From 0ce2eb60384fd60864731711009a37f92170caba Mon Sep 17 00:00:00 2001
From: Damien <maitredede@gmail.com>
Date: Mon, 4 Sep 2023 07:35:36 +1100
Subject: [PATCH] feat(usb): prefer external usb context

---
 acr122usb/deviceid.go       |  4 +---
 acr122usb/driver.go         | 23 +++++++++++------------
 cmd/common/drivers.go       |  5 +++--
 cmd/nfc-list/main.go        |  7 ++++++-
 cmd/nfc-poll/main.go        |  7 ++++++-
 cmd/nfc-scan-device/main.go |  7 ++++++-
 6 files changed, 33 insertions(+), 20 deletions(-)

diff --git a/acr122usb/deviceid.go b/acr122usb/deviceid.go
index 1fff294..4871240 100644
--- a/acr122usb/deviceid.go
+++ b/acr122usb/deviceid.go
@@ -34,9 +34,7 @@ func (d *acr122DeviceID) String() string {
 
 // Open opens an acr122 usb device (libnfc: acr122_usb_open)
 func (d *acr122DeviceID) Open(logger *zap.SugaredLogger) (gonfc.Device, error) {
-	c := usbctx()
-
-	devs, err := c.OpenDevices(func(desc *gousb.DeviceDesc) bool {
+	devs, err := d.driver.usb.OpenDevices(func(desc *gousb.DeviceDesc) bool {
 		return slices.Equal(desc.Path, d.desc.Path)
 	})
 	if len(devs) == 0 {
diff --git a/acr122usb/driver.go b/acr122usb/driver.go
index 9ea20f2..3e5d8f0 100644
--- a/acr122usb/driver.go
+++ b/acr122usb/driver.go
@@ -1,22 +1,22 @@
 package acr122usb
 
 import (
-	"sync"
-
 	"github.com/google/gousb"
 	"github.com/maitredede/gonfc"
 	"go.uber.org/zap"
 )
 
-var (
-	usbctx = sync.OnceValue(initCtx)
-)
-
-func initCtx() *gousb.Context {
-	return gousb.NewContext()
+type Acr122USBDriver struct {
+	usb *gousb.Context
 }
 
-type Acr122USBDriver struct {
+func NewDriver(usb *gousb.Context) *Acr122USBDriver {
+	if usb == nil {
+		panic("gousb context required")
+	}
+	return &Acr122USBDriver{
+		usb: usb,
+	}
 }
 
 var _ gonfc.Driver = (*Acr122USBDriver)(nil)
@@ -24,6 +24,7 @@ var _ gonfc.Driver = (*Acr122USBDriver)(nil)
 func (Acr122USBDriver) Manufacturer() string {
 	return "libusb"
 }
+
 func (Acr122USBDriver) Product() string {
 	return "acr122"
 }
@@ -37,11 +38,9 @@ func (Acr122USBDriver) Conflicts(otherDriver gonfc.Driver) bool {
 
 func (d *Acr122USBDriver) LookupDevices(logger *zap.SugaredLogger) ([]gonfc.DeviceID, error) {
 
-	c := usbctx()
-
 	result := make([]gonfc.DeviceID, 0)
 
-	devs, err := c.OpenDevices(func(desc *gousb.DeviceDesc) bool {
+	devs, err := d.usb.OpenDevices(func(desc *gousb.DeviceDesc) bool {
 		ok := false
 		var deviceInfo Acr122UsbSupportedDevice
 		for _, d := range UsbSupportedDevices {
diff --git a/cmd/common/drivers.go b/cmd/common/drivers.go
index 72dd563..52df4e0 100644
--- a/cmd/common/drivers.go
+++ b/cmd/common/drivers.go
@@ -3,6 +3,7 @@ package common
 import (
 	"flag"
 
