Use string pools in some dictionaries

core/fpdfapi/fpdf_parser/cpdf_dictionary.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_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"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_number.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_reference.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_stream.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_string.h"
 #include "third_party/base/stl_util.h"
 
-CPDF_Dictionary::CPDF_Dictionary() {}
+CPDF_Dictionary::CPDF_Dictionary() : m_pPool(nullptr) {}
+
+CPDF_Dictionary::CPDF_Dictionary(CFX_ByteStringPool* pPool) : m_pPool(pPool) {}
 
 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) {
     if (it.second)
       it.second->Release();
   }
 }
@@ skipping 21 matching lines @@
 }
 
 CPDF_Object* CPDF_Dictionary::Clone() const {
   return CloneObjectNonCyclic(false);
 }
 
 CPDF_Object* CPDF_Dictionary::CloneNonCyclic(
     bool bDirect,
     std::set<const CPDF_Object*>* pVisited) const {
   pVisited->insert(this);
-  CPDF_Dictionary* pCopy = new CPDF_Dictionary();
+  CPDF_Dictionary* pCopy = new CPDF_Dictionary(m_pPool);
   for (const auto& it : *this) {
     CPDF_Object* value = it.second;
     if (!pdfium::ContainsKey(*pVisited, value)) {
       pCopy->m_Map.insert(
           std::make_pair(it.first, value->CloneNonCyclic(bDirect, pVisited)));
     }
   }
   return pCopy;
 }
 
@@ skipping 91 matching lines @@
   CPDF_Object* pType = GetDirectObjectFor("Type");
   if (!pType)
     pType = GetDirectObjectFor("FT");
   return pType && pType->GetString() == "Sig";
 }
 
 void CPDF_Dictionary::SetFor(const CFX_ByteString& key, CPDF_Object* pObj) {
   auto it = m_Map.find(key);
   if (it == m_Map.end()) {
     if (pObj)
-      m_Map.insert(std::make_pair(key, pObj));
+      m_Map.insert(std::make_pair(MaybeIntern(key), pObj));
     return;
   }
 
   if (it->second == pObj)
     return;
   it->second->Release();
 
   if (pObj)
     it->second = pObj;
   else
@@ skipping 16 matching lines @@
     return;
 
   auto new_it = m_Map.find(newkey);
   if (new_it == old_it)
     return;
 
   if (new_it != m_Map.end()) {
     new_it->second->Release();
     new_it->second = old_it->second;
   } else {
-    m_Map.insert(std::make_pair(newkey, old_it->second));
+    m_Map.insert(std::make_pair(MaybeIntern(newkey), old_it->second));
   }
   m_Map.erase(old_it);
 }
 
 void CPDF_Dictionary::SetIntegerFor(const CFX_ByteString& key, int i) {
   SetFor(key, new CPDF_Number(i));
 }
 
 void CPDF_Dictionary::SetNameFor(const CFX_ByteString& key,
                                  const CFX_ByteString& name) {
-  SetFor(key, new CPDF_Name(name));
+  SetFor(key, new CPDF_Name(MaybeIntern(name)));
 }
 
 void CPDF_Dictionary::SetStringFor(const CFX_ByteString& key,
                                    const CFX_ByteString& str) {
-  SetFor(key, new CPDF_String(str, FALSE));
+  SetFor(key, new CPDF_String(MaybeIntern(str), FALSE));
 }
 
 void CPDF_Dictionary::SetReferenceFor(const CFX_ByteString& key,
                                       CPDF_IndirectObjectHolder* pDoc,
                                       uint32_t objnum) {
   SetFor(key, new CPDF_Reference(pDoc, objnum));
 }
 
 void CPDF_Dictionary::SetNumberFor(const CFX_ByteString& key, FX_FLOAT f) {
   SetFor(key, new CPDF_Number(f));
@@ skipping 17 matching lines @@
                                    const CFX_Matrix& matrix) {
   CPDF_Array* pArray = new CPDF_Array;
   pArray->AddNumber(matrix.a);
   pArray->AddNumber(matrix.b);
   pArray->AddNumber(matrix.c);
   pArray->AddNumber(matrix.d);
   pArray->AddNumber(matrix.e);
   pArray->AddNumber(matrix.f);
   SetFor(key, pArray);
 }
+
+CFX_ByteString CPDF_Dictionary::MaybeIntern(const CFX_ByteString& str) {
+  return m_pPool ? m_pPool->Intern(str) : str;
+}