Rename IFGAS_Stream to CFGAS_Stream

This CL replaces IFGAS_Stream with the only implementation CFGAS_Stream.
The CreateReadStream and CreateWriteStream methods are removed in favour
of calling MakeRetain directly.

Change-Id: I882a89258f642e24fc3d631587db05652bd53ded
Reviewed-on: https://pdfium-review.googlesource.com/4210
Commit-Queue: dsinclair <dsinclair@chromium.org>
Reviewed-by: Nicolás Peña <npm@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

3 files changed, 80 insertions, 123 deletions

diff --git a/xfa/fgas/crt/ifgas_stream.cpp b/xfa/fgas/crt/cfgas_stream.cpp
index 7a90626fe8..809c19bdae 100644
--- a/xfa/fgas/crt/ifgas_stream.cpp
+++ b/xfa/fgas/crt/cfgas_stream.cpp
@@ -4,7 +4,7 @@
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
-#include "xfa/fgas/crt/ifgas_stream.h"
+#include "xfa/fgas/crt/cfgas_stream.h"
 
 #if _FX_OS_ == _FX_WIN32_DESKTOP_ || _FX_OS_ == _FX_WIN32_MOBILE_ || \
     _FX_OS_ == _FX_WIN64_
@@ -12,6 +12,7 @@
 #endif
 
 #include <algorithm>
+#include <limits>
 #include <memory>
 #include <utility>
 #include <vector>
@@ -23,39 +24,6 @@
 
 namespace {
 
-class CFGAS_Stream : public IFGAS_Stream {
- public:
-  template <typename T, typename... Args>
-  friend CFX_RetainPtr<T> pdfium::MakeRetain(Args&&... args);
-
-  // 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;
-
- private:
-  CFGAS_Stream(const CFX_RetainPtr<IFX_SeekableStream>& stream,
-               bool isWriteSteam);
-  ~CFGAS_Stream() override;
-
-  FX_STRSIZE ReadData(uint8_t* pBuffer, FX_STRSIZE iBufferSize);
-  void WriteData(const CFX_WideStringC& str);
-
-  uint16_t m_wCodePage;
-  FX_STRSIZE m_wBOMLength;
-  bool m_IsWriteStream;
-  FX_FILESIZE m_iPosition;
-  CFX_RetainPtr<IFX_SeekableStream> m_pStream;
-};
-
 // Returns {src bytes consumed, dst bytes produced}.
 std::pair<FX_STRSIZE, FX_STRSIZE> UTF8Decode(const char* pSrc,
                                              FX_STRSIZE srcLen,
@@ -161,6 +129,8 @@ void SwapByteOrder(wchar_t* pStr, FX_STRSIZE iLength) {
   }
 }
 
+}  // namespace
+
 #if _FX_ENDIAN_ == _FX_LITTLE_ENDIAN_
 #define BOM_MASK 0x00FFFFFF
 #define BOM_UTF8 0x00BFBBEF
@@ -190,7 +160,7 @@ CFGAS_Stream::CFGAS_Stream(const CFX_RetainPtr<IFX_SeekableStream>& stream,
   }
 
   FX_FILESIZE iPosition = GetPosition();
-  Seek(FX_STREAMSEEK_Begin, 0);
+  Seek(CFGAS_Stream::Pos::Begin, 0);
 
   uint32_t bom;
   ReadData(reinterpret_cast<uint8_t*>(&bom), 3);
@@ -213,18 +183,21 @@ CFGAS_Stream::CFGAS_Stream(const CFX_RetainPtr<IFX_SeekableStream>& stream,
     }
   }
 
-  Seek(FX_STREAMSEEK_Begin,
+  Seek(CFGAS_Stream::Pos::Begin,
        std::max(static_cast<FX_FILESIZE>(m_wBOMLength), iPosition));
 }
 
+CFGAS_Stream::CFGAS_Stream(uint8_t* data, FX_STRSIZE size)
+    : CFGAS_Stream(IFX_MemoryStream::Create(data, size), false) {}
+
 CFGAS_Stream::~CFGAS_Stream() {}
 
