Subclass the stream implementations from CFGAS_Stream

Rename CFGAS_TextStream to CFGAS_Stream. CFGAS_Stream is converted
to a base class instead of accepting an IFGAS_StreamImp. Things
which inherted from IFGAS_StreamImp now inherit from CFGAS_Stream.

The stream type inputs are changed to IFX_SeekableStream so that
they can accept the same type (IFX_SeekableStream is an
IFX_SeekableWriteStream and an IFX_SeekableReadStream). This way
the storage can be shared in the base class.

Change-Id: I06645071e68e2a4d4120c0e336529f2c18c2b705
Reviewed-on: https://pdfium-review.googlesource.com/4152
Commit-Queue: dsinclair <dsinclair@chromium.org>
Reviewed-by: Nicolás Peña <npm@chromium.org>

14 files changed, 194 insertions, 273 deletions

diff --git a/xfa/fgas/crt/ifgas_stream.cpp b/xfa/fgas/crt/ifgas_stream.cpp
index 41913b28b6..3f5069e4bb 100644
--- a/xfa/fgas/crt/ifgas_stream.cpp
+++ b/xfa/fgas/crt/ifgas_stream.cpp
@@ -23,91 +23,64 @@
 
 namespace {
 
-class IFGAS_StreamImp {
+class CFGAS_Stream : public IFGAS_Stream {
  public:
-  virtual ~IFGAS_StreamImp() {}
-
-  virtual FX_FILESIZE GetLength() const = 0;
-  virtual FX_FILESIZE GetPosition() = 0;
-
-  virtual void Seek(FX_STREAMSEEK eSeek, FX_FILESIZE iOffset) = 0;
-  virtual bool IsEOF() const = 0;
-
-  virtual FX_STRSIZE ReadData(uint8_t* pBuffer, FX_STRSIZE iBufferSize) = 0;
-  virtual void WriteData(const CFX_WideStringC& str) = 0;
+  // IFGAS_Stream
+  FX_FILESIZE GetLength() const override { return m_pStream->GetSize(); }
+  FX_FILESIZE GetPosition() override { return m_iPosition; }
+  FX_STRSIZE GetBOMLength() const override { return std::max(0, m_wBOMLength); }
+  FX_STRSIZE ReadString(wchar_t* pStr,
+                        FX_STRSIZE iMaxLength,
+                        bool* bEOS) override;
+  void Seek(FX_STREAMSEEK eSeek, FX_FILESIZE iOffset) override;
+  bool IsEOF() const override { return m_iPosition >= GetLength(); }
+  void WriteString(const CFX_WideStringC& str) override;
+  uint16_t GetCodePage() const override { return m_wCodePage; }
+  void SetCodePage(uint16_t wCodePage) override;
 
  protected:
-  IFGAS_StreamImp();
-};
-
-class CFGAS_FileReadStreamImp : public IFGAS_StreamImp {
- public:
-  explicit CFGAS_FileReadStreamImp(
-      const CFX_RetainPtr<IFX_SeekableReadStream>& pFileRead);
-  ~CFGAS_FileReadStreamImp() override {}
+  CFGAS_Stream(const CFX_RetainPtr<IFX_SeekableStream>& stream,
+               bool isWriteSteam);
+  ~CFGAS_Stream() override;
 
-  // IFGAS_StreamImp:
-  FX_FILESIZE GetLength() const override;
-  FX_FILESIZE GetPosition() override { return m_iPosition; }
-  void Seek(FX_STREAMSEEK eSeek, FX_FILESIZE iOffset) override;
-  bool IsEOF() const override;
-  FX_STRSIZE ReadData(uint8_t* pBuffer, FX_STRSIZE iBufferSize) override;
-  void WriteData(const CFX_WideStringC& str) override {}
+  virtual FX_STRSIZE ReadData(uint8_t* pBuffer, FX_STRSIZE iBufferSize) {
+    return 0;
+  }
+  virtual void WriteData(const CFX_WideStringC& str) {}
 
- private:
-  CFX_RetainPtr<IFX_SeekableReadStream> m_pFileRead;
+  uint16_t m_wCodePage;
+  FX_STRSIZE m_wBOMLength;
+  bool m_IsWriteStream;
   FX_FILESIZE m_iPosition;
+  CFX_RetainPtr<IFX_SeekableStream> m_pStream;
 };
 
-class CFGAS_FileWriteStreamImp : public IFGAS_StreamImp {
+class CFGAS_FileReadStreamImp : public CFGAS_Stream {
  public:
-  CFGAS_FileWriteStreamImp(
-      const CFX_RetainPtr<IFX_SeekableWriteStream>& pFileWrite);
-  ~CFGAS_FileWriteStreamImp() override {}
+  template <typename T, typename... Args>
+  friend CFX_RetainPtr<T> pdfium::MakeRetain(Args&&... args);
 
-  // IFGAS_StreamImp:
-  FX_FILESIZE GetLength() const override;
-  FX_FILESIZE GetPosition() override { return m_iPosition; }
-  void Seek(FX_STREAMSEEK eSeek, FX_FILESIZE iOffset) override;
-  bool IsEOF() const override;
-  FX_STRSIZE ReadData(uint8_t* pBuffer, FX_STRSIZE iBufferSize) override {
-    return 0;
-  }
-  void WriteData(const CFX_WideStringC& str) override;
+  // CFGAS_Stream:
+  FX_STRSIZE ReadData(uint8_t* pBuffer, FX_STRSIZE iBufferSize) override;
 
  private:
-  CFX_RetainPtr<IFX_SeekableWriteStream> m_pFileWrite;
-  FX_FILESIZE m_iPosition;
+  explicit CFGAS_FileReadStreamImp(
+      const CFX_RetainPtr<IFX_SeekableStream>& pFileRead);
+  ~CFGAS_FileReadStreamImp() override {}
 };
 
