From b5988111398bf3b5a1cc58c374c1ef1cb58fe0ea Mon Sep 17 00:00:00 2001
From: Bryce Kwon <bryce@brycekwon.com>
Date: Sat, 25 Jul 2026 22:36:52 -1000
Subject: Reorganize the tree into vendor/ and custom/

---
 extensions/about-render.lua     | 592 ----------------------------------------
 extensions/auth-file.lua        | 556 -------------------------------------
 extensions/auth-inline.lua      | 528 -----------------------------------
 extensions/email-gravatar.lua   | 115 --------
 extensions/email-libravatar.lua | 114 --------
 extensions/link-commits.lua     | 153 -----------
 extensions/syntax-highlight.lua | 278 -------------------
 7 files changed, 2336 deletions(-)
 delete mode 100644 extensions/about-render.lua
 delete mode 100644 extensions/auth-file.lua
 delete mode 100644 extensions/auth-inline.lua
 delete mode 100644 extensions/email-gravatar.lua
 delete mode 100644 extensions/email-libravatar.lua
 delete mode 100644 extensions/link-commits.lua
 delete mode 100644 extensions/syntax-highlight.lua

(limited to 'extensions')

diff --git a/extensions/about-render.lua b/extensions/about-render.lua
deleted file mode 100644
index 073b531..0000000
--- a/extensions/about-render.lua
+++ /dev/null
@@ -1,592 +0,0 @@
--- Server-side about-page rendering for cgit, used with the about-filter setting
--- in cgitrc and the lua: prefix so it runs in cgit's embedded interpreter with
--- no per-request process.
---
---     about-filter=lua:/usr/lib/cgit/filters/about-render.lua
---
--- One filter renders the three baseline about formats, chosen by the readme's
--- file extension.
---
---     markdown   .md .markdown .mkd .mdown
---     man page   .1 through .9 and .man
---     plain text everything else, and the fallback for anything that fails
---
--- Add a format by giving it a render function and a row in the handler table
--- near the foot of this file. Nothing else needs to change.
---
--- SUPPORTED LUA
---
--- Lua 5.1 through 5.4 and LuaJIT.
---
--- REQUIREMENTS
---
--- lpeg, the parsing module, for the Lua cgit is linked against. Markdown and
--- man pages are parsed with lpeg grammars, so without lpeg both fall back to
--- escaped plain text. It ships with cgit's syntax highlighter too, so a cgit
--- that colours source already has it.
---
---     # Debian and Ubuntu
---     sudo apt install lua-lpeg
---     # Fedora
---     sudo dnf install lua-lpeg
---     # Alpine
---     sudo apk add lua5.1-lpeg
---     # or with LuaRocks, matched to your Lua version
---     sudo luarocks --lua-version 5.1 install lpeg
---
--- Plain text needs only Lua itself.
---
--- SECURITY
---
--- The about page renders untrusted repository content, so the safety rule is
--- that every run of text reaches the page through cgit's own html_txt, every
--- attribute value through html_attr, and every link or image target through
--- the safe_url scheme allowlist below before html_attr. Only http, https,
--- mailto and relative targets survive, so a hostile readme cannot inject markup
--- or a javascript: url. Because all output is routed through those sinks by
--- construction, a bug in the parser can only mis-render, never inject.
---
--- LIMITATIONS
---
--- Markdown is a deliberate subset, not CommonMark. Headings, thematic breaks,
--- fenced and inline code, blockquotes, pipe tables, single-level lists, links,
--- images and emphasis. No reference links, no raw HTML passthrough, no nested
--- lists, no setext headings. Emphasis does not span a hard line break inside a
--- paragraph. Man rendering covers the common macros (section headings, filled
--- and no-fill paragraphs, bold and italic, font escapes) and drops the rest.
--- cgit sends filter output through a C string sink that stops at the first NUL
--- byte, so content past a NUL is truncated.
---
--- OUTPUT
---
--- Markdown is wrapped in <div class='markdown'>, man pages in
--- <div class='markdown manpage'>, plain text in <pre class='plaintext'>, all
--- styled by assets/cgit.css.
-
-local ok_lpeg, lpeg = pcall(require, "lpeg")
-
-
--- ===== configuration ===================================================
-
--- Readmes larger than this are served as escaped plain text rather than parsed.
-local max_bytes = 512 * 1024
-
--- Ceiling on blockquote and emphasis nesting, so a hostile readme of stacked
--- markers cannot drive the recursive parser into a stack overflow.
-local max_depth = 24
-
-local filename, chunks = "", {}
-
-
--- ===== helpers =========================================================
-
-local function trim(s)
-	return (s:gsub("^%s+", ""):gsub("%s+$", ""))
-end
-
--- Split on newlines after normalising CRLF and CR, returning the lines without
--- their terminators. A trailing newline yields a final empty line, which every
--- caller treats as blank.
-local function split_lines(s)
-	s = s:gsub("\r\n?", "\n")
-	local lines, start = {}, 1
-	while true do
-		local nl = s:find("\n", start, true)
-		if not nl then
-			lines[#lines + 1] = s:sub(start)
-			return lines
-		end
-		lines[#lines + 1] = s:sub(start, nl - 1)
-		start = nl + 1
-	end
-end
-
--- Split a table row into trimmed cells, dropping one optional leading and
--- trailing pipe.
-local function split_cells(row)
-	row = trim(row):gsub("^|", ""):gsub("|$", "")
-	local cells = {}
-	for c in (row .. "|"):gmatch("(.-)|") do
-		cells[#cells + 1] = trim(c)
-	end
-	return cells
-end
-
--- Return the url if its scheme is safe, else nil. Control and whitespace bytes
--- are stripped anywhere first because a browser ignores them when resolving the
--- scheme, so "java\nscript:" must still be caught as javascript. The class is
--- %c%s rather than a literal 0x00 range so it is safe on Lua 5.1, where an
--- embedded zero byte ends a pattern.
-local function safe_url(url)
-	url = url:gsub("[%c%s]", "")
-	-- A leading "//" or "/\" is scheme-relative, which a browser resolves to
-	-- another origin, so it is not the local target the parser meant to allow.
-	if url:sub(1, 2) == "//" or url:sub(1, 2) == "/\\" then
-		return nil
-	end
-	local scheme = url:match("^(%a[%w%+%.%-]*):")
-	if scheme then
-		scheme = scheme:lower()
-		if scheme ~= "http" and scheme ~= "https" and scheme ~= "mailto" then
-			return nil
-		end
-	end
-	return url
-end
-
-
--- ===== emit ============================================================
--- html, html_txt and html_attr are injected by cgit's lua filter host. Tag
--- scaffolding is a literal argument to html; every value that came from the
--- repository goes through html_txt, html_attr or safe_url.
-
-local emit_inline
-
-emit_inline = function(list)
-	for _, nd in ipairs(list) do
-		local t = nd.t
-		if t == "text" then
-			html_txt(nd.v)
-		elseif t == "code" then
-			html("<code>"); html_txt(nd.v); html("</code>")
-		elseif t == "strong" then
-			html("<strong>"); emit_inline(nd.kids); html("</strong>")
-		elseif t == "em" then
-			html("<em>"); emit_inline(nd.kids); html("</em>")
-		elseif t == "link" then
-			local u = safe_url(nd.url)
-			if u then
-				html("<a href='"); html_attr(u); html("'>")
-				emit_inline(nd.kids)
-				html("</a>")
-			else
-				emit_inline(nd.kids)
-			end
-		elseif t == "image" then
-			local u = safe_url(nd.url)
-			if u then
-				html("<img src='"); html_attr(u)
-				html("' alt='"); html_attr(nd.alt); html("'/>")
-			else
-				html_txt("![" .. nd.alt .. "]")
-			end
-		end
-	end
-end
-
-local emit_blocks
-
-emit_blocks = function(blocks)
-	for _, b in ipairs(blocks) do
-		local t = b.t
-		if t == "heading" then
-			html("<h" .. b.level .. ">")
-			emit_inline(b.kids)
-			html("</h" .. b.level .. ">")
-		elseif t == "hr" then
-			html("<hr/>")
-		elseif t == "code" then
-			html("<pre><code")
-			if b.lang and b.lang ~= "" then
-				html(" data-lang='"); html_attr(b.lang); html("'")
-			end
-			html(">"); html_txt(b.text); html("</code></pre>")
-		elseif t == "blockquote" then
-			html("<blockquote>"); emit_blocks(b.blocks); html("</blockquote>")
-		elseif t == "table" then
-			html("<table><thead><tr>")
-			for _, c in ipairs(b.head) do
-				html("<th>"); emit_inline(c); html("</th>")
-			end
-			html("</tr></thead><tbody>")
-			for _, row in ipairs(b.rows) do
-				html("<tr>")
-				for _, c in ipairs(row) do
-					html("<td>"); emit_inline(c); html("</td>")
-				end
-				html("</tr>")
-			end
-			html("</tbody></table>")
-		elseif t == "list" then
-			local tag = b.ordered and "ol" or "ul"
-			html("<" .. tag .. ">")
-			for _, item in ipairs(b.items) do
-				html("<li>"); emit_inline(item); html("</li>")
-			end
-			html("</" .. tag .. ">")
-		elseif t == "para" then
-			html("<p>")
-			for k, line in ipairs(b.lines) do
-				if k > 1 then html("<br/>") end
-				emit_inline(line)
-			end
-			html("</p>")
-		end
-	end
-end
-
-
--- ===== plain text ======================================================
-
-local function render_plaintext(text)
-	html("<pre class='plaintext'>")
-	html_txt(text)
-	html("</pre>")
-end
-
-
--- ===== markdown and man ================================================
--- Both are parsed with lpeg into the block/inline node trees emit_blocks and
--- emit_inline above consume. Parsing is pure and builds a tree; emit is the
--- only step that writes output, so a parse failure falls back to plain text
--- without leaving half a page behind.
-
-local render_markdown, render_man
-
-if ok_lpeg then
-	local P, R, S, C, Ct = lpeg.P, lpeg.R, lpeg.S, lpeg.C, lpeg.Ct
-
-	local sp = S(" \t")
-	local ws = S(" \t\r\n\f\v")
-	local eol = P(-1)
-
-	-- ----- markdown inline -----
-	local marker = S("`![*_")
-	local urlchar = 1 - S(")") - ws
-	-- Bound the link and image inner scans. Without a cap a readme of unclosed
-	-- brackets ("[[[[...") makes each position scan to end of line for a "]"
-	-- that never comes, which is quadratic. Real link text and urls sit far
-	-- under this, and anything longer simply renders as plain text.
