use unique_ptr in xfa_checksum.h

xfa/fxfa/app/xfa_checksum.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 "xfa/fxfa/xfa_checksum.h"
 
 #include "core/fdrm/crypto/fx_crypt.h"
+#include "third_party/base/ptr_util.h"
 
 namespace {
 
 struct FX_BASE64DATA {
   uint32_t data1 : 2;
   uint32_t data2 : 6;
   uint32_t data3 : 4;
   uint32_t data4 : 4;
   uint32_t data5 : 6;
   uint32_t data6 : 2;
@@ skipping 183 matching lines @@
         break;
       }
     }
   }
   if (bUpdata) {
     m_pContext->Update(CFX_ByteStringC(pBuffer, iLength));
   }
   m_SAXContext.m_TextBuf.Clear();
 }
 
-CXFA_ChecksumContext::CXFA_ChecksumContext()
-    : m_pSAXReader(nullptr), m_pByteContext(nullptr) {}
+CXFA_ChecksumContext::CXFA_ChecksumContext() {}
 
-CXFA_ChecksumContext::~CXFA_ChecksumContext() {
-  FinishChecksum();
-}
+CXFA_ChecksumContext::~CXFA_ChecksumContext() {}
 
 void CXFA_ChecksumContext::StartChecksum() {
   FinishChecksum();
-  m_pByteContext = FX_Alloc(CRYPT_sha1_context, 1);
-  CRYPT_SHA1Start(m_pByteContext);
+  m_pByteContext = pdfium::MakeUnique<CRYPT_sha1_context>();
+  CRYPT_SHA1Start(m_pByteContext.get());
   m_bsChecksum.clear();
-  m_pSAXReader = new CFX_SAXReader;
+  m_pSAXReader = pdfium::MakeUnique<CFX_SAXReader>();
 }
 
 bool CXFA_ChecksumContext::UpdateChecksum(
     const CFX_RetainPtr<IFX_SeekableReadStream>& pSrcFile,
     FX_FILESIZE offset,
     size_t size) {
   if (!m_pSAXReader || !pSrcFile)
     return false;
 
   if (size < 1)
     size = pSrcFile->GetSize();
 
   CXFA_SAXReaderHandler handler(this);
   m_pSAXReader->SetHandler(&handler);
   if (m_pSAXReader->StartParse(
           pSrcFile, (uint32_t)offset, (uint32_t)size,
           CFX_SaxParseMode_NotSkipSpace | CFX_SaxParseMode_NotConvert_amp |
               CFX_SaxParseMode_NotConvert_lt | CFX_SaxParseMode_NotConvert_gt |
               CFX_SaxParseMode_NotConvert_sharp) < 0) {
     return false;
   }
   return m_pSAXReader->ContinueParse(nullptr) > 99;
 }
 
 void CXFA_ChecksumContext::FinishChecksum() {
-  delete m_pSAXReader;
-  m_pSAXReader = nullptr;
+  m_pSAXReader.reset();
   if (m_pByteContext) {
     uint8_t digest[20];
     FXSYS_memset(digest, 0, 20);
-    CRYPT_SHA1Finish(m_pByteContext, digest);
+    CRYPT_SHA1Finish(m_pByteContext.get(), digest);
     int32_t nLen = Base64EncodeA(digest, 20, nullptr);
     FX_CHAR* pBuffer = m_bsChecksum.GetBuffer(nLen);
     Base64EncodeA(digest, 20, pBuffer);
     m_bsChecksum.ReleaseBuffer(nLen);
-    FX_Free(m_pByteContext);
-    m_pByteContext = nullptr;
+    m_pByteContext.reset();
   }
 }
 
 CFX_ByteString CXFA_ChecksumContext::GetChecksum() const {
   return m_bsChecksum;
 }
 
 void CXFA_ChecksumContext::Update(const CFX_ByteStringC& bsText) {
-  if (m_pByteContext) {
-    CRYPT_SHA1Update(m_pByteContext, bsText.raw_str(), bsText.GetLength());
-  }
+  if (!m_pByteContext)
+    return;
+
+  CRYPT_SHA1Update(m_pByteContext.get(), bsText.raw_str(), bsText.GetLength());
 }