src/base/scoped_handle.cc

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#include "base/scoped_handle.h"

#ifdef OS_WIN
#include <windows.h>

namespace mozc {

ScopedHandle::ScopedHandle()
    : handle_(NULL) {}

ScopedHandle::ScopedHandle(Win32Handle handle)
    : handle_(NULL) {
  reset(handle);
}

ScopedHandle::~ScopedHandle() {
  Close();
}

void ScopedHandle::reset(Win32Handle handle) {
  Close();
  // Comment by yukawa:
  // FYI, ATL has similar class called CHandle and its document
  // says that we cannot
  // assume INVALID_HANDLE_VALUE is the only invalid handle.
  // See the note section of this document.
  // http://msdn.microsoft.com/en-us/library/5fc6ft2t.aspx
  // .NET approach is also informative.
  // .NET has similar handle wrapper called SafeHandle,
  // which allows us to override
  // the condition of invalid handle.
  // http://msdn.microsoft.com/en-us/library/system.runtime.interopservices.safehandle.isinvalid.aspx
  // They has pre-defined special classes SafeHandleMinusOneIsInvalid and
  // SafeHandleZeroOrMinusOneIsInvalid.
  // http://msdn.microsoft.com/en-us/library/microsoft.win32.safehandles.safehandleminusoneisinvalid.aspx
  // http://msdn.microsoft.com/en-us/library/microsoft.win32.safehandles.safehandlezeroorminusoneisinvalid.aspx
  if (handle != INVALID_HANDLE_VALUE) {
    handle_ = handle;
  }
}

ScopedHandle::Win32Handle ScopedHandle::get() const {
  return handle_;
}

// transfers ownership away from this object
ScopedHandle::Win32Handle ScopedHandle::take() {
  HANDLE handle = handle_;
  handle_ = NULL;
  return handle;
}

void ScopedHandle::Close() {
  if (handle_ != NULL) {
    ::CloseHandle(handle_);
    handle_ = NULL;
  }
}

}  // namespace mozc

#endif  // OS_WIN