-	local CAP = 512
-
-	local parse_inline
-	local inline_depth = 0
-
-	local function node_text(s) return { t = "text", v = s } end
-	local function node_code(s) return { t = "code", v = s } end
-	local function node_strong(s) return { t = "strong", kids = parse_inline(s) } end
-	local function node_em(s) return { t = "em", kids = parse_inline(s) } end
-	local function node_link(text, url) return { t = "link", kids = parse_inline(text), url = url } end
-	local function node_image(alt, url) return { t = "image", alt = alt, url = url } end
-
-	local inline_grammar = Ct((
-		  (P("`") * C((1 - P("`")) ^ 1) * P("`")) / node_code
-		+ (P("![") * C((1 - P("]")) ^ (-CAP)) * P("]") * P("(") * sp ^ 0
-			* C(urlchar * urlchar ^ (-CAP)) * (1 - P(")")) ^ (-CAP) * P(")")) / node_image
-		+ (P("[") * C((1 - P("]")) ^ (-CAP)) * P("]") * P("(") * sp ^ 0
-			* C(urlchar * urlchar ^ (-CAP)) * (1 - P(")")) ^ (-CAP) * P(")")) / node_link
-		+ (P("**") * C((1 - P("**")) ^ 1) * P("**")) / node_strong
-		+ (P("__") * C((1 - P("__")) ^ 1) * P("__")) / node_strong
-		+ (P("*") * C((1 - ws) * (1 - P("*")) ^ 0) * P("*")) / node_em
-		+ (P("_") * C((1 - ws) * (1 - P("_")) ^ 0) * P("_")) / node_em
-		+ C((1 - marker) ^ 1) / node_text
-		+ C(P(1)) / node_text
-	) ^ 0)
-
-	parse_inline = function(s)
-		if inline_depth >= max_depth then
-			return { node_text(s) }
-		end
-		inline_depth = inline_depth + 1
-		local nodes = inline_grammar:match(s) or { node_text(s) }
-		inline_depth = inline_depth - 1
-		return nodes
-	end
-
-	-- ----- markdown blocks -----
-	-- Line matchers. Each is anchored at the start of a single line and returns
-	-- its captures, or nil when the line is not of that kind.
-	local langchar = R("az", "AZ", "09") + S("_.+#-")
-	local m_heading = C(P("#") * P("#") ^ -5) * sp ^ 1 * C(P(1) ^ 0)
-	local function rule(c) return sp ^ 0 * P(c) * (sp ^ 0 * P(c)) ^ 2 * sp ^ 0 * eol end
-	local m_hr = rule("-") + rule("*") + rule("_")
-	local m_fence = sp ^ 0 * (C(P("`") ^ 3) + C(P("~") ^ 3)) * sp ^ 0 * C(langchar ^ 0)
-	local m_close_bt = sp ^ 0 * P("`") ^ 3 * sp ^ 0 * eol
-	local m_close_ti = sp ^ 0 * P("~") ^ 3 * sp ^ 0 * eol
-	local m_bq = sp ^ 0 * P(">")
-	local bullet = S("-*+")
-	local number = R("09") ^ 1 * S(".)")
-	local m_item = sp ^ 0 * C(bullet + number) * sp ^ 1 * C(P(1) ^ 0)
-	local dcell = sp ^ 0 * P(":") ^ -1 * P("-") ^ 1 * P(":") ^ -1 * sp ^ 0
-	-- A delimiter row is dash-cells joined by pipes. Require at least one pipe,
-	-- a leading one or one between cells, so a bare rule of dashes stays a
-	-- thematic break and an ordinary paragraph line is never taken for a table.
-	local pipe = P("|")
-	local m_tdelim = sp ^ 0 * (
-		  pipe * dcell * (pipe * dcell) ^ 0 * pipe ^ -1
-		+ dcell * (pipe * dcell) ^ 1 * pipe ^ -1
-	) * sp ^ 0 * eol
-	local m_blockstart = sp ^ 0 * ((P("#") * P("#") ^ -5 * sp) + P(">")
-		+ P("`") ^ 3 + P("~") ^ 3 + ((bullet + number) * sp))
-
-	local function ordered(mark) return mark:match("%d") ~= nil end
-
-	local parse_blocks
-
-	parse_blocks = function(lines, depth)
-		local blocks, i, n = {}, 1, #lines
-		while i <= n do
-			local line = lines[i]
-			local fence, lang = m_fence:match(line)
-			local hashes, htext = m_heading:match(line)
-			local mark = m_item:match(line)
-			if line:match("^%s*$") then
-				i = i + 1
-			elseif fence then
-				local close = (fence:sub(1, 1) == "`") and m_close_bt or m_close_ti
-				local code = {}
-				i = i + 1
-				while i <= n and not close:match(lines[i]) do
-					code[#code + 1] = lines[i]; i = i + 1
-				end
-				i = i + 1
-				local body = table.concat(code, "\n")
-				if #code > 0 then body = body .. "\n" end
-				blocks[#blocks + 1] = { t = "code", lang = lang, text = body }
-			elseif hashes then
-				blocks[#blocks + 1] = {
-					t = "heading",
-					level = #hashes,
-					kids = parse_inline((htext:gsub("%s*#*%s*$", ""))),
-				}
-				i = i + 1
-			elseif m_hr:match(line) then
-				blocks[#blocks + 1] = { t = "hr" }
-				i = i + 1
-			elseif m_bq:match(line) then
-				local inner = {}
-				while i <= n and m_bq:match(lines[i]) do
-					inner[#inner + 1] = (lines[i]:gsub("^%s*>%s?", ""))
-					i = i + 1
-				end
-				if depth < max_depth then
-					blocks[#blocks + 1] = { t = "blockquote", blocks = parse_blocks(inner, depth + 1) }
-				else
-					local para = {}
-					for _, l in ipairs(inner) do para[#para + 1] = parse_inline(l) end
-					blocks[#blocks + 1] = { t = "para", lines = para }
-				end
-			elseif i + 1 <= n and line:find("|", 1, true) and m_tdelim:match(lines[i + 1]) then
-				local head = {}
-				for _, c in ipairs(split_cells(line)) do head[#head + 1] = parse_inline(c) end
-				local rows = {}
-				i = i + 2
-				while i <= n and lines[i]:find("|", 1, true) and not lines[i]:match("^%s*$") do
-					local row = {}
-					for _, c in ipairs(split_cells(lines[i])) do row[#row + 1] = parse_inline(c) end
-					rows[#rows + 1] = row
-					i = i + 1
-				end
-				blocks[#blocks + 1] = { t = "table", head = head, rows = rows }
-			elseif mark then
-				local is_ol = ordered(mark)
-				local items = {}
-				while i <= n do
-					local mk, ct = m_item:match(lines[i])
-					if not mk or ordered(mk) ~= is_ol then break end
-					items[#items + 1] = parse_inline(ct)
-					i = i + 1
-				end
-				blocks[#blocks + 1] = { t = "list", ordered = is_ol, items = items }
-			else
-				local para = { parse_inline(line) }
-				i = i + 1
-				while i <= n and not lines[i]:match("^%s*$") and not m_blockstart:match(lines[i]) do
-					para[#para + 1] = parse_inline(lines[i]); i = i + 1
-				end
-				blocks[#blocks + 1] = { t = "para", lines = para }
-			end
-		end
-		return blocks
-	end
-
-	render_markdown = function(text)
-		if #text > max_bytes then
-			return render_plaintext(text)
-		end
-		local ok, blocks = pcall(parse_blocks, split_lines(text), 0)
-		if not ok then
-			return render_plaintext(text)
-		end
-		html("<div class='markdown'>")
-		-- Emit is wrapped so a parser bug can at worst truncate the page, never
-		-- error out and let the outer fallback duplicate what was already sent.
-		pcall(emit_blocks, blocks)
-		html("</div>")
-	end
-
-	-- ----- man pages -----
-	-- Macro lines are matched with lpeg, and the roff inline font and character
-	-- escapes are an lpeg grammar producing a flat token list that a fold turns
-	-- into the same inline nodes markdown emits. Bold and italic are the current
-	-- font, which carries across a run, so the inline pass tokenises and folds
-	-- rather than nesting the way markdown does.
