show_usb_devices.rb

#!/usr/bin/env ruby

require 'libusb'
require 'Qt4'
require 'singleton'

class UsbManager
  include Singleton

  def context
    @context ||= LIBUSB::Context.new
  end

  def devices
    context.devices
  end
end

class MainWindow < Qt::Widget
  def initialize(parent = nil)
    super parent

    @layout = Qt::VBoxLayout.new
    @device_table = Qt::TableWidget.new 0, 4
    @device_table.horizontalHeaderLabels = [ tr('Type'), tr('Bus'), tr('ID'), tr('Name') ]
    @device_table.horizontalHeader.setResizeMode 3, Qt::HeaderView::Stretch
    @device_table.verticalHeader.hide

    populate_device_table
    setWindowTitle "QEMU USB Control"
    @layout.addWidget @device_table
    setLayout @layout
  end

  def populate_device_table
    devices = UsbManager.instance.devices
    @device_table.rowCount = devices.size

    devices.each_with_index do |device, row|
      setting = device.interfaces.first.settings.first
      type = LIBUSB.dev_string setting.bInterfaceClass, setting.bInterfaceSubClass, setting.bInterfaceProtocol
      bus = "#{device.bus_number}/#{device.device_address}"
      id = ("%04x:%04x" % [device.idVendor, device.idProduct])
      name = device.product.to_s

      puts "#{row}: #{type} #{bus} #{id} #{name}"

      @device_table.setCellWidget row, 0, Qt::Label.new(type)
      @device_table.setCellWidget row, 1, Qt::Label.new(bus)
      @device_table.setCellWidget row, 2, Qt::Label.new(id)
      @device_table.setCellWidget row, 3, Qt::Label.new(name)
    end
  end
end

$app = Qt::Application.new ARGV
MainWindow.new.show
$app.exec