Check for nullptrs in CPDF_Dictionary dtor. BUG=597440 Review-Url: https://codereview.chromium.org/2273293003

diff --git a/core/fpdfapi/fpdf_parser/cpdf_array.cpp b/core/fpdfapi/fpdf_parser/cpdf_array.cpp
index 83f99c2..5e103fa 100644
--- a/core/fpdfapi/fpdf_parser/cpdf_array.cpp
+++ b/core/fpdfapi/fpdf_parser/cpdf_array.cpp

@@ -6,6 +6,8 @@
 
 #include "core/fpdfapi/fpdf_parser/include/cpdf_array.h"
 
+#include <set>
+
 #include "core/fpdfapi/fpdf_parser/include/cpdf_name.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_number.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_reference.h"
@@ -51,7 +53,7 @@
   pVisited->insert(this);
   CPDF_Array* pCopy = new CPDF_Array();
   for (size_t i = 0; i < GetCount(); i++) {
-    CPDF_Object* value = m_Objects.at(i);
+    CPDF_Object* value = m_Objects[i];
     if (!pdfium::ContainsKey(*pVisited, value))
       pCopy->m_Objects.push_back(value->CloneNonCyclic(bDirect, pVisited));
   }
@@ -83,31 +85,31 @@
 CPDF_Object* CPDF_Array::GetObjectAt(size_t i) const {
   if (i >= m_Objects.size())
     return nullptr;
-  return m_Objects.at(i);
+  return m_Objects[i];
 }
 
 CPDF_Object* CPDF_Array::GetDirectObjectAt(size_t i) const {
   if (i >= m_Objects.size())
     return nullptr;
-  return m_Objects.at(i)->GetDirect();
+  return m_Objects[i]->GetDirect();
 }
 
 CFX_ByteString CPDF_Array::GetStringAt(size_t i) const {
   if (i >= m_Objects.size())
     return CFX_ByteString();
-  return m_Objects.at(i)->GetString();
+  return m_Objects[i]->GetString();
 }
 
 int CPDF_Array::GetIntegerAt(size_t i) const {
   if (i >= m_Objects.size())
     return 0;
-  return m_Objects.at(i)->GetInteger();
+  return m_Objects[i]->GetInteger();
 }
 
 FX_FLOAT CPDF_Array::GetNumberAt(size_t i) const {
   if (i >= m_Objects.size())
     return 0;
-  return m_Objects.at(i)->GetNumber();
+  return m_Objects[i]->GetNumber();
 }
 
 CPDF_Dictionary* CPDF_Array::GetDictAt(size_t i) const {
@@ -137,7 +139,7 @@
     return;
 
   for (size_t j = 0; j < nCount; ++j) {
-    if (CPDF_Object* p = m_Objects.at(i + j))
+    if (CPDF_Object* p = m_Objects[i + j])
       p->Release();
   }
   m_Objects.erase(m_Objects.begin() + i, m_Objects.begin() + i + nCount);
@@ -147,10 +149,11 @@
                        CPDF_Object* pObj,
                        CPDF_IndirectObjectHolder* pObjs) {
   ASSERT(IsArray());
-  ASSERT(i < m_Objects.size());
-  if (i >= m_Objects.size())
+  if (i >= m_Objects.size()) {
+    ASSERT(false);
     return;
-  if (CPDF_Object* pOld = m_Objects.at(i))
+  }
+  if (CPDF_Object* pOld = m_Objects[i])
     pOld->Release();
   if (pObj->GetObjNum()) {
     ASSERT(pObjs);

diff --git a/core/fpdfapi/fpdf_parser/cpdf_dictionary.cpp b/core/fpdfapi/fpdf_parser/cpdf_dictionary.cpp
index 8fef074..e79bac1 100644
--- a/core/fpdfapi/fpdf_parser/cpdf_dictionary.cpp
+++ b/core/fpdfapi/fpdf_parser/cpdf_dictionary.cpp

@@ -6,6 +6,9 @@
 
 #include "core/fpdfapi/fpdf_parser/include/cpdf_dictionary.h"
 
+#include <set>
+#include <utility>
+
 #include "core/fpdfapi/fpdf_parser/cpdf_boolean.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_array.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_name.h"
@@ -18,9 +21,13 @@
 CPDF_Dictionary::CPDF_Dictionary() {}
 