-	local m_macro = S(".'") * sp ^ 0 * C((1 - sp) ^ 1) * sp ^ 0 * C(P(1) ^ 0)
-
-	local one_font = { B = "B", I = "I" }
-	local two_font = { CB = "B", BI = "B", CI = "I" }
-	local man_chars = {
-		aq = "'", cq = "'", oq = "'", dq = '"', lq = '"', rq = '"',
-		hy = "-", en = "-", em = "-",
-	}
-	local esc = P("\\")
-	local function font_tok(f) return { k = "font", f = f } end
-	local function text_tok(v) return { k = "text", v = v } end
-	local skip_tok = { k = "skip" }
-
-	local man_inline_grammar = Ct((
-		  (esc * P("f") * P("(") * C(P(1) * P(1))) / function(nm) return font_tok(two_font[nm] or "R") end
-		+ (esc * P("f") * P("[") * C((1 - P("]")) ^ 0) * P("]")) / function(nm) return font_tok(one_font[nm] or "R") end
-		+ (esc * P("f") * C(P(1))) / function(f) return font_tok(one_font[f] or "R") end
-		+ (esc * P("-")) / function() return text_tok("-") end
-		+ (esc * P("e")) / function() return text_tok("\\") end
-		+ (esc * P(" ")) / function() return text_tok(" ") end
-		+ (esc * S("&|^")) / function() return skip_tok end
-		+ (esc * P("(") * C(P(1) * P(1))) / function(nm) return text_tok(man_chars[nm] or "") end
-		+ (esc * P("*") * (P("(") * P(1) * P(1) + P(1))) / function() return skip_tok end
-		+ (esc * C(P(1))) / text_tok
-		+ esc / function() return skip_tok end
-		+ C((1 - esc) ^ 1) / text_tok
-	) ^ 0)
-
-	local function man_inline(s)
-		local toks = man_inline_grammar:match(s) or {}
-		local nodes, buf, font = {}, {}, "R"
-		local function flush()
-			if #buf == 0 then return end
-			local txt = table.concat(buf); buf = {}
-			if txt == "" then return end
-			if font == "B" then
-				nodes[#nodes + 1] = { t = "strong", kids = { { t = "text", v = txt } } }
-			elseif font == "I" then
-				nodes[#nodes + 1] = { t = "em", kids = { { t = "text", v = txt } } }
-			else
-				nodes[#nodes + 1] = { t = "text", v = txt }
-			end
-		end
-		for _, tk in ipairs(toks) do
-			if tk.k == "text" then
-				buf[#buf + 1] = tk.v
-			elseif tk.k == "font" then
-				flush(); font = tk.f
-			end
-		end
-		flush()
-		return nodes
-	end
-
-	local function parse_man(text)
-		local lines = split_lines(text)
-		local blocks = {}
-		local para, pre, nofill = nil, nil, false
-		local function flush_para()
-			if para and #para > 0 then
-				blocks[#blocks + 1] = { t = "para", lines = para }
-			end
-			para = nil
-		end
-		local function flush_pre()
-			if pre then
-				local body = table.concat(pre, "\n")
-				if #pre > 0 then body = body .. "\n" end
-				blocks[#blocks + 1] = { t = "code", text = body }
-				pre = nil
-			end
-		end
-		local function add_line(nodes)
-			para = para or {}
-			para[#para + 1] = nodes
-		end
-		for _, line in ipairs(lines) do
-			local macro, rest = m_macro:match(line)
-			if rest then rest = (rest:gsub('^"(.*)"$', "%1")) end
-			if nofill then
-				if macro == "fi" then
-					nofill = false; flush_pre()
-				else
-					pre[#pre + 1] = line
-				end
-			elseif line:match("^%s*$") then
-				flush_para()
-			elseif macro and macro:sub(1, 1) == "\\" then
-				-- roff comment, dropped
-			elseif macro == "SH" or macro == "SS" then
-				flush_para()
-				blocks[#blocks + 1] = {
-					t = "heading",
-					level = (macro == "SH") and 2 or 3,
-					kids = man_inline(rest),
-				}
-			elseif macro == "nf" then
-				flush_para(); nofill = true; pre = {}
-			elseif macro == "fi" then
-				flush_pre()
-			elseif macro == "B" or macro == "BR" or macro == "RB"
-			    or macro == "BI" or macro == "IB" then
-				add_line({ { t = "strong", kids = man_inline(rest) } })
-			elseif macro == "I" or macro == "IR" or macro == "RI" then
-				add_line({ { t = "em", kids = man_inline(rest) } })
-			elseif macro == "TH" or macro == "PP" or macro == "LP"
-			    or macro == "P" or macro == "TP" or macro == "IP"
-			    or macro == "HP" or macro == "RS" or macro == "RE"
-			    or macro == "sp" or macro == "br" then
-				flush_para()
-			elseif macro then
-				if rest ~= "" then add_line(man_inline(rest)) end
-			else
-				add_line(man_inline(line))
-			end
-		end
-		flush_para(); flush_pre()
-		return blocks
-	end
-
-	render_man = function(text)
-		if #text > max_bytes then
-			return render_plaintext(text)
-		end
-		local ok, blocks = pcall(parse_man, text)
-		if not ok then
-			return render_plaintext(text)
-		end
-		html("<div class='markdown manpage'>")
-		pcall(emit_blocks, blocks)
-		html("</div>")
-	end
-else
-	-- No lpeg, so markdown and man readmes read as escaped source, not nothing.
-	render_markdown = render_plaintext
-	render_man = render_plaintext
-end
-
-
--- ===== dispatch ========================================================
-
-local handlers = {}
-for _, ext in ipairs({ "md", "markdown", "mkd", "mdown" }) do
-	handlers[ext] = render_markdown
-end
-for _, ext in ipairs({ "1", "2", "3", "4", "5", "6", "7", "8", "9", "man" }) do
-	handlers[ext] = render_man
-end
-
-function filter_open(name)
-	filename = name or ""
-	chunks = {}
-end
-
-function filter_write(str)
-	chunks[#chunks + 1] = str
-end
-
-function filter_close()
-	local text = table.concat(chunks)
-	chunks = {}
-	local ext = (filename:match("%.([^.]+)$") or ""):lower()
-	local render = handlers[ext] or render_plaintext
-	local ok = pcall(render, text)
-	if not ok then
-		render_plaintext(text)
-	end
-	return 0
-end
diff --git a/extensions/auth-file.lua b/extensions/auth-file.lua
deleted file mode 100644
index 5415ca7..0000000
--- a/extensions/auth-file.lua
+++ /dev/null
@@ -1,556 +0,0 @@
--- cgit auth-filter that gates repositories behind a login form and a signed
--- session cookie.
---
--- This is the FILE-BACKED variant. The user accounts, the groups, and the
--- per-repository access lists are read from files on disk, whose paths are set
--- in the CONFIGURATION block below. Edit those files without touching this
--- script. This suits larger or externally managed user sets.
---
--- The companion auth-inline.lua behaves identically but keeps its accounts and
--- access lists inline in the script itself, which suits a small fixed set of
--- users.
---
--- Enable it in cgitrc with
---     auth-filter=lua:/path/to/auth-file.lua
---
--- SUPPORTED LUA
---
--- Lua 5.1, 5.2, 5.3, 5.4 and LuaJIT. Lua 5.5 is not supported, because luaossl
--- has no 5.5 build. Match the runtime to the Lua that cgit is built against.
---
--- HTTPS IS RECOMMENDED
---
--- Serve cgit over HTTPS. Terminate TLS at the web server in front of cgit. The
--- session cookie is marked Secure by default, so a browser only sends it back
--- over HTTPS. If you genuinely run cgit over plain HTTP with no TLS anywhere,
--- set cookie_insecure below, otherwise the cookie is never returned and login
--- appears to loop.
---
--- DEPENDENCIES
---
---     luaossl    OpenSSL binding, provides openssl.rand and openssl.hmac
---                <https://github.com/wahern/luaossl>
---     luaposix   POSIX binding, provides posix.sys.stat and posix.unistd
---                <https://github.com/luaposix/luaposix>
---
--- The reliable cross-platform install is LuaRocks, matched to your Lua
--- version. luaossl also needs the OpenSSL development headers present.
---
---     # Debian and Ubuntu
---     sudo apt install luarocks libssl-dev
---     sudo luarocks --lua-version 5.1 install luaossl
---     sudo luarocks --lua-version 5.1 install luaposix
---
---     # Fedora
---     sudo dnf install luarocks openssl-devel
---     sudo luarocks --lua-version 5.1 install luaossl luaposix
---
---     # Alpine
---     sudo apk add luarocks openssl-dev
---     sudo luarocks-5.1 install luaossl luaposix
---
---     # macOS with Homebrew
---     brew install luarocks openssl
---     luarocks install luaossl OPENSSL_DIR="$(brew --prefix openssl)"
---     luarocks install luaposix
---
--- Some distributions also package these, for example lua-luaossl and lua-posix
--- on Debian. If you use a distribution package, make sure it is built for the
--- same Lua version as cgit.
---
--- SECURITY NOTES
---
--- The cookie carries only a username with no server-side session store, so
--- deleting an account does not revoke a cookie already issued until it
--- expires, and instances that share a secret file accept each other's cookies.
--- The login form carries no CSRF token. Both are acceptable for gating read
--- access to a git browser. Weigh them before guarding anything more sensitive.
-
-local sysstat = require("posix.sys.stat")
-local unistd = require("posix.unistd")
-local rand = require("openssl.rand")
-local hmac = require("openssl.hmac")
-
---
--- ========================= CONFIGURATION =========================
--- Edit the values in this block. Nothing below it needs changing for
--- ordinary use.
---
-
--- Accounts, one per line, as username:hash. Generate a hash with
---     mkpasswd -m sha-512 -R 300000
--- This file should not be world-readable.
-local users_filename = "/etc/cgit-auth/users"
-
--- Group membership, one per line, as groupname:user1,user2,user3,...
-local groups_filename = "/etc/cgit-auth/groups"
-
--- Per-repository access, one per line, as reponame:group1,group2,...
--- A repository listed here is protected. One not listed is public.
-local repos_filename = "/etc/cgit-auth/repos"
-
--- Where the cookie-signing secret is stored. It is created on first use. It
--- must be persistent and writable by cgit. Prefer a path OUTSIDE the cache
--- root, because pruning the cache would delete a secret kept inside it and
--- invalidate every live session. This file should not be world-readable.
-local secret_filename = "/var/cache/cgit/auth-secret"
-
--- How long a login stays valid, in seconds. Default one week.
-local session_seconds = 7 * 24 * 60 * 60
-
--- Name of the session cookie.
-local cookie_name = "cgitauth"
-
--- Path the cookie is scoped to. "/" covers the whole host. Set it to the cgit
--- root to scope the cookie more tightly.
-local cookie_path = "/"
-
--- Leave false so the cookie is marked Secure and only travels over HTTPS. Set
--- it true ONLY if cgit is served over plain HTTP with no TLS anywhere, see the
--- HTTPS note in the header.
-local cookie_insecure = false
-
---
--- =================================================================
---
-
--- A throwaway hash of the documented shape, used only to spend the same work
--- on a missing account as on a present one, so a failed login does not reveal
--- by timing whether the username exists.
-local dummy_hash = "$6$rounds=300000$0000000000000000$"
-
--- Module state shared across the open, write and close calls of one request.
-local action, http, cgit, post
-
---
---
--- Account and access-list storage. This is the ONLY part that differs from
--- auth-inline.lua. Swap these two functions to change where accounts live.
---
---
-
-local function trim(s)
-	return (string.gsub(s, "^%s*(.-)%s*$", "%1"))
-end
-
--- Return the stored password hash for a user, or nil. Reads the users file
--- fresh each call. A missing or unreadable file, and any unparsable line, are
--- skipped rather than fatal.
-function account_hash(user)
-	if user == nil then
-		return nil
-	end
-	local wanted = user:lower()
-	local f = io.open(users_filename, "r")
-	if f == nil then
-		return nil
-	end
-	for line in f:lines() do
-		local u, h = string.match(line, "(.-):(.+)")
-		if u ~= nil and trim(u):lower() == wanted then
-			f:close()
-			return h
-		end
-	end
-	f:close()
-	return nil
-end
-
--- Return the set of users allowed to access a repository, keyed by lowercased
--- username, or nil if the repository is not protected. A protected repository
--- whose groups resolve to no users returns an EMPTY table, which denies
--- everyone rather than falling through to public.
