return false;
 
     if (last_xref_offset <= 0) {
-      m_docStatus = PDF_DATAAVAIL_ERROR;
+      m_internalStatus = InternalStatus::kError;
       return false;
     }
 
-    m_pCrossRefAvail = pdfium::MakeUnique<CPDF_CrossRefAvail>(GetSyntaxParser(),
-                                                              last_xref_offset);
+    m_pCrossRefAvail = std::make_unique<CPDF_CrossRefAvail>(GetSyntaxParser(),
+                                                            last_xref_offset);
   }
 
   switch (m_pCrossRefAvail->CheckAvail()) {
-    case DocAvailStatus::DataAvailable:
+    case kDataAvailable:
       break;
-    case DocAvailStatus::DataNotAvailable:
+    case kDataNotAvailable:
       return false;
-    case DocAvailStatus::DataError:
-      m_docStatus = PDF_DATAAVAIL_ERROR;
+    case kDataError:
+      m_internalStatus = InternalStatus::kError;
       return false;
     default:
       NOTREACHED();
@@ -202,33 +200,29 @@ bool CPDF_DataAvail::CheckAndLoadAllXref() {
 
   if (!m_parser.LoadAllCrossRefV4(m_pCrossRefAvail->last_crossref_offset()) &&
       !m_parser.LoadAllCrossRefV5(m_pCrossRefAvail->last_crossref_offset())) {
-    m_docStatus = PDF_DATAAVAIL_LOADALLFILE;
+    m_internalStatus = InternalStatus::kLoadAllFile;
     return false;
   }
 
-  m_docStatus = PDF_DATAAVAIL_ROOT;
+  m_internalStatus = InternalStatus::kRoot;
   return true;
 }
 
 RetainPtr<CPDF_Object> CPDF_DataAvail::GetObject(uint32_t objnum,
                                                  bool* pExistInFile) {
-  CPDF_Parser* pParser = nullptr;
-
-  if (pExistInFile)
-    *pExistInFile = true;
-
-  pParser = m_pDocument ? m_pDocument->GetParser() : &m_parser;
+  *pExistInFile = false;
+  CPDF_Parser* pParser = m_pDocument ? m_pDocument->GetParser() : &m_parser;
+  if (!pParser)
+    return nullptr;
 
-  RetainPtr<CPDF_Object> pRet;
-  if (pParser) {
-    const CPDF_ReadValidator::Session read_session(GetValidator());
-    pRet = pParser->ParseIndirectObject(objnum);
-    if (GetValidator()->has_read_problems())
-      return nullptr;
-  }
+  CPDF_ReadValidator::ScopedSession read_session(GetValidator());
+  RetainPtr<CPDF_Object> pRet = pParser->ParseIndirectObject(objnum);
+  if (!pRet)
+    return nullptr;
 
-  if (!pRet && pExistInFile)
-    *pExistInFile = false;
+  *pExistInFile = true;
+  if (GetValidator()->has_read_problems())
+    return nullptr;
 
   return pRet;
 }
@@ -236,54 +230,64 @@ RetainPtr<CPDF_Object> CPDF_DataAvail::GetObject(uint32_t objnum,
 bool CPDF_DataAvail::CheckInfo() {
   const uint32_t dwInfoObjNum = m_parser.GetInfoObjNum();
   if (dwInfoObjNum == CPDF_Object::kInvalidObjNum) {
-    m_docStatus = PDF_DATAAVAIL_PAGETREE;
+    m_internalStatus = InternalStatus::kPageTree;
     return true;
   }
 
-  const CPDF_ReadValidator::Session read_session(GetValidator());
+  CPDF_ReadValidator::ScopedSession read_session(GetValidator());
   m_parser.ParseIndirectObject(dwInfoObjNum);
   if (GetValidator()->has_read_problems())
     return false;
 
-  m_docStatus = PDF_DATAAVAIL_PAGETREE;
+  m_internalStatus = InternalStatus::kPageTree;
   return true;
 }
 
 bool CPDF_DataAvail::CheckRoot() {
   const uint32_t dwRootObjNum = m_parser.GetRootObjNum();
   if (dwRootObjNum == CPDF_Object::kInvalidObjNum) {
-    m_docStatus = PDF_DATAAVAIL_ERROR;
+    m_internalStatus = InternalStatus::kError;
     return true;
   }
 
-  const CPDF_ReadValidator::Session read_session(GetValidator());
+  CPDF_ReadValidator::ScopedSession read_session(GetValidator());
   m_pRoot = ToDictionary(m_parser.ParseIndirectObject(dwRootObjNum));
   if (GetValidator()->has_read_problems())
     return false;
 
