Rename Transfer to usbTransfer, it's internal to gousb.

Move usbTransfer and it's methods to transfer.go, it's not only used by
iso transfers.

usb/iso.go

@@ -17,15 +17,10 @@ package usb
 
 /*
 #include <libusb-1.0/libusb.h>
-
-int submit(struct libusb_transfer *xfer);
-void print_xfer(struct libusb_transfer *xfer);
-int extract_data(struct libusb_transfer *xfer, void *data, int max, unsigned char *status);
 */
 import "C"
 
 import (
-	"fmt"
 	"log"
 	"time"
 	"unsafe"
@@ -37,7 +32,7 @@ func iso_callback(cptr unsafe.Pointer) {
 	close(ch)
 }
 
-func (end *endpoint) allocTransfer() *Transfer {
+func (end *endpoint) allocTransfer() *usbTransfer {
 	const (
 		iso_packets = 8 // 128 // 242
 	)
@@ -68,7 +63,7 @@ func (end *endpoint) allocTransfer() *Transfer {
 		}))
 	*/
 
-	t := &Transfer{
+	t := &usbTransfer{
 		xfer: xfer,
 		done: done,
 		buf:  buf,
@@ -78,57 +73,6 @@ func (end *endpoint) allocTransfer() *Transfer {
 	return t
 }
 
-type Transfer struct {
-	xfer *C.struct_libusb_transfer
-	pkts []*C.struct_libusb_packet_descriptor
-	done chan struct{}
-	buf  []byte
-}
-
-func (t *Transfer) Submit(timeout time.Duration) error {
-	//log.Printf("iso: submitting %#v", t.xfer)
-	t.xfer.timeout = C.uint(timeout / time.Millisecond)
-	if errno := C.submit(t.xfer); errno < 0 {
-		return usbError(errno)
-	}
-	return nil
-}
-
-func (t *Transfer) Wait(b []byte) (n int, err error) {
-	select {
-	case <-time.After(10 * time.Second):
-		return 0, fmt.Errorf("wait timed out after 10s")
-	case <-t.done:
-	}
-	// Non-iso transfers:
-	//n = int(t.xfer.actual_length)
-	//copy(b, ((*[1 << 16]byte)(unsafe.Pointer(t.xfer.buffer)))[:n])
-
-	//C.print_xfer(t.xfer)
-	/*
-		buf, offset := ((*[1 << 16]byte)(unsafe.Pointer(t.xfer.buffer))), 0
-		for i, pkt := range *t.pkts {
-			log.Printf("Type is %T", t.pkts)
-			n += copy(b[n:], buf[offset:][:pkt.actual_length])
-			offset += pkt.Length
-			if pkt.status != 0 && err == nil {
-				err = error(TransferStatus(pkt.status))
-			}
-		}
-	*/
-	var status uint8
-	n = int(C.extract_data(t.xfer, unsafe.Pointer(&b[0]), C.int(len(b)), (*C.uchar)(unsafe.Pointer(&status))))
-	if status != 0 {
-		err = TransferStatus(status)
-	}
-	return n, err
-}
-
-func (t *Transfer) Close() error {
-	C.libusb_free_transfer(t.xfer)
-	return nil
-}
-
 func isochronous_xfer(e *endpoint, buf []byte, timeout time.Duration) (int, error) {
 	t := e.allocTransfer()
 	defer t.Close()

usb/transfer.go

@@ -0,0 +1,63 @@
+// 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 extract_data(struct libusb_transfer *xfer, void *data, int max, unsigned char *status);
+int submit(struct libusb_transfer *xfer);
+*/
+import "C"
+
+import (
+	"fmt"
+	"time"
+	"unsafe"
+)
+
+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(b []byte) (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 uint8
+	n = int(C.extract_data(t.xfer, unsafe.Pointer(&b[0]), C.int(len(b)), (*C.uchar)(unsafe.Pointer(&status))))
+	if status != 0 {
+		err = TransferStatus(status)
+	}
+	return n, err
+}
+
+func (t *usbTransfer) Close() error {
+	C.libusb_free_transfer(t.xfer)
+	return nil
+}