-function repo_userset(repo)
-	if repo == nil then
-		return nil
-	end
-	local groups = nil
-	local f = io.open(repos_filename, "r")
-	if f ~= nil then
-		for line in f:lines() do
-			local r, g = string.match(line, "(.-):(.+)")
-			if r ~= nil and trim(r) == repo then
-				groups = {}
-				for group in string.gmatch(g, "([^,]+)") do
-					groups[trim(group):lower()] = true
-				end
-				break
-			end
-		end
-		f:close()
-	end
-	if groups == nil then
-		return nil
-	end
-	local users = {}
-	local gf = io.open(groups_filename, "r")
-	if gf ~= nil then
-		for line in gf:lines() do
-			local g, u = string.match(line, "(.-):(.+)")
-			if g ~= nil and groups[trim(g):lower()] then
-				for user in string.gmatch(u, "([^,]+)") do
-					users[trim(user):lower()] = true
-				end
-			end
-		end
-		gf:close()
-	end
-	return users
-end
-
---
---
--- Utility functions based on keplerproject/wsapi.
---
---
-
-function url_decode(str)
-	if not str then
-		return ""
-	end
-	str = string.gsub(str, "+", " ")
-	str = string.gsub(str, "%%(%x%x)", function(h) return string.char(tonumber(h, 16)) end)
-	str = string.gsub(str, "\r\n", "\n")
-	return str
-end
-
-function url_encode(str)
-	if not str then
-		return ""
-	end
-	str = string.gsub(str, "\n", "\r\n")
-	str = string.gsub(str, "([^%w ])", function(c) return string.format("%%%02X", string.byte(c)) end)
-	str = string.gsub(str, " ", "+")
-	return str
-end
-
--- Parse an application/x-www-form-urlencoded body. A value may itself contain
--- '=', for example a base64 password, so the value runs to the next '&'.
-function parse_qs(qs)
-	local tab = {}
-	for key, val in string.gmatch(qs or "", "([^&=]+)=([^&]*)") do
-		tab[url_decode(key)] = url_decode(val)
-	end
-	return tab
-end
-
--- Return the value of the named cookie, or nil. The stored token was already
--- url-encoded by secure_value, so it is returned verbatim, which keeps the
--- write path (set_cookie) and the read path symmetric. Decoding it here would
--- break the signature check for any value carrying a percent escape.
-function get_cookie(cookies, name)
-	cookies = string.gsub(";" .. (cookies or "") .. ";", "%s*;%s*", ";")
-	return string.match(cookies, ";" .. name .. "=(.-);")
-end
-
-function tohex(b)
-	local x = ""
-	for i = 1, #b do
-		x = x .. string.format("%.2x", string.byte(b, i))
-	end
-	return x
-end
-
---
---
--- Cookie construction and validation helpers.
---
---
-
-local secret = nil
-
--- Load the cookie-signing secret, creating it on first use. Failures raise,
--- which cgit turns into a request error, so a broken secret denies rather than
--- signs with nothing.
-function get_secret()
-	if secret ~= nil then
-		return secret
-	end
-	local secret_file = io.open(secret_filename, "r")
-	if secret_file == nil then
-		local old_umask = sysstat.umask(63)
-		local temporary_filename = secret_filename .. ".tmp." .. tohex(rand.bytes(16))
-		local temporary_file = io.open(temporary_filename, "w")
-		if temporary_file == nil then
-			sysstat.umask(old_umask)
-			error("cgit auth: cannot create secret file " .. secret_filename)
-		end
-		local wrote = temporary_file:write(tohex(rand.bytes(32)))
-		local closed = temporary_file:close()
-		if not wrote or not closed then
-			os.remove(temporary_filename)
-			sysstat.umask(old_umask)
-			error("cgit auth: failed writing secret file " .. secret_filename)
-		end
-		unistd.link(temporary_filename, secret_filename) -- Intentionally fails if another worker won the race.
-		unistd.unlink(temporary_filename)
-		sysstat.umask(old_umask)
-		secret_file = io.open(secret_filename, "r")
-	end
-	if secret_file == nil then
-		error("cgit auth: cannot read secret file " .. secret_filename)
-	end
-	secret = secret_file:read("*l")
-	secret_file:close()
-	if secret == nil or secret:len() ~= 64 then
-		secret = nil
-		error("cgit auth: secret file " .. secret_filename .. " is malformed, expected 64 hex characters")
-	end
-	return secret
-end
-
--- A redirect target is unsafe if a browser would read it as another origin.
--- The only such form cgit can be tricked into signing is a scheme-relative
--- "//host" or "/\host". Everything else stays on this host.
-function is_safe_redirect(url)
-	if type(url) ~= "string" then
-		return false
-	end
-	local head = url:sub(1, 2)
-	if head == "//" or head == "/\\" then
-		return false
-	end
-	return true
-end
-
--- Return the value carried by a signed cookie, or nil if it does not verify.
-function validate_value(expected_field, cookie)
-	local i = 0
-	local value = ""
-	local field = ""
-	local expiration = 0
-	local salt = ""
-	local chmac = ""
-
-	if cookie == nil or cookie:len() < 3 or cookie:sub(1, 1) == "|" then
-		return nil
-	end
-
-	for component in string.gmatch(cookie, "[^|]+") do
-		if i == 0 then
-			field = component
-		elseif i == 1 then
-			value = component
-		elseif i == 2 then
-			-- The expiration must be a plain integer. Rejecting other forms
-			-- keeps the signed bytes canonical, since tonumber and tostring of
-			-- "1e9" or "100.0" differ across Lua versions.
-			if not string.match(component, "^%d+$") then
-				return nil
-			end
-			expiration = tonumber(component)
-		elseif i == 3 then
-			salt = component
-		elseif i == 4 then
-			chmac = component
-		else
-			break
-		end
-		i = i + 1
-	end
-
-	if chmac == nil or chmac:len() == 0 then
-		return nil
-	end
-
-	-- Compare the HMAC without short-circuiting on the first mismatch.
-	if not constant_equals(chmac, tohex(hmac.new(get_secret(), "sha256"):final(field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt))) then
-		return nil
-	end
-
-	-- An expiration of 0 never expires and is used for the redirect token.
-	if expiration ~= 0 and expiration <= os.time() then
-		return nil
-	end
-
-	if url_decode(field) ~= expected_field then
-		return nil
-	end
-
-	local decoded = url_decode(value)
-	-- Reject values carrying control characters so a signed value cannot
-	-- smuggle CR or LF into a response header.
-	if decoded:find("%c") then
-		return nil
-	end
-	return decoded
-end
-
-function secure_value(field, value, expiration)
-	if value == nil or value:len() <= 0 then
-		return ""
-	end
-
-	local salt = tohex(rand.bytes(16))
-	value = url_encode(value)
-	field = url_encode(field)
-	local authstr = field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt
-	authstr = authstr .. "|" .. tohex(hmac.new(get_secret(), "sha256"):final(authstr))
-	return authstr
-end
-
--- Strip control characters that could split an HTTP response header.
-function strip_ctl(s)
-	return (string.gsub(s or "", "%c", ""))
-end
-
--- Compare two strings in time that does not depend on how many leading bytes
--- match, so a mismatch position is not revealed by timing.
-function constant_equals(a, b)
-	if type(a) ~= "string" or type(b) ~= "string" or #a ~= #b then
-		return false
-	end
-	local diff = 0
-	for i = 1, #a do
-		local d = a:byte(i) - b:byte(i)
-		diff = diff + d * d
-	end
-	return diff == 0
-end
-
-function set_cookie(cookie, value)
-	local attrs = "; HttpOnly; SameSite=Lax; Path=" .. cookie_path
-	if not cookie_insecure then
-		attrs = attrs .. "; Secure"
-	end
-	if value == "" then
-		attrs = attrs .. "; Max-Age=0"
-	elseif session_seconds > 0 then
-		attrs = attrs .. "; Max-Age=" .. tostring(session_seconds)
-	end
-	html("Set-Cookie: " .. cookie .. "=" .. strip_ctl(value) .. attrs .. "\n")
-end
-
-function redirect_to(url)
-	html("Status: 302 Redirect\n")
-	html("Cache-Control: no-cache, no-store\n")
-	html("Location: " .. strip_ctl(url) .. "\n")
-end
-
-function not_found()
-	html("Status: 404 Not Found\n")
-	html("Cache-Control: no-cache, no-store\n\n")
-end
-
---
---
--- Authentication actions. Identical to auth-inline.lua from here down.
---
---
-
--- Sets HTTP cookie headers based on post and sets up redirection.
-function authenticate_post()
-	local redirect = validate_value("redirect", post["redirect"])
-
-	if redirect == nil or not is_safe_redirect(redirect) then
-		not_found()
-		return 0
-	end
-
-	redirect_to(redirect)
-
-	local username = post["username"]
-	local password = post["password"]
-	local ok = false
-	if username ~= nil and password ~= nil then
-		local hash = account_hash(username)
-		if hash == nil then
-			-- Spend the work anyway, see dummy_hash.
-			unistd.crypt(password, dummy_hash)
-		elseif constant_equals(hash, unistd.crypt(password, hash)) then
-			ok = true
-		end
-	end
-
-	if ok then
-		set_cookie(cookie_name, secure_value("username", username, os.time() + session_seconds))
-	else
-		set_cookie(cookie_name, "")
-	end
-
-	html("\n")
-	return 0
-end
-
--- Returns 1 if the cookie is valid and 0 if it is not.
-function authenticate_cookie()
-	local accepted_users = repo_userset(cgit["repo"])
-	if accepted_users == nil then
-		-- The repository is not protected.
-		return 1
-	end
-
-	local username = validate_value("username", get_cookie(http["cookie"], cookie_name))
-	if username == nil or not accepted_users[username:lower()] then
-		return 0
-	end
-	return 1
-end
-
--- Prints the html for the login form.