 CPDF_Dictionary::~CPDF_Dictionary() {
+  // Mark the object as deleted so that it will not be deleted again
+  // in case of cyclic references.
   m_ObjNum = kInvalidObjNum;
-  for (const auto& it : m_Map)
-    it.second->Release();
+  for (const auto& it : m_Map) {
+    if (it.second)
+      it.second->Release();
+  }
 }
 
 CPDF_Object::Type CPDF_Dictionary::GetType() const {

diff --git a/core/fpdfapi/fpdf_parser/cpdf_object_unittest.cpp b/core/fpdfapi/fpdf_parser/cpdf_object_unittest.cpp
index 02e50bc..ec982ab 100644
--- a/core/fpdfapi/fpdf_parser/cpdf_object_unittest.cpp
+++ b/core/fpdfapi/fpdf_parser/cpdf_object_unittest.cpp

@@ -747,6 +747,44 @@
   }
 }
 
+TEST(PDFArrayTest, CloneDirectObject) {
+  CPDF_IndirectObjectHolder objects_holder;
+  ScopedArray array(new CPDF_Array);
+  array->AddReference(&objects_holder, 1234);
+  ASSERT_EQ(1U, array->GetCount());
+  CPDF_Object* obj = array->GetObjectAt(0);
+  ASSERT_TRUE(obj);
+  EXPECT_TRUE(obj->IsReference());
+
+  CPDF_Object* cloned_array_object = array->CloneDirectObject();
+  ASSERT_TRUE(cloned_array_object);
+  ASSERT_TRUE(cloned_array_object->IsArray());
+
+  ScopedArray cloned_array(cloned_array_object->AsArray());
+  ASSERT_EQ(1U, cloned_array->GetCount());
+  CPDF_Object* cloned_obj = cloned_array->GetObjectAt(0);
+  EXPECT_FALSE(cloned_obj);
+}
+
+TEST(PDFDictionaryTest, CloneDirectObject) {
+  CPDF_IndirectObjectHolder objects_holder;
+  ScopedDict dict(new CPDF_Dictionary);
+  dict->SetAtReference("foo", &objects_holder, 1234);
+  ASSERT_EQ(1U, dict->GetCount());
+  CPDF_Object* obj = dict->GetObjectBy("foo");
+  ASSERT_TRUE(obj);
+  EXPECT_TRUE(obj->IsReference());
+
+  CPDF_Object* cloned_dict_object = dict->CloneDirectObject();
+  ASSERT_TRUE(cloned_dict_object);
+  ASSERT_TRUE(cloned_dict_object->IsDictionary());
+
+  ScopedDict cloned_dict(cloned_dict_object->AsDictionary());
+  ASSERT_EQ(1U, cloned_dict->GetCount());
+  CPDF_Object* cloned_obj = cloned_dict->GetObjectBy("foo");
+  EXPECT_FALSE(cloned_obj);
+}
+
 TEST(PDFObjectTest, CloneCheckLoop) {
   {
     // Create an object with a reference loop.
@@ -768,15 +806,14 @@
     EXPECT_EQ(nullptr, cloned_dict->AsDictionary()->GetObjectBy("arr"));
   }
   {
-    std::unique_ptr<CPDF_IndirectObjectHolder> m_ObjHolder(
-        new CPDF_IndirectObjectHolder());
+    CPDF_IndirectObjectHolder objects_holder;
     // Create an object with a reference loop.
     CPDF_Dictionary* dict_obj = new CPDF_Dictionary;
     CPDF_Array* arr_obj = new CPDF_Array;
-    m_ObjHolder->AddIndirectObject(dict_obj);
+    objects_holder.AddIndirectObject(dict_obj);
     EXPECT_EQ(1u, dict_obj->GetObjNum());
     dict_obj->SetAt("arr", arr_obj);
-    arr_obj->InsertAt(0, dict_obj, m_ObjHolder.get());
+    arr_obj->InsertAt(0, dict_obj, &objects_holder);
     CPDF_Object* elem0 = arr_obj->GetObjectAt(0);
     ASSERT_TRUE(elem0);
     ASSERT_TRUE(elem0->IsReference());