-  const CPDF_Reference* pRef =
-      ToReference(m_pRoot ? m_pRoot->GetObjectFor("Pages") : nullptr);
+  if (!m_pRoot) {
+    m_internalStatus = InternalStatus::kError;
+    return false;
+  }
+
+  RetainPtr<const CPDF_Reference> pRef =
+      ToReference(m_pRoot->GetObjectFor("Pages"));
   if (!pRef) {
-    m_docStatus = PDF_DATAAVAIL_ERROR;
+    m_internalStatus = InternalStatus::kError;
     return false;
   }
 
   m_PagesObjNum = pRef->GetRefObjNum();
-  m_docStatus = PDF_DATAAVAIL_INFO;
+  m_internalStatus = InternalStatus::kInfo;
   return true;
 }
 
 bool CPDF_DataAvail::PreparePageItem() {
   const CPDF_Dictionary* pRoot = m_pDocument->GetRoot();
-  const CPDF_Reference* pRef =
-      ToReference(pRoot ? pRoot->GetObjectFor("Pages") : nullptr);
+  if (!pRoot) {
+    m_internalStatus = InternalStatus::kError;
+    return false;
+  }
+
+  RetainPtr<const CPDF_Reference> pRef =
+      ToReference(pRoot->GetObjectFor("Pages"));
   if (!pRef) {
-    m_docStatus = PDF_DATAAVAIL_ERROR;
+    m_internalStatus = InternalStatus::kError;
     return false;
   }
 
   m_PagesObjNum = pRef->GetRefObjNum();
-  m_docStatus = PDF_DATAAVAIL_PAGETREE;
+  m_internalStatus = InternalStatus::kPageTree;
   return true;
 }
 
@@ -305,21 +309,23 @@ bool CPDF_DataAvail::CheckPage() {
         UnavailObjList.push_back(dwPageObjNum);
       continue;
     }
-    CPDF_Array* pArray = ToArray(pObj.Get());
-    if (pArray) {
-      CPDF_ArrayLocker locker(pArray);
-      for (const auto& pArrayObj : locker) {
-        if (CPDF_Reference* pRef = ToReference(pArrayObj.Get()))
-          UnavailObjList.push_back(pRef->GetRefObjNum());
-      }
-    }
-    if (!pObj->IsDictionary())
-      continue;
 
-    ByteString type = pObj->GetDict()->GetStringFor("Type");
-    if (type == "Pages") {
-      m_PagesArray.push_back(std::move(pObj));
-      continue;
+    switch (pObj->GetType()) {
+      case CPDF_Object::kArray: {
+        CPDF_ArrayLocker locker(pObj->AsArray());
+        for (const auto& pArrayObj : locker) {
+          const CPDF_Reference* pRef = ToReference(pArrayObj.Get());
+          if (pRef)
+            UnavailObjList.push_back(pRef->GetRefObjNum());
+        }
+        break;
+      }
+      case CPDF_Object::kDictionary:
+        if (pObj->GetDict()->GetNameFor("Type") == "Pages")
+          m_PagesArray.push_back(std::move(pObj));
+        break;
+      default:
+        break;
     }
   }
   m_PageObjList.clear();
@@ -332,39 +338,50 @@ bool CPDF_DataAvail::CheckPage() {
     RetainPtr<CPDF_Object> pPages = std::move(m_PagesArray[i]);
     if (pPages && !GetPageKids(pPages.Get())) {
       m_PagesArray.clear();
-      m_docStatus = PDF_DATAAVAIL_ERROR;
+      m_internalStatus = InternalStatus::kError;
       return false;
     }
   }
   m_PagesArray.clear();
   if (m_PageObjList.empty())
-    m_docStatus = PDF_DATAAVAIL_DONE;
+    m_internalStatus = InternalStatus::kDone;
 
   return true;
 }
 
 bool CPDF_DataAvail::GetPageKids(CPDF_Object* pPages) {
-  CPDF_Dictionary* pDict = pPages->GetDict();
-  CPDF_Object* pKids = pDict ? pDict->GetObjectFor("Kids") : nullptr;
+  RetainPtr<const CPDF_Dictionary> pDict = pPages->GetDict();
+  if (!pDict)
+    return true;
+
+  RetainPtr<const CPDF_Object> pKids = pDict->GetObjectFor("Kids");
   if (!pKids)
     return true;
 
+  std::vector<uint32_t> object_numbers;
   switch (pKids->GetType()) {
     case CPDF_Object::kReference:
-      m_PageObjList.push_back(pKids->AsReference()->GetRefObjNum());
+      object_numbers.push_back(pKids->AsReference()->GetRefObjNum());
       break;
     case CPDF_Object::kArray: {
-      CPDF_Array* pKidsArray = pKids->AsArray();
-      for (size_t i = 0; i < pKidsArray->size(); ++i) {
-        if (CPDF_Reference* pRef = ToReference(pKidsArray->GetObjectAt(i)))
-          m_PageObjList.push_back(pRef->GetRefObjNum());
+      CPDF_ArrayLocker locker(pKids->AsArray());
+      for (const auto& pArrayObj : locker) {
+        const CPDF_Reference* pRef = ToReference(pArrayObj.Get());
+        if (pRef)
+          object_numbers.push_back(pRef->GetRefObjNum());
       }
       break;
     }
     default:
-      m_docStatus = PDF_DATAAVAIL_ERROR;
+      m_internalStatus = InternalStatus::kError;
       return false;
   }
+
+  for (uint32_t num : object_numbers) {
+    bool inserted = m_SeenPageObjList.insert(num).second;
+    if (inserted)
+      m_PageObjList.push_back(num);
+  }
   return true;
 }
 