-function body()
-	local target = cgit["url"]
-	if not is_safe_redirect(target) then
-		target = cgit["login"]
-	end
-
-	html("<h2>Authentication Required</h2>")
-	html("<form method='post' action='")
-	html_attr(cgit["login"])
-	html("'>")
-	html("<input type='hidden' name='redirect' value='")
-	html_attr(secure_value("redirect", target, 0))
-	html("' />")
-	html("<table>")
-	html("<tr><td><label for='username'>Username:</label></td><td><input id='username' name='username' autofocus /></td></tr>")
-	html("<tr><td><label for='password'>Password:</label></td><td><input id='password' name='password' type='password' /></td></tr>")
-	html("<tr><td colspan='2'><input value='Login' type='submit' /></td></tr>")
-	html("</table></form>")
-
-	return 0
-end
-
---
---
--- Wrapper around the filter API, exposing the http, cgit and post tables to
--- the functions above.
---
---
-
-local actions = {}
-actions["authenticate-post"] = authenticate_post
-actions["authenticate-cookie"] = authenticate_cookie
-actions["body"] = body
-
-function filter_open(...)
-	action = actions[select(1, ...)]
-
-	post = {}
-
-	http = {}
-	http["cookie"] = select(2, ...)
-	http["method"] = select(3, ...)
-	http["query"] = select(4, ...)
-	http["referer"] = select(5, ...)
-	http["path"] = select(6, ...)
-	http["host"] = select(7, ...)
-	http["https"] = select(8, ...)
-
-	cgit = {}
-	cgit["repo"] = select(9, ...)
-	cgit["page"] = select(10, ...)
-	cgit["url"] = select(11, ...)
-	cgit["login"] = select(12, ...)
-end
-
-function filter_close()
-	if action == nil then
-		-- Unknown action, deny rather than raise.
-		return 0
-	end
-	return action()
-end
-
-function filter_write(str)
-	post = parse_qs(str)
-end
diff --git a/extensions/auth-inline.lua b/extensions/auth-inline.lua
deleted file mode 100644
index 168a444..0000000
--- a/extensions/auth-inline.lua
+++ /dev/null
@@ -1,528 +0,0 @@
--- cgit auth-filter that gates repositories behind a login form and a signed
--- session cookie.
---
--- This is the INLINE variant. The user accounts and the per-repository access
--- lists are written directly in this script, in the two tables in the
--- CONFIGURATION block below. Edit them here and reload. This suits a small
--- fixed set of users that rarely changes.
---
--- The companion auth-file.lua behaves identically but reads its accounts and
--- access lists from files on disk instead, which suits larger or externally
--- managed user sets.
---
--- Enable it in cgitrc with
---     auth-filter=lua:/path/to/auth-inline.lua
---
--- SUPPORTED LUA
---
--- Lua 5.1, 5.2, 5.3, 5.4 and LuaJIT. Lua 5.5 is not supported, because luaossl
--- has no 5.5 build. Match the runtime to the Lua that cgit is built against.
---
--- HTTPS IS RECOMMENDED
---
--- Serve cgit over HTTPS. Terminate TLS at the web server in front of cgit. The
--- session cookie is marked Secure by default, so a browser only sends it back
--- over HTTPS. If you genuinely run cgit over plain HTTP with no TLS anywhere,
--- set cookie_insecure below, otherwise the cookie is never returned and login
--- appears to loop.
---
--- DEPENDENCIES
---
---     luaossl    OpenSSL binding, provides openssl.rand and openssl.hmac
---                <https://github.com/wahern/luaossl>
---     luaposix   POSIX binding, provides posix.sys.stat and posix.unistd
---                <https://github.com/luaposix/luaposix>
---
--- The reliable cross-platform install is LuaRocks, matched to your Lua
--- version. luaossl also needs the OpenSSL development headers present.
---
---     # Debian and Ubuntu
---     sudo apt install luarocks libssl-dev
---     sudo luarocks --lua-version 5.1 install luaossl
---     sudo luarocks --lua-version 5.1 install luaposix
---
---     # Fedora
---     sudo dnf install luarocks openssl-devel
---     sudo luarocks --lua-version 5.1 install luaossl luaposix
---
---     # Alpine
---     sudo apk add luarocks openssl-dev
---     sudo luarocks-5.1 install luaossl luaposix
---
---     # macOS with Homebrew
---     brew install luarocks openssl
---     luarocks install luaossl OPENSSL_DIR="$(brew --prefix openssl)"
---     luarocks install luaposix
---
--- Some distributions also package these, for example lua-luaossl and lua-posix
--- on Debian. If you use a distribution package, make sure it is built for the
--- same Lua version as cgit.
---
--- SECURITY NOTES
---
--- The cookie carries only a username with no server-side session store, so
--- deleting an account does not revoke a cookie already issued until it
--- expires, and instances that share a secret file accept each other's cookies.
--- The login form carries no CSRF token. Both are acceptable for gating read
--- access to a git browser. Weigh them before guarding anything more sensitive.
-
-local sysstat = require("posix.sys.stat")
-local unistd = require("posix.unistd")
-local rand = require("openssl.rand")
-local hmac = require("openssl.hmac")
-
---
--- ========================= CONFIGURATION =========================
--- Edit the values in this block. Nothing below it needs changing for
--- ordinary use.
---
-
--- Protected repositories and the users allowed into each. A repository listed
--- here is protected. One not listed is public. Keys and user names are matched
--- case-insensitively. REPLACE THE EXAMPLES BELOW, they are commented out so an
--- unedited copy protects nothing and grants no accounts.
-local protected_repos = {
-	-- ["secret-repo"] = { alice = true, bob = true },
-	-- ["another"]     = { alice = true },
-}
-
--- Accounts as name = hash. Generate a hash with
---     mkpasswd -m sha-512 -R 300000
--- REPLACE THE EXAMPLES BELOW. The commented lines are not real credentials and
--- must not be deployed as-is.
-local users = {
-	-- alice = "$6$rounds=300000$REPLACE_THIS_SALT$REPLACE_THIS_HASH",
-	-- bob   = "$6$rounds=300000$REPLACE_THIS_SALT$REPLACE_THIS_HASH",
-}
-
--- Where the cookie-signing secret is stored. It is created on first use. It
--- must be persistent and writable by cgit. Prefer a path OUTSIDE the cache
--- root, because pruning the cache would delete a secret kept inside it and
--- invalidate every live session. This file should not be world-readable.
-local secret_filename = "/var/cache/cgit/auth-secret"
-
--- How long a login stays valid, in seconds. Default one week.
-local session_seconds = 7 * 24 * 60 * 60
-
--- Name of the session cookie.
-local cookie_name = "cgitauth"
-
--- Path the cookie is scoped to. "/" covers the whole host. Set it to the cgit
--- root to scope the cookie more tightly.
-local cookie_path = "/"
-
--- Leave false so the cookie is marked Secure and only travels over HTTPS. Set
--- it true ONLY if cgit is served over plain HTTP with no TLS anywhere, see the
--- HTTPS note in the header.
-local cookie_insecure = false
-
---
--- =================================================================
---
-
--- A throwaway hash of the documented shape, used only to spend the same work
--- on a missing account as on a present one, so a failed login does not reveal
--- by timing whether the username exists.
-local dummy_hash = "$6$rounds=300000$0000000000000000$"
-
--- Module state shared across the open, write and close calls of one request.
-local action, http, cgit, post
-
---
---
--- Account and access-list storage. This is the ONLY part that differs from
--- auth-file.lua. Swap these two functions to change where accounts live.
---
---
-
--- Fold the configured tables to lowercased user names once, so lookups match
--- case-insensitively the same way auth-file.lua does. Repository names keep
--- their case.
-do
-	local folded = {}
-	for name, hash in pairs(users) do
-		folded[tostring(name):lower()] = hash
-	end
-	users = folded
-	for repo, set in pairs(protected_repos) do
-		local fs = {}
-		for name, allowed in pairs(set) do
-			fs[tostring(name):lower()] = allowed
-		end
-		protected_repos[repo] = fs
-	end
-end
-
--- Return the stored password hash for a user, or nil.
-function account_hash(user)
-	if user == nil then
-		return nil
-	end
-	return users[user:lower()]
-end
-
--- Return the set of users allowed to access a repository, keyed by lowercased
--- user name, or nil if the repository is not protected.
-function repo_userset(repo)
-	if repo == nil then
-		return nil
-	end
-	return protected_repos[repo]
-end
-
---
---
--- Utility functions based on keplerproject/wsapi.
---
---
-
-function url_decode(str)
-	if not str then
-		return ""
-	end
-	str = string.gsub(str, "+", " ")
-	str = string.gsub(str, "%%(%x%x)", function(h) return string.char(tonumber(h, 16)) end)
-	str = string.gsub(str, "\r\n", "\n")
-	return str
-end
-
-function url_encode(str)
-	if not str then
-		return ""
-	end
-	str = string.gsub(str, "\n", "\r\n")
-	str = string.gsub(str, "([^%w ])", function(c) return string.format("%%%02X", string.byte(c)) end)
-	str = string.gsub(str, " ", "+")
-	return str
-end
-
--- Parse an application/x-www-form-urlencoded body. A value may itself contain
--- '=', for example a base64 password, so the value runs to the next '&'.
-function parse_qs(qs)
-	local tab = {}
-	for key, val in string.gmatch(qs or "", "([^&=]+)=([^&]*)") do
-		tab[url_decode(key)] = url_decode(val)
-	end
-	return tab
-end
-
--- Return the value of the named cookie, or nil. The stored token was already
--- url-encoded by secure_value, so it is returned verbatim, which keeps the
--- write path (set_cookie) and the read path symmetric. Decoding it here would
--- break the signature check for any value carrying a percent escape.
-function get_cookie(cookies, name)
-	cookies = string.gsub(";" .. (cookies or "") .. ";", "%s*;%s*", ";")
-	return string.match(cookies, ";" .. name .. "=(.-);")
-end
-
-function tohex(b)
-	local x = ""
-	for i = 1, #b do
-		x = x .. string.format("%.2x", string.byte(b, i))
-	end
-	return x
-end
-
---
---
--- Cookie construction and validation helpers.
---
---
-
-local secret = nil
-
--- Load the cookie-signing secret, creating it on first use. Failures raise,
--- which cgit turns into a request error, so a broken secret denies rather than
--- signs with nothing.
