feat: improved deploy progress reporting

See toolshed/abra#478

vendor/github.com/muesli/ansi/buffer.go

@@ -0,0 +1,40 @@
+package ansi
+
+import (
+	"bytes"
+
+	"github.com/mattn/go-runewidth"
+)
+
+// Buffer is a buffer aware of ANSI escape sequences.
+type Buffer struct {
+	bytes.Buffer
+}
+
+// PrintableRuneWidth returns the cell width of all printable runes in the
+// buffer.
+func (w Buffer) PrintableRuneWidth() int {
+	return PrintableRuneWidth(w.String())
+}
+
+// PrintableRuneWidth returns the cell width of the given string.
+func PrintableRuneWidth(s string) int {
+	var n int
+	var ansi bool
+
+	for _, c := range s {
+		if c == Marker {
+			// ANSI escape sequence
+			ansi = true
+		} else if ansi {
+			if IsTerminator(c) {
+				// ANSI sequence terminated
+				ansi = false
+			}
+		} else {
+			n += runewidth.RuneWidth(c)
+		}
+	}
+
+	return n
+}