Files
gousb/usb/usb.go
2012-03-26 22:51:37 -07:00

76 lines
1.6 KiB
Go

package usb
// #cgo LDFLAGS: -lusb-1.0
// #include <libusb-1.0/libusb.h>
import "C"
import (
"reflect"
"runtime"
"unsafe"
)
type Context struct {
ctx *C.libusb_context
}
func (c *Context) Debug(level int) {
C.libusb_set_debug(c.ctx, C.int(level))
}
func NewContext() *Context {
c := new(Context)
//log.Printf("gousb initialized")
if errno := C.libusb_init(&c.ctx); errno != 0 {
panic(usbError(errno))
}
// This doesn't seem to actually get called. Sigh.
runtime.SetFinalizer(c, (*Context).Close)
return c
}
// ListDevices calls each with each enumerated device. If the function returns
// true, the device is added to the list of *DeviceInfo to return. All of
// these must be Closed, even if an error is also returned.
func (c *Context) ListDevices(each func(bus, addr int, desc *Descriptor) bool) ([]*DeviceInfo, error) {
var list **C.libusb_device
cnt := C.libusb_get_device_list(c.ctx, &list)
if cnt < 0 {
return nil, usbError(cnt)
}
defer C.libusb_free_device_list(list, 1)
var slice []*C.libusb_device
*(*reflect.SliceHeader)(unsafe.Pointer(&slice)) = reflect.SliceHeader{
Data: uintptr(unsafe.Pointer(list)),
Len: int(cnt),
Cap: int(cnt),
}
ret := []*DeviceInfo{}
for _, dev := range slice {
bus := int(C.libusb_get_bus_number(dev))
addr := int(C.libusb_get_device_address(dev))
desc, err := newDescriptor(dev)
if err != nil {
return ret, err
}
if each(bus, addr, desc) {
ret = append(ret, newDeviceInfo(dev))
}
}
return ret, nil
}
func (c *Context) Close() error {
if c.ctx != nil {
C.libusb_exit(c.ctx)
//log.Printf("gousb finished")
}
c.ctx = nil
return nil
}