Return unique_ptr from GetAlphaMask.

core/fpdfapi/page/cpdf_image.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/page/cpdf_image.h"
 
 #include <algorithm>
 #include <memory>
@@ skipping 212 matching lines @@
     }
     pDict->SetNewFor<CPDF_Number>("BitsPerComponent", 8);
     dest_pitch = BitmapWidth;
   } else {
     pDict->SetNewFor<CPDF_Name>("ColorSpace", "DeviceRGB");
     pDict->SetNewFor<CPDF_Number>("BitsPerComponent", 8);
     dest_pitch = BitmapWidth * 3;
     bCopyWithoutAlpha = false;
   }
 
-  const CFX_DIBitmap* pMaskBitmap =
-      pBitmap->HasAlpha() ? pBitmap->GetAlphaMask() : nullptr;
+  std::unique_ptr<CFX_DIBitmap> pMaskBitmap;
+  if (pBitmap->HasAlpha())
+    pMaskBitmap = pBitmap->CloneAlphaMask();
+
   if (pMaskBitmap) {
     int32_t maskWidth = pMaskBitmap->GetWidth();
     int32_t maskHeight = pMaskBitmap->GetHeight();
     uint8_t* mask_buf = nullptr;
     FX_STRSIZE mask_size = 0;
     auto pMaskDict =
         pdfium::MakeUnique<CPDF_Dictionary>(m_pDocument->GetByteStringPool());
     pMaskDict->SetNewFor<CPDF_Name>("Type", "XObject");
     pMaskDict->SetNewFor<CPDF_Name>("Subtype", "Image");
     pMaskDict->SetNewFor<CPDF_Number>("Width", maskWidth);
     pMaskDict->SetNewFor<CPDF_Number>("Height", maskHeight);
     pMaskDict->SetNewFor<CPDF_Name>("ColorSpace", "DeviceGray");
     pMaskDict->SetNewFor<CPDF_Number>("BitsPerComponent", 8);
     if (pMaskBitmap->GetFormat() != FXDIB_1bppMask) {
       mask_buf = FX_Alloc2D(uint8_t, maskHeight, maskWidth);
       mask_size = maskHeight * maskWidth;  // Safe since checked alloc returned.
       for (int32_t a = 0; a < maskHeight; a++) {
         FXSYS_memcpy(mask_buf + a * maskWidth, pMaskBitmap->GetScanline(a),
                      maskWidth);
       }
     }
     pMaskDict->SetNewFor<CPDF_Number>("Length", mask_size);
     CPDF_Stream* pNewStream = m_pDocument->NewIndirect<CPDF_Stream>(
         mask_buf, mask_size, std::move(pMaskDict));
     pDict->SetNewFor<CPDF_Reference>("SMask", m_pDocument,
                                      pNewStream->GetObjNum());
-    delete pMaskBitmap;
   }
 
   uint8_t* src_buf = pBitmap->GetBuffer();
   int32_t src_pitch = pBitmap->GetPitch();
   uint8_t* dest_buf = FX_Alloc2D(uint8_t, dest_pitch, BitmapHeight);
   // Safe as checked alloc returned.
   FX_STRSIZE dest_size = dest_pitch * BitmapHeight;
   uint8_t* pDest = dest_buf;
   if (bCopyWithoutAlpha) {
     for (int32_t i = 0; i < BitmapHeight; i++) {
@@ skipping 90 matching lines @@
   }
   if (!ret) {
     delete m_pDIBSource;
     m_pDIBSource = nullptr;
     return false;
   }
   m_pMask = pSource->DetachMask();
   m_MatteColor = pSource->GetMatteColor();
   return false;
 }