Cleanup XML buffer code

This CL removes the CXML_DataStmAcc class which was unused and moves the
CXML_DataBufAcc to a separate file. This removes the use of the
IFX_BufferedReadStream as the parent class and removes default
implemented methods.

Change-Id: I5a3921d5a6f882d54cc1c74305f1a777aa4cebfc
Reviewed-on: https://pdfium-review.googlesource.com/4292
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>

6 files changed, 58 insertions, 157 deletions

diff --git a/BUILD.gn b/BUILD.gn
index 9b879f5b1b..9c370c258b 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -793,6 +793,8 @@ static_library("fxcrt") {
     "core/fxcrt/xml/cxml_attrmap.cpp",
     "core/fxcrt/xml/cxml_attrmap.h",
     "core/fxcrt/xml/cxml_content.h",
+    "core/fxcrt/xml/cxml_databufacc.cpp",
+    "core/fxcrt/xml/cxml_databufacc.h",
     "core/fxcrt/xml/cxml_element.cpp",
     "core/fxcrt/xml/cxml_element.h",
     "core/fxcrt/xml/cxml_parser.cpp",
diff --git a/core/fxcrt/fx_stream.h b/core/fxcrt/fx_stream.h
index f77da29de3..c9306c9548 100644
--- a/core/fxcrt/fx_stream.h
+++ b/core/fxcrt/fx_stream.h
@@ -127,19 +127,6 @@ class IFX_MemoryStream : public IFX_SeekableStream {
   virtual void DetachBuffer() = 0;
 };
 
-class IFX_BufferedReadStream : public IFX_ReadStream {
- public:
-  // IFX_ReadStream:
-  bool IsEOF() override = 0;
-  FX_FILESIZE GetPosition() override = 0;
-  size_t ReadBlock(void* buffer, size_t size) override = 0;
-
-  virtual bool ReadNextBlock(bool bRestart = false) = 0;
-  virtual const uint8_t* GetBlockBuffer() = 0;
-  virtual size_t GetBlockSize() = 0;
-  virtual FX_FILESIZE GetBlockOffset() = 0;
-};
-
 #ifdef PDF_ENABLE_XFA
 class IFX_FileAccess : public CFX_Retainable {
  public:
diff --git a/core/fxcrt/xml/cxml_databufacc.cpp b/core/fxcrt/xml/cxml_databufacc.cpp
new file mode 100644
index 0000000000..b3e2e1f3e0
--- /dev/null
+++ b/core/fxcrt/xml/cxml_databufacc.cpp
@@ -0,0 +1,20 @@
+// Copyright 2017 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/xml/cxml_databufacc.h"
+
+CXML_DataBufAcc::CXML_DataBufAcc(const uint8_t* pBuffer, size_t size)
+    : m_pBuffer(pBuffer), m_dwSize(size), m_dwCurPos(0) {}
+
+CXML_DataBufAcc::~CXML_DataBufAcc() {}
+
+bool CXML_DataBufAcc::ReadNextBlock() {
+  if (m_dwCurPos >= m_dwSize)
+    return false;
+
+  m_dwCurPos = m_dwSize;
+  return true;
+}
diff --git a/core/fxcrt/xml/cxml_databufacc.h b/core/fxcrt/xml/cxml_databufacc.h
new file mode 100644
index 0000000000..4fb44b302c
--- /dev/null
+++ b/core/fxcrt/xml/cxml_databufacc.h
@@ -0,0 +1,31 @@
+// Copyright 2017 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_FXCRT_XML_CXML_DATABUFACC_H_
+#define CORE_FXCRT_XML_CXML_DATABUFACC_H_
+
+#include "core/fxcrt/fx_system.h"
+
+class CXML_DataBufAcc {
+ public:
+  CXML_DataBufAcc(const uint8_t* pBuffer, size_t size);
+  ~CXML_DataBufAcc();
+
+  bool IsEOF() const { return m_dwCurPos >= m_dwSize; }
+  FX_FILESIZE GetPosition() const {
+    return static_cast<FX_FILESIZE>(m_dwCurPos);
+  }
+  bool ReadNextBlock();
+  const uint8_t* GetBlockBuffer() const { return m_pBuffer; }
+  size_t GetBlockSize() const { return m_dwSize; }
+
+ private:
+  const uint8_t* m_pBuffer;
+  size_t m_dwSize;
+  size_t m_dwCurPos;
+};
+
+#endif  // CORE_FXCRT_XML_CXML_DATABUFACC_H_
diff --git a/core/fxcrt/xml/cxml_parser.cpp b/core/fxcrt/xml/cxml_parser.cpp
index be48b7adc2..09c61d1b32 100644
--- a/core/fxcrt/xml/cxml_parser.cpp
+++ b/core/fxcrt/xml/cxml_parser.cpp
@@ -69,147 +69,6 @@ bool g_FXCRT_XML_IsNameChar(uint8_t ch) {
   return !!(g_FXCRT_XML_ByteTypes[ch] & FXCRTM_XML_CHARTYPE_NameChar);
 }
 
