From 5b160ea59959c5cd2e4b384fe9af87a77cd48076 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Fri, 3 Mar 2023 15:20:35 +0530
Subject: [PATCH] Use Once for CachedHostname

---
 tools/cli/markup/prettify.go |  4 ++--
 tools/utils/hostname.go      | 16 ++++++----------
 2 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/tools/cli/markup/prettify.go b/tools/cli/markup/prettify.go
index d42c0d858..a78f5dbf0 100644
--- a/tools/cli/markup/prettify.go
+++ b/tools/cli/markup/prettify.go
@@ -96,7 +96,7 @@ func (self *Context) hyperlink_for_path(path string, text string) string {
 	if err == nil && fi.IsDir() {
 		path = strings.TrimSuffix(path, "/") + "/"
 	}
-	host := utils.CachedHostname()
+	host := utils.Hostname()
 	url := "file://" + host + path
 	return self.hyperlink_for_url(url, text)
 }
@@ -119,7 +119,7 @@ func (self *Context) link(x string) string {
 
 func (self *Context) ref_hyperlink(x string, prefix string) string {
 	text, target := text_and_target(x)
-	url := "kitty+doc://" + utils.CachedHostname() + "/#ref=" + prefix + target
+	url := "kitty+doc://" + utils.Hostname() + "/#ref=" + prefix + target
 	text = replace_all_rst_roles(text, func(group rst_format_match) string {
 		return group.payload
 	})
diff --git a/tools/utils/hostname.go b/tools/utils/hostname.go
index 471cacd67..a7e81b9a0 100644
--- a/tools/utils/hostname.go
+++ b/tools/utils/hostname.go
@@ -11,14 +11,10 @@ var _ = fmt.Print
 
 var hostname string = "*"
 
-func CachedHostname() string {
-	if hostname == "*" {
-		h, err := os.Hostname()
-		if err != nil {
-			hostname = h
-		} else {
-			hostname = ""
-		}
+var Hostname = (&Once[string]{Run: func() string {
+	h, err := os.Hostname()
+	if err == nil {
+		return h
 	}
-	return hostname
-}
+	return ""
+}}).Get