Properly ref count IFX_FileAccess.

core/fxcrt/fx_extension.cpp

 // Copyright 2014 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/fxcrt/extension.h"
 
 #include <algorithm>
 #include <memory>
 #include <utility>
 
 #include "core/fxcrt/fx_basic.h"
 #include "core/fxcrt/fx_ext.h"
 
 #if _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_
 #include <wincrypt.h>
 #else
 #include <ctime>
 #endif
 
 namespace {
 
 #ifdef PDF_ENABLE_XFA
 
 class CFX_CRTFileAccess : public IFX_FileAccess {
  public:
-  CFX_CRTFileAccess();
-  ~CFX_CRTFileAccess() override;
+  template <typename T, typename... Args>
+  friend CFX_RetainPtr<T> pdfium::MakeRetain(Args&&... args);

[dsinclair, 2016/12/07 23:05:03]

Does this need to be public?

[Tom Sepez, 2016/12/07 23:26:55]

In C++, the placement of the friend statement doesn't matter with regards to
public/protected/private (I had too look it up, too) -- the friend gets all
access.

I placed this here to give the reader a hint that the only way to get
one of these is via MakeRetain, since this is where you'd look for a ctor
normallly.

 
   // IFX_FileAccess
-  void Release() override;
-  IFX_FileAccess* Retain() override;
   void GetPath(CFX_WideString& wsPath) override;
   CFX_RetainPtr<IFX_SeekableStream> CreateFileStream(uint32_t dwModes) override;
 
   bool Init(const CFX_WideStringC& wsPath);
 
  private:
+  CFX_CRTFileAccess();
+  ~CFX_CRTFileAccess() override;
+
   CFX_WideString m_path;
-  uint32_t m_RefCount;
 };
 
-CFX_CRTFileAccess::CFX_CRTFileAccess() : m_RefCount(0) {}
+CFX_CRTFileAccess::CFX_CRTFileAccess() {}
 
 CFX_CRTFileAccess::~CFX_CRTFileAccess() {}
 
-void CFX_CRTFileAccess::Release() {
-  if (--m_RefCount == 0)
-    delete this;
-}
-
-IFX_FileAccess* CFX_CRTFileAccess::Retain() {
-  m_RefCount++;
-  return (IFX_FileAccess*)this;
-}
-
 void CFX_CRTFileAccess::GetPath(CFX_WideString& wsPath) {
   wsPath = m_path;
 }
 
 CFX_RetainPtr<IFX_SeekableStream> CFX_CRTFileAccess::CreateFileStream(
     uint32_t dwModes) {
   return IFX_SeekableStream::CreateFromFilename(m_path.c_str(), dwModes);
 }
 
 bool CFX_CRTFileAccess::Init(const CFX_WideStringC& wsPath) {
   m_path = wsPath;
-  m_RefCount = 1;
   return true;
 }
 
 #endif  // PDF_ENABLE_XFA
 
 class CFX_CRTFileStream final : public IFX_SeekableStream {
  public:
   template <typename T, typename... Args>
   friend CFX_RetainPtr<T> pdfium::MakeRetain(Args&&... args);
 
@@ skipping 298 matching lines @@
     uint8_t* pBlock = FX_Alloc(uint8_t, m_nGrowSize);
     m_Blocks.SetAt(iCount++, pBlock);
     m_nTotalSize += m_nGrowSize;
   }
   return true;
 }
 
 }  // namespace
 
 #ifdef PDF_ENABLE_XFA
-IFX_FileAccess* IFX_FileAccess::CreateDefault(const CFX_WideStringC& wsPath) {
+CFX_RetainPtr<IFX_FileAccess> IFX_FileAccess::CreateDefault(
+    const CFX_WideStringC& wsPath) {
   if (wsPath.GetLength() == 0)
     return nullptr;
 
-  CFX_CRTFileAccess* pFA = new CFX_CRTFileAccess;
+  auto pFA = pdfium::MakeRetain<CFX_CRTFileAccess>();
   pFA->Init(wsPath);
   return pFA;
 }
 #endif  // PDF_ENABLE_XFA
 
 // static
 CFX_RetainPtr<IFX_SeekableStream> IFX_SeekableStream::CreateFromFilename(
     const FX_CHAR* filename,
     uint32_t dwModes) {
   std::unique_ptr<IFXCRT_FileAccess> pFA(IFXCRT_FileAccess::Create());
@@ skipping 274 matching lines @@
     b = ((const uint8_t*)pGUID)[i];
     *pBuf++ = gs_FX_pHexChars[b >> 4];
     *pBuf++ = gs_FX_pHexChars[b & 0x0F];
     if (bSeparator && (i == 3 || i == 5 || i == 7 || i == 9)) {
       *pBuf++ = L'-';
     }
   }
   bsStr.ReleaseBuffer(bSeparator ? 36 : 32);
 }
 #endif  // PDF_ENABLE_XFA