-class CXML_DataBufAcc : public IFX_BufferedReadStream {
- public:
-  template <typename T, typename... Args>
-  friend CFX_RetainPtr<T> pdfium::MakeRetain(Args&&... args);
-
-  // IFX_BufferedReadStream
-  bool IsEOF() override;
-  FX_FILESIZE GetPosition() override;
-  size_t ReadBlock(void* buffer, size_t size) override;
-  bool ReadNextBlock(bool bRestart) override;
-  const uint8_t* GetBlockBuffer() override;
-  size_t GetBlockSize() override;
-  FX_FILESIZE GetBlockOffset() override;
-
- private:
-  CXML_DataBufAcc(const uint8_t* pBuffer, size_t size);
-  ~CXML_DataBufAcc() override;
-
-  const uint8_t* m_pBuffer;
-  size_t m_dwSize;
-  size_t m_dwCurPos;
-};
-
-CXML_DataBufAcc::CXML_DataBufAcc(const uint8_t* pBuffer, size_t size)
-    : m_pBuffer(pBuffer), m_dwSize(size), m_dwCurPos(0) {}
-
-CXML_DataBufAcc::~CXML_DataBufAcc() {}
-
-bool CXML_DataBufAcc::IsEOF() {
-  return m_dwCurPos >= m_dwSize;
-}
-
-FX_FILESIZE CXML_DataBufAcc::GetPosition() {
-  return static_cast<FX_FILESIZE>(m_dwCurPos);
-}
-
-size_t CXML_DataBufAcc::ReadBlock(void* buffer, size_t size) {
-  return 0;
-}
-
-bool CXML_DataBufAcc::ReadNextBlock(bool bRestart) {
-  if (bRestart)
-    m_dwCurPos = 0;
-
-  if (m_dwCurPos < m_dwSize) {
-    m_dwCurPos = m_dwSize;
-    return true;
-  }
-  return false;
-}
-
-const uint8_t* CXML_DataBufAcc::GetBlockBuffer() {
-  return m_pBuffer;
-}
-
-size_t CXML_DataBufAcc::GetBlockSize() {
-  return m_dwSize;
-}
-
-FX_FILESIZE CXML_DataBufAcc::GetBlockOffset() {
-  return 0;
-}
-
-class CXML_DataStmAcc : public IFX_BufferedReadStream {
- public:
-  template <typename T, typename... Args>
-  friend CFX_RetainPtr<T> pdfium::MakeRetain(Args&&... args);
-
-  // IFX_BufferedReadStream
-  bool IsEOF() override;
-  FX_FILESIZE GetPosition() override;
-  size_t ReadBlock(void* buffer, size_t size) override;
-  bool ReadNextBlock(bool bRestart) override;
-  const uint8_t* GetBlockBuffer() override;
-  size_t GetBlockSize() override;
-  FX_FILESIZE GetBlockOffset() override;
-
- private:
-  explicit CXML_DataStmAcc(
-      const CFX_RetainPtr<IFX_SeekableReadStream>& pFileRead);
-  ~CXML_DataStmAcc() override;
-
-  CFX_RetainPtr<IFX_SeekableReadStream> m_pFileRead;
-  uint8_t* m_pBuffer;
-  FX_FILESIZE m_nStart;
-  size_t m_dwSize;
-};
-
-CXML_DataStmAcc::CXML_DataStmAcc(
-    const CFX_RetainPtr<IFX_SeekableReadStream>& pFileRead)
-    : m_pFileRead(pFileRead), m_pBuffer(nullptr), m_nStart(0), m_dwSize(0) {
-  ASSERT(m_pFileRead);
-}
-
-CXML_DataStmAcc::~CXML_DataStmAcc() {
-  FX_Free(m_pBuffer);
-}
-
-bool CXML_DataStmAcc::IsEOF() {
-  return m_nStart + static_cast<FX_FILESIZE>(m_dwSize) >=
-         m_pFileRead->GetSize();
-}
-
-FX_FILESIZE CXML_DataStmAcc::GetPosition() {
-  return m_nStart + static_cast<FX_FILESIZE>(m_dwSize);
-}
-
-size_t CXML_DataStmAcc::ReadBlock(void* buffer, size_t size) {
-  return 0;
-}
-
-bool CXML_DataStmAcc::ReadNextBlock(bool bRestart) {
-  if (bRestart)
-    m_nStart = 0;
-
-  FX_FILESIZE nLength = m_pFileRead->GetSize();
-  m_nStart += static_cast<FX_FILESIZE>(m_dwSize);
-  if (m_nStart >= nLength)
-    return false;
-
-  static const FX_FILESIZE FX_XMLDATASTREAM_BufferSize = 32 * 1024;
-  m_dwSize = static_cast<size_t>(
-      std::min(FX_XMLDATASTREAM_BufferSize, nLength - m_nStart));
-  if (!m_pBuffer)
-    m_pBuffer = FX_Alloc(uint8_t, m_dwSize);
-
-  return m_pFileRead->ReadBlock(m_pBuffer, m_nStart, m_dwSize);
-}
-
-const uint8_t* CXML_DataStmAcc::GetBlockBuffer() {
-  return (const uint8_t*)m_pBuffer;
-}
-
-size_t CXML_DataStmAcc::GetBlockSize() {
-  return m_dwSize;
-}
-
-FX_FILESIZE CXML_DataStmAcc::GetBlockOffset() {
-  return m_nStart;
-}
-
 }  // namespace
 
