1 files changed, 88 insertions, 0 deletions
diff --git a/vendor/github.com/moby/term/proxy.go b/vendor/github.com/moby/term/proxy.go
new file mode 100644
index 000000000..c47756b89
--- /dev/null
+++ b/vendor/github.com/moby/term/proxy.go
@@ -0,0 +1,88 @@
+package 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
+	buf          []byte
+}
+
+// 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) (n int, err error) {
+	if len(r.escapeKeys) > 0 && r.escapeKeyPos == len(r.escapeKeys) {
+		return 0, EscapeError{}
+	}
+
+	if len(r.buf) > 0 {
+		n = copy(buf, r.buf)
+		r.buf = r.buf[n:]
+	}
+
+	nr, err := r.r.Read(buf[n:])
+	n += nr
+	if len(r.escapeKeys) == 0 {
+		return n, err
+	}
+
+	for i := 0; i < n; i++ {
+		if buf[i] == r.escapeKeys[r.escapeKeyPos] {
+			r.escapeKeyPos++
+
+			// Check if the full escape sequence is matched.
+			if r.escapeKeyPos == len(r.escapeKeys) {
+				n = i + 1 - r.escapeKeyPos
+				if n < 0 {
+					n = 0
+				}
+				return n, EscapeError{}
+			}
+			continue
+		}
+
+		// If we need to prepend a partial escape sequence from the previous
+		// read, make sure the new buffer size doesn't exceed len(buf).
+		// Otherwise, preserve any extra data in a buffer for the next read.
+		if i < r.escapeKeyPos {
+			preserve := make([]byte, 0, r.escapeKeyPos+n)
+			preserve = append(preserve, r.escapeKeys[:r.escapeKeyPos]...)
+			preserve = append(preserve, buf[:n]...)
+			n = copy(buf, preserve)
+			i += r.escapeKeyPos
+			r.buf = append(r.buf, preserve[n:]...)
+		}
+		r.escapeKeyPos = 0
+	}
+
+	// If we're in the middle of reading an escape sequence, make sure we don't
+	// let the caller read it. If later on we find that this is not the escape
+	// sequence, we'll prepend it back to buf.
+	n -= r.escapeKeyPos
+	if n < 0 {
+		n = 0
+	}
+	return n, err
+}