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-rw-r--r--hswg/main.go217
1 files changed, 217 insertions, 0 deletions
diff --git a/hswg/main.go b/hswg/main.go
new file mode 100644
index 0000000..595bb4a
--- /dev/null
+++ b/hswg/main.go
@@ -0,0 +1,217 @@
+// Program hswg is a static website generator employing libasciidoc with added
+// support for two-line/underlined titles, and postprocessing "wiki" InterLinks.
+package main
+
+import (
+ "bytes"
+ "fmt"
+ "io"
+ "io/ioutil"
+ "log"
+ "os"
+ "path/filepath"
+ "regexp"
+ "sort"
+ "strings"
+ "time"
+ "unicode"
+ "unicode/utf8"
+
+ "github.com/bytesparadise/libasciidoc"
+ "github.com/bytesparadise/libasciidoc/pkg/configuration"
+ "github.com/bytesparadise/libasciidoc/pkg/types"
+)
+
+// isTitle returns the title level if the lines seem to form a title,
+// zero otherwise. Input lines may inclide trailing newlines.
+func isTitle(line1, line2 []byte) int {
+ // This is a very naïve method, we should target graphemes (thus at least
+ // NFC normalize the lines first) and account for wide characters.
+ diff := utf8.RuneCount(line1) - utf8.RuneCount(line2)
+ if len(line2) < 2 || diff < -1 || diff > 1 {
+ return 0
+ }
+
+ // "Don't be fooled by back-to-back delimited blocks."
+ // Still gets fooled by other things, though.
+ if bytes.IndexFunc(line1, func(r rune) bool {
+ return unicode.IsLetter(r) || unicode.IsNumber(r)
+ }) < 0 {
+ return 0
+ }
+
+ // The underline must be homogenous.
+ for _, r := range bytes.TrimRight(line2, "\r\n") {
+ if r != line2[0] {
+ return 0
+ }
+ }
+ return 1 + strings.IndexByte("=-~^+", line2[0])
+}
+
+func writeLine(w *io.PipeWriter, cur, next []byte) []byte {
+ if level := isTitle(cur, next); level > 0 {
+ w.Write(append(bytes.Repeat([]byte{'='}, level), ' '))
+ next = nil
+ }
+ w.Write(cur)
+ return next
+}
+
+// ConvertTitles converts AsciiDoc two-line (underlined) titles to single-line.
+func ConvertTitles(w *io.PipeWriter, input []byte) {
+ var last []byte
+ for _, cur := range bytes.SplitAfter(input, []byte{'\n'}) {
+ last = writeLine(w, last, cur)
+ }
+ writeLine(w, last, nil)
+}
+
+// entry contains all context information about a single page.
+type entry struct {
+ path string // path
+ mtime time.Time // modification time
+ metadata types.Metadata // metadata
+ document []byte // inner document with expanded LinkWords
+ backlinks []string // what documents link back here
+}
+
+var extRE = regexp.MustCompile(`\.[^/.]*$`)
+
+func stripExtension(path string) string {
+ return extRE.ReplaceAllString(path, "")
+}
+
+func resultPath(path string) string {
+ if m := extRE.FindStringIndex(path); m != nil {
+ return path[:m[0]] + ".html"
+ }
+ return path + ".html"
+}
+
+func makeLink(m *map[string]*entry, name string) string {
+ e := (*m)[name]
+ return fmt.Sprintf("<a href='%s'>%s</a>", resultPath(e.path), name)
+}
+
+var linkWordRE = regexp.MustCompile(`\b\p{Lu}\p{L}*\b`)
+
+func expand(m *map[string]*entry, name string, chunk []byte) []byte {
+ return linkWordRE.ReplaceAllFunc(chunk, func(match []byte) []byte {
+ if link, ok := (*m)[string(match)]; ok {
+ link.backlinks = append(link.backlinks, name)
+ return []byte(makeLink(m, string(match)))
+ }
+ return match
+ })
+}
+
+func main() {
+ if len(os.Args) < 3 {
+ log.Fatalf("usage: %s TEMPLATE GLOB...\n", os.Args[0])
+ }
+
+ // Read the common page header.
+ header, err := ioutil.ReadFile(os.Args[1])
+ if err != nil {
+ log.Fatalln(err)
+ }
+
+ // Create a map from document names to their page entries.
+ entries := map[string]*entry{}
+ for _, glob := range os.Args[2:] {
+ matches, err := filepath.Glob(glob)
+ if err != nil {
+ log.Fatalf("%s: %s\n", glob, err)
+ }
+ for _, path := range matches {
+ name := stripExtension(filepath.Base(path))
+ if conflict, ok := entries[name]; ok {
+ log.Fatalf("%s: conflicts with %s\n", name, conflict.path)
+ }
+ entries[name] = &entry{path: path}
+ }
+ }
+
+ tagRE := regexp.MustCompile(`<[^<>]+>`)
+ for name, e := range entries {
+ f, err := os.Open(e.path)
+ if err != nil {
+ log.Fatalln(err)
+ }
+
+ if i, err := f.Stat(); err != nil {
+ log.Fatalln(err)
+ } else {
+ e.mtime = i.ModTime()
+ }
+
+ input, err := ioutil.ReadAll(f)
+ if err != nil {
+ log.Fatalln(err)
+ }
+
+ pr, pw := io.Pipe()
+ go func() {
+ defer pw.Close()
+ ConvertTitles(pw, input)
+ }()
+
+ config := configuration.NewConfiguration(
+ configuration.WithHeaderFooter(false),
+ configuration.WithFilename(e.path),
+ configuration.WithLastUpdated(e.mtime),
+ )
+
+ buf := bytes.NewBuffer(nil)
+ e.metadata, err = libasciidoc.ConvertToHTML(pr, buf, config)
+ if err != nil {
+ log.Fatalln(err)
+ }
+
+ // Expand LinkWords anywhere between <tags>.
+ // We want something like the inverse of Regexp.ReplaceAllStringFunc.
+ raw, last, expanded := buf.Bytes(), 0, bytes.NewBuffer(nil)
+ for _, where := range tagRE.FindAllIndex(raw, -1) {
+ _, _ = expanded.Write(expand(&entries, name, raw[last:where[0]]))
+ _, _ = expanded.Write(raw[where[0]:where[1]])
+ last = where[1]
+ }
+ _, _ = expanded.Write(expand(&entries, name, raw[last:]))
+ e.document = expanded.Bytes()
+ }
+
+ for name, e := range entries {
+ f, err := os.Create(resultPath(e.path))
+ if err != nil {
+ log.Fatalln(err)
+ }
+
+ _, _ = f.Write(header)
+
+ title := e.metadata.Title
+ if title == "" {
+ title = name
+ }
+
+ _, _ = f.WriteString(fmt.Sprintf("<title>%s</title>\n", title))
+ _, _ = f.WriteString(fmt.Sprintf("<h1>%s</h1>\n", title))
+
+ sort.Strings(e.backlinks)
+
+ backlinks := []string{}
+ for _, name := range e.backlinks {
+ backlinks = append(backlinks, makeLink(&entries, name))
+ }
+
+ if len(backlinks) > 0 {
+ _, _ = f.WriteString(fmt.Sprintf("<p id=links>Links here: %s</p>\n",
+ strings.Join(backlinks, ", ")))
+ }
+
+ _, _ = f.Write(e.document)
+ _, _ = f.WriteString(fmt.Sprintf("<p id=footer>Last updated: %s"+
+ " &mdash; <a href='%s'>Source</p>\n",
+ e.metadata.LastUpdated, e.path))
+ }
+}