1 files changed, 188 insertions, 0 deletions
diff --git a/modules/charset/ambiguous/generate.go b/modules/charset/ambiguous/generate.go
new file mode 100644
index 00000000..e3fda5be
--- /dev/null
+++ b/modules/charset/ambiguous/generate.go
@@ -0,0 +1,188 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package main
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"go/format"
+	"os"
+	"sort"
+	"text/template"
+	"unicode"
+
+	"code.gitea.io/gitea/modules/json"
+
+	"golang.org/x/text/unicode/rangetable"
+)
+
+// ambiguous.json provides a one to one mapping of ambiguous characters to other characters
+// See https://github.com/hediet/vscode-unicode-data/blob/main/out/ambiguous.json
+
+type AmbiguousTable struct {
+	Confusable []rune
+	With       []rune
+	Locale     string
+	RangeTable *unicode.RangeTable
+}
+
+type RunePair struct {
+	Confusable rune
+	With       rune
+}
+
+var verbose bool
+
+func main() {
+	flag.Usage = func() {
+		fmt.Fprintf(os.Stderr, `%s: Generate AmbiguousCharacter
+
+Usage: %[1]s [-v] [-o output.go] ambiguous.json
+`, os.Args[0])
+		flag.PrintDefaults()
+	}
+
+	output := ""
+	flag.BoolVar(&verbose, "v", false, "verbose output")
+	flag.StringVar(&output, "o", "ambiguous_gen.go", "file to output to")
+	flag.Parse()
+	input := flag.Arg(0)
+	if input == "" {
+		input = "ambiguous.json"
+	}
+
+	bs, err := os.ReadFile(input)
+	if err != nil {
+		fatalf("Unable to read: %s Err: %v", input, err)
+	}
+
+	var unwrapped string
+	if err := json.Unmarshal(bs, &unwrapped); err != nil {
+		fatalf("Unable to unwrap content in: %s Err: %v", input, err)
+	}
+
+	fromJSON := map[string][]uint32{}
+	if err := json.Unmarshal([]byte(unwrapped), &fromJSON); err != nil {
+		fatalf("Unable to unmarshal content in: %s Err: %v", input, err)
+	}
+
+	tables := make([]*AmbiguousTable, 0, len(fromJSON))
+	for locale, chars := range fromJSON {
+		table := &AmbiguousTable{Locale: locale}
+		table.Confusable = make([]rune, 0, len(chars)/2)
+		table.With = make([]rune, 0, len(chars)/2)
+		pairs := make([]RunePair, len(chars)/2)
+		for i := 0; i < len(chars); i += 2 {
+			pairs[i/2].Confusable, pairs[i/2].With = rune(chars[i]), rune(chars[i+1])
+		}
+		sort.Slice(pairs, func(i, j int) bool {
+			return pairs[i].Confusable < pairs[j].Confusable
+		})
+		for _, pair := range pairs {
+			table.Confusable = append(table.Confusable, pair.Confusable)
+			table.With = append(table.With, pair.With)
+		}
+		table.RangeTable = rangetable.New(table.Confusable...)
+		tables = append(tables, table)
+	}
+	sort.Slice(tables, func(i, j int) bool {
+		return tables[i].Locale < tables[j].Locale
+	})
+	data := map[string]any{
+		"Tables": tables,
+	}
+
+	if err := runTemplate(generatorTemplate, output, &data); err != nil {
+		fatalf("Unable to run template: %v", err)
+	}
+}
+
+func runTemplate(t *template.Template, filename string, data any) error {
+	buf := bytes.NewBuffer(nil)
+	if err := t.Execute(buf, data); err != nil {
+		return fmt.Errorf("unable to execute template: %w", err)
+	}
+	bs, err := format.Source(buf.Bytes())
+	if err != nil {
+		verbosef("Bad source:\n%s", buf.String())
+		return fmt.Errorf("unable to format source: %w", err)
+	}
+
+	old, err := os.ReadFile(filename)
+	if err != nil && !os.IsNotExist(err) {
+		return fmt.Errorf("failed to read old file %s because %w", filename, err)
+	} else if err == nil {
+		if bytes.Equal(bs, old) {
+			// files are the same don't rewrite it.
+			return nil
+		}
+	}
+
+	file, err := os.Create(filename)
+	if err != nil {
+		return fmt.Errorf("failed to create file %s because %w", filename, err)
+	}
+	defer file.Close()
+	_, err = file.Write(bs)
+	if err != nil {
+		return fmt.Errorf("unable to write generated source: %w", err)
+	}
+	return nil
+}
+
+var generatorTemplate = template.Must(template.New("ambiguousTemplate").Parse(`// This file is generated by modules/charset/ambiguous/generate.go DO NOT EDIT
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+
+package charset
+
+import "unicode"
+
+// This file is generated from https://github.com/hediet/vscode-unicode-data/blob/main/out/ambiguous.json
+
+// AmbiguousTable matches a confusable rune with its partner for the Locale
+type AmbiguousTable struct {
+	Confusable []rune
+	With       []rune
+	Locale     string
+	RangeTable *unicode.RangeTable
+}
+
+// AmbiguousCharacters provides a map by locale name to the confusable characters in that locale
+var AmbiguousCharacters = map[string]*AmbiguousTable{
+	{{range .Tables}}{{printf "%q:" .Locale}} {
+			Confusable: []rune{ {{range .Confusable}}{{.}},{{end}} },
+			With: []rune{ {{range .With}}{{.}},{{end}} },
+			Locale: {{printf "%q" .Locale}},
+			RangeTable: &unicode.RangeTable{
+				R16: []unicode.Range16{
+			{{range .RangeTable.R16 }}		{Lo:{{.Lo}}, Hi:{{.Hi}}, Stride: {{.Stride}}},
+			{{end}}	},
+				R32: []unicode.Range32{
+			{{range .RangeTable.R32}}		{Lo:{{.Lo}}, Hi:{{.Hi}}, Stride: {{.Stride}}},
+			{{end}}	},
+				LatinOffset: {{.RangeTable.LatinOffset}},
+			},
+		},
+	{{end}}
+}
+
+`))
+
+func logf(format string, args ...any) {
+	fmt.Fprintf(os.Stderr, format+"\n", args...)
+}
+
+func verbosef(format string, args ...any) {
+	if verbose {
+		logf(format, args...)
+	}
+}
+
+func fatalf(format string, args ...any) {
+	logf("fatal: "+format+"\n", args...)
+	os.Exit(1)
+}