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//
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#ifndef MOZC_BASE_SCOPED_HANDLE_H_
#define MOZC_BASE_SCOPED_HANDLE_H_

#ifdef OS_WINDOWS
#include <windows.h>
// Example:
//   ScopedHandle hfile(CreateFile(...));
//   if (!hfile.get())
//     ...process error
//   ReadFile(hfile.get(), ...);
namespace mozc {
class ScopedHandle {
 public:
  ScopedHandle() : handle_(NULL) {}

  explicit ScopedHandle(HANDLE handle) : handle_(NULL) {
    reset(handle);
  }

  ~ScopedHandle() {
    Close();
  }

  void reset(HANDLE 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;
    }
  }

  HANDLE get() const {
    return handle_;
  }

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

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

  HANDLE handle_;
};
}  //  mozc
#endif  // OS_WINDOWS
#endif  // MOZC_BASE_SCOPED_HANDLE_H_