From 12eff94815f5d1a8847519c96148831aa7850a85 Mon Sep 17 00:00:00 2001
From: Jack Wilsdon <jack@wilsdon.me>
Date: Wed, 13 Nov 2024 00:49:46 +0000
Subject: [PATCH] Filter OSC 8 correctly

This allows Nix to use lowdown 1.2.0 which outputs OSC-8 links.

(cherry picked from commit 1301f8434d041be060fa5789effc0fac17a31879)
---
 src/libutil-tests/terminal.cc | 5 +++++
 src/libutil/terminal.cc       | 7 +++++++
 2 files changed, 12 insertions(+)

diff --git a/src/libutil-tests/terminal.cc b/src/libutil-tests/terminal.cc
index cdeb9fd94..714d5a237 100644
--- a/src/libutil-tests/terminal.cc
+++ b/src/libutil-tests/terminal.cc
@@ -57,4 +57,9 @@ TEST(filterANSIEscapes, utf8)
     ASSERT_EQ(filterANSIEscapes("f𐍈𐍈bär", true, 4), "f𐍈𐍈b");
 }
 
+TEST(filterANSIEscapes, osc8)
+{
+    ASSERT_EQ(filterANSIEscapes("\e]8;;http://example.com\e\\This is a link\e]8;;\e\\"), "This is a link");
+}
+
 } // namespace nix
diff --git a/src/libutil/terminal.cc b/src/libutil/terminal.cc
index 5d5ff7dcb..db7a6fcd1 100644
--- a/src/libutil/terminal.cc
+++ b/src/libutil/terminal.cc
@@ -45,6 +45,13 @@ std::string filterANSIEscapes(std::string_view s, bool filterAll, unsigned int w
                 while (i != s.end() && *i >= 0x20 && *i <= 0x2f) e += *i++;
                 // eat final byte
                 if (i != s.end() && *i >= 0x40 && *i <= 0x7e) e += last = *i++;
+            } else if (i != s.end() && *i == ']') {
+                // OSC
+                e += *i++;
+                // eat ESC
+                while (i != s.end() && *i != '\e') e += *i++;
+                // eat backslash
+                if (i != s.end() && *i == '\\') e += last = *i++;
             } else {
                 if (i != s.end() && *i >= 0x40 && *i <= 0x5f) e += *i++;
             }