tools/docs2wiki: place source edit link instead of static footer

As suggested in
#2094 (comment)

Since we rely on GitHub's default wiki feature instead of GH pages or
custom hosting sites, options are limited currently.

Updates #2094

Change-Id: I3090ee79c9794e2b56fc78fa564770266767f3dd
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/412055
Reviewed-by: Jamal Carvalho <[email protected]>

Author: hyangah

docs/_Footer.md

@@ -17,6 +17,7 @@ import (
 	"path/filepath"
 	"regexp"
 	"strings"
+	"text/template"
 )
 
 var writeFlag = flag.Bool("w", false, "Overwrite new file contents to disk.")
@@ -28,13 +29,15 @@ func main() {
 		errorf("Usage: %v <dir>", os.Args[0])
 		os.Exit(1)
 	}
-	if err := rewriteLinks(flag.Arg(0), *writeFlag); err != nil {
+
+	genFooter := footerGenerator("https://github.com/golang/vscode-go/edit/master/docs/")
+	if err := rewriteLinks(flag.Arg(0), genFooter, *writeFlag); err != nil {
 		errorf("failed to rewrite links: %v", err)
 		os.Exit(1)
 	}
 }
 
-func rewriteLinks(dir string, overwrite bool) error {
+func rewriteLinks(dir string, genFooter func(srcPath string) []byte, overwrite bool) error {
 	return filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
 		if err != nil {
 			return err
@@ -55,6 +58,10 @@ func rewriteLinks(dir string, overwrite bool) error {
 		}
 		converted := stripTitleInPage(data)
 		converted = markdownLink2WikiLink(converted)
+		if name != "_Footer.md" && name != "_Sidebar.md" {
+			relPath, _ := filepath.Rel(dir, path)
+			converted = append(converted, genFooter(filepath.ToSlash(relPath))...)
+		}
 		if overwrite {
 			return ioutil.WriteFile(path, converted, 0644)
 		}
@@ -128,3 +135,19 @@ func markdownLink2WikiLink(src []byte) []byte {
 func errorf(format string, a ...interface{}) {
 	fmt.Fprintf(os.Stderr, format+"\n", a...)
 }
+
+func footerGenerator(sourceEditURL string) func(string) []byte {
+	return func(srcPath string) []byte {
+		editURL := sourceEditURL + srcPath
+		buf := new(bytes.Buffer)
+		footerTmpl.Execute(buf, editURL)
+		return buf.Bytes()
+	}
+}
+
+var footerTmpl = template.Must(template.New("footer").Parse(`
+
+---
+[*✏️ Want to contribute to this wiki?*]({{.}})
+
+Update [the source]({{.}}) and send a PR.`))

tools/docs2wiki/main.go

@@ -8,6 +8,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -29,7 +30,8 @@ func TestRewriteLinks(t *testing.T) {
 			// which we will read back for comparison against tt.want.
 			// With overwrite=false, rewriteLinks just prints out the diff
 			// which will be difficult to test.
-			err := rewriteLinks(dir, true)
+			genFooter := func(string) []byte { return nil }
+			err := rewriteLinks(dir, genFooter, true)
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -82,3 +84,30 @@ var wikiStyle = `
 
 [This doesn't change](https://go.dev/foo.md)
 [Untouchable.md](foo)`
+
+func TestGenFooter(t *testing.T) {
+	const editURLPrefix = "https://source.com/edit/docs/"
+
+	for _, tt := range []struct{ filename, wantURL string }{
+		{filename: "doc.md", wantURL: editURLPrefix + "doc.md"},
+		{filename: "sub/doc.md", wantURL: editURLPrefix + "sub/doc.md"},
+	} {
+		dir := prepareTestData(t, tt.filename, "")
+		defer os.RemoveAll(dir)
+
+		genFooter := footerGenerator(editURLPrefix)
+		err := rewriteLinks(dir, genFooter, true)
+		if err != nil {
+			t.Fatal(err)
+		}
+		// rewriteLinks overwrites the original file,
+		// so reread the content for comparison.
+		got, err := ioutil.ReadFile(filepath.Join(dir, tt.filename))
+		if err != nil {
+			t.Fatal(err)
+		}
+		if !strings.Contains(string(got), tt.wantURL) {
+			t.Errorf("missing %s, got:\n%s", tt.wantURL, got)
+		}
+	}
+}