-class CFGAS_TextStream : public IFGAS_Stream {
+class CFGAS_FileWriteStreamImp : public CFGAS_Stream {
  public:
   template <typename T, typename... Args>
   friend CFX_RetainPtr<T> pdfium::MakeRetain(Args&&... args);
 
-  // IFGAS_Stream
-  FX_FILESIZE GetLength() const override;
-  FX_FILESIZE GetPosition() override;
-  FX_STRSIZE GetBOMLength() const override;
-  void Seek(FX_STREAMSEEK eSeek, FX_FILESIZE iOffset) override;
-  bool IsEOF() const override;
-  FX_STRSIZE ReadString(wchar_t* pStr,
-                        FX_STRSIZE iMaxLength,
-                        bool* bEOS) override;
-  void WriteString(const CFX_WideStringC& str) override;
-  uint16_t GetCodePage() const override;
-  void SetCodePage(uint16_t wCodePage) override;
+  // CFGAS_Stream:
+  void WriteData(const CFX_WideStringC& str) override;
 
  private:
-  CFGAS_TextStream(std::unique_ptr<IFGAS_StreamImp> imp, bool isWriteSteam);
-  ~CFGAS_TextStream() override;
-
-  void InitStream();
-
-  uint16_t m_wCodePage;
-  FX_STRSIZE m_wBOMLength;
-  bool m_IsWriteStream;
-  std::unique_ptr<IFGAS_StreamImp> m_pStreamImp;
+  explicit CFGAS_FileWriteStreamImp(
+      const CFX_RetainPtr<IFX_SeekableStream>& pFileWrite);
+  ~CFGAS_FileWriteStreamImp() override {}
 };
 
 class CFGAS_WideStringReadStream : public IFGAS_Stream {
@@ -116,16 +89,20 @@ class CFGAS_WideStringReadStream : public IFGAS_Stream {
   friend CFX_RetainPtr<T> pdfium::MakeRetain(Args&&... args);
 
   // IFGAS_Stream
-  FX_FILESIZE GetLength() const override;
-  FX_FILESIZE GetPosition() override;
+  FX_FILESIZE GetLength() const override {
+    return m_wsBuffer.GetLength() * sizeof(wchar_t);
+  }
+  FX_FILESIZE GetPosition() override { return m_iPosition * sizeof(wchar_t); }
   FX_STRSIZE GetBOMLength() const override { return 0; }
   void Seek(FX_STREAMSEEK eSeek, FX_FILESIZE iOffset) override;
-  bool IsEOF() const override;
+  bool IsEOF() const override { return m_iPosition >= m_wsBuffer.GetLength(); }
   FX_STRSIZE ReadString(wchar_t* pStr,
                         FX_STRSIZE iMaxLength,
                         bool* bEOS) override;
   void WriteString(const CFX_WideStringC& str) override {}
-  uint16_t GetCodePage() const override;
+  uint16_t GetCodePage() const override {
+    return sizeof(wchar_t) == 2 ? FX_CODEPAGE_UTF16LE : FX_CODEPAGE_UTF32LE;
+  }
   void SetCodePage(uint16_t wCodePage) override {}
 
  private:
@@ -228,7 +205,7 @@ void SwapByteOrder(wchar_t* pStr, FX_STRSIZE iLength) {
       wch = (wch >> 8) | (wch << 8);
       wch &= 0x00FF;
       *pStr = wch;
-      pStr++;
+      ++pStr;
     }
     return;
   }
@@ -237,117 +214,10 @@ void SwapByteOrder(wchar_t* pStr, FX_STRSIZE iLength) {
     wch = static_cast<uint16_t>(*pStr);
     wch = (wch >> 8) | (wch << 8);
     *pStr = wch;
-    pStr++;
+    ++pStr;
   }
 }
 
