Cleanup the fx_extension code.

This CL cleans up the fx_extension file. The stream code was moved to
fx_stream. IFX_FileAccess was removed and CFX_CRTFileAccess split to its
own file. Code shuffled from header to cpp file.

Change-Id: I700fdfcc9797cf4e8050cd9ba010ad8854feefbf
Reviewed-on: https://pdfium-review.googlesource.com/4371
Reviewed-by: Nicolás Peña <npm@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>

1 files changed, 307 insertions, 0 deletions

diff --git a/core/fxcrt/fx_stream.cpp b/core/fxcrt/fx_stream.cpp
new file mode 100644
index 0000000000..c60a546ddd
--- /dev/null
+++ b/core/fxcrt/fx_stream.cpp
@@ -0,0 +1,307 @@
+// 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/fx_stream.h"
+
+#include <algorithm>
+#include <memory>
+#include <utility>
+#include <vector>
+
+#include "core/fxcrt/fx_safe_types.h"
+#include "core/fxcrt/ifxcrt_fileaccess.h"
+
+#define FX_MEMSTREAM_BlockSize (64 * 1024)
+#define FX_MEMSTREAM_Consecutive 0x01
+#define FX_MEMSTREAM_TakeOver 0x02
+
+namespace {
+
+class CFX_CRTFileStream final : public IFX_SeekableStream {
+ public:
+  template <typename T, typename... Args>
+  friend CFX_RetainPtr<T> pdfium::MakeRetain(Args&&... args);
+
+  // IFX_SeekableStream:
+  FX_FILESIZE GetSize() override { return m_pFile->GetSize(); }
+  bool IsEOF() override { return GetPosition() >= GetSize(); }
+  FX_FILESIZE GetPosition() override { return m_pFile->GetPosition(); }
+  bool ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override {
+    return m_pFile->ReadPos(buffer, size, offset) > 0;
+  }
+  size_t ReadBlock(void* buffer, size_t size) override {
+    return m_pFile->Read(buffer, size);
+  }
+  bool WriteBlock(const void* buffer,
+                  FX_FILESIZE offset,
+                  size_t size) override {
+    return !!m_pFile->WritePos(buffer, size, offset);
+  }
+  bool Flush() override { return m_pFile->Flush(); }
+
+ private:
+  explicit CFX_CRTFileStream(std::unique_ptr<IFXCRT_FileAccess> pFA)
+      : m_pFile(std::move(pFA)) {}
+  ~CFX_CRTFileStream() override {}
+
+  std::unique_ptr<IFXCRT_FileAccess> m_pFile;
+};
+
+class CFX_MemoryStream final : public IFX_MemoryStream {
+ public:
+  template <typename T, typename... Args>
+  friend CFX_RetainPtr<T> pdfium::MakeRetain(Args&&... args);
+
+  // IFX_MemoryStream
+  FX_FILESIZE GetSize() override {
+    return static_cast<FX_FILESIZE>(m_nCurSize);
+  }
+  bool IsEOF() override { return m_nCurPos >= static_cast<size_t>(GetSize()); }
+  FX_FILESIZE GetPosition() override {
+    return static_cast<FX_FILESIZE>(m_nCurPos);
+  }
+  bool ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override;
+  size_t ReadBlock(void* buffer, size_t size) override;
+  bool WriteBlock(const void* buffer, FX_FILESIZE offset, size_t size) override;
+  bool Flush() override { return true; }
+  bool IsConsecutive() const override {
+    return !!(m_dwFlags & FX_MEMSTREAM_Consecutive);
+  }
+  void EstimateSize(size_t nInitSize, size_t nGrowSize) override;
+  uint8_t* GetBuffer() const override {
+    return !m_Blocks.empty() ? m_Blocks.front() : nullptr;
+  }
+  void AttachBuffer(uint8_t* pBuffer,
+                    size_t nSize,
+                    bool bTakeOver = false) override;
+  void DetachBuffer() override;
+
+ private:
+  explicit CFX_MemoryStream(bool bConsecutive);
+  CFX_MemoryStream(uint8_t* pBuffer, size_t nSize, bool bTakeOver);
