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