From 1cccfa7331ebf7d983e27c1d6847649a8e6a5dd0 Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Fri, 17 Aug 2018 16:59:59 +0100
Subject: [PATCH] cmd: Make --progress work on Windows

---
 cmd/progress.go         |  2 +-
 cmd/progress_other.go   |  9 +++++++++
 cmd/progress_windows.go | 28 ++++++++++++++++++++++++++++
 3 files changed, 38 insertions(+), 1 deletion(-)
 create mode 100644 cmd/progress_other.go
 create mode 100644 cmd/progress_windows.go

diff --git a/cmd/progress.go b/cmd/progress.go
index 5aa43fc7d..a76acf882 100644
--- a/cmd/progress.go
+++ b/cmd/progress.go
@@ -114,5 +114,5 @@ func printProgress(logMessage string) {
 			out("\n")
 		}
 	}
-	os.Stdout.Write(buf.Bytes())
+	writeToTerminal(buf.Bytes())
 }
diff --git a/cmd/progress_other.go b/cmd/progress_other.go
new file mode 100644
index 000000000..aef00cd4b
--- /dev/null
+++ b/cmd/progress_other.go
@@ -0,0 +1,9 @@
+//+build !windows
+
+package cmd
+
+import "os"
+
+func writeToTerminal(b []byte) {
+	_, _ = os.Stdout.Write(b)
+}
diff --git a/cmd/progress_windows.go b/cmd/progress_windows.go
new file mode 100644
index 000000000..aa7493b8f
--- /dev/null
+++ b/cmd/progress_windows.go
@@ -0,0 +1,28 @@
+//+build windows
+
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"sync"
+
+	ansiterm "github.com/Azure/go-ansiterm"
+	"github.com/Azure/go-ansiterm/winterm"
+)
+
+var (
+	initAnsiParser sync.Once
+	ansiParser     *ansiterm.AnsiParser
+)
+
+func writeToTerminal(b []byte) {
+	initAnsiParser.Do(func() {
+		winEventHandler := winterm.CreateWinEventHandler(os.Stdout.Fd(), os.Stdout)
+		ansiParser = ansiterm.CreateParser("Ground", winEventHandler)
+	})
+	_, err := ansiParser.Parse(b)
+	if err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "\n*** Error from ANSI parser: %v\n", err)
+	}
+}