-void CFGAS_Stream::Seek(FX_STREAMSEEK eSeek, FX_FILESIZE iOffset) {
+void CFGAS_Stream::Seek(CFGAS_Stream::Pos eSeek, FX_FILESIZE iOffset) {
   switch (eSeek) {
-    case FX_STREAMSEEK_Begin:
+    case CFGAS_Stream::Pos::Begin:
       m_iPosition = iOffset;
       break;
-    case FX_STREAMSEEK_Current:
+    case CFGAS_Stream::Pos::Current:
       m_iPosition += iOffset;
       break;
   }
@@ -300,7 +273,7 @@ FX_STRSIZE CFGAS_Stream::ReadString(wchar_t* pStr,
       FX_STRSIZE iSrc = 0;
       std::tie(iSrc, iMaxLength) = UTF8Decode(
           reinterpret_cast<const char*>(buf.data()), iLen, pStr, iMaxLength);
-      Seek(FX_STREAMSEEK_Current, iSrc - iLen);
+      Seek(CFGAS_Stream::Pos::Current, iSrc - iLen);
     } else {
       iMaxLength = 0;
     }
@@ -310,48 +283,22 @@ FX_STRSIZE CFGAS_Stream::ReadString(wchar_t* pStr,
   return iMaxLength;
 }
 
-void CFGAS_Stream::WriteData(const CFX_WideStringC& str) {
-  if (!m_IsWriteStream || str.GetLength() == 0)
-    return;
-  if (m_pStream->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();
-  }
-}
-
 void CFGAS_Stream::WriteString(const CFX_WideStringC& str) {
-  if (!m_IsWriteStream)
-    return;
-  if (str.GetLength() == 0)
+  if (!m_IsWriteStream || str.GetLength() == 0 ||
+      m_wCodePage != FX_CODEPAGE_UTF8) {
     return;
-  if (m_wCodePage != FX_CODEPAGE_UTF8)
+  }
+  if (!m_pStream->WriteBlock(str.c_str(), m_iPosition,
+                             str.GetLength() * sizeof(wchar_t))) {
     return;
+  }
 
-  WriteData(str);
-}
-
-}  // namespace
-
-// static
-CFX_RetainPtr<IFGAS_Stream> IFGAS_Stream::CreateReadStream(
-    const CFX_RetainPtr<IFX_SeekableStream>& pFileRead) {
-  if (!pFileRead)
-    return nullptr;
-
-  return pdfium::MakeRetain<CFGAS_Stream>(pFileRead, false);
-}
-
-// static
-CFX_RetainPtr<IFGAS_Stream> IFGAS_Stream::CreateWriteStream(
-    const CFX_RetainPtr<IFX_SeekableStream>& pFileWrite) {
-  if (!pFileWrite)
-    return nullptr;
+  pdfium::base::CheckedNumeric<FX_STRSIZE> new_pos = m_iPosition;
+  new_pos += str.GetLength() * sizeof(wchar_t);
+  if (!new_pos.IsValid()) {
+    m_iPosition = std::numeric_limits<FX_STRSIZE>::max();
+    return;
+  }
 