-IFGAS_StreamImp::IFGAS_StreamImp() {}
-
-CFGAS_FileReadStreamImp::CFGAS_FileReadStreamImp(
-    const CFX_RetainPtr<IFX_SeekableReadStream>& pFileRead)
-    : m_pFileRead(pFileRead), m_iPosition(0) {
-  ASSERT(m_pFileRead);
-}
-
-FX_FILESIZE CFGAS_FileReadStreamImp::GetLength() const {
-  return m_pFileRead->GetSize();
-}
-
-void CFGAS_FileReadStreamImp::Seek(FX_STREAMSEEK eSeek, FX_FILESIZE iOffset) {
-  switch (eSeek) {
-    case FX_STREAMSEEK_Begin:
-      m_iPosition = iOffset;
-      break;
-    case FX_STREAMSEEK_Current:
-      m_iPosition += iOffset;
-      break;
-  }
-  m_iPosition = pdfium::clamp(m_iPosition, static_cast<FX_FILESIZE>(0),
-                              m_pFileRead->GetSize());
-}
-
-bool CFGAS_FileReadStreamImp::IsEOF() const {
-  return m_iPosition >= m_pFileRead->GetSize();
-}
-
-FX_STRSIZE CFGAS_FileReadStreamImp::ReadData(uint8_t* pBuffer,
-                                             FX_STRSIZE iBufferSize) {
-  ASSERT(pBuffer && iBufferSize > 0);
-
-  iBufferSize =
-      std::min(iBufferSize,
-               static_cast<FX_STRSIZE>(m_pFileRead->GetSize() - m_iPosition));
-  if (iBufferSize <= 0)
-    return 0;
-
-  if (m_pFileRead->ReadBlock(pBuffer, m_iPosition, iBufferSize)) {
-    pdfium::base::CheckedNumeric<FX_FILESIZE> new_pos = m_iPosition;
-    new_pos += iBufferSize;
-    if (!new_pos.IsValid())
-      return 0;
-
-    m_iPosition = new_pos.ValueOrDie();
-    return iBufferSize;
-  }
-  return 0;
-}
-
-CFGAS_FileWriteStreamImp::CFGAS_FileWriteStreamImp(
-    const CFX_RetainPtr<IFX_SeekableWriteStream>& pFileWrite)
-    : m_pFileWrite(pFileWrite), m_iPosition(m_pFileWrite->GetSize()) {
-  ASSERT(m_pFileWrite);
-}
-
-FX_FILESIZE CFGAS_FileWriteStreamImp::GetLength() const {
-  return m_pFileWrite->GetSize();
-}
-
-void CFGAS_FileWriteStreamImp::Seek(FX_STREAMSEEK eSeek, FX_FILESIZE iOffset) {
-  FX_FILESIZE iLength = GetLength();
-  switch (eSeek) {
-    case FX_STREAMSEEK_Begin:
-      m_iPosition = iOffset;
-      break;
-    case FX_STREAMSEEK_Current:
-      m_iPosition += iOffset;
-      break;
-  }
-  m_iPosition =
-      pdfium::clamp(m_iPosition, static_cast<FX_FILESIZE>(0), iLength);
-}
-
-bool CFGAS_FileWriteStreamImp::IsEOF() const {
-  return m_iPosition >= GetLength();
-}
-
-void CFGAS_FileWriteStreamImp::WriteData(const CFX_WideStringC& str) {
-  if (str.GetLength() == 0)
-    return;
-
-  if (m_pFileWrite->WriteBlock(str.c_str(), m_iPosition,
-                               str.GetLength() * sizeof(wchar_t))) {
-    pdfium::base::CheckedNumeric<FX_STRSIZE> new_pos = m_iPosition;
-    new_pos += str.GetLength() * sizeof(wchar_t);
-    // TODO(dsinclair): Not sure what to do if we over flow ....
-    if (!new_pos.IsValid())
-      return;
-
-    m_iPosition = new_pos.ValueOrDie();
-  }
-}
-
-CFGAS_TextStream::CFGAS_TextStream(std::unique_ptr<IFGAS_StreamImp> imp,
-                                   bool isWriteStream)
-    : m_wCodePage(FX_CODEPAGE_DefANSI),
-      m_wBOMLength(0),
-      m_IsWriteStream(isWriteStream),
-      m_pStreamImp(std::move(imp)) {
-  ASSERT(m_pStreamImp);
-  InitStream();
-}
-
-CFGAS_TextStream::~CFGAS_TextStream() {}
-
 #if _FX_ENDIAN_ == _FX_LITTLE_ENDIAN_
 #define BOM_MASK 0x00FFFFFF
 #define BOM_UTF8 0x00BFBBEF
@@ -362,12 +232,14 @@ CFGAS_TextStream::~CFGAS_TextStream() {}
 #define BOM_UTF16_LE 0xFFFE0000
 #endif  // _FX_ENDIAN_ == _FX_LITTLE_ENDIAN_
 
-void CFGAS_TextStream::InitStream() {
-  FX_FILESIZE iPosition = m_pStreamImp->GetPosition();
-  m_pStreamImp->Seek(FX_STREAMSEEK_Begin, 0);
+CFGAS_FileReadStreamImp::CFGAS_FileReadStreamImp(
+    const CFX_RetainPtr<IFX_SeekableStream>& pFileRead)
+    : CFGAS_Stream(pFileRead, false) {
+  FX_FILESIZE iPosition = GetPosition();
+  Seek(FX_STREAMSEEK_Begin, 0);
 
   uint32_t bom;
-  m_pStreamImp->ReadData(reinterpret_cast<uint8_t*>(&bom), 3);
+  ReadData(reinterpret_cast<uint8_t*>(&bom), 3);
 
   bom &= BOM_MASK;
   if (bom == BOM_UTF8) {
@@ -387,46 +259,88 @@ void CFGAS_TextStream::InitStream() {
     }
   }
 
-  m_pStreamImp->Seek(
-      FX_STREAMSEEK_Begin,
-      std::max(static_cast<FX_FILESIZE>(m_wBOMLength), iPosition));
+  Seek(FX_STREAMSEEK_Begin,
+       std::max(static_cast<FX_FILESIZE>(m_wBOMLength), iPosition));
 }
 
-FX_FILESIZE CFGAS_TextStream::GetLength() const {
-  return m_pStreamImp->GetLength();
-}
+FX_STRSIZE CFGAS_FileReadStreamImp::ReadData(uint8_t* pBuffer,
+                                             FX_STRSIZE iBufferSize) {
+  ASSERT(pBuffer && iBufferSize > 0);
+
+  iBufferSize = std::min(
+      iBufferSize, static_cast<FX_STRSIZE>(m_pStream->GetSize() - m_iPosition));
+  if (iBufferSize <= 0)
+    return 0;
 
