feat: improved deploy progress reporting

See #478

vendor/github.com/muesli/cancelreader/cancelreader_bsd.go

@@ -0,0 +1,146 @@
+//go:build darwin || freebsd || netbsd || openbsd || dragonfly
+// +build darwin freebsd netbsd openbsd dragonfly
+
+package cancelreader
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	"golang.org/x/sys/unix"
+)
+
+// NewReader returns a reader and a cancel function. If the input reader is a
+// File, the cancel function can be used to interrupt a blocking read call.
+// In this case, the cancel function returns true if the call was canceled
+// successfully. If the input reader is not a File, the cancel function
+// does nothing and always returns false. The BSD and macOS implementation is
+// based on the kqueue mechanism.
+func NewReader(reader io.Reader) (CancelReader, error) {
+	file, ok := reader.(File)
+	if !ok {
+		return newFallbackCancelReader(reader)
+	}
+
+	// kqueue returns instantly when polling /dev/tty so fallback to select
+	if file.Name() == "/dev/tty" {
+		return newSelectCancelReader(reader)
+	}
+
+	kQueue, err := unix.Kqueue()
+	if err != nil {
+		return nil, fmt.Errorf("create kqueue: %w", err)
+	}
+
+	r := &kqueueCancelReader{
+		file:   file,
+		kQueue: kQueue,
+	}
+
+	r.cancelSignalReader, r.cancelSignalWriter, err = os.Pipe()
+	if err != nil {
+		_ = unix.Close(kQueue)
+		return nil, err
+	}
+
+	unix.SetKevent(&r.kQueueEvents[0], int(file.Fd()), unix.EVFILT_READ, unix.EV_ADD)
+	unix.SetKevent(&r.kQueueEvents[1], int(r.cancelSignalReader.Fd()), unix.EVFILT_READ, unix.EV_ADD)
+
+	return r, nil
+}
+
+type kqueueCancelReader struct {
+	file               File
+	cancelSignalReader File
+	cancelSignalWriter File
+	cancelMixin
+	kQueue       int
+	kQueueEvents [2]unix.Kevent_t
+}
+
+func (r *kqueueCancelReader) Read(data []byte) (int, error) {
+	if r.isCanceled() {
+		return 0, ErrCanceled
+	}
+
+	err := r.wait()
+	if err != nil {
+		if errors.Is(err, ErrCanceled) {
+			// remove signal from pipe
+			var b [1]byte
+			_, errRead := r.cancelSignalReader.Read(b[:])
+			if errRead != nil {
+				return 0, fmt.Errorf("reading cancel signal: %w", errRead)
+			}
+		}
+
+		return 0, err
+	}
+
+	return r.file.Read(data)
+}
+
+func (r *kqueueCancelReader) Cancel() bool {
+	r.setCanceled()
+
+	// send cancel signal
+	_, err := r.cancelSignalWriter.Write([]byte{'c'})
+	return err == nil
+}
+
+func (r *kqueueCancelReader) Close() error {
+	var errMsgs []string
+
+	// close kqueue
+	err := unix.Close(r.kQueue)
+	if err != nil {
+		errMsgs = append(errMsgs, fmt.Sprintf("closing kqueue: %v", err))
+	}
+
+	// close pipe
+	err = r.cancelSignalWriter.Close()
+	if err != nil {
+		errMsgs = append(errMsgs, fmt.Sprintf("closing cancel signal writer: %v", err))
+	}
+
+	err = r.cancelSignalReader.Close()
+	if err != nil {
+		errMsgs = append(errMsgs, fmt.Sprintf("closing cancel signal reader: %v", err))
+	}
+
+	if len(errMsgs) > 0 {
+		return fmt.Errorf(strings.Join(errMsgs, ", "))
+	}
+
+	return nil
+}
+
+func (r *kqueueCancelReader) wait() error {
+	events := make([]unix.Kevent_t, 1)
+
+	for {
+		_, err := unix.Kevent(r.kQueue, r.kQueueEvents[:], events, nil)
+		if errors.Is(err, unix.EINTR) {
+			continue // try again if the syscall was interrupted
+		}
+
+		if err != nil {
+			return fmt.Errorf("kevent: %w", err)
+		}
+
+		break
+	}
+
+	ident := uint64(events[0].Ident)
+	switch ident {
+	case uint64(r.file.Fd()):
+		return nil
+	case uint64(r.cancelSignalReader.Fd()):
+		return ErrCanceled
+	}
+
+	return fmt.Errorf("unknown error")
+}