// Copyright 2016 The Hugo Authors. All rights reserved. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. package helpers import ( "bytes" "crypto/sha1" "fmt" "io" "io/ioutil" "os/exec" "path/filepath" "regexp" "sort" "strconv" "strings" "github.com/alecthomas/chroma" "github.com/alecthomas/chroma/formatters" "github.com/alecthomas/chroma/formatters/html" "github.com/alecthomas/chroma/lexers" "github.com/alecthomas/chroma/styles" bp "github.com/gohugoio/hugo/bufferpool" "github.com/gohugoio/hugo/config" "github.com/gohugoio/hugo/hugofs" jww "github.com/spf13/jwalterweatherman" ) const pygmentsBin = "pygmentize" // TODO(bep) document chroma -s perldoc --html --html-styles // hasPygments checks to see if Pygments is installed and available // on the system. func hasPygments() bool { if _, err := exec.LookPath(pygmentsBin); err != nil { return false } return true } type highlighters struct { cs *ContentSpec ignoreCache bool cacheDir string } func newHiglighters(cs *ContentSpec) highlighters { return highlighters{cs: cs, ignoreCache: cs.cfg.GetBool("ignoreCache"), cacheDir: cs.cfg.GetString("cacheDir")} } func (h highlighters) chromaHighlight(code, lang, optsStr string) (string, error) { opts, err := h.cs.parsePygmentsOpts(optsStr) if err != nil { jww.ERROR.Print(err.Error()) return code, err } style, found := opts["style"] if !found || style == "" { style = "friendly" } f, err := h.cs.chromaFormatterFromOptions(opts) if err != nil { jww.ERROR.Print(err.Error()) return code, err } b := bp.GetBuffer() defer bp.PutBuffer(b) err = chromaHighlight(b, code, lang, style, f) if err != nil { jww.ERROR.Print(err.Error()) return code, err } return h.injectCodeTag(`
`+b.String()+"
", lang), nil } func (h highlighters) pygmentsHighlight(code, lang, optsStr string) (string, error) { options, err := h.cs.createPygmentsOptionsString(optsStr) if err != nil { jww.ERROR.Print(err.Error()) return code, nil } // Try to read from cache first hash := sha1.New() io.WriteString(hash, code) io.WriteString(hash, lang) io.WriteString(hash, options) fs := hugofs.Os var cachefile string if !h.ignoreCache && h.cacheDir != "" { cachefile = filepath.Join(h.cacheDir, fmt.Sprintf("pygments-%x", hash.Sum(nil))) exists, err := Exists(cachefile, fs) if err != nil { jww.ERROR.Print(err.Error()) return code, nil } if exists { f, err := fs.Open(cachefile) if err != nil { jww.ERROR.Print(err.Error()) return code, nil } s, err := ioutil.ReadAll(f) if err != nil { jww.ERROR.Print(err.Error()) return code, nil } return string(s), nil } } // No cache file, render and cache it var out bytes.Buffer var stderr bytes.Buffer var langOpt string if lang == "" { langOpt = "-g" // Try guessing the language } else { langOpt = "-l" + lang } cmd := exec.Command(pygmentsBin, langOpt, "-fhtml", "-O", options) cmd.Stdin = strings.NewReader(code) cmd.Stdout = &out cmd.Stderr = &stderr if err := cmd.Run(); err != nil { jww.ERROR.Print(stderr.String()) return code, err } str := string(normalizeExternalHelperLineFeeds([]byte(out.String()))) str = h.injectCodeTag(str, lang) if !h.ignoreCache && cachefile != "" { // Write cache file if err := WriteToDisk(cachefile, strings.NewReader(str), fs); err != nil { jww.ERROR.Print(stderr.String()) } } return str, nil } var preRe = regexp.MustCompile(`(?s)(.*?)(.*?)()`) func (h highlighters) injectCodeTag(code, lang string) string { if lang == "" { return code } codeTag := fmt.Sprintf(``, lang, lang) return preRe.ReplaceAllString(code, fmt.Sprintf("$1%s$2$3", codeTag)) } func chromaHighlight(w io.Writer, source, lexer, style string, f chroma.Formatter) error { l := lexers.Get(lexer) if l == nil { l = lexers.Analyse(source) } if l == nil { l = lexers.Fallback } l = chroma.Coalesce(l) if f == nil { f = formatters.Fallback } s := styles.Get(style) if s == nil { s = styles.Fallback } it, err := l.Tokenise(nil, source) if err != nil { return err } return f.Format(w, s, it) } var pygmentsKeywords = make(map[string]bool) func init() { pygmentsKeywords["encoding"] = true pygmentsKeywords["outencoding"] = true