@@ -372,37 +389,37 @@ bool CPDF_DataAvail::CheckPages() {
   bool bExists = false;
   RetainPtr<CPDF_Object> pPages = GetObject(m_PagesObjNum, &bExists);
   if (!bExists) {
-    m_docStatus = PDF_DATAAVAIL_LOADALLFILE;
+    m_internalStatus = InternalStatus::kLoadAllFile;
     return true;
   }
 
   if (!pPages) {
-    if (m_docStatus == PDF_DATAAVAIL_ERROR) {
-      m_docStatus = PDF_DATAAVAIL_LOADALLFILE;
+    if (m_internalStatus == InternalStatus::kError) {
+      m_internalStatus = InternalStatus::kLoadAllFile;
       return true;
     }
     return false;
   }
 
   if (!GetPageKids(pPages.Get())) {
-    m_docStatus = PDF_DATAAVAIL_ERROR;
+    m_internalStatus = InternalStatus::kError;
     return false;
   }
 
-  m_docStatus = PDF_DATAAVAIL_PAGE;
+  m_internalStatus = InternalStatus::kPage;
   return true;
 }
 
 bool CPDF_DataAvail::CheckHeader() {
   switch (CheckHeaderAndLinearized()) {
-    case DocAvailStatus::DataAvailable:
-      m_docStatus = m_pLinearized ? PDF_DATAAVAIL_FIRSTPAGE
-                                  : PDF_DATAAVAIL_LOADALLCROSSREF;
+    case kDataAvailable:
+      m_internalStatus = m_pLinearized ? InternalStatus::kFirstPage
+                                       : InternalStatus::kLoadAllCrossRef;
       return true;
-    case DocAvailStatus::DataNotAvailable:
+    case kDataNotAvailable:
       return false;
-    case DocAvailStatus::DataError:
-      m_docStatus = PDF_DATAAVAIL_ERROR;
+    case kDataError:
+      m_internalStatus = InternalStatus::kError;
       return true;
     default:
       NOTREACHED();
@@ -414,7 +431,7 @@ bool CPDF_DataAvail::CheckFirstPage() {
   if (!m_pLinearized->GetFirstPageEndOffset() ||
       !m_pLinearized->GetFileSize() ||
       !m_pLinearized->GetMainXRefTableFirstEntryOffset()) {
-    m_docStatus = PDF_DATAAVAIL_ERROR;
+    m_internalStatus = InternalStatus::kError;
     return false;
   }
 
@@ -429,24 +446,23 @@ bool CPDF_DataAvail::CheckFirstPage() {
                                                              data_size))
     return false;
 
-  m_docStatus =
-      m_bSupportHintTable ? PDF_DATAAVAIL_HINTTABLE : PDF_DATAAVAIL_DONE;
+  m_internalStatus = InternalStatus::kHintTable;
   return true;
 }
 
 bool CPDF_DataAvail::CheckHintTables() {
-  const CPDF_ReadValidator::Session read_session(GetValidator());
+  CPDF_ReadValidator::ScopedSession read_session(GetValidator());
   m_pHintTables =
       CPDF_HintTables::Parse(GetSyntaxParser(), m_pLinearized.get());
 
   if (GetValidator()->read_error()) {
-    m_docStatus = PDF_DATAAVAIL_ERROR;
+    m_internalStatus = InternalStatus::kError;
     return true;
   }
   if (GetValidator()->has_unavailable_data())
     return false;
 
-  m_docStatus = PDF_DATAAVAIL_DONE;
+  m_internalStatus = InternalStatus::kDone;
   return true;
 }
 
@@ -466,59 +482,59 @@ RetainPtr<CPDF_Object> CPDF_DataAvail::ParseIndirectObjectAt(
 
 CPDF_DataAvail::DocLinearizationStatus CPDF_DataAvail::IsLinearizedPDF() {
   switch (CheckHeaderAndLinearized()) {
-    case DocAvailStatus::DataAvailable:
-      return m_pLinearized ? DocLinearizationStatus::Linearized
-                           : DocLinearizationStatus::NotLinearized;
-    case DocAvailStatus::DataNotAvailable:
-      return DocLinearizationStatus::LinearizationUnknown;
-    case DocAvailStatus::DataError:
-      return DocLinearizationStatus::NotLinearized;
+    case kDataAvailable:
+      return m_pLinearized ? kLinearized : kNotLinearized;
+    case kDataNotAvailable:
+      return kLinearizationUnknown;
+    case kDataError:
+      return kNotLinearized;
     default:
       NOTREACHED();
-      return DocLinearizationStatus::LinearizationUnknown;
+      return kLinearizationUnknown;
   }
 }
 
 CPDF_DataAvail::DocAvailStatus CPDF_DataAvail::CheckHeaderAndLinearized() {
   if (m_bHeaderAvail)
-    return DocAvailStatus::DataAvailable;
+    return kDataAvailable;
 
-  const CPDF_ReadValidator::Session read_session(GetValidator());
-  const Optional<FX_FILESIZE> header_offset = GetHeaderOffset(GetValidator());
+  CPDF_ReadValidator::ScopedSession read_session(GetValidator());
+  const absl::optional<FX_FILESIZE> header_offset =
+      GetHeaderOffset(GetValidator());
   if (GetValidator()->has_read_problems())
-    return DocAvailStatus::DataNotAvailable;
+    return kDataNotAvailable;
 
-  if (!header_offset)
-    return DocAvailStatus::DataError;
+  if (!header_offset.has_value())
+    return kDataError;
 
