qpipewire_instance.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 "qpipewire_instance_p.h"
 
#include <QtMultimedia/private/qpipewire_propertydict_p.h>
#include <QtMultimedia/private/qpipewire_support_p.h>
#include <QtMultimedia/private/qtmultimediaglobal_p.h>
#if QT_CONFIG(pipewire_symbolloader)
#  include <QtMultimedia/private/qpipewire_symbolloader_p.h>
#endif
 
#include <QtDBus/qdbusinterface.h>
#include <QtDBus/qdbusmessage.h>
 
#include <QtCore/qcoreapplication.h>
#include <QtCore/qmutex.h>
 
#include <spa/utils/names.h>
 
#include <array>
#include <mutex>
 
QT_BEGIN_NAMESPACE
 
namespace QtPipeWire {
 
using namespace Qt::Literals;
 
Q_LOGGING_CATEGORY(lcPipewire, "qt.multimedia.pipewire");
 
namespace {
 
struct InstanceHolder
{
    QMutex mutex;
    std::weak_ptr<QPipeWireInstance> instance;
};
 
Q_GLOBAL_STATIC(InstanceHolder, s_pipeWireInstance);
 
} // namespace
 
QPipewireInitializer::QPipewireInitializer()
{
    pw_init(nullptr, nullptr);
 
    qCDebug(lcPipewire) << "PipeWire initialized: compiled against" << pw_get_headers_version()
                        << " running " << pw_get_library_version();
}
 
QPipewireInitializer::~QPipewireInitializer()
{
    if (pw_check_library_version(0, 3, 49))
        pw_deinit();
}
 
std::shared_ptr<QPipeWireInstance> QPipeWireInstance::instance()
{
    std::lock_guard guard{ s_pipeWireInstance->mutex };
    std::shared_ptr<QPipeWireInstance> ret = s_pipeWireInstance->instance.lock();
    if (!ret) {
        ret = QPipeWireInstance::create();
        if (ret)
            s_pipeWireInstance->instance = ret;
    }
    return ret;
}
 
bool QPipeWireInstance::isLoaded()
{
#if QT_CONFIG(pipewire_symbolloader)
    return qPipewireIsLoaded();
#else
    return 1;
#endif
}
 
q23::expected<void, std::error_code> QPipeWireInstance::hasSPAFactory(const char *factoryName)
{
    std::array<spa_support, 32> support{};
    uint32_t n_support = pw_get_support(support.data(), uint32_t(support.size()));
 
    SpaHandleHandle handle{
        pw_load_spa_handle(/*lib=*/nullptr, factoryName, /*info=*/nullptr, n_support,
                           support.data()),
    };
    if (!handle)
        return q23::unexpected{ make_error_code() };
 
    return {};
}
 
bool QPipeWireInstance::isInPwThreadLoop() const
{
    return m_eventLoop.isInThread();
}
 
pw_loop *QPipeWireInstance::eventLoop() const
{
    return m_eventLoop.loop();
}
 
static std::optional<uint> portalInterfaceVersion(const QString &interface)
{
    QDBusInterface properties(u"org.freedesktop.portal.Desktop"_s,
                              u"/org/freedesktop/portal/desktop"_s,
                              u"org.freedesktop.DBus.Properties"_s, QDBusConnection::sessionBus());
 
    QDBusMessage reply = properties.call(u"Get"_s, interface, u"version"_s);
 
    if (reply.type() != QDBusMessage::ReplyMessage || reply.arguments().size() != 1) {
        qCDebug(lcPipewire) << interface << "not available:" << reply.errorName()
                            << reply.errorMessage();
        return std::nullopt;
    }
 
    // The property is a variant, which arrives wrapped in a QDBusVariant.
    const uint version = reply.arguments().at(0).toUInt();
    qCDebug(lcPipewire) << interface << "version" << version;
    return version;
}
 
bool QPipeWireInstance::hasScreenCastPortal()
{
    if (!m_hasScreenCastPortal)
        m_hasScreenCastPortal =
                portalInterfaceVersion(u"org.freedesktop.portal.ScreenCast"_s).has_value();
    return *m_hasScreenCastPortal;
}
 
q23::expected<PwCoreConnectionHandle, std::error_code> QPipeWireInstance::connectToDaemon()
{
    auto connection = PwCoreConnectionHandle{
        pw_context_connect(m_context.get(), /*props=*/nullptr,
                           /*user_data_size=*/0),
    };
 
    if (!connection)
        return q23::unexpected(make_error_code(errno));
    return connection;
}
 
q23::expected<PwCoreConnectionHandle, std::error_code> QPipeWireInstance::connectToPortal(int fd)
{
    auto connection = PwCoreConnectionHandle{
        pw_context_connect_fd(m_context.get(), fd, /*props=*/nullptr,
                              /*user_data_size=*/0),
    };
 
    if (!connection)
        return q23::unexpected(make_error_code(errno));
    return connection;
}
 
std::unique_ptr<QPipeWireInstance> QPipeWireInstance::create()
{
    auto instance = std::unique_ptr<QPipeWireInstance>(new QPipeWireInstance);
    if (!instance->m_eventLoop || !instance->m_context)
        return nullptr;
 
    return instance;
}
 
QPipeWireInstance::QPipeWireInstance()
{
    if (!m_eventLoop)
        return;
 
    int status = m_eventLoop.start();
    if (status < 0)
        qFatal() << "Failed to start event loop" << make_error_code(-status).message();
 
    m_context = runWithEventLoopLock([&] {
        auto applicationName = qApp->applicationName().toUtf8();
        PwPropertiesHandle props = makeProperties({
                { PW_KEY_APP_NAME, applicationName.data() },
        });
 
        return PwContextHandle{
            pw_context_new(m_eventLoop.loop(), props.release(), /*user_data_size=*/0),
        };
    });
}
 
QPipeWireInstance::~QPipeWireInstance()
{
    runWithEventLoopLock([&] { m_context = {}; });
    m_eventLoop.stop();
}
 
} // namespace QtPipeWire
 
QT_END_NAMESPACE