Wayland 窗口激活机制

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<!-- xdg-activation-v1.xml -->
<request name="get_activation_token">
    <description summary="requests a token">
        Creates an xdg_activation_token_v1 object that will provide
        the initiating client with a unique token for this activation.
    </description>
    <arg name="id" type="new_id" interface="xdg_activation_token_v1"/>
</request>

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// glib/gio/gdesktopappinfo.c
if (info->startup_notify) {
    sn_id = g_app_launch_context_get_startup_notify_id(launch_context,
                                                       G_APP_INFO(info), launched_files);
    if (sn_id) {
        envp = g_environ_setenv(envp, "DESKTOP_STARTUP_ID", sn_id, TRUE);
        envp = g_environ_setenv(envp, "XDG_ACTIVATION_TOKEN", sn_id, TRUE);
    }
}

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// glib/gio/gdesktopappinfo.c
sn_id = g_app_launch_context_get_startup_notify_id(launch_context,
                                                   G_APP_INFO(info), launched_files);
if (sn_id) {
    g_variant_builder_add(&builder, "{sv}", "desktop-startup-id",
                           g_variant_new_string(sn_id));
    g_variant_builder_add(&builder, "{sv}", "activation-token",
                           g_variant_new_take_string(g_steal_pointer(&sn_id)));
}
// 通过 org.freedesktop.Application.Open/Activate D-Bus 方法传递
g_dbus_connection_call(session_bus, info->app_id, object_path,
                       "org.freedesktop.Application",
                       uris ? "Open" : "Activate",
                       g_variant_builder_end(&builder), ...);

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// src/gui/platform/unix/dbusmenu/qdbusmenuconnection.cpp
bool QDBusMenuConnection::registerTrayIconWithWatcher(QDBusTrayIcon *item)
{
    QDBusMessage registerMethod = QDBusMessage::createMethodCall(
        StatusNotifierWatcherService, StatusNotifierWatcherPath,
        StatusNotifierWatcherService, "RegisterStatusNotifierItem"_L1);
    registerMethod.setArguments(QVariantList() << m_connection.baseService());
    return m_connection.callWithCallback(registerMethod, this,
           SIGNAL(trayIconRegistered()), SLOT(dbusError(QDBusError)));
}

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// src/gui/platform/unix/dbustray/qstatusnotifieritemadaptor.cpp
void QStatusNotifierItemAdaptor::ProvideXdgActivationToken(const QString &token)
{
    qCDebug(qLcTray) << token;
    qputenv("XDG_ACTIVATION_TOKEN", token.toUtf8());
}

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// src/gui/platform/unix/dbustray/qstatusnotifieritemadaptor.cpp
void QStatusNotifierItemAdaptor::Activate(int x, int y)
{
    qCDebug(qLcTray) << x << y;
    emit m_trayIcon->activated(QPlatformSystemTrayIcon::Trigger);
}

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void Sandbox::socketConnected() {
    _secondInstance = true;
    QString commands;
    if (qEnvironmentVariableIsSet("XDG_ACTIVATION_TOKEN")) {
        commands += u"XDG_ACTIVATION_TOKEN:"_q
                 + qgetenv("XDG_ACTIVATION_TOKEN").toBase64() + ';';
    }
    // ... 其他命令
    _localSocket.write(commands.toLatin1());
}

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// kio/src/gui/kprocessrunner.cpp
#if HAVE_WAYLAND
    if (KWindowSystem::isPlatformWayland()) {
        if (!asn.isEmpty()) {
            // 调用方已提供 token，直接设入子进程环境变量
            m_process->setEnv(QStringLiteral("XDG_ACTIVATION_TOKEN"),
                               QString::fromUtf8(asn));
        } else {
            // 无现成 token，从焦点窗口异步请求
            auto window = qGuiApp->focusWindow();
            if (!window && !qGuiApp->allWindows().isEmpty()) {
                window = qGuiApp->allWindows().constFirst();
            }
            if (window) {
                m_waitingForXdgToken = true;
                m_xdgActivationTokenFuture = KWaylandExtras::xdgActivationToken(
                    window, resolveServiceAlias());
                m_xdgActivationTokenFuture.then(this, [this](const QString &token) {
                    m_process->setEnv(QStringLiteral("XDG_ACTIVATION_TOKEN"), token);
                    m_waitingForXdgToken = false;
                    startProcess();
                });
                return;  // 等 token 到达后再启动进程
            }
        }
    }
#endif

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<!-- xdg-activation-v1.xml -->
<request name="activate">
    <description summary="notify new interaction being available">
        Requests surface activation. It's up to the compositor to display
        this information as desired, for example by placing the surface above
        the rest.

        The compositor may know who requested this by checking the activation
        token and might decide not to follow through with the activation if it's
        considered unwanted.

        Compositors can ignore unknown activation tokens when an invalid
        token is passed.
    </description>
    <arg name="token" type="string" summary="the activation token of the initiating client"/>
    <arg name="surface" type="object" interface="wl_surface"
         summary="the wl_surface to activate"/>
</request>

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// src/plugins/platforms/wayland/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp
bool QWaylandXdgSurface::requestActivate()
{
    if (auto *activation = m_shell->activation()) {
        // 优先级 1（最高）：预设 token，通过 setXdgActivationToken() 提前设置
        if (!m_activationToken.isEmpty()) {
            activation->activate(m_activationToken, window()->wlSurface());
            m_activationToken = {};
            return true;
        }
        // 优先级 2：环境变量（托盘激活的主要路径）
        else if (const auto token = qEnvironmentVariable("XDG_ACTIVATION_TOKEN");
                 !token.isEmpty()) {
            activation->activate(token, window()->wlSurface());
            qunsetenv("XDG_ACTIVATION_TOKEN");  // 一次性消费，防止泄露给子进程
            return true;
        }
        // 优先级 3：实时请求（需要用户输入事件关联）
        else {
            const auto tokenProvider = activation->requestXdgActivationToken(
                wlWindow->display(), wlWindow->wlSurface(), serial, appId);
            connect(tokenProvider, &QWaylandXdgActivationTokenV1::done, this,
                    [this](const QString &token) {
                        m_shell->activation()->activate(token, window()->wlSurface());
                    });
            return true;
        }
    }
    return false;
}

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QWindow::requestActivate()
    │
    ▼
QPlatformWindow::requestActivateWindow()
    │
    ▼
QWaylandWindow::requestActivateWindow()     [qwaylandwindow.cpp]
    │
    ▼
QWaylandXdgSurface::requestActivate()       [qwaylandxdgshell.cpp]
    │
    ▼
activation->activate(token, surface)       [xdg-activation-v1 协议]
    │
    ▼
Compositor 验证 token，决定是否授权焦点