-  m_parser.m_pSyntax =
-      pdfium::MakeUnique<CPDF_SyntaxParser>(GetValidator(), *header_offset);
+  m_parser.m_pSyntax = std::make_unique<CPDF_SyntaxParser>(
+      GetValidator(), header_offset.value());
   m_pLinearized = m_parser.ParseLinearizedHeader();
   if (GetValidator()->has_read_problems())
-    return DocAvailStatus::DataNotAvailable;
+    return kDataNotAvailable;
 
   m_bHeaderAvail = true;
-  return DocAvailStatus::DataAvailable;
+  return kDataAvailable;
 }
 
 bool CPDF_DataAvail::CheckPage(uint32_t dwPage) {
   while (true) {
-    switch (m_docStatus) {
-      case PDF_DATAAVAIL_PAGETREE:
+    switch (m_internalStatus) {
+      case InternalStatus::kPageTree:
         if (!LoadDocPages())
           return false;
         break;
-      case PDF_DATAAVAIL_PAGE:
+      case InternalStatus::kPage:
         if (!LoadDocPage(dwPage))
           return false;
         break;
-      case PDF_DATAAVAIL_ERROR:
+      case InternalStatus::kError:
         return LoadAllFile();
       default:
         m_bPagesTreeLoad = true;
         m_bPagesLoad = true;
         m_bCurPageDictLoadOK = true;
-        m_docStatus = PDF_DATAAVAIL_PAGE;
+        m_internalStatus = InternalStatus::kPage;
         return true;
     }
   }
@@ -529,26 +545,26 @@ bool CPDF_DataAvail::CheckArrayPageNode(uint32_t dwPageNo,
   bool bExists = false;
   RetainPtr<CPDF_Object> pPages = GetObject(dwPageNo, &bExists);
   if (!bExists) {
-    m_docStatus = PDF_DATAAVAIL_ERROR;
+    m_internalStatus = InternalStatus::kError;
     return false;
   }
 
   if (!pPages)
     return false;
 
-  CPDF_Array* pArray = pPages->AsArray();
+  const CPDF_Array* pArray = pPages->AsArray();
   if (!pArray) {
-    m_docStatus = PDF_DATAAVAIL_ERROR;
+    m_internalStatus = InternalStatus::kError;
     return false;
   }
 
-  pPageNode->m_type = PDF_PAGENODE_PAGES;
+  pPageNode->m_type = PageNode::Type::kPages;
   for (size_t i = 0; i < pArray->size(); ++i) {
-    CPDF_Reference* pKid = ToReference(pArray->GetObjectAt(i));
+    RetainPtr<const CPDF_Reference> pKid = ToReference(pArray->GetObjectAt(i));
     if (!pKid)
       continue;
 
-    auto pNode = pdfium::MakeUnique<PageNode>();
+    auto pNode = std::make_unique<PageNode>();
     pNode->m_dwPageNo = pKid->GetRefObjNum();
     pPageNode->m_ChildNodes.push_back(std::move(pNode));
   }
@@ -560,7 +576,7 @@ bool CPDF_DataAvail::CheckUnknownPageNode(uint32_t dwPageNo,
   bool bExists = false;
   RetainPtr<CPDF_Object> pPage = GetObject(dwPageNo, &bExists);
   if (!bExists) {
-    m_docStatus = PDF_DATAAVAIL_ERROR;
+    m_internalStatus = InternalStatus::kError;
     return false;
   }
 
@@ -569,51 +585,52 @@ bool CPDF_DataAvail::CheckUnknownPageNode(uint32_t dwPageNo,
 
   if (pPage->IsArray()) {
     pPageNode->m_dwPageNo = dwPageNo;
-    pPageNode->m_type = PDF_PAGENODE_ARRAY;
+    pPageNode->m_type = PageNode::Type::kArray;
     return true;
   }
 
   if (!pPage->IsDictionary()) {
-    m_docStatus = PDF_DATAAVAIL_ERROR;
+    m_internalStatus = InternalStatus::kError;
     return false;
   }
 
   pPageNode->m_dwPageNo = dwPageNo;
-  CPDF_Dictionary* pDict = pPage->GetDict();
-  const ByteString type = pDict->GetStringFor("Type");
+  RetainPtr<CPDF_Dictionary> pDict = pPage->GetMutableDict();
+  const ByteString type = pDict->GetNameFor("Type");
   if (type == "Page") {
-    pPageNode->m_type = PDF_PAGENODE_PAGE;
+    pPageNode->m_type = PageNode::Type::kPage;
     return true;
   }
 
   if (type != "Pages") {
-    m_docStatus = PDF_DATAAVAIL_ERROR;
+    m_internalStatus = InternalStatus::kError;
     return false;
   }
 