-void CFGAS_TextStream::Seek(FX_STREAMSEEK eSeek, FX_FILESIZE iOffset) {
-  m_pStreamImp->Seek(eSeek, iOffset);
+  if (m_pStream->ReadBlock(pBuffer, m_iPosition, iBufferSize)) {
+    pdfium::base::CheckedNumeric<FX_FILESIZE> new_pos = m_iPosition;
+    new_pos += iBufferSize;
+    if (!new_pos.IsValid())
+      return 0;
+
+    m_iPosition = new_pos.ValueOrDie();
+    return iBufferSize;
+  }
+  return 0;
 }
 
-FX_FILESIZE CFGAS_TextStream::GetPosition() {
-  return m_pStreamImp->GetPosition();
+CFGAS_FileWriteStreamImp::CFGAS_FileWriteStreamImp(
+    const CFX_RetainPtr<IFX_SeekableStream>& pFileWrite)
+    : CFGAS_Stream(pFileWrite, true) {
+  m_iPosition = m_pStream->GetSize();
 }
 
-bool CFGAS_TextStream::IsEOF() const {
-  return m_pStreamImp->IsEOF();
+void CFGAS_FileWriteStreamImp::WriteData(const CFX_WideStringC& str) {
+  if (str.GetLength() == 0)
+    return;
+
+  if (!m_pStream->WriteBlock(str.c_str(), m_iPosition,
+                             str.GetLength() * sizeof(wchar_t)))
+    return;
+
+  pdfium::base::CheckedNumeric<FX_STRSIZE> new_pos = m_iPosition;
+  new_pos += str.GetLength() * sizeof(wchar_t);
+  // TODO(dsinclair): Not sure what to do if we over flow ....
+  if (!new_pos.IsValid())
+    return;
+
+  m_iPosition = new_pos.ValueOrDie();
 }
 
-FX_STRSIZE CFGAS_TextStream::GetBOMLength() const {
-  if (m_wBOMLength < 1)
-    return 0;
-  return m_wBOMLength;
+CFGAS_Stream::CFGAS_Stream(const CFX_RetainPtr<IFX_SeekableStream>& stream,
+                           bool isWriteStream)
+    : m_wCodePage(FX_CODEPAGE_DefANSI),
+      m_wBOMLength(0),
+      m_IsWriteStream(isWriteStream),
+      m_iPosition(0),
+      m_pStream(stream) {
+  ASSERT(m_pStream);
 }
 
-uint16_t CFGAS_TextStream::GetCodePage() const {
-  return m_wCodePage;
+CFGAS_Stream::~CFGAS_Stream() {}
+
+void CFGAS_Stream::Seek(FX_STREAMSEEK eSeek, FX_FILESIZE iOffset) {
+  switch (eSeek) {
+    case FX_STREAMSEEK_Begin:
+      m_iPosition = iOffset;
+      break;
+    case FX_STREAMSEEK_Current:
+      m_iPosition += iOffset;
+      break;
+  }
+  m_iPosition =
+      pdfium::clamp(m_iPosition, static_cast<FX_FILESIZE>(0), GetLength());
 }
 
-void CFGAS_TextStream::SetCodePage(uint16_t wCodePage) {
+void CFGAS_Stream::SetCodePage(uint16_t wCodePage) {
   if (m_wBOMLength > 0)
     return;
   m_wCodePage = wCodePage;
 }
 
-FX_STRSIZE CFGAS_TextStream::ReadString(wchar_t* pStr,
-                                        FX_STRSIZE iMaxLength,
-                                        bool* bEOS) {
+FX_STRSIZE CFGAS_Stream::ReadString(wchar_t* pStr,
+                                    FX_STRSIZE iMaxLength,
+                                    bool* bEOS) {
   ASSERT(pStr && iMaxLength > 0);
 
   if (m_IsWriteStream)
@@ -435,8 +349,7 @@ FX_STRSIZE CFGAS_TextStream::ReadString(wchar_t* pStr,
   if (m_wCodePage == FX_CODEPAGE_UTF16LE ||
       m_wCodePage == FX_CODEPAGE_UTF16BE) {
     FX_FILESIZE iBytes = iMaxLength * 2;
-    FX_STRSIZE iLen =
-        m_pStreamImp->ReadData(reinterpret_cast<uint8_t*>(pStr), iBytes);
+    FX_STRSIZE iLen = ReadData(reinterpret_cast<uint8_t*>(pStr), iBytes);
     iMaxLength = iLen / 2;
     if (sizeof(wchar_t) > 2)
       UTF16ToWChar(pStr, iMaxLength);
@@ -450,31 +363,31 @@ FX_STRSIZE CFGAS_TextStream::ReadString(wchar_t* pStr,
 #endif
 
   } else {
-    FX_FILESIZE pos = m_pStreamImp->GetPosition();
-    FX_STRSIZE iBytes = std::min(
-        iMaxLength, static_cast<FX_STRSIZE>(m_pStreamImp->GetLength() - pos));
+    FX_FILESIZE pos = GetPosition();
+    FX_STRSIZE iBytes =
+        std::min(iMaxLength, static_cast<FX_STRSIZE>(GetLength() - pos));
 
     if (iBytes > 0) {
       std::vector<uint8_t> buf(iBytes);
 
-      FX_STRSIZE iLen = m_pStreamImp->ReadData(buf.data(), iBytes);
+      FX_STRSIZE iLen = ReadData(buf.data(), iBytes);
       if (m_wCodePage != FX_CODEPAGE_UTF8)
         return -1;
 
