From 273d2de099491278e7248b791f36395ab1a2e11a Mon Sep 17 00:00:00 2001
From: Alexandros Naskos <alex_naskos@hotmail.com>
Date: Wed, 29 Apr 2020 19:49:02 +0300
Subject: [PATCH 1/2] Progress will now use ANSI escape codes on windows for
 terminals that support it

---
 lib/std/progress.zig | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/std/progress.zig b/lib/std/progress.zig
index bde67f1a23..a66a8e097f 100644
--- a/lib/std/progress.zig
+++ b/lib/std/progress.zig
@@ -13,6 +13,9 @@ pub const Progress = struct {
     /// not print on update()
     terminal: ?std.fs.File = undefined,
 
+    /// Whether the terminal supports ANSI escape codes.
+    supports_ansi_escape_codes: bool = false,
+
     root: Node = undefined,
 
     /// Keeps track of how much time has passed since the beginning.
@@ -103,6 +106,7 @@ pub const Progress = struct {
         self.terminal = null;
         if (stderr.supportsAnsiEscapeCodes()) {
             self.terminal = stderr;
+            self.supports_ansi_escape_codes = true;
         } else if (std.builtin.os.tag == .windows and stderr.isTty()) {
             self.terminal = stderr;
         }
@@ -138,10 +142,10 @@ pub const Progress = struct {
             // restore the cursor position by moving the cursor
             // `columns_written` cells to the left, then clear the rest of the
             // line
-            if (std.builtin.os.tag != .windows) {
+            if (self.supports_ansi_escape_codes) {
                 end += (std.fmt.bufPrint(self.output_buffer[end..], "\x1b[{}D", .{self.columns_written}) catch unreachable).len;
                 end += (std.fmt.bufPrint(self.output_buffer[end..], "\x1b[0K", .{}) catch unreachable).len;
-            } else {
+            } else if (std.builtin.os.tag == .windows) {
                 var info: windows.CONSOLE_SCREEN_BUFFER_INFO = undefined;
                 if (windows.kernel32.GetConsoleScreenBufferInfo(file.handle, &info) != windows.TRUE)
                     unreachable;

From 61ba52b9e306f967ea38cd4494dfd3318d3266b8 Mon Sep 17 00:00:00 2001
From: Alexandros Naskos <alex_naskos@hotmail.com>
Date: Wed, 29 Apr 2020 20:07:23 +0300
Subject: [PATCH 2/2] Add unreachable branch

---
 lib/std/progress.zig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/std/progress.zig b/lib/std/progress.zig
index a66a8e097f..def438da79 100644
--- a/lib/std/progress.zig
+++ b/lib/std/progress.zig
@@ -178,7 +178,7 @@ pub const Progress = struct {
 
                 if (windows.kernel32.SetConsoleCursorPosition(file.handle, cursor_pos) != windows.TRUE)
                     unreachable;
-            }
+            } else unreachable;
 
             self.columns_written = 0;
         }