move descriptor to the device, like config and interface.

Clear separation between descriptor stringers and value stringers for
the device and interface.

usb/descriptor.go

@@ -1,46 +0,0 @@
-// Copyright 2013 Google Inc.  All rights reserved.
-// Copyright 2016 the gousb Authors.  All rights reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package usb
-
-import "fmt"
-
-// Descriptor is a representation of a USB device descriptor.
-type Descriptor struct {
-	// Bus information
-	Bus     uint8 // The bus on which the device was detected
-	Address uint8 // The address of the device on the bus
-
-	// Version information
-	Spec   BCD // USB Specification Release Number
-	Device BCD // The device version
-
-	// Product information
-	Vendor  ID // The Vendor identifer
-	Product ID // The Product identifier
-
-	// Protocol information
-	Class    Class    // The class of this device
-	SubClass Class    // The sub-class (within the class) of this device
-	Protocol Protocol // The protocol (within the sub-class) of this device
-
-	// Configuration information
-	Configs []ConfigInfo
-}
-
-// String represents a human readable representation of the device in the descriptor.
-func (d *Descriptor) String() string {
-	return fmt.Sprintf("vid=%s,pid=%s,bus=%d,addr=%d", d.Vendor, d.Product, d.Bus, d.Address)
-}

usb/device.go

@@ -20,6 +20,38 @@ import (
 	"sync"
 )
 
+// Descriptor is a representation of a USB device descriptor.
+type Descriptor struct {
+	// Bus information
+	Bus     uint8 // The bus on which the device was detected
+	Address uint8 // The address of the device on the bus
+
+	// Version information
+	Spec   BCD // USB Specification Release Number
+	Device BCD // The device version
+
+	// Product information
+	Vendor  ID // The Vendor identifer
+	Product ID // The Product identifier
+
+	// Protocol information
+	Class    Class    // The class of this device
+	SubClass Class    // The sub-class (within the class) of this device
+	Protocol Protocol // The protocol (within the sub-class) of this device
+
+	// Configuration information
+	Configs []ConfigInfo
+}
+
+// String returns a human-readable version of the device descriptor.
+func (d *Descriptor) String() string {
+	var cfgs []int
+	for _, c := range d.Configs {
+		cfgs = append(cfgs, c.Config)
+	}
+	return fmt.Sprintf("%d:%d: %s:%s (available configs: %v)", d.Bus, d.Address, d.Vendor, d.Product, cfgs)
+}
+
 // Device represents an opened USB device.
 type Device struct {
 	handle *libusbDevHandle
@@ -32,6 +64,11 @@ type Device struct {
 	claimed *Config
 }
 
+// String represents a human readable representation of the device.
+func (d *Device) String() string {
+	return fmt.Sprintf("vid=%s,pid=%s,bus=%d,addr=%d", d.Vendor, d.Product, d.Bus, d.Address)
+}
+
 // Reset performs a USB port reset to reinitialize a device.
 func (d *Device) Reset() error {
 	if d.handle == nil {

usb/interface.go

@@ -29,10 +29,10 @@ type InterfaceInfo struct {
 	AltSettings []InterfaceSetting
 }
 
-// String returns a human-readable descripton of the interface and it's
+// String returns a human-readable descripton of the interface descriptor and
-// alternate settings.
+// it's alternate settings.
 func (i InterfaceInfo) String() string {
-	return fmt.Sprintf("if=%d", i.Number)
+	return fmt.Sprintf("Interface %d (%d alternate settings)", i.Number, len(i.AltSettings))
 }
 
 // InterfaceSetting contains information about a USB interface with a particular