From 821bf3e80b1db9de826100e7b03577d690c5d7bf Mon Sep 17 00:00:00 2001
From: rsteube <rsteube@users.noreply.github.com>
Date: Sun, 8 Dec 2024 14:47:34 +0100
Subject: [PATCH] windows: swap executable

---
 selfupdate.go   |  7 +------
 swap.go         | 12 ++++++++++++
 swap_windows.go | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 59 insertions(+), 6 deletions(-)
 create mode 100644 swap.go
 create mode 100644 swap_windows.go

diff --git a/selfupdate.go b/selfupdate.go
index 3917b31..a91efb7 100644
--- a/selfupdate.go
+++ b/selfupdate.go
@@ -230,12 +230,7 @@ func (c config) Install(tag, asset string) error {
 		}
 	}
 
-	c.Printf("moving to %#v\n", target)
-	if err = os.Rename(fExecutable.Name(), target); err != nil {
-		return err
-	}
-
-	return nil
+	return c.swap(fExecutable.Name(), target)
 }
 
 func (c config) verify(executable string) error {
diff --git a/swap.go b/swap.go
new file mode 100644
index 0000000..eba4088
--- /dev/null
+++ b/swap.go
@@ -0,0 +1,12 @@
+//go:build !windows
+
+package selfupdate
+
+import (
+	"os"
+)
+
+func (c config) swap(source, target string) error {
+	c.Printf("moving to %#v\n", target)
+	return os.Rename(source, target)
+}
diff --git a/swap_windows.go b/swap_windows.go
new file mode 100644
index 0000000..31992ce
--- /dev/null
+++ b/swap_windows.go
@@ -0,0 +1,46 @@
+package selfupdate
+
+import (
+	"os"
+	"syscall"
+)
+
+func (c config) swap(source, target string) error {
+	old := target + ".old"
+	if _, err := os.Stat(old); err == nil {
+		if err := c.confirm("remove %#v\n", old); err != nil {
+			return err
+		}
+		if err := os.Remove(old); err != nil {
+			return err
+		}
+	}
+
+	c.Printf("moving current executable to %#v\n", old)
+	if err := os.Rename(target, old); err != nil {
+		return err
+	}
+
+	c.Printf("moving new executable to %#v\n", target)
+	if err := os.Rename(source, target); err != nil {
+		_ = os.Rename(old, target) // try to restore old executable
+		return err
+	}
+
+	c.Printf("hiding %#v\n", old)
+	return hide(old)
+}
+
+func hide(path string) error {
+	p, err := syscall.UTF16PtrFromString(path)
+	if err != nil {
+		return err
+	}
+
+	err = syscall.SetFileAttributes(p, syscall.FILE_ATTRIBUTE_HIDDEN)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}