       FX_STRSIZE iSrc = 0;
       std::tie(iSrc, iMaxLength) = UTF8Decode(
           reinterpret_cast<const char*>(buf.data()), iLen, pStr, iMaxLength);
-      m_pStreamImp->Seek(FX_STREAMSEEK_Current, iSrc - iLen);
+      Seek(FX_STREAMSEEK_Current, iSrc - iLen);
     } else {
       iMaxLength = 0;
     }
   }
 
-  *bEOS = m_pStreamImp->IsEOF();
+  *bEOS = IsEOF();
   return iMaxLength;
 }
 
-void CFGAS_TextStream::WriteString(const CFX_WideStringC& str) {
+void CFGAS_Stream::WriteString(const CFX_WideStringC& str) {
   if (!m_IsWriteStream)
     return;
   if (str.GetLength() == 0)
@@ -482,7 +395,7 @@ void CFGAS_TextStream::WriteString(const CFX_WideStringC& str) {
   if (m_wCodePage != FX_CODEPAGE_UTF8)
     return;
 
-  m_pStreamImp->WriteData(str);
+  WriteData(str);
 }
 
 CFGAS_WideStringReadStream::CFGAS_WideStringReadStream(
@@ -491,10 +404,6 @@ CFGAS_WideStringReadStream::CFGAS_WideStringReadStream(
 
 CFGAS_WideStringReadStream::~CFGAS_WideStringReadStream() {}
 
-FX_FILESIZE CFGAS_WideStringReadStream::GetLength() const {
-  return m_wsBuffer.GetLength() * sizeof(wchar_t);
-}
-
 void CFGAS_WideStringReadStream::Seek(FX_STREAMSEEK eSeek,
                                       FX_FILESIZE iOffset) {
   switch (eSeek) {
@@ -509,14 +418,6 @@ void CFGAS_WideStringReadStream::Seek(FX_STREAMSEEK eSeek,
                               static_cast<FX_FILESIZE>(m_wsBuffer.GetLength()));
 }
 
-FX_FILESIZE CFGAS_WideStringReadStream::GetPosition() {
-  return m_iPosition * sizeof(wchar_t);
-}
-
-bool CFGAS_WideStringReadStream::IsEOF() const {
-  return m_iPosition >= m_wsBuffer.GetLength();
-}
-
 FX_STRSIZE CFGAS_WideStringReadStream::ReadString(wchar_t* pStr,
                                                   FX_STRSIZE iMaxLength,
                                                   bool* bEOS) {
@@ -532,30 +433,24 @@ FX_STRSIZE CFGAS_WideStringReadStream::ReadString(wchar_t* pStr,
   return iMaxLength;
 }
 
-uint16_t CFGAS_WideStringReadStream::GetCodePage() const {
-  return (sizeof(wchar_t) == 2) ? FX_CODEPAGE_UTF16LE : FX_CODEPAGE_UTF32LE;
-}
-
 }  // namespace
 
 // static
 CFX_RetainPtr<IFGAS_Stream> IFGAS_Stream::CreateReadStream(
-    const CFX_RetainPtr<IFX_SeekableReadStream>& pFileRead) {
+    const CFX_RetainPtr<IFX_SeekableStream>& pFileRead) {
   if (!pFileRead)
     return nullptr;
 
-  return pdfium::MakeRetain<CFGAS_TextStream>(
-      pdfium::MakeUnique<CFGAS_FileReadStreamImp>(pFileRead), false);
+  return pdfium::MakeRetain<CFGAS_FileReadStreamImp>(pFileRead);
 }
 
 // static
 CFX_RetainPtr<IFGAS_Stream> IFGAS_Stream::CreateWriteStream(
-    const CFX_RetainPtr<IFX_SeekableWriteStream>& pFileWrite) {
+    const CFX_RetainPtr<IFX_SeekableStream>& pFileWrite) {
   if (!pFileWrite)
     return nullptr;
 
-  return pdfium::MakeRetain<CFGAS_TextStream>(
-      pdfium::MakeUnique<CFGAS_FileWriteStreamImp>(pFileWrite), true);
+  return pdfium::MakeRetain<CFGAS_FileWriteStreamImp>(pFileWrite);
 }
 
 // static
diff --git a/xfa/fgas/crt/ifgas_stream.h b/xfa/fgas/crt/ifgas_stream.h
index be42fe5ca3..620a023dd8 100644
--- a/xfa/fgas/crt/ifgas_stream.h
+++ b/xfa/fgas/crt/ifgas_stream.h
@@ -19,9 +19,9 @@ enum FX_STREAMSEEK {
 class IFGAS_Stream : public CFX_Retainable {
  public:
   static CFX_RetainPtr<IFGAS_Stream> CreateReadStream(
-      const CFX_RetainPtr<IFX_SeekableReadStream>& pFileRead);
+      const CFX_RetainPtr<IFX_SeekableStream>& pFileRead);
   static CFX_RetainPtr<IFGAS_Stream> CreateWriteStream(
-      const CFX_RetainPtr<IFX_SeekableWriteStream>& pFileWrite);
+      const CFX_RetainPtr<IFX_SeekableStream>& pFileWrite);
   static CFX_RetainPtr<IFGAS_Stream> CreateWideStringReadStream(
       const CFX_WideString& buffer);
 
diff --git a/xfa/fxfa/cxfa_ffdoc.cpp b/xfa/fxfa/cxfa_ffdoc.cpp
index 2bbdfa1b9c..3565370bde 100644
--- a/xfa/fxfa/cxfa_ffdoc.cpp
+++ b/xfa/fxfa/cxfa_ffdoc.cpp
@@ -281,7 +281,7 @@ CXFA_FFDocView* CXFA_FFDoc::GetDocView() {
   return m_DocView.get();
 }
 