pygmentsKeywords["nowrap"] = true pygmentsKeywords["full"] = true pygmentsKeywords["title"] = true pygmentsKeywords["style"] = true pygmentsKeywords["noclasses"] = true pygmentsKeywords["classprefix"] = true pygmentsKeywords["cssclass"] = true pygmentsKeywords["cssstyles"] = true pygmentsKeywords["prestyles"] = true pygmentsKeywords["linenos"] = true pygmentsKeywords["hl_lines"] = true pygmentsKeywords["linenostart"] = true pygmentsKeywords["linenostep"] = true pygmentsKeywords["linenospecial"] = true pygmentsKeywords["nobackground"] = true pygmentsKeywords["lineseparator"] = true pygmentsKeywords["lineanchors"] = true pygmentsKeywords["linespans"] = true pygmentsKeywords["anchorlinenos"] = true pygmentsKeywords["startinline"] = true } func parseOptions(defaults map[string]string, in string) (map[string]string, error) { in = strings.Trim(in, " ") opts := make(map[string]string) if defaults != nil { for k, v := range defaults { opts[k] = v } } if in == "" { return opts, nil } for _, v := range strings.Split(in, ",") { keyVal := strings.Split(v, "=") key := strings.ToLower(strings.Trim(keyVal[0], " ")) if len(keyVal) != 2 || !pygmentsKeywords[key] { return opts, fmt.Errorf("invalid Pygments option: %s", key) } opts[key] = keyVal[1] } return opts, nil } func createOptionsString(options map[string]string) string { var keys []string for k := range options { keys = append(keys, k) } sort.Strings(keys) var optionsStr string for i, k := range keys { optionsStr += fmt.Sprintf("%s=%s", k, options[k]) if i < len(options)-1 { optionsStr += "," } } return optionsStr } func parseDefaultPygmentsOpts(cfg config.Provider) (map[string]string, error) { options, err := parseOptions(nil, cfg.GetString("pygmentsOptions")) if err != nil { return nil, err } if cfg.IsSet("pygmentsStyle") { options["style"] = cfg.GetString("pygmentsStyle") } if cfg.IsSet("pygmentsUseClasses") { if cfg.GetBool("pygmentsUseClasses") { options["noclasses"] = "false" } else { options["noclasses"] = "true" } } if _, ok := options["encoding"]; !ok { options["encoding"] = "utf8" } return options, nil } func (cs *ContentSpec) chromaFormatterFromOptions(pygmentsOpts map[string]string) (chroma.Formatter, error) { var options = []html.Option{html.TabWidth(4)} if pygmentsOpts["noclasses"] == "false" { options = append(options, html.WithClasses()) } if pygmentsOpts["linenos"] != "" { options = append(options, html.WithLineNumbers()) } startLineStr := pygmentsOpts["linenostart"] var startLine = 1 if startLineStr != "" { line, err := strconv.Atoi(strings.TrimSpace(startLineStr)) if err == nil { startLine = line options = append(options, html.BaseLineNumber(startLine)) } } hlLines := pygmentsOpts["hl_lines"] if hlLines != "" { ranges, err := hlLinesToRanges(startLine, hlLines) if err == nil { options = append(options, html.HighlightLines(ranges)) } } return html.New(options...), nil } func (cs *ContentSpec) parsePygmentsOpts(in string) (map[string]string, error) { opts, err := parseOptions(cs.defatultPygmentsOpts, in) if err != nil { return nil, err } return opts, nil } func (cs *ContentSpec) createPygmentsOptionsString(in string) (string, error) { opts, err := cs.parsePygmentsOpts(in) if err != nil { return "", err } return createOptionsString(opts), nil } // startLine compansates for https://github.com/alecthomas/chroma/issues/30 func hlLinesToRanges(startLine int, s string) ([][2]int, error) { var ranges [][2]int s = strings.TrimSpace(s) if s == "" { return ranges, nil } // Variants: // 1 2 3 4 // 1-2 3-4 // 1-2 3 // 1 3-4 // 1 3-4 fields := strings.Split(s, " ") for _, field := range fields { field = strings.TrimSpace(field) if field == "" { continue } numbers := strings.Split(field, "-") var r [2]int first, err := strconv.Atoi(numbers[0]) if err != nil { return ranges, err } first = first + startLine - 1 r[0] = first if len(numbers) > 1 { second, err := strconv.Atoi(numbers[1]) if err != nil { return ranges, err } second = second + startLine - 1 r[1] = second } else { r[1] = first } ranges = append(ranges, r) } return ranges, nil }