From 46ee28ce7fa59af4e67eee55b241d51af15cef4b Mon Sep 17 00:00:00 2001
From: Bryce Kwon <bryce@brycekwon.com>
Date: Fri, 16 Oct 2026 06:29:21 -1000
Subject: Trim avatar addresses in linear time

The trim pattern backtracked over a run of spaces inside an address,
which a commit can carry, and a log page runs the filter for every row.
Forty thousand spaces took two seconds per row.
---
 custom/extensions/email-gravatar.lua   | 16 +++++++++++++++-
 custom/extensions/email-libravatar.lua | 16 +++++++++++++++-
 2 files changed, 30 insertions(+), 2 deletions(-)

(limited to 'custom/extensions')

diff --git a/custom/extensions/email-gravatar.lua b/custom/extensions/email-gravatar.lua
index 6eb5376..01db3f9 100644
--- a/custom/extensions/email-gravatar.lua
+++ b/custom/extensions/email-gravatar.lua
@@ -58,6 +58,20 @@ local function hash_hex(input)
 	return hex
 end
 
+-- Lua patterns backtrack, so "^%s*(.-)%s*$" would cost the square of a long
+-- run of spaces inside the address. Finding each end directly stays linear.
+local function trim(text)
+	local first = text:find("%S")
+	if first == nil then
+		return ""
+	end
+	local last = #text
+	while text:find("^%s", last) do
+		last = last - 1
+	end
+	return text:sub(first, last)
+end
+
 -- cgit can hand over the address still wrapped in angle brackets, and the
 -- service hashes the trimmed lowercase form, so an address that skipped this
 -- would hash to something the service has never heard of. A missing or empty
@@ -70,7 +84,7 @@ local function normalize_email(email)
 	if inner ~= nil then
 		email = inner
 	end
-	email = (email:gsub("^%s*(.-)%s*$", "%1")):lower()
+	email = trim(email):lower()
 	if email == "" then
 		return nil
 	end
diff --git a/custom/extensions/email-libravatar.lua b/custom/extensions/email-libravatar.lua
index 9b3d595..1fb979d 100644
--- a/custom/extensions/email-libravatar.lua
+++ b/custom/extensions/email-libravatar.lua
@@ -56,6 +56,20 @@ local function hash_hex(input)
 	return hex
 end
 
+-- Lua patterns backtrack, so "^%s*(.-)%s*$" would cost the square of a long
+-- run of spaces inside the address. Finding each end directly stays linear.
+local function trim(text)
+	local first = text:find("%S")
+	if first == nil then
+		return ""
+	end
+	local last = #text
+	while text:find("^%s", last) do
+		last = last - 1
+	end
+	return text:sub(first, last)
+end
+
 -- cgit can hand over the address still wrapped in angle brackets, and the
 -- service hashes the trimmed lowercase form, so an address that skipped this
 -- would hash to something the service has never heard of. A missing or empty
@@ -68,7 +82,7 @@ local function normalize_email(email)
 	if inner ~= nil then
 		email = inner
 	end
-	email = (email:gsub("^%s*(.-)%s*$", "%1")):lower()
+	email = trim(email):lower()
 	if email == "" then
 		return nil
 	end
-- 
cgit