-bool CXFA_FFDoc::OpenDoc(const CFX_RetainPtr<IFX_SeekableReadStream>& pStream) {
+bool CXFA_FFDoc::OpenDoc(const CFX_RetainPtr<IFX_SeekableStream>& pStream) {
   m_pStream = pStream;
   return true;
 }
@@ -389,9 +389,8 @@ CFX_RetainPtr<CFX_DIBitmap> CXFA_FFDoc::GetPDFNamedImage(
   auto pAcc = pdfium::MakeRetain<CPDF_StreamAcc>(pStream);
   pAcc->LoadAllData();
 
-  CFX_RetainPtr<IFX_SeekableReadStream> pImageFileRead =
-      IFX_MemoryStream::Create(const_cast<uint8_t*>(pAcc->GetData()),
-                               pAcc->GetSize());
+  CFX_RetainPtr<IFX_SeekableStream> pImageFileRead = IFX_MemoryStream::Create(
+      const_cast<uint8_t*>(pAcc->GetData()), pAcc->GetSize());
 
   CFX_RetainPtr<CFX_DIBitmap> pDibSource = XFA_LoadImageFromBuffer(
       pImageFileRead, FXCODEC_IMAGE_UNKNOWN, iImageXDpi, iImageYDpi);
@@ -399,10 +398,9 @@ CFX_RetainPtr<CFX_DIBitmap> CXFA_FFDoc::GetPDFNamedImage(
   return pDibSource;
 }
 
-bool CXFA_FFDoc::SavePackage(
-    XFA_HashCode code,
-    const CFX_RetainPtr<IFX_SeekableWriteStream>& pFile,
-    CFX_ChecksumContext* pCSContext) {
+bool CXFA_FFDoc::SavePackage(XFA_HashCode code,
+                             const CFX_RetainPtr<IFX_SeekableStream>& pFile,
+                             CFX_ChecksumContext* pCSContext) {
   CXFA_Document* doc = m_pDocumentParser->GetDocument();
   auto pExport = pdfium::MakeUnique<CXFA_DataExporter>(doc);
   CXFA_Node* pNode = code == XFA_HASHCODE_Xfa ? doc->GetRoot()
@@ -418,9 +416,8 @@ bool CXFA_FFDoc::SavePackage(
       pFile, pNode, 0, bsChecksum.GetLength() ? bsChecksum.c_str() : nullptr);
 }
 
-bool CXFA_FFDoc::ImportData(
-    const CFX_RetainPtr<IFX_SeekableReadStream>& pStream,
-    bool bXDP) {
+bool CXFA_FFDoc::ImportData(const CFX_RetainPtr<IFX_SeekableStream>& pStream,
+                            bool bXDP) {
   auto importer =
       pdfium::MakeUnique<CXFA_DataImporter>(m_pDocumentParser->GetDocument());
   return importer->ImportData(pStream);
diff --git a/xfa/fxfa/cxfa_ffdoc.h b/xfa/fxfa/cxfa_ffdoc.h
index 0bba956f14..c5822e3577 100644
--- a/xfa/fxfa/cxfa_ffdoc.h
+++ b/xfa/fxfa/cxfa_ffdoc.h
@@ -58,7 +58,7 @@ class CXFA_FFDoc {
 
   CXFA_FFDocView* CreateDocView();
 
-  bool OpenDoc(const CFX_RetainPtr<IFX_SeekableReadStream>& pStream);
+  bool OpenDoc(const CFX_RetainPtr<IFX_SeekableStream>& pStream);
   bool OpenDoc(CPDF_Document* pPDFDoc);
   bool CloseDoc();
 
@@ -72,15 +72,15 @@ class CXFA_FFDoc {
                                                int32_t& iImageYDpi);
 
   bool SavePackage(XFA_HashCode code,
-                   const CFX_RetainPtr<IFX_SeekableWriteStream>& pFile,
+                   const CFX_RetainPtr<IFX_SeekableStream>& pFile,
                    CFX_ChecksumContext* pCSContext);
-  bool ImportData(const CFX_RetainPtr<IFX_SeekableReadStream>& pStream,
+  bool ImportData(const CFX_RetainPtr<IFX_SeekableStream>& pStream,
                   bool bXDP = true);
 