+  ~CFX_MemoryStream() override;
+
+  bool ExpandBlocks(size_t size);
+
+  std::vector<uint8_t*> m_Blocks;
+  size_t m_nTotalSize;
+  size_t m_nCurSize;
+  size_t m_nCurPos;
+  size_t m_nGrowSize;
+  uint32_t m_dwFlags;
+};
+
+CFX_MemoryStream::CFX_MemoryStream(bool bConsecutive)
+    : m_nTotalSize(0),
+      m_nCurSize(0),
+      m_nCurPos(0),
+      m_nGrowSize(FX_MEMSTREAM_BlockSize) {
+  m_dwFlags =
+      FX_MEMSTREAM_TakeOver | (bConsecutive ? FX_MEMSTREAM_Consecutive : 0);
+}
+
+CFX_MemoryStream::CFX_MemoryStream(uint8_t* pBuffer,
+                                   size_t nSize,
+                                   bool bTakeOver)
+    : m_nTotalSize(nSize),
+      m_nCurSize(nSize),
+      m_nCurPos(0),
+      m_nGrowSize(FX_MEMSTREAM_BlockSize) {
+  m_Blocks.push_back(pBuffer);
+  m_dwFlags =
+      FX_MEMSTREAM_Consecutive | (bTakeOver ? FX_MEMSTREAM_TakeOver : 0);
+}
+
+CFX_MemoryStream::~CFX_MemoryStream() {
+  if (m_dwFlags & FX_MEMSTREAM_TakeOver) {
+    for (uint8_t* pBlock : m_Blocks)
+      FX_Free(pBlock);
+  }
+}
+
+bool CFX_MemoryStream::ReadBlock(void* buffer,
+                                 FX_FILESIZE offset,
+                                 size_t size) {
+  if (!buffer || !size || offset < 0)
+    return false;
+
+  FX_SAFE_SIZE_T newPos = size;
+  newPos += offset;
+  if (!newPos.IsValid() || newPos.ValueOrDefault(0) == 0 ||
+      newPos.ValueOrDie() > m_nCurSize) {
+    return false;
+  }
+
+  m_nCurPos = newPos.ValueOrDie();
+  if (m_dwFlags & FX_MEMSTREAM_Consecutive) {
+    memcpy(buffer, m_Blocks[0] + static_cast<size_t>(offset), size);
+    return true;
+  }
+
+  size_t nStartBlock = static_cast<size_t>(offset) / m_nGrowSize;
+  offset -= static_cast<FX_FILESIZE>(nStartBlock * m_nGrowSize);
+  while (size) {
+    size_t nRead = std::min(size, m_nGrowSize - static_cast<size_t>(offset));
+    memcpy(buffer, m_Blocks[nStartBlock] + offset, nRead);
+    buffer = static_cast<uint8_t*>(buffer) + nRead;
+    size -= nRead;
+    ++nStartBlock;
+    offset = 0;
+  }
+  return true;
+}
+
+size_t CFX_MemoryStream::ReadBlock(void* buffer, size_t size) {
+  if (m_nCurPos >= m_nCurSize)
+    return 0;
+
+  size_t nRead = std::min(size, m_nCurSize - m_nCurPos);
+  if (!ReadBlock(buffer, static_cast<int32_t>(m_nCurPos), nRead))
+    return 0;
+
+  return nRead;
+}
+
+bool CFX_MemoryStream::WriteBlock(const void* buffer,
+                                  FX_FILESIZE offset,
+                                  size_t size) {
+  if (!buffer || !size)
+    return false;
+
+  if (m_dwFlags & FX_MEMSTREAM_Consecutive) {
+    FX_SAFE_SIZE_T newPos = size;
+    newPos += offset;
+    if (!newPos.IsValid())
+      return false;
+
+    m_nCurPos = newPos.ValueOrDie();
+    if (m_nCurPos > m_nTotalSize) {
+      m_nTotalSize = (m_nCurPos + m_nGrowSize - 1) / m_nGrowSize * m_nGrowSize;
+      if (m_Blocks.empty())
+        m_Blocks.push_back(FX_Alloc(uint8_t, m_nTotalSize));
+      else
+        m_Blocks[0] = FX_Realloc(uint8_t, m_Blocks[0], m_nTotalSize);
+    }
+
+    memcpy(m_Blocks[0] + offset, buffer, size);
+    m_nCurSize = std::max(m_nCurSize, m_nCurPos);
+
+    return true;
+  }
+
+  FX_SAFE_SIZE_T newPos = size;
+  newPos += offset;
+  if (!newPos.IsValid())
+    return false;
+  if (!ExpandBlocks(newPos.ValueOrDie()))
+    return false;
+