-  pPageNode->m_type = PDF_PAGENODE_PAGES;
-  CPDF_Object* pKids = pDict->GetObjectFor("Kids");
+  pPageNode->m_type = PageNode::Type::kPages;
+  RetainPtr<CPDF_Object> pKids = pDict->GetMutableObjectFor("Kids");
   if (!pKids) {
-    m_docStatus = PDF_DATAAVAIL_PAGE;
+    m_internalStatus = InternalStatus::kPage;
     return true;
   }
 
   switch (pKids->GetType()) {
     case CPDF_Object::kReference: {
-      CPDF_Reference* pKid = pKids->AsReference();
-      auto pNode = pdfium::MakeUnique<PageNode>();
+      const CPDF_Reference* pKid = pKids->AsReference();
+      auto pNode = std::make_unique<PageNode>();
       pNode->m_dwPageNo = pKid->GetRefObjNum();
       pPageNode->m_ChildNodes.push_back(std::move(pNode));
       break;
     }
     case CPDF_Object::kArray: {
-      CPDF_Array* pKidsArray = pKids->AsArray();
+      const CPDF_Array* pKidsArray = pKids->AsArray();
       for (size_t i = 0; i < pKidsArray->size(); ++i) {
-        CPDF_Reference* pKid = ToReference(pKidsArray->GetObjectAt(i));
+        RetainPtr<const CPDF_Reference> pKid =
+            ToReference(pKidsArray->GetObjectAt(i));
         if (!pKid)
           continue;
 
-        auto pNode = pdfium::MakeUnique<PageNode>();
+        auto pNode = std::make_unique<PageNode>();
         pNode->m_dwPageNo = pKid->GetRefObjNum();
         pPageNode->m_ChildNodes.push_back(std::move(pNode));
       }
@@ -632,9 +649,9 @@ bool CPDF_DataAvail::CheckPageNode(const CPDF_DataAvail::PageNode& pageNode,
   if (level >= kMaxPageRecursionDepth)
     return false;
 
-  int32_t iSize = pdfium::CollectionSize<int32_t>(pageNode.m_ChildNodes);
+  int32_t iSize = fxcrt::CollectionSize<int32_t>(pageNode.m_ChildNodes);
   if (iSize <= 0 || iPage >= iSize) {
-    m_docStatus = PDF_DATAAVAIL_ERROR;
+    m_internalStatus = InternalStatus::kError;
     return false;
   }
   for (int32_t i = 0; i < iSize; ++i) {
@@ -642,33 +659,33 @@ bool CPDF_DataAvail::CheckPageNode(const CPDF_DataAvail::PageNode& pageNode,
     if (!pNode)
       continue;
 
-    if (pNode->m_type == PDF_PAGENODE_UNKNOWN) {
+    if (pNode->m_type == PageNode::Type::kUnknown) {
       // Updates the type for the unknown page node.
       if (!CheckUnknownPageNode(pNode->m_dwPageNo, pNode))
         return false;
     }
-    if (pNode->m_type == PDF_PAGENODE_ARRAY) {
+    if (pNode->m_type == PageNode::Type::kArray) {
       // Updates a more specific type for the array page node.
       if (!CheckArrayPageNode(pNode->m_dwPageNo, pNode))
         return false;
     }
     switch (pNode->m_type) {
-      case PDF_PAGENODE_PAGE:
+      case PageNode::Type::kPage:
         iCount++;
         if (iPage == iCount && m_pDocument)
           m_pDocument->SetPageObjNum(iPage, pNode->m_dwPageNo);
         break;
-      case PDF_PAGENODE_PAGES:
+      case PageNode::Type::kPages:
         if (!CheckPageNode(*pNode, iPage, iCount, level + 1))
           return false;
         break;
-      case PDF_PAGENODE_UNKNOWN:
-      case PDF_PAGENODE_ARRAY:
+      case PageNode::Type::kUnknown:
+      case PageNode::Type::kArray:
         // Already converted above, error if we get here.
         return false;
     }
     if (iPage == iCount) {
-      m_docStatus = PDF_DATAAVAIL_DONE;
+      m_internalStatus = InternalStatus::kDone;
       return true;
     }
   }
@@ -676,15 +693,15 @@ bool CPDF_DataAvail::CheckPageNode(const CPDF_DataAvail::PageNode& pageNode,
 }
 
 bool CPDF_DataAvail::LoadDocPage(uint32_t dwPage) {
-  FX_SAFE_INT32 safePage = pdfium::base::checked_cast<int32_t>(dwPage);
-  int32_t iPage = safePage.ValueOrDie();
+  int iPage = pdfium::base::checked_cast<int>(dwPage);
   if (m_pDocument->GetPageCount() <= iPage ||
       m_pDocument->IsPageLoaded(iPage)) {
-    m_docStatus = PDF_DATAAVAIL_DONE;
+    m_internalStatus = InternalStatus::kDone;
     return true;
   }
-  if (m_PageNode.m_type == PDF_PAGENODE_PAGE) {
-    m_docStatus = iPage == 0 ? PDF_DATAAVAIL_DONE : PDF_DATAAVAIL_ERROR;
+  if (m_PageNode.m_type == PageNode::Type::kPage) {
+    m_internalStatus =
+        iPage == 0 ? InternalStatus::kDone : InternalStatus::kError;
     return true;
   }
   int32_t iCount = -1;
@@ -695,15 +712,15 @@ bool CPDF_DataAvail::CheckPageCount() {
   bool bExists = false;
   RetainPtr<CPDF_Object> pPages = GetObject(m_PagesObjNum, &bExists);
   if (!bExists) {
-    m_docStatus = PDF_DATAAVAIL_ERROR;
+    m_internalStatus = InternalStatus::kError;
     return false;
   }
   if (!pPages)
     return false;
 
