First version of streaming transfers.

usb/transfer_stream_test.go

@@ -0,0 +1,132 @@
+// Copyright 2017 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
+
+import (
+	"errors"
+	"io"
+	"testing"
+)
+
+var fakeTransferBuf = make([]byte, 1500)
+
+type fakeStreamResult struct {
+	n         int
+	waitErr   error
+	submitErr error
+}
+
+type fakeStreamTransfer struct {
+	res      []fakeStreamResult
+	inFlight bool
+	released bool
+}
+
+func (f *fakeStreamTransfer) submit() error {
+	if f.released {
+		return errors.New("submit() called on a free()d transfer")
+	}
+	if f.inFlight {
+		return errors.New("submit() called twice")
+	}
+	if len(f.res) == 0 {
+		return io.ErrUnexpectedEOF
+	}
+	f.inFlight = true
+	res := f.res[0]
+	if res.submitErr != nil {
+		f.res = nil
+		return res.submitErr
+	}
+	return nil
+}
+
+func (f *fakeStreamTransfer) wait() (int, error) {
+	if f.released {
+		return 0, errors.New("wait() called on a free()d transfer")
+	}
+	if !f.inFlight {
+		return 0, errors.New("wait() called without submit()")
+	}
+	if len(f.res) == 0 {
+		return 0, io.ErrUnexpectedEOF
+	}
+	f.inFlight = false
+	res := f.res[0]
+	if res.waitErr != nil {
+		f.res = nil
+	}
+	return res.n, res.waitErr
+}
+
+func (f *fakeStreamTransfer) free() error {
+	if f.released {
+		return errors.New("free() called twice")
+	}
+	f.released = true
+	return nil
+}
+
+func (f *fakeStreamTransfer) cancel() error { return nil }
+func (f *fakeStreamTransfer) data() []byte  { return fakeTransferBuf }
+
+var sentinelError = errors.New("sentinel error")
+
+func TestReadStream(t *testing.T) {
+	transfers := []*fakeStreamTransfer{
+		{res: []fakeStreamResult{
+			{n: 500},
+		}},
+		{res: []fakeStreamResult{
+			{n: 500},
+		}},
+		{res: []fakeStreamResult{
+			{n: 123, waitErr: sentinelError},
+		}},
+		{res: []fakeStreamResult{
+			{n: 500},
+		}},
+	}
+	intfs := make([]transferIntf, len(transfers))
+	for i := range transfers {
+		intfs[i] = transfers[i]
+	}
+	s := ReadStream{newStream(intfs, true)}
+	buf := make([]byte, 400)
+	for _, rs := range []struct {
+		want int
+		err  error
+	}{
+		{400, nil},
+		{100, nil},
+		{400, nil},
+		{100, nil},
+		{123, sentinelError},
+		{0, io.ErrClosedPipe},
+	} {
+		n, err := s.Read(buf)
+		if n != rs.want {
+			t.Errorf("Read(): got %d bytes, want %d", n, rs.want)
+		}
+		if err != rs.err {
+			t.Errorf("Read(): got error %v, want %v", err, rs.err)
+		}
+	}
+	for i := range transfers {
+		if !transfers[i].released {
+			t.Errorf("Transfer #%d was not freed after stream completed", i)
+		}
+	}
+}