Make CPDF_Object subclass constructors intern strings

core/fpdfapi/parser/cpdf_indirect_object_holder.h

 // 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
 
 #ifndef CORE_FPDFAPI_PARSER_CPDF_INDIRECT_OBJECT_HOLDER_H_
 #define CORE_FPDFAPI_PARSER_CPDF_INDIRECT_OBJECT_HOLDER_H_
 
 #include <map>
 #include <memory>
+#include <type_traits>
 
 #include "core/fxcrt/cfx_string_pool_template.h"
 #include "core/fxcrt/cfx_weak_ptr.h"
 #include "core/fxcrt/fx_system.h"
 #include "third_party/base/ptr_util.h"
 
 class CPDF_Object;
+class CPDF_Name;
 
 class CPDF_IndirectObjectHolder {
  public:
   using const_iterator =
       std::map<uint32_t, std::unique_ptr<CPDF_Object>>::const_iterator;
 
   CPDF_IndirectObjectHolder();
   virtual ~CPDF_IndirectObjectHolder();
 
   CPDF_Object* GetIndirectObject(uint32_t objnum) const;
   CPDF_Object* GetOrParseIndirectObject(uint32_t objnum);
   void DeleteIndirectObject(uint32_t objnum);
 
   // Creates and adds a new object owned by the indirect object holder,
-  // and returns an unowned pointer to it.
+  // and returns an unowned pointer to it.  We have a special case to
+  // handle objects that can intern strings from our ByteStringPool.
   template <typename T, typename... Args>
-  T* NewIndirect(Args... args) {
+  typename std::enable_if<!std::is_same<T, CPDF_Name>::value, T*>::type
+      NewIndirect(Args... args) {
     return static_cast<T*>(AddIndirectObject(pdfium::MakeUnique<T>(args...)));
   }
 
+  template <typename T, typename... Args>
+  typename std::enable_if<std::is_same<T, CPDF_Name>::value, T*>::type
+      NewIndirect(Args... args) {
+    return static_cast<T*>(
+        AddIndirectObject(pdfium::MakeUnique<T>(m_pByteStringPool, args...)));

[Tom Sepez, 2016/11/16 22:36:36]

Here, the indirect object holder injects its own bytestringpool into the ctor
call, transparently to the callers if the type is expected to take it.

+  }
+
   // Takes ownership of |pObj|, returns unowned pointer to it.
   CPDF_Object* AddIndirectObject(std::unique_ptr<CPDF_Object> pObj);
 
   // Always takes ownership of |pObj|, return true if higher generation number.
   bool ReplaceIndirectObjectIfHigherGeneration(
       uint32_t objnum,
       std::unique_ptr<CPDF_Object> pObj);
 
   uint32_t GetLastObjNum() const { return m_LastObjNum; }
   void SetLastObjNum(uint32_t objnum) { m_LastObjNum = objnum; }
 
   CFX_WeakPtr<CFX_ByteStringPool> GetByteStringPool() const {
     return m_pByteStringPool;
   }
 
   const_iterator begin() const { return m_IndirectObjs.begin(); }
   const_iterator end() const { return m_IndirectObjs.end(); }
 
  protected:
   virtual std::unique_ptr<CPDF_Object> ParseIndirectObject(uint32_t objnum);
 
  private:
   uint32_t m_LastObjNum;
   std::map<uint32_t, std::unique_ptr<CPDF_Object>> m_IndirectObjs;
   CFX_WeakPtr<CFX_ByteStringPool> m_pByteStringPool;
 };
 
 #endif  // CORE_FPDFAPI_PARSER_CPDF_INDIRECT_OBJECT_HOLDER_H_