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Diffstat (limited to 'custom/extensions/about-render.lua')
| -rw-r--r-- | custom/extensions/about-render.lua | 91 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 file changed, 37 insertions, 54 deletions
diff --git a/custom/extensions/about-render.lua b/custom/extensions/about-render.lua index ea13746..f4e7685 100644 --- a/custom/extensions/about-render.lua +++ b/custom/extensions/about-render.lua @@ -1,20 +1,15 @@ -- Server-side rendering of a repository's about page, named by the -- about-filter setting in cgitrc and run inside cgit's embedded Lua --- interpreter so a readme costs no extra process per request. --- Markdown, man pages and plain text are the three formats, chosen from the --- readme's file extension, and anything that fails to parse falls back to --- escaped plain text. Adding a format takes a render function and a row in --- the handler table at the foot of this file, and nothing else. The wrappers --- it emits carry the classes that assets/cgit.css styles. It runs on Lua 5.1 --- through 5.4 and LuaJIT. +-- interpreter so a readme costs no extra process per request. Markdown, man +-- pages and plain text are the three formats, chosen from the readme's file +-- extension, and anything that fails to parse falls back to escaped plain +-- text. The wrappers it emits carry the classes that assets/cgit.css styles. +-- It runs on Lua 5.1 through 5.4 and LuaJIT. -- --- about-filter=lua:/usr/lib/cgit/filters/about-render.lua +-- about-filter=lua:/usr/local/lib/cgit/filters/about-render.lua --- Markdown and man pages are parsed with lpeg grammars, so where the parsing --- module is missing both fall back to escaped plain text and only plain text --- still renders. It has to be built for the Lua cgit is linked against. --- cgit's syntax highlighter needs it too, so a cgit that colours source --- already has it. +-- Markdown and man pages need lpeg, built for the Lua cgit is linked +-- against. Without it both fall back to escaped plain text. -- -- # Debian and Ubuntu -- sudo apt install lua-lpeg @@ -42,9 +37,8 @@ local function trim(text) return (text:gsub("^%s+", ""):gsub("%s+$", "")) end --- Split on newlines after normalising CRLF and CR, returning the lines --- without their terminators. A trailing newline yields a final empty line, --- which every caller treats as blank. +-- Normalise CRLF and CR to newlines, then split. A trailing newline yields +-- a final empty line, which every caller treats as blank. local function split_lines(text) text = text:gsub("\r\n?", "\n") local lines, start = {}, 1 @@ -59,8 +53,6 @@ local function split_lines(text) end end --- Split a table row into trimmed cells, dropping one optional leading and one --- optional trailing pipe. local function split_cells(row) row = trim(row):gsub("^|", ""):gsub("|$", "") local cells = {} @@ -70,11 +62,10 @@ local function split_cells(row) 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. +-- Control and whitespace bytes are stripped before the scheme check because +-- a browser ignores them when resolving it, 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 @@ -94,14 +85,10 @@ local function safe_url(url) end --- The about page renders untrusted repository content, so the rule the two --- functions below keep 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 safe_url before html_attr. Those three come --- from cgit's Lua filter host rather than from here, and the only thing --- passed to html is literal tag scaffolding. Because all output is routed --- through those sinks by construction, a bug in the parser can only --- mis-render, never inject markup or a URL with a javascript scheme. +-- The page renders untrusted repository content. Every run of text goes out +-- through cgit's html_txt, every attribute value through html_attr, and +-- every link or image target through safe_url before html_attr. html() only +-- ever gets literal tag scaffolding. local emit_inline @@ -198,16 +185,12 @@ local function render_plaintext(text) end --- Markdown here is a deliberate subset rather than CommonMark, covering --- headings, thematic breaks, fenced and inline code, blockquotes, pipe --- tables, single-level lists, links, images and emphasis, and leaving out --- reference links, raw HTML passthrough, nested lists and setext headings. --- Emphasis does not span a hard line break inside a paragraph. Man rendering --- covers the common macros, that is section headings, filled and no-fill --- paragraphs, bold and italic and the font escapes, and drops the rest. Both --- are parsed with lpeg into the node trees emit_blocks and emit_inline above --- consume, and parsing only builds a tree, so a parse that fails falls back --- to plain text without leaving half a page behind. +-- Markdown is a deliberate subset rather than CommonMark, leaving out +-- reference links, raw HTML passthrough, nested lists and setext headings, +-- and emphasis does not span a hard line break. Man rendering covers the +-- common macros and drops the rest. Both parse into a node tree before +-- anything is emitted, so a failed parse falls back to plain text without +-- leaving half a page behind. local render_markdown, render_man @@ -223,8 +206,6 @@ if has_lpeg then -- Bound the link and image inner scans. Without a cap a readme of -- unclosed brackets ("[[[[...") makes every position scan to the -- end of the 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 max_scan = 512 local parse_inline @@ -275,8 +256,6 @@ if has_lpeg then return nodes end - -- 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 lang_char = R("az", "AZ", "09") + S("_.+#-") local heading_line = C(P("#") * P("#") ^ -5) * space ^ 1 * C(P(1) ^ 0) local function thematic(mark) @@ -434,20 +413,24 @@ if has_lpeg then html("</div>") end - -- Macro lines are matched with lpeg, and the roff inline font and - -- character escapes are a 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 rather - -- than being opened and closed, so the inline pass tokenises and - -- folds instead of nesting the way markdown does. + -- Roff fonts are a current state carried across a run rather than + -- opened and closed, so the inline pass tokenises to a flat list + -- and folds it into the nodes markdown emits, instead of nesting. local macro_line = S(".'") * space ^ 0 * C((1 - space) ^ 1) * space ^ 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 = "-", + aq = "'", + cq = "'", + oq = "'", + dq = '"', + lq = '"', + rq = '"', + hy = "-", + en = "-", + em = "-", } local backslash = P("\\") local function font_token(name) return { kind = "font", font = name } end @@ -610,7 +593,7 @@ function filter_write(str) end -- cgit takes filter output through a C string sink that stops at the first --- NUL byte, so a readme holding one is truncated there. +-- NUL byte, so a write holding one loses everything from the NUL on. function filter_close() local text = table.concat(chunks) chunks = {} |