-  CPDF_Dictionary* pPagesDict = pPages->GetDict();
+  RetainPtr<const CPDF_Dictionary> pPagesDict = pPages->GetDict();
   if (!pPagesDict) {
-    m_docStatus = PDF_DATAAVAIL_ERROR;
+    m_internalStatus = InternalStatus::kError;
     return false;
   }
   if (!pPagesDict->KeyExist("Kids"))
@@ -717,7 +734,7 @@ bool CPDF_DataAvail::LoadDocPages() {
     return false;
 
   if (CheckPageCount()) {
-    m_docStatus = PDF_DATAAVAIL_PAGE;
+    m_internalStatus = InternalStatus::kPage;
     return true;
   }
 
@@ -740,11 +757,11 @@ bool CPDF_DataAvail::LoadPages() {
 
 CPDF_DataAvail::DocAvailStatus CPDF_DataAvail::CheckLinearizedData() {
   if (m_bLinearedDataOK)
-    return DataAvailable;
-  ASSERT(m_pLinearized);
+    return kDataAvailable;
+  DCHECK(m_pLinearized);
   if (!m_pLinearized->GetMainXRefTableFirstEntryOffset() || !m_pDocument ||
       !m_pDocument->GetParser() || !m_pDocument->GetParser()->GetTrailer()) {
-    return DataError;
+    return kDataError;
   }
 
   if (!m_bMainXRefLoadTried) {
@@ -752,68 +769,66 @@ CPDF_DataAvail::DocAvailStatus CPDF_DataAvail::CheckLinearizedData() {
         m_pDocument->GetParser()->GetTrailer()->GetIntegerFor("Prev");
     const FX_FILESIZE main_xref_offset = prev.ValueOrDefault(-1);
     if (main_xref_offset < 0)
-      return DataError;
+      return kDataError;
 
     if (main_xref_offset == 0)
-      return DataAvailable;
+      return kDataAvailable;
 
     FX_SAFE_SIZE_T data_size = m_dwFileLen;
     data_size -= main_xref_offset;
     if (!data_size.IsValid())
-      return DataError;
+      return kDataError;
 
     if (!GetValidator()->CheckDataRangeAndRequestIfUnavailable(
             main_xref_offset, data_size.ValueOrDie()))
-      return DataNotAvailable;
+      return kDataNotAvailable;
 
     CPDF_Parser::Error eRet =
         m_pDocument->GetParser()->LoadLinearizedMainXRefTable();
     m_bMainXRefLoadTried = true;
     if (eRet != CPDF_Parser::SUCCESS)
-      return DataError;
+      return kDataError;
 
     if (!PreparePageItem())
-      return DataNotAvailable;
+      return kDataNotAvailable;
 
     m_bMainXRefLoadedOK = true;
     m_bLinearedDataOK = true;
   }
 
-  return m_bLinearedDataOK ? DataAvailable : DataNotAvailable;
+  return m_bLinearedDataOK ? kDataAvailable : kDataNotAvailable;
 }
 
 CPDF_DataAvail::DocAvailStatus CPDF_DataAvail::IsPageAvail(
     uint32_t dwPage,
     DownloadHints* pHints) {
   if (!m_pDocument)
-    return DataError;
+    return kDataError;
 
-  const FX_SAFE_INT32 safePage = pdfium::base::checked_cast<int32_t>(dwPage);
-  if (!safePage.IsValid())
-    return DataError;
-
-  if (safePage.ValueOrDie() >= m_pDocument->GetPageCount()) {
+  const int iPage = pdfium::base::checked_cast<int>(dwPage);
+  if (iPage >= m_pDocument->GetPageCount()) {
     // This is XFA page.
-    return DataAvailable;
+    return kDataAvailable;
   }
 
   if (IsFirstCheck(dwPage)) {
     m_bCurPageDictLoadOK = false;
   }
 
-  if (pdfium::ContainsKey(m_pagesLoadState, dwPage))
-    return DataAvailable;
+  if (pdfium::Contains(m_pagesLoadState, dwPage))
+    return kDataAvailable;
 
   const HintsScope hints_scope(GetValidator(), pHints);
   if (m_pLinearized) {
     if (dwPage == m_pLinearized->GetFirstPageNo()) {
-      auto* pPageDict = m_pDocument->GetPageDictionary(safePage.ValueOrDie());
+      RetainPtr<const CPDF_Dictionary> pPageDict =
+          m_pDocument->GetPageDictionary(iPage);
       if (!pPageDict)
-        return DataError;
+        return kDataError;
 
-      auto page_num_obj = std::make_pair(
-          dwPage, pdfium::MakeUnique<CPDF_PageObjectAvail>(
-                      GetValidator(), m_pDocument.Get(), pPageDict));
+      auto page_num_obj =
+          std::make_pair(dwPage, std::make_unique<CPDF_PageObjectAvail>(
+                                     GetValidator(), m_pDocument, pPageDict));
 
       CPDF_PageObjectAvail* page_obj_avail =
           m_PagesObjAvail.insert(std::move(page_num_obj)).first->second.get();
@@ -822,83 +837,84 @@ CPDF_DataAvail::DocAvailStatus CPDF_DataAvail::IsPageAvail(
     }
 