  private:
   IXFA_DocEnvironment* const m_pDocEnvironment;
   std::unique_ptr<CXFA_DocumentParser> m_pDocumentParser;
-  CFX_RetainPtr<IFX_SeekableReadStream> m_pStream;
+  CFX_RetainPtr<IFX_SeekableStream> m_pStream;
   CXFA_FFApp* m_pApp;
   std::unique_ptr<CXFA_FFNotify> m_pNotify;
   CPDF_Document* m_pPDFDoc;
diff --git a/xfa/fxfa/cxfa_fileread.cpp b/xfa/fxfa/cxfa_fileread.cpp
index e2ecad2e93..acd81a2232 100644
--- a/xfa/fxfa/cxfa_fileread.cpp
+++ b/xfa/fxfa/cxfa_fileread.cpp
@@ -54,3 +54,28 @@ bool CXFA_FileRead::ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) {
   }
   return false;
 }
+
+size_t CXFA_FileRead::ReadBlock(void* buffer, size_t size) {
+  ASSERT(false);
+  return 0;
+}
+
+FX_FILESIZE CXFA_FileRead::GetPosition() {
+  return 0;
+}
+
+bool CXFA_FileRead::IsEOF() {
+  return false;
+}
+
+bool CXFA_FileRead::Flush() {
+  ASSERT(false);
+  return false;
+}
+
+bool CXFA_FileRead::WriteBlock(const void* pData,
+                               FX_FILESIZE offset,
+                               size_t size) {
+  ASSERT(false);
+  return false;
+}
diff --git a/xfa/fxfa/cxfa_fileread.h b/xfa/fxfa/cxfa_fileread.h
index 0c3348b8d5..2dba4d23df 100644
--- a/xfa/fxfa/cxfa_fileread.h
+++ b/xfa/fxfa/cxfa_fileread.h
@@ -15,14 +15,19 @@
 class CPDF_Stream;
 class CPDF_StreamAcc;
 
-class CXFA_FileRead : public IFX_SeekableReadStream {
+class CXFA_FileRead : public IFX_SeekableStream {
  public:
   explicit CXFA_FileRead(const std::vector<CPDF_Stream*>& streams);
   ~CXFA_FileRead() override;
 
   // IFX_SeekableReadStream
+  FX_FILESIZE GetPosition() override;
   FX_FILESIZE GetSize() override;
   bool ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override;
+  size_t ReadBlock(void* buffer, size_t size) override;
+  bool IsEOF() override;
+  bool Flush() override;
+  bool WriteBlock(const void* pData, FX_FILESIZE offset, size_t size) override;
 
  private:
   std::vector<CFX_RetainPtr<CPDF_StreamAcc>> m_Data;
diff --git a/xfa/fxfa/parser/cxfa_dataexporter.cpp b/xfa/fxfa/parser/cxfa_dataexporter.cpp
index 3976fd6912..4e3b0b3ffa 100644
--- a/xfa/fxfa/parser/cxfa_dataexporter.cpp
+++ b/xfa/fxfa/parser/cxfa_dataexporter.cpp
@@ -474,15 +474,14 @@ CXFA_DataExporter::CXFA_DataExporter(CXFA_Document* pDocument)
 }
 
 bool CXFA_DataExporter::Export(
-    const CFX_RetainPtr<IFX_SeekableWriteStream>& pWrite) {
+    const CFX_RetainPtr<IFX_SeekableStream>& pWrite) {
   return Export(pWrite, m_pDocument->GetRoot(), 0, nullptr);
 }
 
-bool CXFA_DataExporter::Export(
-    const CFX_RetainPtr<IFX_SeekableWriteStream>& pWrite,
-    CXFA_Node* pNode,
-    uint32_t dwFlag,
-    const char* pChecksum) {
+bool CXFA_DataExporter::Export(const CFX_RetainPtr<IFX_SeekableStream>& pWrite,
+                               CXFA_Node* pNode,
+                               uint32_t dwFlag,
+                               const char* pChecksum) {
   ASSERT(pWrite);
   if (!pWrite)
     return false;
diff --git a/xfa/fxfa/parser/cxfa_dataexporter.h b/xfa/fxfa/parser/cxfa_dataexporter.h
index ac441ca21d..8f405b188d 100644
--- a/xfa/fxfa/parser/cxfa_dataexporter.h
+++ b/xfa/fxfa/parser/cxfa_dataexporter.h
@@ -12,15 +12,15 @@
 
 class CXFA_Document;
 class CXFA_Node;
-class IFX_SeekableWriteStream;
+class IFX_SeekableStream;
 class IFGAS_Stream;
 
 class CXFA_DataExporter {
  public:
   explicit CXFA_DataExporter(CXFA_Document* pDocument);
 
-  bool Export(const CFX_RetainPtr<IFX_SeekableWriteStream>& pWrite);
-  bool Export(const CFX_RetainPtr<IFX_SeekableWriteStream>& pWrite,
+  bool Export(const CFX_RetainPtr<IFX_SeekableStream>& pWrite);
+  bool Export(const CFX_RetainPtr<IFX_SeekableStream>& pWrite,
               CXFA_Node* pNode,
               uint32_t dwFlag,
               const char* pChecksum);
diff --git a/xfa/fxfa/parser/cxfa_dataimporter.cpp b/xfa/fxfa/parser/cxfa_dataimporter.cpp
index 200841f5cb..d87d0914e4 100644
--- a/xfa/fxfa/parser/cxfa_dataimporter.cpp
+++ b/xfa/fxfa/parser/cxfa_dataimporter.cpp
@@ -23,7 +23,7 @@ CXFA_DataImporter::CXFA_DataImporter(CXFA_Document* pDocument)
 }
 
 bool CXFA_DataImporter::ImportData(
-    const CFX_RetainPtr<IFX_SeekableReadStream>& pDataDocument) {
+    const CFX_RetainPtr<IFX_SeekableStream>& pDataDocument) {
   auto pDataDocumentParser =
       pdfium::MakeUnique<CXFA_SimpleParser>(m_pDocument, false);
   if (pDataDocumentParser->StartParse(pDataDocument, XFA_XDPPACKET_Datasets) !=
diff --git a/xfa/fxfa/parser/cxfa_dataimporter.h b/xfa/fxfa/parser/cxfa_dataimporter.h
index 4e8bdda314..e76475cd1e 100644
--- a/xfa/fxfa/parser/cxfa_dataimporter.h
+++ b/xfa/fxfa/parser/cxfa_dataimporter.h
@@ -11,13 +11,13 @@
 #include "core/fxcrt/fx_system.h"
 
 class CXFA_Document;
-class IFX_SeekableReadStream;
+class IFX_SeekableStream;
 
 class CXFA_DataImporter {
  public:
   explicit CXFA_DataImporter(CXFA_Document* pDocument);
 
