diff --git a/key.go b/key.go index b712228..fe438a6 100644 --- a/key.go +++ b/key.go @@ -543,6 +543,8 @@ var spaceRunes = []rune{' '} func readInputs(ctx context.Context, msgs chan<- Msg, input io.Reader) error { var buf [256]byte + var leftOverFromPrevIteration []byte +loop: for { // Read and block. numBytes, err := input.Read(buf[:]) @@ -550,11 +552,31 @@ func readInputs(ctx context.Context, msgs chan<- Msg, input io.Reader) error { return fmt.Errorf("error reading input: %w", err) } b := buf[:numBytes] + if leftOverFromPrevIteration != nil { + b = append(leftOverFromPrevIteration, b...) + } + + // If we had a short read (numBytes < len(buf)), we're sure that + // the end of this read is an event boundary, so there is no doubt + // if we are encountering the end of the buffer while parsing a message. + // However, if we've succeeded in filling up the buffer, there may + // be more data in the OS buffer ready to be read in, to complete + // the last message in the input. In that case, we will retry with + // the left over data in the next iteration. + canHaveMoreData := numBytes == len(buf) var i, w int for i, w = 0, 0; i < len(b); i += w { var msg Msg - w, msg = detectOneMsg(b[i:]) + w, msg = detectOneMsg(b[i:], canHaveMoreData) + if w == 0 { + // Expecting more bytes beyond the current buffer. Try waiting + // for more input. + leftOverFromPrevIteration = make([]byte, 0, len(b[i:])+len(buf)) + leftOverFromPrevIteration = append(leftOverFromPrevIteration, b[i:]...) + continue loop + } + select { case msgs <- msg: case <-ctx.Done(): @@ -565,12 +587,13 @@ func readInputs(ctx context.Context, msgs chan<- Msg, input io.Reader) error { return err } } + leftOverFromPrevIteration = nil } } var unknownCSIRe = regexp.MustCompile(`^\x1b\[[\x30-\x3f]*[\x20-\x2f]*[\x40-\x7e]`) -func detectOneMsg(b []byte) (w int, msg Msg) { +func detectOneMsg(b []byte, canHaveMoreData bool) (w int, msg Msg) { // Detect mouse events. const mouseEventLen = 6 if len(b) >= mouseEventLen && b[0] == '\x1b' && b[1] == '[' && b[2] == 'M' { @@ -618,6 +641,15 @@ func detectOneMsg(b []byte) (w int, msg Msg) { break } } + if i >= len(b) && canHaveMoreData { + // We have encountered the end of the input buffer. Alas, we can't + // be sure whether the data in the remainder of the buffer is + // complete (maybe there was a short read). Instead of sending anything + // dumb to the message channel, do a short read. The outer loop will + // handle this case by extending the buffer as necessary. + return 0, nil + } + // If we found at least one rune, we report the bunch of them as // a single KeyRunes or KeySpace event. if len(runes) > 0 { diff --git a/key_test.go b/key_test.go index d466b05..ae8643b 100644 --- a/key_test.go +++ b/key_test.go @@ -200,7 +200,7 @@ func TestDetectOneMsg(t *testing.T) { for _, tc := range td { t.Run(fmt.Sprintf("%q", string(tc.seq)), func(t *testing.T) { - width, msg := detectOneMsg(tc.seq) + width, msg := detectOneMsg(tc.seq, false /* canHaveMoreData */) if width != len(tc.seq) { t.Errorf("parser did not consume the entire input: got %d, expected %d", width, len(tc.seq)) } @@ -211,6 +211,25 @@ func TestDetectOneMsg(t *testing.T) { } } +func TestReadLongInput(t *testing.T) { + input := strings.Repeat("a", 1000) + msgs := testReadInputs(t, bytes.NewReader([]byte(input))) + if len(msgs) != 1 { + t.Errorf("expected 1 messages, got %d", len(msgs)) + } + km := msgs[0] + k := Key(km.(KeyMsg)) + if k.Type != KeyRunes { + t.Errorf("expected key runes, got %d", k.Type) + } + if len(k.Runes) != 1000 || !reflect.DeepEqual(k.Runes, []rune(input)) { + t.Errorf("unexpected runes: %+v", k) + } + if k.Alt { + t.Errorf("unexpected alt") + } +} + func TestReadInput(t *testing.T) { type test struct { keyname string