     DocAvailStatus nResult = CheckLinearizedData();
-    if (nResult != DataAvailable)
+    if (nResult != kDataAvailable)
       return nResult;
 
     if (m_pHintTables) {
       nResult = m_pHintTables->CheckPage(dwPage);
-      if (nResult != DataAvailable)
+      if (nResult != kDataAvailable)
         return nResult;
       if (GetPageDictionary(dwPage)) {
         m_pagesLoadState.insert(dwPage);
-        return DataAvailable;
+        return kDataAvailable;
       }
     }
 
     if (!m_bMainXRefLoadedOK) {
       if (!LoadAllFile())
-        return DataNotAvailable;
+        return kDataNotAvailable;
       m_pDocument->GetParser()->RebuildCrossRef();
       ResetFirstCheck(dwPage);
-      return DataAvailable;
+      return kDataAvailable;
     }
     if (m_bTotalLoadPageTree) {
       if (!LoadPages())
-        return DataNotAvailable;
+        return kDataNotAvailable;
     } else {
       if (!m_bCurPageDictLoadOK && !CheckPage(dwPage))
-        return DataNotAvailable;
+        return kDataNotAvailable;
     }
   } else {
     if (!m_bTotalLoadPageTree && !m_bCurPageDictLoadOK && !CheckPage(dwPage)) {
-      return DataNotAvailable;
+      return kDataNotAvailable;
     }
   }
 
-  if (CheckAcroForm() == DocFormStatus::FormNotAvailable)
-    return DataNotAvailable;
+  if (CheckAcroForm() == kFormNotAvailable)
+    return kDataNotAvailable;
 
-  auto* pPageDict = m_pDocument->GetPageDictionary(safePage.ValueOrDie());
+  RetainPtr<CPDF_Dictionary> pPageDict =
+      m_pDocument->GetMutablePageDictionary(iPage);
   if (!pPageDict)
-    return DataError;
+    return kDataError;
 
   {
-    auto page_num_obj = std::make_pair(
-        dwPage, pdfium::MakeUnique<CPDF_PageObjectAvail>(
-                    GetValidator(), m_pDocument.Get(), pPageDict));
+    auto page_num_obj =
+        std::make_pair(dwPage, std::make_unique<CPDF_PageObjectAvail>(
+                                   GetValidator(), m_pDocument, pPageDict));
     CPDF_PageObjectAvail* page_obj_avail =
         m_PagesObjAvail.insert(std::move(page_num_obj)).first->second.get();
     const DocAvailStatus status = page_obj_avail->CheckAvail();
-    if (status != DocAvailStatus::DataAvailable)
+    if (status != kDataAvailable)
       return status;
   }
 
-  const DocAvailStatus resources_status = CheckResources(pPageDict);
-  if (resources_status != DocAvailStatus::DataAvailable)
+  const DocAvailStatus resources_status = CheckResources(std::move(pPageDict));
+  if (resources_status != kDataAvailable)
     return resources_status;
 
   m_bCurPageDictLoadOK = false;
   ResetFirstCheck(dwPage);
   m_pagesLoadState.insert(dwPage);
-  return DataAvailable;
+  return kDataAvailable;
 }
 
 CPDF_DataAvail::DocAvailStatus CPDF_DataAvail::CheckResources(
-    CPDF_Dictionary* page) {
-  ASSERT(page);
-  const CPDF_ReadValidator::Session read_session(GetValidator());
-  CPDF_Object* resources = GetResourceObject(page);
+    RetainPtr<CPDF_Dictionary> page) {
+  DCHECK(page);
+  CPDF_ReadValidator::ScopedSession read_session(GetValidator());
+  RetainPtr<CPDF_Object> resources = GetResourceObject(std::move(page));
   if (GetValidator()->has_read_problems())
-    return DocAvailStatus::DataNotAvailable;
+    return kDataNotAvailable;
 
   if (!resources)
-    return DocAvailStatus::DataAvailable;
+    return kDataAvailable;
 
   CPDF_PageObjectAvail* resource_avail =
       m_PagesResourcesAvail
-          .insert(std::make_pair(
-              resources, pdfium::MakeUnique<CPDF_PageObjectAvail>(
-                             GetValidator(), m_pDocument.Get(), resources)))
+          .insert(std::make_pair(resources,
+                                 std::make_unique<CPDF_PageObjectAvail>(
+                                     GetValidator(), m_pDocument, resources)))
           .first->second.get();
   return resource_avail->CheckAvail();
 }
@@ -918,10 +934,11 @@ int CPDF_DataAvail::GetPageCount() const {
   return m_pDocument ? m_pDocument->GetPageCount() : 0;
 }
 
-CPDF_Dictionary* CPDF_DataAvail::GetPageDictionary(int index) const {
+RetainPtr<const CPDF_Dictionary> CPDF_DataAvail::GetPageDictionary(
+    int index) const {
   if (!m_pDocument || index < 0 || index >= GetPageCount())
     return nullptr;
-  CPDF_Dictionary* page = m_pDocument->GetPageDictionary(index);
+  RetainPtr<const CPDF_Dictionary> page = m_pDocument->GetPageDictionary(index);
   if (page)
     return page;
   if (!m_pLinearized || !m_pHintTables)
@@ -941,8 +958,7 @@ CPDF_Dictionary* CPDF_DataAvail::GetPageDictionary(int index) const {
   // Page object already can be parsed in document.
   if (!m_pDocument->GetIndirectObject(dwObjNum)) {
     m_pDocument->ReplaceIndirectObjectIfHigherGeneration(
-        dwObjNum,
-        ParseIndirectObjectAt(szPageStartPos, dwObjNum, m_pDocument.Get()));
+        dwObjNum, ParseIndirectObjectAt(szPageStartPos, dwObjNum, m_pDocument));
   }
   if (!ValidatePage(index))
     return nullptr;
@@ -957,64 +973,67 @@ CPDF_DataAvail::DocFormStatus CPDF_DataAvail::IsFormAvail(
 
