QAbstractNativeEventFilter监听USB热插拔事件

1，需求：监听Windows下USB设备拔插事件，并将指定vid，pid的USB设备过滤出来。

QAbstractNativeEventFilter类：主要作用是捕获全局系统消息

怎么用？先来看下文档。

QAbstractNativeEventFilter::nativeEventFilter简介：

 Linux example：

// Linux example

  class MyXcbEventFilter : public QAbstractNativeEventFilter
  {
  public:
      bool nativeEventFilter(const QByteArray &eventType, void *message, long *) override
      {
          if (eventType == "xcb_generic_event_t") {
              xcb_generic_event_t* ev = static_cast<xcb_generic_event_t *>(message);
              // ...
          }
          return false;
      }
  };

2，文档告诉我们，需要创建一个类去继承QAbstractNativeEventFilter，并重写nativeEventFilter方法。

直接上代码：

USBDeviceManager.h

#pragma once

#include <QObject>
#include <QDebug>
#include <QList>
#include <QApplication>
#include <QAbstractNativeEventFilter>

#ifdef WIN32
#include <windowsx.h>
#include <dwmapi.h>
#include <dbt.h>
#include <stdio.h>
#pragma comment(lib, "Dwmapi.lib")
#endif  // WIN32

static const QList<GUID> GuidList = {
    // GUID_DEVINTERFACE_USB_DEVICE
    { 0xA5DCBF10, 0x6530, 0x11D2, { 0x90, 0x1F, 0x00, 0xC0, 0x4F, 0xB9, 0x51, 0xED } },
    // KSCATEGORY_CAPTURE
    { 0x65E8773D, 0x8F56, 0x11D0, { 0xA3, 0xB9, 0x00, 0xA0, 0xC9, 0x22, 0x31, 0x96 } },
    //// GUID_DEVINTERFACE_DISK
    //{ 0x53f56307, 0xb6bf, 0x11d0, { 0x94, 0xf2, 0x00, 0xa0, 0xc9, 0x1e, 0xfb, 0x8b } },
    // GUID_DEVINTERFACE_HID,
    { 0x4D1E55B2, 0xF16F, 0x11CF, { 0x88, 0xCB, 0x00, 0x11, 0x11, 0x00, 0x00, 0x30 } },
    //// GUID_NDIS_LAN_CLASS
    //{ 0xad498944, 0x762f, 0x11d0, { 0x8d, 0xcb, 0x00, 0xc0, 0x4f, 0xc3, 0x35, 0x8c } },
    //// GUID_DEVINTERFACE_COMPORT
    //{ 0x86e0d1e0, 0x8089, 0x11d0, { 0x9c, 0xe4, 0x08, 0x00, 0x3e, 0x30, 0x1f, 0x73 } },
    //// GUID_DEVINTERFACE_SERENUM_BUS_ENUMERATOR
    //{ 0x4D36E978, 0xE325, 0x11CE, { 0xBF, 0xC1, 0x08, 0x00, 0x2B, 0xE1, 0x03, 0x18 } },
    //// GUID_DEVINTERFACE_PARALLEL
    //{ 0x97F76EF0, 0xF883, 0x11D0, { 0xAF, 0x1F, 0x00, 0x00, 0xF8, 0x00, 0x84, 0x5C } },
    //// GUID_DEVINTERFACE_PARCLASS
    //{ 0x811FC6A5, 0xF728, 0x11D0, { 0xA5, 0x37, 0x00, 0x00, 0xF8, 0x75, 0x3E, 0xD1 } }
};

class USBDeviceManager : public QObject, public QAbstractNativeEventFilter {
		Q_OBJECT

public:
    USBDeviceManager();
    ~USBDeviceManager() = default;
    USBDeviceManager(const USBDeviceManager&) = delete;
    USBDeviceManager* operator=(const USBDeviceManager&) = delete;

public:
    static USBDeviceManager& getInstance();  // 单例

    void registerSystemMessage(HANDLE);
    QString Wchat_tToQString(wchar_t*);
    void usbDeviceFilter(bool, bool, QString);

protected:
    bool nativeEventFilter(const QByteArray&, void*, long*) override;
};

把USBDeviceManager设计成一个单例，多继承于 QAbstractNativeEventFilter，QObject，方便使用Qt的信号与槽机制。

USBDeviceManager.cpp

#include "USBDeviceManager.h"

USBDeviceManager::USBDeviceManager() : QObject(nullptr), QAbstractNativeEventFilter() { }

USBDeviceManager& USBDeviceManager::getInstance() {
		static USBDeviceManagerinstance;
		return instance;
}

void USBDeviceManager::registerSystemMessage(HANDLE window) {
    constexpr uint32_t Interface_Size = sizeof(DEV_BROADCAST_DEVICEINTERFACE);
    for (const auto& guid : GuidList) {
        DEV_BROADCAST_DEVICEINTERFACE device_interface;
        ZeroMemory(&device_interface, Interface_Size);
        device_interface.dbcc_size = Interface_Size;
        device_interface.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE;
        device_interface.dbcc_classguid = guid;
        if (!RegisterDeviceNotification(window, &device_interface, DEVICE_NOTIFY_WINDOW_HANDLE)) {
            int Err = GetLastError();
            qDebug() << "注册失败";
        }
    }
}

QString USBDeviceManager::Wchat_tToQString(wchar_t* name) {
    QString ret = QString((QChar*)name, wcslen(name));
    return ret;
}

bool USBDeviceManager::nativeEventFilter(const QByteArray& eventType, void* message, long* result) {
    Q_UNUSED(eventType);
    MSG* pMsg = reinterpret_cast<MSG*>(message);
    if (pMsg->message == WM_DEVICECHANGE) {
        PDEV_BROADCAST_HDR lpdb = (PDEV_BROADCAST_HDR)pMsg->lParam;
        // 过滤接入/拔出以外的消息
        bool isDeviceArrival = pMsg->wParam == DBT_DEVICEARRIVAL;
        bool isDeviceRemoved = pMsg->wParam == DBT_DEVICEREMOVECOMPLETE;
        if (!isDeviceArrival && !isDeviceRemoved) { return false; }
        // 过滤 device interface class 以外类型的消息
        auto* broadcast = (DEV_BROADCAST_HDR*)pMsg->lParam;
        if (!broadcast || broadcast->dbch_devicetype != DBT_DEVTYP_DEVICEINTERFACE) { return false; }
        // 过滤不监听的设备类型
        auto* device_interface = (DEV_BROADCAST_DEVICEINTERFACE*)broadcast;
        if (!device_interface || !GuidList.contains(device_interface->dbcc_classguid)) { return false; }
        // 处理消息
        QString path = Wchat_tToQString(device_interface->dbcc_name).toLower();
        // 设备过滤
        usbDeviceFilter(isDeviceArrival, isDeviceRemoved, path); 

        if (path.isEmpty() || !(path.contains("hid") || path.contains("usb"))) { return false; }
    }

    return false; 
};

void USBDeviceManager::usbDeviceFilter(bool isDeviceArrival, bool isDeviceRemoved, QString path) {
    if (path.contains("usb#vid_xxxxf&pid_xxxx")) { 
        if (isDeviceArrival) {
            qDebug() << "isDeviceArrival";
        }
        if (isDeviceRemoved) {
            qDebug() << "isDeviceRemoved";
        }
    }
}

注意：必须调用registerSystemMessage，否则很多USB设备会监听不到。

在主窗口调用方法：

USBDeviceManager::getInstance().registerSystemMessage(reinterpret_cast<HWND>(window->winId()));