Make CPDF_Object containers hold objects via unique pointers

core/fpdfapi/parser/cpdf_array.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/parser/cpdf_array.h"
 
 #include <set>
 
 #include "core/fpdfapi/parser/cpdf_name.h"
 #include "core/fpdfapi/parser/cpdf_number.h"
 #include "core/fpdfapi/parser/cpdf_reference.h"
 #include "core/fpdfapi/parser/cpdf_stream.h"
 #include "core/fpdfapi/parser/cpdf_string.h"
 #include "third_party/base/logging.h"
 #include "third_party/base/stl_util.h"
 
 CPDF_Array::CPDF_Array() {}
 
 CPDF_Array::~CPDF_Array() {
   // Mark the object as deleted so that it will not be deleted again
-  // in case of cyclic references.
+  // in case of cyclic references, then break cycles.
   m_ObjNum = kInvalidObjNum;
   for (auto& it : m_Objects) {
-    if (it && it->GetObjNum() != kInvalidObjNum)
-      it->Release();
+    if (it && it->GetObjNum() == kInvalidObjNum)
+      it.release();
   }
 }
 
 CPDF_Object::Type CPDF_Array::GetType() const {
   return ARRAY;
 }
 
 bool CPDF_Array::IsArray() const {
   return true;
 }
 
 CPDF_Array* CPDF_Array::AsArray() {
   return this;
 }
 
 const CPDF_Array* CPDF_Array::AsArray() const {
   return this;
 }
 
 CPDF_Object* CPDF_Array::Clone() const {
   return CloneObjectNonCyclic(false);
 }
 
 CPDF_Object* CPDF_Array::CloneNonCyclic(
     bool bDirect,
     std::set<const CPDF_Object*>* pVisited) const {
   pVisited->insert(this);
   CPDF_Array* pCopy = new CPDF_Array();
-  for (size_t i = 0; i < GetCount(); i++) {
-    CPDF_Object* value = m_Objects[i];
-    if (!pdfium::ContainsKey(*pVisited, value))
-      pCopy->m_Objects.push_back(value->CloneNonCyclic(bDirect, pVisited));
+  for (const auto& pObj : m_Objects) {
+    if (!pdfium::ContainsKey(*pVisited, pObj.get())) {
+      pCopy->m_Objects.push_back(
+          UniqueObject(pObj->CloneNonCyclic(bDirect, pVisited)));
+    }
   }
   return pCopy;
 }
 
 CFX_FloatRect CPDF_Array::GetRect() {
   CFX_FloatRect rect;
   if (!IsArray() || m_Objects.size() != 4)
     return rect;
 
   rect.left = GetNumberAt(0);
   rect.bottom = GetNumberAt(1);
   rect.right = GetNumberAt(2);
   rect.top = GetNumberAt(3);
   return rect;
 }
 
 CFX_Matrix CPDF_Array::GetMatrix() {
   CFX_Matrix matrix;
   if (!IsArray() || m_Objects.size() != 6)
     return matrix;
 
   matrix.Set(GetNumberAt(0), GetNumberAt(1), GetNumberAt(2), GetNumberAt(3),
              GetNumberAt(4), GetNumberAt(5));
   return matrix;
 }
 
 CPDF_Object* CPDF_Array::GetObjectAt(size_t i) const {
   if (i >= m_Objects.size())
     return nullptr;
-  return m_Objects[i];
+  return m_Objects[i].get();
 }
 
 CPDF_Object* CPDF_Array::GetDirectObjectAt(size_t i) const {
   if (i >= m_Objects.size())
     return nullptr;
   return m_Objects[i]->GetDirect();
 }
 
 CFX_ByteString CPDF_Array::GetStringAt(size_t i) const {
   if (i >= m_Objects.size())
@@ skipping 32 matching lines @@
   return ToArray(GetDirectObjectAt(i));
 }
 
 void CPDF_Array::RemoveAt(size_t i, size_t nCount) {
   if (i >= m_Objects.size())
     return;
 
   if (nCount <= 0 || nCount > m_Objects.size() - i)
     return;
 
-  for (size_t j = 0; j < nCount; ++j) {
-    if (CPDF_Object* p = m_Objects[i + j])
-      p->Release();
-  }
-  m_Objects.erase(m_Objects.begin() + i, m_Objects.begin() + i + nCount);
+  auto it = m_Objects.begin() + i;
+  m_Objects.erase(it, it + nCount);
 }
 
 void CPDF_Array::ConvertToIndirectObjectAt(size_t i,
                                            CPDF_IndirectObjectHolder* pHolder) {
   if (i >= m_Objects.size())
     return;
 
-  CPDF_Object* pObj = m_Objects[i];
-  if (!pObj || pObj->IsReference())
+  if (!m_Objects[i] || m_Objects[i]->IsReference())
     return;
 
-  uint32_t dwObjNum = pHolder->AddIndirectObject(pObj);
-  m_Objects[i] = new CPDF_Reference(pHolder, dwObjNum);
+  uint32_t dwObjNum = pHolder->AddIndirectObject(m_Objects[i].release());
+  m_Objects[i] = UniqueObject(new CPDF_Reference(pHolder, dwObjNum));
 }
 
 void CPDF_Array::SetAt(size_t i, CPDF_Object* pObj) {
   ASSERT(IsArray());
   CHECK(!pObj || pObj->IsInline());
   if (i >= m_Objects.size()) {
     ASSERT(false);
     return;
   }
-  if (CPDF_Object* pOld = m_Objects[i])
-    pOld->Release();
-
-  m_Objects[i] = pObj;
+  m_Objects[i] = UniqueObject(pObj);
 }
 
 void CPDF_Array::InsertAt(size_t index, CPDF_Object* pObj) {
   ASSERT(IsArray());
   CHECK(!pObj || pObj->IsInline());
   if (index >= m_Objects.size()) {
     // Allocate space first.
-    m_Objects.resize(index + 1, nullptr);
-    m_Objects[index] = pObj;
+    m_Objects.resize(index + 1);
+    m_Objects[index] = UniqueObject(pObj);
   } else {
     // Directly insert.
-    m_Objects.insert(m_Objects.begin() + index, pObj);
+    m_Objects.insert(m_Objects.begin() + index, UniqueObject(pObj));
   }
 }
 
 void CPDF_Array::Add(CPDF_Object* pObj) {
   ASSERT(IsArray());
   CHECK(!pObj || pObj->IsInline());
-  m_Objects.push_back(pObj);
+  m_Objects.push_back(UniqueObject(pObj));
 }
 
 void CPDF_Array::AddName(const CFX_ByteString& str) {
   Add(new CPDF_Name(str));
 }
 
 void CPDF_Array::AddString(const CFX_ByteString& str) {
   Add(new CPDF_String(str, FALSE));
 }
 
 void CPDF_Array::AddInteger(int i) {
   Add(new CPDF_Number(i));
 }
 
 void CPDF_Array::AddNumber(FX_FLOAT f) {
   Add(new CPDF_Number(f));
 }
 
 void CPDF_Array::AddReference(CPDF_IndirectObjectHolder* pDoc,
                               uint32_t objnum) {
   Add(new CPDF_Reference(pDoc, objnum));
 }