 CPDF_DataAvail::DocFormStatus CPDF_DataAvail::CheckAcroForm() {
   if (!m_pDocument)
-    return FormAvailable;
+    return kFormAvailable;
 
   if (m_pLinearized) {
     DocAvailStatus nDocStatus = CheckLinearizedData();
-    if (nDocStatus == DataError)
-      return FormError;
-    if (nDocStatus == DataNotAvailable)
-      return FormNotAvailable;
+    if (nDocStatus == kDataError)
+      return kFormError;
+    if (nDocStatus == kDataNotAvailable)
+      return kFormNotAvailable;
   }
 
   if (!m_pFormAvail) {
-    CPDF_Dictionary* pRoot = m_pDocument->GetRoot();
+    const CPDF_Dictionary* pRoot = m_pDocument->GetRoot();
     if (!pRoot)
-      return FormAvailable;
+      return kFormAvailable;
 
-    CPDF_Object* pAcroForm = pRoot->GetObjectFor("AcroForm");
+    RetainPtr<const CPDF_Object> pAcroForm = pRoot->GetObjectFor("AcroForm");
     if (!pAcroForm)
-      return FormNotExist;
+      return kFormNotExist;
 
-    m_pFormAvail = pdfium::MakeUnique<CPDF_PageObjectAvail>(
-        GetValidator(), m_pDocument.Get(), pAcroForm);
+    m_pFormAvail = std::make_unique<CPDF_PageObjectAvail>(
+        GetValidator(), m_pDocument, std::move(pAcroForm));
   }
   switch (m_pFormAvail->CheckAvail()) {
-    case DocAvailStatus::DataError:
-      return DocFormStatus::FormError;
-    case DocAvailStatus::DataNotAvailable:
-      return DocFormStatus::FormNotAvailable;
-    case DocAvailStatus::DataAvailable:
-      return DocFormStatus::FormAvailable;
+    case kDataError:
+      return kFormError;
+    case kDataNotAvailable:
+      return kFormNotAvailable;
+    case kDataAvailable:
+      return kFormAvailable;
     default:
       NOTREACHED();
   }
-  return DocFormStatus::FormError;
+  return kFormError;
 }
 
 bool CPDF_DataAvail::ValidatePage(uint32_t dwPage) const {
-  FX_SAFE_INT32 safePage = pdfium::base::checked_cast<int32_t>(dwPage);
-  auto* pPageDict = m_pDocument->GetPageDictionary(safePage.ValueOrDie());
+  int iPage = pdfium::base::checked_cast<int>(dwPage);
+  RetainPtr<const CPDF_Dictionary> pPageDict =
+      m_pDocument->GetPageDictionary(iPage);
   if (!pPageDict)
     return false;
-  CPDF_PageObjectAvail obj_avail(GetValidator(), m_pDocument.Get(), pPageDict);
-  return obj_avail.CheckAvail() == DocAvailStatus::DataAvailable;
+
+  CPDF_PageObjectAvail obj_avail(GetValidator(), m_pDocument,
+                                 std::move(pPageDict));
+  return obj_avail.CheckAvail() == kDataAvailable;
 }
 
 std::pair<CPDF_Parser::Error, std::unique_ptr<CPDF_Document>>
 CPDF_DataAvail::ParseDocument(
     std::unique_ptr<CPDF_Document::RenderDataIface> pRenderData,
     std::unique_ptr<CPDF_Document::PageDataIface> pPageData,
-    const char* password) {
+    const ByteString& password) {
   if (m_pDocument) {
     // We already returned parsed document.
     return std::make_pair(CPDF_Parser::HANDLER_ERROR, nullptr);
   }
-  auto document = pdfium::MakeUnique<CPDF_Document>(std::move(pRenderData),
-                                                    std::move(pPageData));
+  auto document = std::make_unique<CPDF_Document>(std::move(pRenderData),
+                                                  std::move(pPageData));
   document->AddObserver(this);
 
-  CPDF_ReadValidator::Session read_session(GetValidator());
+  CPDF_ReadValidator::ScopedSession read_session(GetValidator());
   CPDF_Parser::Error error =
       document->LoadLinearizedDoc(GetValidator(), password);
 
@@ -1031,6 +1050,6 @@ CPDF_DataAvail::ParseDocument(
   return std::make_pair(CPDF_Parser::SUCCESS, std::move(document));
 }
 
-CPDF_DataAvail::PageNode::PageNode() : m_type(PDF_PAGENODE_UNKNOWN) {}
+CPDF_DataAvail::PageNode::PageNode() = default;
 
-CPDF_DataAvail::PageNode::~PageNode() {}
+CPDF_DataAvail::PageNode::~PageNode() = default;