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-rw-r--r--hasp/main.go91
1 files changed, 91 insertions, 0 deletions
diff --git a/hasp/main.go b/hasp/main.go
new file mode 100644
index 0000000..e19d48a
--- /dev/null
+++ b/hasp/main.go
@@ -0,0 +1,91 @@
+// Program hasp is a preprocessor for libasciidoc to make it understand
+// two-line/underlined titles, intended to be used in Gitea.
+package main
+
+import (
+ "bytes"
+ "context"
+ "encoding/xml"
+ "io"
+ "io/ioutil"
+ "os"
+ "strings"
+ "unicode"
+ "unicode/utf8"
+
+ "github.com/bytesparadise/libasciidoc"
+ "github.com/bytesparadise/libasciidoc/pkg/renderer"
+)
+
+// 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)
+}
+
+func main() {
+ input, err := ioutil.ReadAll(os.Stdin)
+ if err != nil {
+ panic(err)
+ }
+
+ pr, pw := io.Pipe()
+ go func() {
+ defer pw.Close()
+ ConvertTitles(pw, input)
+ }()
+
+ // io.Copy(os.Stdout, pr)
+ // return
+
+ _, err = libasciidoc.ConvertToHTML(context.Background(), pr, os.Stdout,
+ renderer.IncludeHeaderFooter(true))
+ if err != nil {
+ // Fallback: output all the text sanitized for direct inclusion.
+ os.Stdout.WriteString("<pre>")
+ for _, line := range bytes.Split(input, []byte{'\n'}) {
+ xml.EscapeText(os.Stdout, line)
+ os.Stdout.WriteString("\n")
+ }
+ os.Stdout.WriteString("</pre>")
+ }
+}