Re-land "Make CPDF_IndirectObjectHolder use unique_ptr to objects""

core/fpdfapi/fpdf_parser/cpdf_indirect_object_holder.cpp

 // Copyright 2016 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "core/fpdfapi/fpdf_parser/include/cpdf_indirect_object_holder.h"
 
 #include "core/fpdfapi/fpdf_parser/include/cpdf_object.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_parser.h"
 
 CPDF_IndirectObjectHolder::CPDF_IndirectObjectHolder() : m_LastObjNum(0) {}
 
-CPDF_IndirectObjectHolder::~CPDF_IndirectObjectHolder() {
-  for (const auto& pair : m_IndirectObjs)
-    delete pair.second;
-}
+CPDF_IndirectObjectHolder::~CPDF_IndirectObjectHolder() {}
 
 CPDF_Object* CPDF_IndirectObjectHolder::GetIndirectObject(
     uint32_t objnum) const {
   auto it = m_IndirectObjs.find(objnum);
-  return it != m_IndirectObjs.end() ? it->second : nullptr;
+  return it != m_IndirectObjs.end() ? it->second.get() : nullptr;
 }
 
 CPDF_Object* CPDF_IndirectObjectHolder::GetOrParseIndirectObject(
     uint32_t objnum) {
   if (objnum == 0)
     return nullptr;
 
   CPDF_Object* pObj = GetIndirectObject(objnum);
   if (pObj)
     return pObj->GetObjNum() != CPDF_Object::kInvalidObjNum ? pObj : nullptr;
 
   pObj = ParseIndirectObject(objnum);
   if (!pObj)
     return nullptr;
 
   pObj->m_ObjNum = objnum;
   m_LastObjNum = std::max(m_LastObjNum, objnum);
-  if (m_IndirectObjs[objnum])
-    delete m_IndirectObjs[objnum];
-
-  m_IndirectObjs[objnum] = pObj;
+  m_IndirectObjs[objnum].reset(pObj);
   return pObj;
 }
 
 CPDF_Object* CPDF_IndirectObjectHolder::ParseIndirectObject(uint32_t objnum) {
   return nullptr;
 }
 
 uint32_t CPDF_IndirectObjectHolder::AddIndirectObject(CPDF_Object* pObj) {
   if (pObj->m_ObjNum)
     return pObj->m_ObjNum;
 
   m_LastObjNum++;
-  m_IndirectObjs[m_LastObjNum] = pObj;
+  m_IndirectObjs[m_LastObjNum].reset(pObj);
   pObj->m_ObjNum = m_LastObjNum;
   return m_LastObjNum;
 }
 
 bool CPDF_IndirectObjectHolder::ReplaceIndirectObjectIfHigherGeneration(
     uint32_t objnum,
     CPDF_Object* pObj) {
   if (!objnum || !pObj)
     return false;
 
   CPDF_Object* pOldObj = GetIndirectObject(objnum);
-  if (pOldObj) {
-    if (pObj->GetGenNum() <= pOldObj->GetGenNum()) {
-      delete pObj;
-      return false;
-    }
-    delete pOldObj;
+  if (pOldObj && pObj->GetGenNum() <= pOldObj->GetGenNum()) {
+    delete pObj;
+    return false;
   }
   pObj->m_ObjNum = objnum;
-  m_IndirectObjs[objnum] = pObj;
+  m_IndirectObjs[objnum].reset(pObj);
   m_LastObjNum = std::max(m_LastObjNum, objnum);
   return true;
 }
 
 void CPDF_IndirectObjectHolder::ReleaseIndirectObject(uint32_t objnum) {
   CPDF_Object* pObj = GetIndirectObject(objnum);
   if (!pObj || pObj->GetObjNum() == CPDF_Object::kInvalidObjNum)
     return;
 
-  delete pObj;
   m_IndirectObjs.erase(objnum);
 }