qwindows_propertystore.cpp

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// Copyright (C) 2025 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qwindows_propertystore_p.h"
 
#include <QtCore/qstring.h>
#include <QtCore/qdebug.h>
#include <QtCore/private/qsystemerror_p.h>
#include <QtMultimedia/private/qcomtaskresource_p.h>
#include <QtMultimedia/private/qwindows_scopedpropvariant_p.h>
 
#include <mmdeviceapi.h>
#include <propsys.h>
#include <propvarutil.h>
 
QT_BEGIN_NAMESPACE
 
namespace QtMultimediaPrivate {
 
PropertyStoreHelper::PropertyStoreHelper(ComPtr<IPropertyStore> props) : m_props(std::move(props))
{
}
 
q23::expected<PropertyStoreHelper, QString>
PropertyStoreHelper::open(const ComPtr<IMMDevice> &device)
{
    ComPtr<IPropertyStore> props;
    HRESULT hr = device->OpenPropertyStore(STGM_READ, props.GetAddressOf());
    if (!SUCCEEDED(hr)) {
        return q23::unexpected{ QSystemError::windowsComString(hr) };
    }
    return PropertyStoreHelper(std::move(props));
}
 
std::optional<QString> PropertyStoreHelper::getString(const PROPERTYKEY &property)
{
    ScopedPropVariant variant;
 
    if (!SUCCEEDED(m_props->GetValue(property, variant.get())))
        return std::nullopt;
 
    QComTaskResource<WCHAR> str;
    HRESULT hr = PropVariantToStringAlloc(*variant, str.address());
    if (SUCCEEDED(hr))
        return QString::fromWCharArray(variant->pwszVal);
 
    qWarning() << "PropertyStoreHelper::getString: PropVariantToStringAlloc failed"
               << QSystemError::windowsComString(hr);
    return std::nullopt;
}
 
std::optional<uint32_t> PropertyStoreHelper::getUInt32(const PROPERTYKEY &property)
{
    ScopedPropVariant variant;
 
    if (!SUCCEEDED(m_props->GetValue(property, variant.get())))
        return std::nullopt;
 
    ULONG ret;
    HRESULT hr = PropVariantToUInt32(*variant, &ret);
    if (SUCCEEDED(hr))
        return uint32_t{ ret };
 
    qWarning() << "PropertyStoreHelper::getUInt32: PropVariantToUInt32 failed"
               << QSystemError::windowsComString(hr);
    return std::nullopt;
}
 
namespace {
 
// mingw workaround: PropVariantToGUID does not provide correct signature
// https://github.com/mingw-w64/mingw-w64/issues/153
 
template <typename T>
struct first_arg_is_ptr;
 
// Function type
template <typename Result, typename Arg, typename... Args>
struct first_arg_is_ptr<Result (*)(Arg, Args...)> : std::bool_constant<std::is_pointer_v<Arg>>
{
};
 
auto wrapPropVariantArg(const PROPVARIANT &arg)
{
    if constexpr (first_arg_is_ptr<decltype(&PropVariantToGUID)>::value) {
        return &arg;
    } else {
        return arg;
    }
}
 
} // namespace
 
std::optional<QUuid> PropertyStoreHelper::getGUID(const PROPERTYKEY &property)
{
    ScopedPropVariant variant;
 
    if (!SUCCEEDED(m_props->GetValue(property, variant.get())))
        return std::nullopt;
 
    GUID ret;
    HRESULT hr = PropVariantToGUID(wrapPropVariantArg(*variant), &ret);
    if (SUCCEEDED(hr))
        return QUuid{ ret };
 
    qWarning() << "PropertyStoreHelper::getUInt32: PropVariantToUInt32 failed"
               << QSystemError::windowsComString(hr);
    return std::nullopt;
}
 
} // namespace QtMultimediaPrivate
 
QT_END_NAMESPACE