-  return pdfium::MakeRetain<CFGAS_Stream>(pFileWrite, true);
+  m_iPosition = new_pos.ValueOrDie();
 }
diff --git a/xfa/fgas/crt/cfgas_stream.h b/xfa/fgas/crt/cfgas_stream.h
new file mode 100644
index 0000000000..5d2e5e6242
--- /dev/null
+++ b/xfa/fgas/crt/cfgas_stream.h
@@ -0,0 +1,54 @@
+// 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 XFA_FGAS_CRT_CFGAS_STREAM_H_
+#define XFA_FGAS_CRT_CFGAS_STREAM_H_
+
+#include <algorithm>
+
+#include "core/fxcrt/cfx_retain_ptr.h"
+#include "core/fxcrt/fx_stream.h"
+#include "core/fxcrt/fx_system.h"
+
+class CFGAS_Stream : public CFX_Retainable {
+ public:
+  enum class Pos {
+    Begin = 0,
+    Current,
+  };
+
+  template <typename T, typename... Args>
+  friend CFX_RetainPtr<T> pdfium::MakeRetain(Args&&... args);
+
+  FX_FILESIZE GetLength() const { return m_pStream->GetSize(); }
+  FX_FILESIZE GetPosition() { return m_iPosition; }
+  FX_STRSIZE GetBOMLength() const { return std::max(0, m_wBOMLength); }
+  bool IsEOF() const { return m_iPosition >= GetLength(); }
+
+  void Seek(CFGAS_Stream::Pos eSeek, FX_FILESIZE iOffset);
+  FX_STRSIZE ReadString(wchar_t* pStr, FX_STRSIZE iMaxLength, bool* bEOS);
+
+  void WriteString(const CFX_WideStringC& str);
+
+  uint16_t GetCodePage() const { return m_wCodePage; }
+  void SetCodePage(uint16_t wCodePage);
+
+ private:
+  CFGAS_Stream(const CFX_RetainPtr<IFX_SeekableStream>& stream,
+               bool isWriteSteam);
+  CFGAS_Stream(uint8_t* data, FX_STRSIZE size);
+  ~CFGAS_Stream() override;
+
+  FX_STRSIZE ReadData(uint8_t* pBuffer, FX_STRSIZE iBufferSize);
+
+  uint16_t m_wCodePage;
+  FX_STRSIZE m_wBOMLength;
+  bool m_IsWriteStream;
+  FX_FILESIZE m_iPosition;
+  CFX_RetainPtr<IFX_SeekableStream> m_pStream;
+};
+
+#endif  // XFA_FGAS_CRT_CFGAS_STREAM_H_
diff --git a/xfa/fgas/crt/ifgas_stream.h b/xfa/fgas/crt/ifgas_stream.h
deleted file mode 100644
index acc9f1c4eb..0000000000
--- a/xfa/fgas/crt/ifgas_stream.h
+++ /dev/null
@@ -1,44 +0,0 @@
-// 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
-
-#ifndef XFA_FGAS_CRT_IFGAS_STREAM_H_
-#define XFA_FGAS_CRT_IFGAS_STREAM_H_
-
-#include "core/fxcrt/cfx_retain_ptr.h"
-#include "core/fxcrt/fx_stream.h"
-#include "core/fxcrt/fx_system.h"
-
-enum FX_STREAMSEEK {
-  FX_STREAMSEEK_Begin = 0,
-  FX_STREAMSEEK_Current,
-};
-
-class IFGAS_Stream : public CFX_Retainable {
- public:
-  static CFX_RetainPtr<IFGAS_Stream> CreateReadStream(
-      const CFX_RetainPtr<IFX_SeekableStream>& pFileRead);
-  static CFX_RetainPtr<IFGAS_Stream> CreateWriteStream(
-      const CFX_RetainPtr<IFX_SeekableStream>& pFileWrite);
-
-  virtual FX_FILESIZE GetLength() const = 0;
-  virtual FX_FILESIZE GetPosition() = 0;
-  virtual FX_STRSIZE GetBOMLength() const = 0;
-
-  virtual void Seek(FX_STREAMSEEK eSeek, FX_FILESIZE iOffset) = 0;
-
-  virtual FX_STRSIZE ReadString(wchar_t* pStr,
-                                FX_STRSIZE iMaxLength,
-                                bool* bEOS) = 0;
-  virtual void WriteString(const CFX_WideStringC& str) = 0;
-
-  virtual uint16_t GetCodePage() const = 0;
-  virtual void SetCodePage(uint16_t wCodePage) = 0;
-
- protected:
-  virtual bool IsEOF() const = 0;
-};
-
-#endif  // XFA_FGAS_CRT_IFGAS_STREAM_H_