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Diffstat (limited to 'extensions/syntax-highlight.lua')
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1 file changed, 0 insertions, 278 deletions
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 = { ["&"] = "&", ["<"] = "<", [">"] = ">" } - --- 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 |