 void FX_XML_SplitQualifiedName(const CFX_ByteStringC& bsFullName,
@@ -237,7 +96,7 @@ CXML_Parser::CXML_Parser()
 CXML_Parser::~CXML_Parser() {}
 
 bool CXML_Parser::Init(const uint8_t* pBuffer, size_t size) {
-  m_pDataAcc = pdfium::MakeRetain<CXML_DataBufAcc>(pBuffer, size);
+  m_pDataAcc = pdfium::MakeUnique<CXML_DataBufAcc>(pBuffer, size);
   m_nOffset = 0;
   return ReadNextBlock();
 }
@@ -248,7 +107,7 @@ bool CXML_Parser::ReadNextBlock() {
 
   m_pBuffer = m_pDataAcc->GetBlockBuffer();
   m_dwBufferSize = m_pDataAcc->GetBlockSize();
-  m_nBufferOffset = m_pDataAcc->GetBlockOffset();
+  m_nBufferOffset = 0;
   m_dwIndex = 0;
   return m_dwBufferSize > 0;
 }
diff --git a/core/fxcrt/xml/cxml_parser.h b/core/fxcrt/xml/cxml_parser.h
index 37f14e9834..371edf2ebb 100644
--- a/core/fxcrt/xml/cxml_parser.h
+++ b/core/fxcrt/xml/cxml_parser.h
@@ -11,6 +11,7 @@
 #include <memory>
 
 #include "core/fxcrt/fx_stream.h"
+#include "core/fxcrt/xml/cxml_databufacc.h"
 
 class CFX_UTF8Decoder;
 class CXML_Element;
@@ -40,7 +41,8 @@ class CXML_Parser {
                             CXML_Element* pElement);
   void InsertCDATASegment(CFX_UTF8Decoder& decoder, CXML_Element* pElement);
 
-  CFX_RetainPtr<IFX_BufferedReadStream> m_pDataAcc;
+ private:
+  std::unique_ptr<CXML_DataBufAcc> m_pDataAcc;
   FX_FILESIZE m_nOffset;
   const uint8_t* m_pBuffer;
   size_t m_dwBufferSize;