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// Copyright 2019 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_WIN_SCOPED_SAFEARRAY_H_
#define BASE_WIN_SCOPED_SAFEARRAY_H_
#include <objbase.h>
#include "base/base_export.h"
#include "base/check_op.h"
#include "base/macros.h"
namespace base {
namespace win {
// Manages a Windows SAFEARRAY. This is a minimal wrapper that simply provides
// RAII semantics and does not duplicate the extensive functionality that
// CComSafeArray offers.
class BASE_EXPORT ScopedSafearray {
public:
explicit ScopedSafearray(SAFEARRAY* safearray = nullptr)
: safearray_(safearray) {}
// Move constructor
ScopedSafearray(ScopedSafearray&& r) noexcept : safearray_(r.safearray_) {
r.safearray_ = nullptr;
}
// Move operator=. Allows assignment from a ScopedSafearray rvalue.
ScopedSafearray& operator=(ScopedSafearray&& rvalue) {
Reset(rvalue.Release());
return *this;
}
~ScopedSafearray() { Destroy(); }
void Destroy() {
if (safearray_) {
HRESULT hr = SafeArrayDestroy(safearray_);
DCHECK_EQ(S_OK, hr);
safearray_ = nullptr;
}
}
// Give ScopedSafearray ownership over an already allocated SAFEARRAY or
// nullptr.
void Reset(SAFEARRAY* safearray = nullptr) {
if (safearray != safearray_) {
Destroy();
safearray_ = safearray;
}
}
// Releases ownership of the SAFEARRAY to the caller.
SAFEARRAY* Release() {
SAFEARRAY* safearray = safearray_;
safearray_ = nullptr;
return safearray;
}
// Retrieves the pointer address.
// Used to receive SAFEARRAYs as out arguments (and take ownership).
// This function releases any existing references because it will leak
// the existing ref otherwise.
// Usage: GetSafearray(safearray.Receive());
SAFEARRAY** Receive() {
Destroy();
return &safearray_;
}
// Returns the internal pointer. Prefer using operator SAFEARRAY*() instead,
// as that will automatically convert for function calls expecting a raw
// SAFEARRAY*
SAFEARRAY* Get() const { return safearray_; }
// Forbid comparison of ScopedSafearray types. You should never have the same
// SAFEARRAY owned by two different scoped_ptrs.
bool operator==(const ScopedSafearray& safearray2) const = delete;
bool operator!=(const ScopedSafearray& safearray2) const = delete;
private:
SAFEARRAY* safearray_;
DISALLOW_COPY_AND_ASSIGN(ScopedSafearray);
};
} // namespace win
} // namespace base
#endif // BASE_WIN_SCOPED_SAFEARRAY_H_
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