+	"github.com/google/gousb"
 	"github.com/maitredede/gonfc"
 	"github.com/maitredede/gonfc/acr122usb"
 	"github.com/maitredede/gonfc/periphio"
@@ -20,9 +21,9 @@ func init() {
 	flag.BoolVar(&disablePeriphioI2C, "disable-periphio-i2c", false, "Disable periph.io I2C")
 }
 
-func RegisterAllDrivers(logger *zap.SugaredLogger) []gonfc.Driver {
+func RegisterAllDrivers(logger *zap.SugaredLogger, usb *gousb.Context) []gonfc.Driver {
 	drvs := []gonfc.Driver{
-		&acr122usb.Acr122USBDriver{},
+		acr122usb.NewDriver(usb),
 	}
 	if !disablePigpioI2C {
 		// Remote raspberry pi with pigpiod installed
diff --git a/cmd/nfc-list/main.go b/cmd/nfc-list/main.go
index d7982dd..24e482c 100644
--- a/cmd/nfc-list/main.go
+++ b/cmd/nfc-list/main.go
@@ -3,6 +3,7 @@ package main
 import (
 	goflag "flag"
 
+	"github.com/google/gousb"
 	"github.com/maitredede/gonfc"
 	"github.com/maitredede/gonfc/cmd/common"
 	flag "github.com/spf13/pflag"
@@ -24,13 +25,17 @@ func main() {
 	logger = log.Sugar()
 	logger.Infof("gonfc version of nfc-list")
 
+	//gousb
+	usb := gousb.NewContext()
+	defer usb.Close()
+
 	//periphio
 	_, err := host.Init()
 	if err != nil {
 		logger.Fatal(err)
 	}
 
-	drvs := common.RegisterAllDrivers(logger)
+	drvs := common.RegisterAllDrivers(logger, usb)
 
 	devices := make([]gonfc.DeviceID, 0)
 	for _, d := range drvs {
diff --git a/cmd/nfc-poll/main.go b/cmd/nfc-poll/main.go
index 30319d5..64206b7 100644
--- a/cmd/nfc-poll/main.go
+++ b/cmd/nfc-poll/main.go
@@ -4,6 +4,7 @@ import (
 	goflag "flag"
 	"time"
 
+	"github.com/google/gousb"
 	"github.com/maitredede/gonfc"
 	"github.com/maitredede/gonfc/cmd/common"
 	flag "github.com/spf13/pflag"
@@ -25,13 +26,17 @@ func main() {
 	logger = log.Sugar()
 	logger.Infof("gonfc version of nfc-poll")
 
+	//gousb
+	usb := gousb.NewContext()
+	defer usb.Close()
+
 	//periphio
 	_, err := host.Init()
 	if err != nil {
 		logger.Fatal(err)
 	}
 
-	drvs := common.RegisterAllDrivers(logger)
+	drvs := common.RegisterAllDrivers(logger, usb)
 
 	devices := make([]gonfc.DeviceID, 0)
 	for _, d := range drvs {
diff --git a/cmd/nfc-scan-device/main.go b/cmd/nfc-scan-device/main.go
index 5cae0bb..a1a6b4c 100644
--- a/cmd/nfc-scan-device/main.go
+++ b/cmd/nfc-scan-device/main.go
@@ -3,6 +3,7 @@ package main
 import (
 	goflag "flag"
 
+	"github.com/google/gousb"
 	"github.com/maitredede/gonfc"
 	"github.com/maitredede/gonfc/cmd/common"
 	flag "github.com/spf13/pflag"
@@ -24,13 +25,17 @@ func main() {
 	logger := log.Sugar()
 	logger.Infof("gonfc version of nfc-scan-device")
 
+	//gousb
+	usb := gousb.NewContext()
+	defer usb.Close()
+
 	//periphio
 	_, err := host.Init()
 	if err != nil {
 		logger.Fatal(err)
 	}
 
-	drvs := common.RegisterAllDrivers(logger)
+	drvs := common.RegisterAllDrivers(logger, usb)
 
 	devices := make([]gonfc.DeviceID, 0)
 	for _, d := range drvs {