refactor(usb): move usbconfig to a seperated package

internal/usbgadget/usbgadget.go

@@ -0,0 +1,110 @@
+// Package usbgadget provides a high-level interface to manage USB gadgets
+// THIS PACKAGE IS FOR INTERNAL USE ONLY AND ITS API MAY CHANGE WITHOUT NOTICE
+package usbgadget
+
+import (
+	"os"
+	"path"
+	"sync"
+	"time"
+
+	"github.com/pion/logging"
+)
+
+// Devices is a struct that represents the USB devices that can be enabled on a USB gadget.
+type Devices struct {
+	AbsoluteMouse bool `json:"absolute_mouse"`
+	RelativeMouse bool `json:"relative_mouse"`
+	Keyboard      bool `json:"keyboard"`
+	MassStorage   bool `json:"mass_storage"`
+}
+
+// Config is a struct that represents the customizations for a USB gadget.
+// TODO: rename to something else that won't confuse with the USB gadget configuration
+type Config struct {
+	VendorId     string `json:"vendor_id"`
+	ProductId    string `json:"product_id"`
+	SerialNumber string `json:"serial_number"`
+	Manufacturer string `json:"manufacturer"`
+	Product      string `json:"product"`
+
+	isEmpty bool
+}
+
+var defaultUsbGadgetDevices = Devices{
+	AbsoluteMouse: true,
+	RelativeMouse: true,
+	Keyboard:      true,
+	MassStorage:   true,
+}
+
+// UsbGadget is a struct that represents a USB gadget.
+type UsbGadget struct {
+	name          string
+	udc           string
+	kvmGadgetPath string
+	configC1Path  string
+
+	configMap    map[string]gadgetConfigItem
+	customConfig Config
+
+	configLock sync.Mutex
+
+	keyboardHidFile *os.File
+	keyboardLock    sync.Mutex
+	absMouseHidFile *os.File
+	absMouseLock    sync.Mutex
+	relMouseHidFile *os.File
+	relMouseLock    sync.Mutex
+
+	enabledDevices Devices
+
+	absMouseAccumulatedWheelY float64
+
+	lastUserInput time.Time
+
+	log logging.LeveledLogger
+}
+
+const configFSPath = "/sys/kernel/config"
+const gadgetPath = "/sys/kernel/config/usb_gadget"
+
+var defaultLogger = logging.NewDefaultLoggerFactory().NewLogger("usbgadget")
+
+// NewUsbGadget creates a new UsbGadget.
+func NewUsbGadget(name string, enabledDevices *Devices, config *Config, logger *logging.LeveledLogger) *UsbGadget {
+	if logger == nil {
+		logger = &defaultLogger
+	}
+
+	if enabledDevices == nil {
+		enabledDevices = &defaultUsbGadgetDevices
+	}
+
+	if config == nil {
+		config = &Config{isEmpty: true}
+	}
+
+	g := &UsbGadget{
+		name:           name,
+		kvmGadgetPath:  path.Join(gadgetPath, name),
+		configC1Path:   path.Join(gadgetPath, name, "configs/c.1"),
+		configMap:      defaultGadgetConfig,
+		customConfig:   *config,
+		configLock:     sync.Mutex{},
+		keyboardLock:   sync.Mutex{},
+		absMouseLock:   sync.Mutex{},
+		relMouseLock:   sync.Mutex{},
+		enabledDevices: *enabledDevices,
+		lastUserInput:  time.Now(),
+		log:            *logger,
+
+		absMouseAccumulatedWheelY: 0,
+	}
+	if err := g.Init(); err != nil {
+		g.log.Errorf("failed to init USB gadget: %v", err)
+		return nil
+	}
+
+	return g
+}