update vendor

Signed-off-by: Davanum Srinivas <davanum@gmail.com>

vendor/github.com/moby/term/proxy.go

@@ -0,0 +1,78 @@
+package term // import "github.com/moby/term"
+
+import (
+	"io"
+)
+
+// EscapeError is special error which returned by a TTY proxy reader's Read()
+// method in case its detach escape sequence is read.
+type EscapeError struct{}
+
+func (EscapeError) Error() string {
+	return "read escape sequence"
+}
+
+// escapeProxy is used only for attaches with a TTY. It is used to proxy
+// stdin keypresses from the underlying reader and look for the passed in
+// escape key sequence to signal a detach.
+type escapeProxy struct {
+	escapeKeys   []byte
+	escapeKeyPos int
+	r            io.Reader
+}
+
+// NewEscapeProxy returns a new TTY proxy reader which wraps the given reader
+// and detects when the specified escape keys are read, in which case the Read
+// method will return an error of type EscapeError.
+func NewEscapeProxy(r io.Reader, escapeKeys []byte) io.Reader {
+	return &escapeProxy{
+		escapeKeys: escapeKeys,
+		r:          r,
+	}
+}
+
+func (r *escapeProxy) Read(buf []byte) (int, error) {
+	nr, err := r.r.Read(buf)
+
+	if len(r.escapeKeys) == 0 {
+		return nr, err
+	}
+
+	preserve := func() {
+		// this preserves the original key presses in the passed in buffer
+		nr += r.escapeKeyPos
+		preserve := make([]byte, 0, r.escapeKeyPos+len(buf))
+		preserve = append(preserve, r.escapeKeys[:r.escapeKeyPos]...)
+		preserve = append(preserve, buf...)
+		r.escapeKeyPos = 0
+		copy(buf[0:nr], preserve)
+	}
+
+	if nr != 1 || err != nil {
+		if r.escapeKeyPos > 0 {
+			preserve()
+		}
+		return nr, err
+	}
+
+	if buf[0] != r.escapeKeys[r.escapeKeyPos] {
+		if r.escapeKeyPos > 0 {
+			preserve()
+		}
+		return nr, nil
+	}
+
+	if r.escapeKeyPos == len(r.escapeKeys)-1 {
+		return 0, EscapeError{}
+	}
+
+	// Looks like we've got an escape key, but we need to match again on the next
+	// read.
+	// Store the current escape key we found so we can look for the next one on
+	// the next read.
+	// Since this is an escape key, make sure we don't let the caller read it
+	// If later on we find that this is not the escape sequence, we'll add the
+	// keys back
+	r.escapeKeyPos++
+	return nr - r.escapeKeyPos, nil
+}