// Copyright 2013 Google Inc. 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 provides a wrapper around libusb-1.0.
package usb
/*
#cgo CFLAGS: -I../internal/libusb/libusb
#cgo CFLAGS: -DDEFAULT_VISIBILITY=""
#cgo linux CFLAGS: -DOS_LINUX -D_GNU_SOURCE -DPOLL_NFDS_TYPE=int
#cgo darwin CFLAGS: -DOS_DARWIN -DPOLL_NFDS_TYPE=int
#cgo darwin LDFLAGS: -framework CoreFoundation -framework IOKit -lobjc
#cgo openbsd CFLAGS: -DOS_OPENBSD -DPOLL_NFDS_TYPE=int
#cgo windows CFLAGS: -DOS_WINDOWS -DUSE_USBDK -DPOLL_NFDS_TYPE=int
#if defined(OS_LINUX) || defined(OS_DARWIN) || defined(OS_OPENBSD)
#include <sys/poll.h>
#include "os/threads_posix.c"
#include "os/poll_posix.c"
#elif defined(OS_WINDOWS)
#include "os/threads_windows.c"
#include "os/poll_windows.c"
#endif
#ifdef OS_LINUX
#include "os/linux_usbfs.c"
#include "os/linux_netlink.c"
#elif OS_DARWIN
#include "os/darwin_usb.c"
#elif OS_OPENBSD
#include "os/openbsd_usb.c"
#elif OS_WINDOWS
#include "os/windows_nt_common.c"
#include "os/windows_usbdk.c"
#endif
#include "core.c"
#include "descriptor.c"
#include "hotplug.c"
#include "io.c"
#include "strerror.c"
#include "sync.c"
*/
import "C"
import (
"log"
"reflect"
"unsafe"
)
type Context struct {
ctx *C.libusb_context
done chan struct{}
}
func (c *Context) Debug(level int) {
C.libusb_set_debug(c.ctx, C.int(level))
}
func NewContext() (*Context, error) {
c := &Context{
done: make(chan struct{}),
}
if errno := C.libusb_init(&c.ctx); errno != 0 {
return nil, usbError(errno)
}
go func() {
tv := C.struct_timeval{
tv_sec: 0,
tv_usec: 100000,
}
for {
select {
case <-c.done:
return
default:
}
if errno := C.libusb_handle_events_timeout_completed(c.ctx, &tv, nil); errno < 0 {
log.Printf("handle_events: error: %s", usbError(errno))
continue
}
//log.Printf("handle_events returned")
}
}()
return c, nil
}
// ListDevices calls each with each enumerated device.
// If the function returns true, the device is opened and a Device is returned if the operation succeeds.
// Every Device returned (whether an error is also returned or not) must be closed.
// If there are any errors enumerating the devices,
// the final one is returned along with any successfully opened devices.
func (c *Context) ListDevices(each func(desc *Descriptor) bool) ([]*Device, 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),
}
var reterr error
var ret []*Device
for _, dev := range slice {
desc, err := newDescriptor(dev)
if err != nil {
reterr = err
continue
}
if each(desc) {
var handle *C.libusb_device_handle
if errno := C.libusb_open(dev, &handle); errno != 0 {
reterr = usbError(errno)
continue
}
if dev, err := newDevice(handle, desc); err != nil {
reterr = err
} else {
ret = append(ret, dev)
}
}
}
return ret, reterr
}
// OpenDeviceWithVidPid opens Device from specific VendorId and ProductId.
// If there are any errors, it'll returns at second value.
func (c *Context) OpenDeviceWithVidPid(vid, pid int) (*Device, error) {
handle := C.libusb_open_device_with_vid_pid(c.ctx, (C.uint16_t)(vid), (C.uint16_t)(pid))
if handle == nil {
return nil, ERROR_NOT_FOUND
}
dev := C.libusb_get_device(handle)
if dev == nil {
return nil, ERROR_NO_DEVICE
}
desc, err := newDescriptor(dev)
// return an error from nil-handle and nil-device
if err != nil {
return nil, err
}
return newDevice(handle, desc)
}
func (c *Context) Close() error {
close(c.done)
if c.ctx != nil {
C.libusb_exit(c.ctx)
}
c.ctx = nil
return nil
}