-  bool ImportData(const CFX_RetainPtr<IFX_SeekableReadStream>& pDataDocument);
+  bool ImportData(const CFX_RetainPtr<IFX_SeekableStream>& pDataDocument);
 
  private:
   CXFA_Document* const m_pDocument;
diff --git a/xfa/fxfa/parser/cxfa_document_parser.cpp b/xfa/fxfa/parser/cxfa_document_parser.cpp
index b855513f52..a6860d6b52 100644
--- a/xfa/fxfa/parser/cxfa_document_parser.cpp
+++ b/xfa/fxfa/parser/cxfa_document_parser.cpp
@@ -18,7 +18,7 @@ CXFA_DocumentParser::~CXFA_DocumentParser() {
 }
 
 int32_t CXFA_DocumentParser::StartParse(
-    const CFX_RetainPtr<IFX_SeekableReadStream>& pStream,
+    const CFX_RetainPtr<IFX_SeekableStream>& pStream,
     XFA_XDPPACKET ePacketID) {
   m_pDocument.reset();
   m_nodeParser.CloseParser();
diff --git a/xfa/fxfa/parser/cxfa_document_parser.h b/xfa/fxfa/parser/cxfa_document_parser.h
index 9a219f74c1..90bd47f829 100644
--- a/xfa/fxfa/parser/cxfa_document_parser.h
+++ b/xfa/fxfa/parser/cxfa_document_parser.h
@@ -15,7 +15,7 @@ class CFDE_XMLDoc;
 class CXFA_Document;
 class CXFA_FFNotify;
 class CXFA_Notify;
-class IFX_SeekableReadStream;
+class IFX_SeekableStream;
 class IFX_Pause;
 
 class CXFA_DocumentParser {
@@ -23,7 +23,7 @@ class CXFA_DocumentParser {
   explicit CXFA_DocumentParser(CXFA_FFNotify* pNotify);
   ~CXFA_DocumentParser();
 
-  int32_t StartParse(const CFX_RetainPtr<IFX_SeekableReadStream>& pStream,
+  int32_t StartParse(const CFX_RetainPtr<IFX_SeekableStream>& pStream,
                      XFA_XDPPACKET ePacketID);
   int32_t DoParse(IFX_Pause* pPause);
 
diff --git a/xfa/fxfa/parser/cxfa_simple_parser.cpp b/xfa/fxfa/parser/cxfa_simple_parser.cpp
index cce4b68a27..806e5445a0 100644
--- a/xfa/fxfa/parser/cxfa_simple_parser.cpp
+++ b/xfa/fxfa/parser/cxfa_simple_parser.cpp
@@ -273,7 +273,7 @@ void CXFA_SimpleParser::SetFactory(CXFA_Document* pFactory) {
 }
 
 int32_t CXFA_SimpleParser::StartParse(
-    const CFX_RetainPtr<IFX_SeekableReadStream>& pStream,
+    const CFX_RetainPtr<IFX_SeekableStream>& pStream,
     XFA_XDPPACKET ePacketID) {
   CloseParser();
   m_pFileRead = pStream;
diff --git a/xfa/fxfa/parser/cxfa_simple_parser.h b/xfa/fxfa/parser/cxfa_simple_parser.h
index a9bcec2139..ccb258a7d4 100644
--- a/xfa/fxfa/parser/cxfa_simple_parser.h
+++ b/xfa/fxfa/parser/cxfa_simple_parser.h
@@ -17,7 +17,7 @@ class CFDE_XMLDoc;
 class CFDE_XMLInstruction;
 class CFDE_XMLNode;
 class CFDE_XMLParser;
-class IFX_SeekableReadStream;
+class IFX_SeekableStream;
 class IFX_Pause;
 class IFGAS_Stream;
 
@@ -26,7 +26,7 @@ class CXFA_SimpleParser {
   CXFA_SimpleParser(CXFA_Document* pFactory, bool bDocumentParser);
   ~CXFA_SimpleParser();
 
-  int32_t StartParse(const CFX_RetainPtr<IFX_SeekableReadStream>& pStream,
+  int32_t StartParse(const CFX_RetainPtr<IFX_SeekableStream>& pStream,
                      XFA_XDPPACKET ePacketID);
   int32_t DoParse(IFX_Pause* pPause);
   int32_t ParseXMLData(const CFX_WideString& wsXML,
@@ -81,7 +81,7 @@ class CXFA_SimpleParser {
   CFDE_XMLParser* m_pXMLParser;
   std::unique_ptr<CFDE_XMLDoc> m_pXMLDoc;
   CFX_RetainPtr<IFGAS_Stream> m_pStream;
-  CFX_RetainPtr<IFX_SeekableReadStream> m_pFileRead;
+  CFX_RetainPtr<IFX_SeekableStream> m_pFileRead;
   CXFA_Document* m_pFactory;
   CXFA_Node* m_pRootNode;
   XFA_XDPPACKET m_ePacketID;