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// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_WIN_SCOPED_PROPVARIANT_H_
#define BASE_WIN_SCOPED_PROPVARIANT_H_
#include <propidl.h>
#include "base/check_op.h"
namespace base {
namespace win {
// A PROPVARIANT that is automatically initialized and cleared upon respective
// construction and destruction of this class.
class ScopedPropVariant {
public:
ScopedPropVariant() { PropVariantInit(&pv_); }
ScopedPropVariant(const ScopedPropVariant&) = delete;
ScopedPropVariant& operator=(const ScopedPropVariant&) = delete;
~ScopedPropVariant() { Reset(); }
// Returns a pointer to the underlying PROPVARIANT for use as an out param in
// a function call.
PROPVARIANT* Receive() {
DCHECK_EQ(pv_.vt, VT_EMPTY);
return &pv_;
}
// Clears the instance to prepare it for re-use (e.g., via Receive).
void Reset() {
if (pv_.vt != VT_EMPTY) {
HRESULT result = PropVariantClear(&pv_);
DCHECK_EQ(result, S_OK);
}
}
const PROPVARIANT& get() const { return pv_; }
const PROPVARIANT* ptr() const { return &pv_; }
// Comparison operators for ScopedPropVariant are not supported at this point.
bool operator==(const ScopedPropVariant&) const = delete;
bool operator!=(const ScopedPropVariant&) const = delete;
private:
PROPVARIANT pv_;
};
} // namespace win
} // namespace base
#endif // BASE_WIN_SCOPED_PROPVARIANT_H_
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