framework/device/information.go

// Copyright (C) 2016 The Android Open Source Project
//
// 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 device

import "net/url"

// URL returns the address in URL form.
func (i *Information) URL() *url.URL {
	u, _ := url.Parse(i.Address)
	return u
}

// ID returns a short identifier for the device that will be unique to the device and stable if possible.
func (i *Information) ID() string {
	if i.Serial != "" {
		return i.Serial
	}
	if i.Address != "" {
		return i.Address
	}
	if i.Name != "" {
		return i.Name
	}
	return i.Configuration.String()
}

// SamePhysicalDevice returns true if the two information objects refer to the same physical device.
func SamePhysicalDevice(a, b *Information) bool {
	if a == b {
		// Same pointer must be same device
		return true
	}
	if a == nil || b == nil {
		// only one of them is nil no match
		return false
	}
	// If the serial is set, treat it as an authoratitive comparison point
	if a.Serial != "" && b.Serial != "" {
		return a.Serial == b.Serial
	}
	// No serial, if the address is set and the same, it must be the same device
	if a.Address != "" && a.Address == b.Address {
		return true
	}
	// If the hardware is different, cannot be the same
	if !SameHardware(a.Configuration.Hardware, b.Configuration.Hardware) {
		return false
	}

	// If we get here, and the devices have names, we trust the names
	if a.Name != "" && b.Name != "" {
		return a.Name == b.Name
	}

	// If we get here, we have no strong information that the devices are either different
	// or the same, assume different for safty
	return false
}