-function get_secret()
-	if secret ~= nil then
-		return secret
-	end
-	local secret_file = io.open(secret_filename, "r")
-	if secret_file == nil then
-		local old_umask = sysstat.umask(63)
-		local temporary_filename = secret_filename .. ".tmp." .. tohex(rand.bytes(16))
-		local temporary_file = io.open(temporary_filename, "w")
-		if temporary_file == nil then
-			sysstat.umask(old_umask)
-			error("cgit auth: cannot create secret file " .. secret_filename)
-		end
-		local wrote = temporary_file:write(tohex(rand.bytes(32)))
-		local closed = temporary_file:close()
-		if not wrote or not closed then
-			os.remove(temporary_filename)
-			sysstat.umask(old_umask)
-			error("cgit auth: failed writing secret file " .. secret_filename)
-		end
-		unistd.link(temporary_filename, secret_filename) -- Intentionally fails if another worker won the race.
-		unistd.unlink(temporary_filename)
-		sysstat.umask(old_umask)
-		secret_file = io.open(secret_filename, "r")
-	end
-	if secret_file == nil then
-		error("cgit auth: cannot read secret file " .. secret_filename)
-	end
-	secret = secret_file:read("*l")
-	secret_file:close()
-	if secret == nil or secret:len() ~= 64 then
-		secret = nil
-		error("cgit auth: secret file " .. secret_filename .. " is malformed, expected 64 hex characters")
-	end
-	return secret
-end
-
--- A redirect target is unsafe if a browser would read it as another origin.
--- The only such form cgit can be tricked into signing is a scheme-relative
--- "//host" or "/\host". Everything else stays on this host.
-function is_safe_redirect(url)
-	if type(url) ~= "string" then
-		return false
-	end
-	local head = url:sub(1, 2)
-	if head == "//" or head == "/\\" then
-		return false
-	end
-	return true
-end
-
--- Return the value carried by a signed cookie, or nil if it does not verify.
-function validate_value(expected_field, cookie)
-	local i = 0
-	local value = ""
-	local field = ""
-	local expiration = 0
-	local salt = ""
-	local chmac = ""
-
-	if cookie == nil or cookie:len() < 3 or cookie:sub(1, 1) == "|" then
-		return nil
-	end
-
-	for component in string.gmatch(cookie, "[^|]+") do
-		if i == 0 then
-			field = component
-		elseif i == 1 then
-			value = component
-		elseif i == 2 then
-			-- The expiration must be a plain integer. Rejecting other forms
-			-- keeps the signed bytes canonical, since tonumber and tostring of
-			-- "1e9" or "100.0" differ across Lua versions.
-			if not string.match(component, "^%d+$") then
-				return nil
-			end
-			expiration = tonumber(component)
-		elseif i == 3 then
-			salt = component
-		elseif i == 4 then
-			chmac = component
-		else
-			break
-		end
-		i = i + 1
-	end
-
-	if chmac == nil or chmac:len() == 0 then
-		return nil
-	end
-
-	-- Compare the HMAC without short-circuiting on the first mismatch.
-	if not constant_equals(chmac, tohex(hmac.new(get_secret(), "sha256"):final(field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt))) then
-		return nil
-	end
-
-	-- An expiration of 0 never expires and is used for the redirect token.
-	if expiration ~= 0 and expiration <= os.time() then
-		return nil
-	end
-
-	if url_decode(field) ~= expected_field then
-		return nil
-	end
-
-	local decoded = url_decode(value)
-	-- Reject values carrying control characters so a signed value cannot
-	-- smuggle CR or LF into a response header.
-	if decoded:find("%c") then
-		return nil
-	end
-	return decoded
-end
-
-function secure_value(field, value, expiration)
-	if value == nil or value:len() <= 0 then
-		return ""
-	end
-
-	local salt = tohex(rand.bytes(16))
-	value = url_encode(value)
-	field = url_encode(field)
-	local authstr = field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt
-	authstr = authstr .. "|" .. tohex(hmac.new(get_secret(), "sha256"):final(authstr))
-	return authstr
-end
-
--- Strip control characters that could split an HTTP response header.
-function strip_ctl(s)
-	return (string.gsub(s or "", "%c", ""))
-end
-
--- Compare two strings in time that does not depend on how many leading bytes
--- match, so a mismatch position is not revealed by timing.
-function constant_equals(a, b)
-	if type(a) ~= "string" or type(b) ~= "string" or #a ~= #b then
-		return false
-	end
-	local diff = 0
-	for i = 1, #a do
-		local d = a:byte(i) - b:byte(i)
-		diff = diff + d * d
-	end
-	return diff == 0
-end
-
-function set_cookie(cookie, value)
-	local attrs = "; HttpOnly; SameSite=Lax; Path=" .. cookie_path
-	if not cookie_insecure then
-		attrs = attrs .. "; Secure"
-	end
-	if value == "" then
-		attrs = attrs .. "; Max-Age=0"
-	elseif session_seconds > 0 then
-		attrs = attrs .. "; Max-Age=" .. tostring(session_seconds)
-	end
-	html("Set-Cookie: " .. cookie .. "=" .. strip_ctl(value) .. attrs .. "\n")
-end
-
-function redirect_to(url)
-	html("Status: 302 Redirect\n")
-	html("Cache-Control: no-cache, no-store\n")
-	html("Location: " .. strip_ctl(url) .. "\n")
-end
-
-function not_found()
-	html("Status: 404 Not Found\n")
-	html("Cache-Control: no-cache, no-store\n\n")
-end
-
---
---
--- Authentication actions. Identical to auth-inline.lua from here down.
---
---
-
--- Sets HTTP cookie headers based on post and sets up redirection.
-function authenticate_post()
-	local redirect = validate_value("redirect", post["redirect"])
-
-	if redirect == nil or not is_safe_redirect(redirect) then
-		not_found()
-		return 0
-	end
-
-	redirect_to(redirect)
-
-	local username = post["username"]
-	local password = post["password"]
-	local ok = false
-	if username ~= nil and password ~= nil then
-		local hash = account_hash(username)
-		if hash == nil then
-			-- Spend the work anyway, see dummy_hash.
-			unistd.crypt(password, dummy_hash)
-		elseif constant_equals(hash, unistd.crypt(password, hash)) then
-			ok = true
-		end
-	end
-
-	if ok then
-		set_cookie(cookie_name, secure_value("username", username, os.time() + session_seconds))
-	else
-		set_cookie(cookie_name, "")
-	end
-
-	html("\n")
-	return 0
-end
-
--- Returns 1 if the cookie is valid and 0 if it is not.
-function authenticate_cookie()
-	local accepted_users = repo_userset(cgit["repo"])
-	if accepted_users == nil then
-		-- The repository is not protected.
-		return 1
-	end
-
-	local username = validate_value("username", get_cookie(http["cookie"], cookie_name))
-	if username == nil or not accepted_users[username:lower()] then
-		return 0
-	end
-	return 1
-end
-
--- Prints the html for the login form.
-function body()
-	local target = cgit["url"]
-	if not is_safe_redirect(target) then
-		target = cgit["login"]
-	end
-
-	html("<h2>Authentication Required</h2>")
-	html("<form method='post' action='")
-	html_attr(cgit["login"])
-	html("'>")
-	html("<input type='hidden' name='redirect' value='")
-	html_attr(secure_value("redirect", target, 0))
-	html("' />")
-	html("<table>")
-	html("<tr><td><label for='username'>Username:</label></td><td><input id='username' name='username' autofocus /></td></tr>")
-	html("<tr><td><label for='password'>Password:</label></td><td><input id='password' name='password' type='password' /></td></tr>")
-	html("<tr><td colspan='2'><input value='Login' type='submit' /></td></tr>")
-	html("</table></form>")
-
-	return 0
-end
-
---
---
--- Wrapper around the filter API, exposing the http, cgit and post tables to
--- the functions above.
---
---
-
-local actions = {}
-actions["authenticate-post"] = authenticate_post
-actions["authenticate-cookie"] = authenticate_cookie
-actions["body"] = body
-
-function filter_open(...)
-	action = actions[select(1, ...)]
-
-	post = {}
-
-	http = {}
-	http["cookie"] = select(2, ...)
-	http["method"] = select(3, ...)
-	http["query"] = select(4, ...)
-	http["referer"] = select(5, ...)
-	http["path"] = select(6, ...)
-	http["host"] = select(7, ...)
-	http["https"] = select(8, ...)
-
-	cgit = {}
-	cgit["repo"] = select(9, ...)
-	cgit["page"] = select(10, ...)
-	cgit["url"] = select(11, ...)
-	cgit["login"] = select(12, ...)
-end
-
-function filter_close()
-	if action == nil then
-		-- Unknown action, deny rather than raise.
-		return 0
-	end
-	return action()
-end
-
-function filter_write(str)
-	post = parse_qs(str)
-end
diff --git a/extensions/email-gravatar.lua b/extensions/email-gravatar.lua
deleted file mode 100644
index 47c359e..0000000
--- a/extensions/email-gravatar.lua
+++ /dev/null
@@ -1,115 +0,0 @@
--- cgit email-filter that shows a Gravatar icon next to author names. Use it
--- with the email-filter or repo.email-filter setting and the lua: prefix.
---
---     email-filter=lua:/path/to/email-gravatar.lua
---
--- SUPPORTED LUA
---
--- Lua 5.1, 5.2, 5.3, 5.4 and LuaJIT. Lua 5.5 is not supported, because luaossl
--- has no 5.5 build.
---
--- DEPENDENCY
---
---     luaossl    OpenSSL binding, provides openssl.digest
---                <https://github.com/wahern/luaossl>
---
---     # Debian and Ubuntu
---     sudo apt install luarocks libssl-dev
---     sudo luarocks --lua-version 5.1 install luaossl
---
---     # Fedora
---     sudo dnf install luarocks openssl-devel
---     sudo luarocks --lua-version 5.1 install luaossl
---
---     # macOS with Homebrew
---     brew install luarocks openssl
---     luarocks install luaossl OPENSSL_DIR="$(brew --prefix openssl)"
---
--- PRIVACY
---
--- Every page view sends the visitor's IP address and a hash of each
--- committer's email to a third-party service. Leave this filter off if that is
--- not acceptable for your instance.
---
--- Addresses are hashed with MD5, which Gravatar still accepts. Gravatar also
--- supports SHA-256 now, change the digest in hash_hex if you prefer it.
-
-local digest = require("openssl.digest")
-
---
--- ===== CONFIGURATION =====
---
-
--- Pixel size of the avatar.
-local avatar_size = 13
-
--- Fallback style for an address with no avatar. See the Gravatar docs for the
--- choices, for example retro, identicon, monsterid or mp.
