Files
gousb/usb/transfer.go
Sebastian Zagrodzki a47809fda8 Simplify the C part even more - the buffer that xfer uses for
transferring data is the same as the one that was created in
newUSBTransfer.
2017-02-13 02:50:47 +01:00

76 lines
1.8 KiB
Go

// 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
/*
#include <libusb-1.0/libusb.h>
int compact_iso_data(struct libusb_transfer *xfer, unsigned char *status);
int submit(struct libusb_transfer *xfer);
*/
import "C"
import (
"fmt"
"time"
"unsafe"
)
//export xfer_callback
func xfer_callback(cptr unsafe.Pointer) {
ch := *(*chan struct{})(cptr)
close(ch)
}
type usbTransfer struct {
xfer *C.struct_libusb_transfer
pkts []*C.struct_libusb_packet_descriptor
done chan struct{}
buf []byte
}
func (t *usbTransfer) submit(timeout time.Duration) error {
t.xfer.timeout = C.uint(timeout / time.Millisecond)
if errno := C.submit(t.xfer); errno < 0 {
return usbError(errno)
}
return nil
}
func (t *usbTransfer) wait() (n int, err error) {
select {
case <-time.After(10 * time.Second):
return 0, fmt.Errorf("wait timed out after 10s")
case <-t.done:
}
var status TransferStatus
switch TransferType(t.xfer._type) {
case TRANSFER_TYPE_ISOCHRONOUS:
n = int(C.compact_iso_data(t.xfer, (*C.uchar)(unsafe.Pointer(&status))))
default:
n = int(t.xfer.length)
status = TransferStatus(t.xfer.status)
}
if status != LIBUSB_TRANSFER_COMPLETED {
return 0, status
}
return n, err
}
func (t *usbTransfer) free() error {
C.libusb_free_transfer(t.xfer)
return nil
}