Docs: add zh-CN entrypoint translations (#6300)

* Docs: add zh-CN entrypoint translations

* Docs: harden docs-i18n parsing

scripts/docs-i18n/html_translate.go

@@ -0,0 +1,160 @@
+package main
+
+import (
+	"context"
+	"io"
+	"strings"
+
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/extension"
+	"github.com/yuin/goldmark/text"
+	"golang.org/x/net/html"
+	"sort"
+)
+
+type htmlReplacement struct {
+	Start int
+	Stop  int
+	Value string
+}
+
+func translateHTMLBlocks(ctx context.Context, translator *PiTranslator, body, srcLang, tgtLang string) (string, error) {
+	source := []byte(body)
+	r := text.NewReader(source)
+	md := goldmark.New(
+		goldmark.WithExtensions(extension.GFM),
+	)
+	doc := md.Parser().Parse(r)
+
+	replacements := make([]htmlReplacement, 0, 8)
+
+	_ = ast.Walk(doc, func(n ast.Node, entering bool) (ast.WalkStatus, error) {
+		if !entering {
+			return ast.WalkContinue, nil
+		}
+		block, ok := n.(*ast.HTMLBlock)
+		if !ok {
+			return ast.WalkContinue, nil
+		}
+		start, stop, ok := htmlBlockSpan(block, source)
+		if !ok {
+			return ast.WalkSkipChildren, nil
+		}
+		htmlText := string(source[start:stop])
+		translated, err := translateHTMLBlock(ctx, translator, htmlText, srcLang, tgtLang)
+		if err != nil {
+			return ast.WalkStop, err
+		}
+		replacements = append(replacements, htmlReplacement{Start: start, Stop: stop, Value: translated})
+		return ast.WalkSkipChildren, nil
+	})
+
+	if len(replacements) == 0 {
+		return body, nil
+	}
+
+	return applyHTMLReplacements(body, replacements), nil
+}
+
+func htmlBlockSpan(block *ast.HTMLBlock, source []byte) (int, int, bool) {
+	lines := block.Lines()
+	if lines.Len() == 0 {
+		return 0, 0, false
+	}
+	start := lines.At(0).Start
+	stop := lines.At(lines.Len() - 1).Stop
+	if start >= stop {
+		return 0, 0, false
+	}
+	return start, stop, true
+}
+
+func applyHTMLReplacements(body string, replacements []htmlReplacement) string {
+	if len(replacements) == 0 {
+		return body
+	}
+	sortHTMLReplacements(replacements)
+	var out strings.Builder
+	last := 0
+	for _, rep := range replacements {
+		if rep.Start < last {
+			continue
+		}
+		out.WriteString(body[last:rep.Start])
+		out.WriteString(rep.Value)
+		last = rep.Stop
+	}
+	out.WriteString(body[last:])
+	return out.String()
+}
+
+func sortHTMLReplacements(replacements []htmlReplacement) {
+	sort.Slice(replacements, func(i, j int) bool {
+		return replacements[i].Start < replacements[j].Start
+	})
+}
+
+func translateHTMLBlock(ctx context.Context, translator *PiTranslator, htmlText, srcLang, tgtLang string) (string, error) {
+	tokenizer := html.NewTokenizer(strings.NewReader(htmlText))
+	var out strings.Builder
+	skipDepth := 0
+
+	for {
+		tt := tokenizer.Next()
+		if tt == html.ErrorToken {
+			if err := tokenizer.Err(); err != nil && err != io.EOF {
+				return "", err
+			}
+			break
+		}
+
+		raw := string(tokenizer.Raw())
+		tok := tokenizer.Token()
+
+		switch tt {
+		case html.StartTagToken:
+			out.WriteString(raw)
+			if isSkipTag(strings.ToLower(tok.Data)) {
+				skipDepth++
+			}
+		case html.EndTagToken:
+			out.WriteString(raw)
+			if isSkipTag(strings.ToLower(tok.Data)) && skipDepth > 0 {
+				skipDepth--
+			}
+		case html.SelfClosingTagToken:
+			out.WriteString(raw)
+		case html.TextToken:
+			if shouldTranslateHTMLText(skipDepth, raw) {
+				translated, err := translator.Translate(ctx, raw, srcLang, tgtLang)
+				if err != nil {
+					return "", err
+				}
+				out.WriteString(translated)
+			} else {
+				out.WriteString(raw)
+			}
+		default:
+			out.WriteString(raw)
+		}
+	}
+
+	return out.String(), nil
+}
+
+func shouldTranslateHTMLText(skipDepth int, text string) bool {
+	if strings.TrimSpace(text) == "" {
+		return false
+	}
+	return skipDepth == 0
+}
+
+func isSkipTag(tag string) bool {
+	switch tag {
+	case "code", "pre", "script", "style":
+		return true
+	default:
+		return false
+	}
+}