+  m_nCurPos = newPos.ValueOrDie();
+  size_t nStartBlock = static_cast<size_t>(offset) / m_nGrowSize;
+  offset -= static_cast<FX_FILESIZE>(nStartBlock * m_nGrowSize);
+  while (size) {
+    size_t nWrite = std::min(size, m_nGrowSize - static_cast<size_t>(offset));
+    memcpy(m_Blocks[nStartBlock] + offset, buffer, nWrite);
+    buffer = static_cast<const uint8_t*>(buffer) + nWrite;
+    size -= nWrite;
+    ++nStartBlock;
+    offset = 0;
+  }
+  return true;
+}
+
+void CFX_MemoryStream::EstimateSize(size_t nInitSize, size_t nGrowSize) {
+  if (m_dwFlags & FX_MEMSTREAM_Consecutive) {
+    if (m_Blocks.empty()) {
+      m_Blocks.push_back(
+          FX_Alloc(uint8_t, std::max(nInitSize, static_cast<size_t>(4096))));
+    }
+    m_nGrowSize = std::max(nGrowSize, static_cast<size_t>(4096));
+  } else if (m_Blocks.empty()) {
+    m_nGrowSize = std::max(nGrowSize, static_cast<size_t>(4096));
+  }
+}
+
+void CFX_MemoryStream::AttachBuffer(uint8_t* pBuffer,
+                                    size_t nSize,
+                                    bool bTakeOver) {
+  if (!(m_dwFlags & FX_MEMSTREAM_Consecutive))
+    return;
+
+  m_Blocks.clear();
+  m_Blocks.push_back(pBuffer);
+  m_nTotalSize = nSize;
+  m_nCurSize = nSize;
+  m_nCurPos = 0;
+  m_dwFlags =
+      FX_MEMSTREAM_Consecutive | (bTakeOver ? FX_MEMSTREAM_TakeOver : 0);
+}
+
+void CFX_MemoryStream::DetachBuffer() {
+  if (!(m_dwFlags & FX_MEMSTREAM_Consecutive))
+    return;
+
+  m_Blocks.clear();
+  m_nTotalSize = 0;
+  m_nCurSize = 0;
+  m_nCurPos = 0;
+  m_dwFlags = FX_MEMSTREAM_TakeOver;
+}
+
+bool CFX_MemoryStream::ExpandBlocks(size_t size) {
+  m_nCurSize = std::max(m_nCurSize, size);
+  if (size <= m_nTotalSize)
+    return true;
+
+  size = (size - m_nTotalSize + m_nGrowSize - 1) / m_nGrowSize;
+  size_t iCount = m_Blocks.size();
+  m_Blocks.resize(iCount + size);
+  while (size--) {
+    m_Blocks[iCount++] = FX_Alloc(uint8_t, m_nGrowSize);
+    m_nTotalSize += m_nGrowSize;
+  }
+  return true;
+}
+
+}  // namespace
+
+// static
+CFX_RetainPtr<IFX_SeekableStream> IFX_SeekableStream::CreateFromFilename(
+    const char* filename,
+    uint32_t dwModes) {
+  std::unique_ptr<IFXCRT_FileAccess> pFA(IFXCRT_FileAccess::Create());
+  if (!pFA->Open(filename, dwModes))
+    return nullptr;
+  return pdfium::MakeRetain<CFX_CRTFileStream>(std::move(pFA));
+}
+
+// static
+CFX_RetainPtr<IFX_SeekableStream> IFX_SeekableStream::CreateFromFilename(
+    const wchar_t* filename,
+    uint32_t dwModes) {
+  std::unique_ptr<IFXCRT_FileAccess> pFA(IFXCRT_FileAccess::Create());
+  if (!pFA->Open(filename, dwModes))
+    return nullptr;
+  return pdfium::MakeRetain<CFX_CRTFileStream>(std::move(pFA));
+}
+
+// static
+CFX_RetainPtr<IFX_SeekableReadStream>
+IFX_SeekableReadStream::CreateFromFilename(const char* filename) {
+  return IFX_SeekableStream::CreateFromFilename(filename, FX_FILEMODE_ReadOnly);
+}
+
+// static
+CFX_RetainPtr<IFX_MemoryStream> IFX_MemoryStream::Create(uint8_t* pBuffer,
+                                                         size_t dwSize,
+                                                         bool bTakeOver) {
+  return pdfium::MakeRetain<CFX_MemoryStream>(pBuffer, dwSize, bTakeOver);
+}
+
+// static
+CFX_RetainPtr<IFX_MemoryStream> IFX_MemoryStream::Create(bool bConsecutive) {
+  return pdfium::MakeRetain<CFX_MemoryStream>(bConsecutive);
+}