-local default_image = "retro"
-
--- Avatar endpoint. Kept https so the image is not blocked as mixed content on
--- an https page.
-local base_url = "https://www.gravatar.com/avatar/"
-
--- Text for the image alt attribute.
-local alt_text = "Gravatar"
-
---
--- =========================
---
-
--- State shared across the open, write and close calls of one invocation.
-local buffer = ""
-local avatar = nil
-
-local function hash_hex(input)
-	local b = digest.new("md5"):final(input)
-	local x = ""
-	for i = 1, #b do
-		x = x .. string.format("%.2x", string.byte(b, i))
-	end
-	return x
-end
-
--- Take the address, strip the angle brackets if present, then trim and
--- lowercase as the avatar services expect. Returns nil for a missing or empty
--- address.
-local function normalize_email(email)
-	if email == nil then
-		return nil
-	end
-	local inner = email:match("<(.*)>")
-	if inner ~= nil then
-		email = inner
-	end
-	email = (email:gsub("^%s*(.-)%s*$", "%1")):lower()
-	if email == "" then
-		return nil
-	end
-	return email
-end
-
-function filter_open(email, page)
-	buffer = ""
-	local addr = normalize_email(email)
-	if addr == nil then
-		avatar = nil
-	else
-		avatar = hash_hex(addr)
-	end
-end
-
-function filter_close()
-	if avatar == nil then
-		-- No usable address, render the name without an icon.
-		html(buffer)
-	else
-		html("<img src='" .. base_url .. avatar .. "?s=" .. avatar_size .. "&amp;d=" .. default_image ..
-			"' width='" .. avatar_size .. "' height='" .. avatar_size .. "' alt='" .. alt_text .. "' /> " .. buffer)
-	end
-	return 0
-end
-
-function filter_write(str)
-	buffer = buffer .. str
-end
diff --git a/extensions/email-libravatar.lua b/extensions/email-libravatar.lua
deleted file mode 100644
index 812bef5..0000000
--- a/extensions/email-libravatar.lua
+++ /dev/null
@@ -1,114 +0,0 @@
--- cgit email-filter that shows a Libravatar icon next to author names. Use it
--- with the email-filter or repo.email-filter setting and the lua: prefix.
---
---     email-filter=lua:/path/to/email-libravatar.lua
---
--- SUPPORTED LUA
---
--- Lua 5.1, 5.2, 5.3, 5.4 and LuaJIT. Lua 5.5 is not supported, because luaossl
--- has no 5.5 build.
---
--- DEPENDENCY
---
---     luaossl    OpenSSL binding, provides openssl.digest
---                <https://github.com/wahern/luaossl>
---
---     # Debian and Ubuntu
---     sudo apt install luarocks libssl-dev
---     sudo luarocks --lua-version 5.1 install luaossl
---
---     # Fedora
---     sudo dnf install luarocks openssl-devel
---     sudo luarocks --lua-version 5.1 install luaossl
---
---     # macOS with Homebrew
---     brew install luarocks openssl
---     luarocks install luaossl OPENSSL_DIR="$(brew --prefix openssl)"
---
--- PRIVACY
---
--- Every page view sends the visitor's IP address and a hash of each
--- committer's email to a third-party service. Leave this filter off if that is
--- not acceptable for your instance.
---
--- The secure CDN is always used, so the icon loads over https and is never
--- blocked as mixed content. Addresses are hashed with MD5.
-
-local digest = require("openssl.digest")
-
---
--- ===== CONFIGURATION =====
---
-
--- Pixel size of the avatar.
-local avatar_size = 13
-
--- Fallback style for an address with no avatar. See the Libravatar docs for
--- the choices, for example retro, identicon, monsterid or mm.
-local default_image = "retro"
-
--- Avatar endpoint. The secure CDN is used so the image loads over https.
-local base_url = "https://seccdn.libravatar.org/avatar/"
-
--- Text for the image alt attribute.
-local alt_text = "Libravatar"
-
---
--- =========================
---
-
--- State shared across the open, write and close calls of one invocation.
-local buffer = ""
-local avatar = nil
-
-local function hash_hex(input)
-	local b = digest.new("md5"):final(input)
-	local x = ""
-	for i = 1, #b do
-		x = x .. string.format("%.2x", string.byte(b, i))
-	end
-	return x
-end
-
--- Take the address, strip the angle brackets if present, then trim and
--- lowercase as the avatar services expect. Returns nil for a missing or empty
--- address.
-local function normalize_email(email)
-	if email == nil then
-		return nil
-	end
-	local inner = email:match("<(.*)>")
-	if inner ~= nil then
-		email = inner
-	end
-	email = (email:gsub("^%s*(.-)%s*$", "%1")):lower()
-	if email == "" then
-		return nil
-	end
-	return email
-end
-
-function filter_open(email, page)
-	buffer = ""
-	local addr = normalize_email(email)
-	if addr == nil then
-		avatar = nil
-	else
-		avatar = hash_hex(addr)
-	end
-end
-
-function filter_close()
-	if avatar == nil then
-		-- No usable address, render the name without an icon.
-		html(buffer)
-	else
-		html("<img src='" .. base_url .. avatar .. "?s=" .. avatar_size .. "&amp;d=" .. default_image ..
-			"' width='" .. avatar_size .. "' height='" .. avatar_size .. "' alt='" .. alt_text .. "' /> " .. buffer)
-	end
-	return 0
-end
-
-function filter_write(str)
-	buffer = buffer .. str
-end
diff --git a/extensions/link-commits.lua b/extensions/link-commits.lua
deleted file mode 100644
index e7b17cc..0000000
--- a/extensions/link-commits.lua
+++ /dev/null
@@ -1,153 +0,0 @@
--- cgit commit-filter that turns git object names and configurable text
--- references in commit messages into links. Use it with the commit-filter or
--- repo.commit-filter setting and the lua: prefix.
---
---     commit-filter=lua:/path/to/link-commits.lua
---
--- cgit hands the filter the message already HTML-escaped, so this only wraps
--- matches in anchors. No external dependencies. Runs on Lua 5.1 through 5.4
--- and LuaJIT.
---
--- Two kinds of thing are linked, object names (runs of hex that look like git
--- hashes) and any number of text-reference rules you define, each a pattern
--- and a URL. Both are configured in the block below. All matches are resolved
--- in a single left-to-right pass, so nothing is ever linked twice.
-
---
--- ===== CONFIGURATION =====
---
-
--- Object names (git hashes). Handled specially, because the length rule cannot
--- be written as a plain Lua pattern.
---
--- Recognition is by shape, since a commit-filter cannot ask the repository
--- whether a hash is real. Any hex run within the length bounds is linked,
--- whatever mix of digits and letters it has, so abbreviated and all-digit
--- hashes are both caught. The cost is that a long hex-looking number can now
--- and then link to an object that does not exist, which cgit renders as a
--- harmless "bad object name" page. Shape matching is inherently approximate,
--- the length bounds are the only filter.
-local objects = {
-	-- Set false to stop linking bare hashes.
-	enabled = true,
-	-- A hex run within these lengths is linked. Git abbreviations run about 7
-	-- to 12 characters, full names are 40 (sha1) or 64 (sha256).
-	min_length = 7,
-	max_length = 64,
-	-- Link target, %s is replaced with the matched hash. "./?id=%s" is relative
-	-- to the current page and works for the common virtual-root layout.
-	url = "./?id=%s",
-}
-
--- Text-reference rules. Each rule is a Lua pattern with ONE capture and a URL
--- where %s is replaced by that capture, percent-encoded. The whole match is
--- shown, the capture is what goes in the URL. Rules are tried in order and the
--- leftmost match on the line wins, so put more specific patterns first. Leave
--- the list empty to link only object names.
---
--- Lua patterns are not regular expressions. There is no alternation and no
--- {n,m} repetition. %d is a digit, %a a letter, %w a letter or digit, %x a hex
--- digit, and a literal magic character is escaped with %, so a literal '-' is
--- '%-'. Reference: https://www.lua.org/manual/5.1/manual.html#5.4.1
-local rules = {
-	{ pattern = "#(%d+)", url = "https://bugs.example.com/?bug=%s" },
-	-- { pattern = "CVE%-(%d%d%d%d%-%d+)", url = "https://www.cve.org/CVERecord?id=CVE-%s" },
-	-- { pattern = "!(%d+)",               url = "https://gitlab.example.com/group/repo/-/merge_requests/%s" },
-	-- { pattern = "RFC%s?(%d+)",          url = "https://www.rfc-editor.org/rfc/rfc%s" },
-}
-
---
--- =========================
---
-
-local chunks = {}
-
--- Percent-encode everything but the URL-unreserved characters, so a captured
--- value cannot break out of the href attribute or the URL.
-local function url_encode(s)
-	return (string.gsub(s, "[^%w._~-]", function(c)
-		return string.format("%%%02X", string.byte(c))
-	end))
-end
-
--- Build one anchor. url_template has %s where the encoded capture goes, display
--- is the text shown. A function replacement is used so a '%' in the encoded
--- value is not treated as a gsub reference.
-local function make_link(url_template, capture, display)
-	local encoded = url_encode(capture)
-	local href = string.gsub(url_template, "%%s", function() return encoded end)
-	return '<a href="' .. href .. '">' .. display .. '</a>'
-end
-
--- Collect every candidate match as {s, e, pri, link}. A lower pri wins a tie on
--- the same start position.
-local function collect(text)
-	local cands = {}
-	for pri, rule in ipairs(rules) do
-		-- A malformed pattern is an operator error, skip that rule rather than
-		-- failing the whole page.
-		pcall(function()
-			local init = 1
-			while init <= #text do
-				local s, e, cap = string.find(text, rule.pattern, init)
-				if not s then break end
-				if cap == nil then
-					cap = string.sub(text, s, e)
-				end
-				cands[#cands + 1] = {
-					s = s, e = e, pri = pri,
-					link = make_link(rule.url, cap, string.sub(text, s, e)),
-				}
-				init = (e >= s) and e + 1 or s + 1
-			end
-		end)
-	end
-	if objects.enabled then
-		local objpri = #rules + 1
-		local init = 1
-		while init <= #text do
-			local s, e, run = string.find(text, "%f[%w](%x+)%f[%W]", init)
-			if not s then break end
-			if #run >= objects.min_length and #run <= objects.max_length then
-				cands[#cands + 1] = {
-					s = s, e = e, pri = objpri,
-					link = make_link(objects.url, run, run),
-				}
-			end
-			init = e + 1
-		end
-	end
-	return cands
-end
-
-function filter_open(...)
-	chunks = {}
-end
-
-function filter_write(str)
-	chunks[#chunks + 1] = str
-end
-
-function filter_close()
-	local text = table.concat(chunks)
-	local cands = collect(text)
-	table.sort(cands, function(a, b)
-		if a.s ~= b.s then
-			return a.s < b.s
-		end
-		return a.pri < b.pri
-	end)
-	local out = {}
-	local i = 1
-	for _, c in ipairs(cands) do
-		-- Skip a candidate that overlaps one already emitted.
-		if c.s >= i then
-			out[#out + 1] = string.sub(text, i, c.s - 1)
-			out[#out + 1] = c.link
-			i = c.e + 1
-		end
-	end
-	out[#out + 1] = string.sub(text, i)
-	html(table.concat(out))
-	return 0
-end
diff --git a/extensions/syntax-highlight.lua b/extensions/syntax-highlight.lua
deleted file mode 100644
index 8310504..0000000
--- a/extensions/syntax-highlight.lua
+++ /dev/null
@@ -1,278 +0,0 @@
--- Server-side syntax highlighting for the tree and blob views, used with the
--- source-filter setting in cgitrc and the lua: prefix so it runs in cgit's
--- embedded interpreter with no per-request process.
---
---     source-filter=lua:/usr/lib/cgit/extensions/syntax-highlight.lua
---
--- Highlighting is deliberately not built into cgit itself. Without this filter
--- cgit serves plain escaped text, and any other program can take its place.
---
--- SUPPORTED LUA
---
--- Lua 5.1 through 5.4 and LuaJIT. The Scintillua version matters too. Recent
--- Scintillua (6.x) needs Lua 5.3 or newer to load its lexers, older Scintillua
--- releases still load under 5.1 and 5.2. Pick a Scintillua release that matches
--- the Lua cgit is built against.
---
--- REQUIREMENTS
---
--- Two pieces, and BOTH must be installed. When either is missing the filter
--- serves plain escaped text by design, so uncolored code means a missing
--- dependency, not an error.
---
--- 1. lpeg, the parsing module, for the Lua cgit is linked against. Scintillua
---    does NOT bundle it, it must come from the system, and forgetting it is the
---    usual reason nothing happens.
---
---        # Debian and Ubuntu
---        sudo apt install lua-lpeg
---        # Fedora
---        sudo dnf install lua-lpeg
---        # Alpine
---        sudo apk add lua5.1-lpeg
---        # or with LuaRocks, matched to your Lua version
---        sudo luarocks --lua-version 5.1 install lpeg
---
--- 2. Scintillua, the lexer collection from the Textadept editor. Roughly 120
---    languages as plain .lua files, nothing to compile. Download a release and
---    unpack it anywhere.
---
---        https://orbitalquark.github.io/scintillua/
---
--- The lexers are found by probing, in order
---
---     $CGIT_SCINTILLUA_PATH        (used alone when set, no fallback)
---     <dir of $CGIT_CONFIG>/scintillua/lexers
---     the scintillua_dirs list in the CONFIGURATION block below
---
--- so either set the variable in the web server environment, or place (or
--- symlink) the scintillua directory next to your cgitrc.
---
--- SECURITY
---
--- Every probed directory is placed on package.path and its Lua is executed in
--- cgit's process. Make sure none of them is writable by other users, or someone
--- who can write there gains code execution as the web server. On macOS in
--- particular, /opt/homebrew/share is group-writable by default.
---
--- LIMITATIONS
---
--- cgit sends the filter output through a C string sink that stops at the first
--- NUL byte, so a blob containing a NUL is truncated there. This affects binary
--- files that slip past cgit's text detection, not ordinary source.
---
--- OUTPUT
---
--- Tokens are wrapped in <span> elements carrying the hl- classes that
--- assets/cgit.css styles. Every input byte up to the first NUL is preserved, so
--- the line number gutter stays aligned.
-
---
--- ===== CONFIGURATION =====
---
-
--- Files larger than this many bytes are served escaped but unhighlighted, so a
--- huge blob does not cost a lexing pass. Kept well below cgit's max-blob-size.
-local max_bytes = 512 * 1024
-
--- Environment variable that, when set, points straight at the Scintillua
--- lexers directory and is used alone.
-local scintillua_env = "CGIT_SCINTILLUA_PATH"
-
--- Directories probed for the lexers when that variable is not set. The
--- directory of $CGIT_CONFIG, when set, is tried ahead of these. Keep every one
--- of these unwritable by others, see the SECURITY note above.
-local scintillua_dirs = {
-	"/usr/local/share/scintillua/lexers",
-	"/usr/share/scintillua/lexers",
-	"/opt/homebrew/share/scintillua/lexers",
-}
-
--- Scintillua tag name (its first dotted component) to a cgit css class. Only
--- the six classes below exist in assets/cgit.css. Add a class there and a row
--- here to style more token kinds. Tokens with no row render as plain text,
--- which is what most themes want for operators and identifiers.
-local css = {
-	comment      = "hl-comment",
-	string       = "hl-string",
-	regex        = "hl-string",
-	number       = "hl-number",
-	constant     = "hl-number",
-	keyword      = "hl-keyword",
-	preprocessor = "hl-keyword",
-	tag          = "hl-keyword",
-	label        = "hl-keyword",
-	annotation   = "hl-keyword",
-	type         = "hl-type",
-	class        = "hl-type",
-	attribute    = "hl-type",
-	["function"] = "hl-func",
-}
-
--- Extension to lexer-name fixes for the fallback path, used only when this
--- Scintillua has no detect(). Most extensions already equal their lexer name,
--- these are the frequent exceptions. A wrong guess just falls back to plain
--- text, so there is no harm in listing best-effort entries.
-local ext_lexer = {
-	py = "python", js = "javascript", ts = "typescript",
-	rb = "ruby", pl = "perl", pm = "perl", sh = "bash",
-	md = "markdown", htm = "html", yml = "yaml",
-	rs = "rust", c = "ansi_c", h = "ansi_c",
-}
-
---
--- =========================
---
-
-local lexer_mod = nil
-local filename = ""
-local chunks = {}
-
-local escape_map = { ["&"] = "&amp;", ["<"] = "&lt;", [">"] = "&gt;" }
-
--- Escape the three HTML metacharacters in a single pass.
-local function escape(s)
-	return (string.gsub(s, "[&<>]", escape_map))
-end
-
-local function scintillua_path()
-	local env = os.getenv(scintillua_env)
-	if env then
-		return env
-	end
-	local candidates = {}
-	local config = os.getenv("CGIT_CONFIG")
-	if config then
-		local dir = string.match(config, "^(.*)/[^/]+$")
-		if dir then
-			candidates[#candidates + 1] = dir .. "/scintillua/lexers"
-		end
-	end
-	for _, d in ipairs(scintillua_dirs) do
-		candidates[#candidates + 1] = d
-	end
-	for _, dir in ipairs(candidates) do
-		local f = io.open(dir .. "/lexer.lua", "r")
-		if f then
-			f:close()
-			return dir
-		end
-	end
-	return nil
-end
-
-local function load_scintillua()
-	local dir = scintillua_path()
-	if not dir then
-		return nil
-	end
-	if not string.find(package.path, dir, 1, true) then
-		package.path = dir .. "/?.lua;" .. package.path
-	end
-	local ok, mod = pcall(require, "lexer")
-	-- A real Scintillua exposes load(). Anything else on the path that happens
-	-- to be called lexer is not usable.
-	if ok and type(mod) == "table" and type(mod.load) == "function" then
-		return mod
-	end
-	return nil
-end
-
-local function load_lexer_name(name)
-	if name == nil then
-		return nil
-	end
-	local ok, lex = pcall(lexer_mod.load, name)
-	if ok and lex then
-		return lex
-	end
-	return nil
-end
-
--- Resolve a lexer for the file, preferring Scintillua's own filename detection
--- when this version provides it, then an extension map, then the raw extension.
-local function lexer_for(name)
-	if type(lexer_mod.detect) == "function" then
-		local ok, lang = pcall(lexer_mod.detect, name)
-		if ok and lang then
-			local lex = load_lexer_name(lang)
-			if lex then
-				return lex
-			end
-		end
-	end
-	local ext = string.match(name, "%.([^.]+)$")
-	if not ext then
-		return nil
-	end
-	ext = string.lower(ext)
-	return load_lexer_name(ext_lexer[ext]) or load_lexer_name(ext)
-end
-
-local function highlight(text)
-	local lex = lexer_for(filename)
-	if not lex then
-		return nil
-	end
-	local ok, tokens = pcall(lex.lex, lex, text)
-	if not ok or type(tokens) ~= "table" then
-		return nil
-	end
-	local out = {}
-	local pos = 1
-	for i = 1, #tokens, 2 do
-		local tag = tokens[i]
-		local fin = tokens[i + 1]
-		local part = escape(string.sub(text, pos, fin - 1))
-		local class = css[string.match(tag, "^[%w_]+")]
-		if class and part ~= "" then
-			part = "<span class='" .. class .. "'>" .. part .. "</span>"
-		end
-		out[#out + 1] = part
-		pos = fin
-	end
-	-- Anything the lexer left unconsumed is kept, escaped.
-	if pos <= #text then
-		out[#out + 1] = escape(string.sub(text, pos))
-	end
-	return table.concat(out)
-end
-
-function filter_open(name)
-	filename = name or ""
-	chunks = {}
-end
-
-function filter_write(str)
-	chunks[#chunks + 1] = str
-end
-
-function filter_close()
-	local text = table.concat(chunks)
-	chunks = {}
-	if #text <= max_bytes then
-		if lexer_mod == nil then
-			lexer_mod = load_scintillua() or false
-		end
-		if lexer_mod then
-			local ok, marked = pcall(highlight, text)
-			if ok and marked then
-				html(marked)
-				return 0
-			end
-		end
-	end
-	-- Fallback, escaped plain text emitted in slices so a large blob does not
-	-- cost a full-size second copy all at once.
-	local n = #text
-	if n == 0 then
-		html("")
-		return 0
-	end
-	local pos = 1
-	while pos <= n do
-		html(escape(string.sub(text, pos, pos + 65535)))
-		pos = pos + 65536
-	end
-	return 0
-end
-- 
cgit v2.8.0