tpl: Rework to handle both text and HTML templates

Before this commit, Hugo used `html/template` for all Go templates.

While this is a fine choice for HTML and maybe also RSS feeds, it is painful for plain text formats such as CSV, JSON etc.

This commit fixes that by using the `IsPlainText` attribute on the output format to decide what to use.

A couple of notes:

* The above requires a nonambiguous template name to type mapping. I.e. `/layouts/_default/list.json` will only work if there is only one JSON output format, `/layouts/_default/list.mytype.json` will always work.
* Ambiguous types will fall back to HTML.
* Partials inherits the text vs HTML identificator of the container template. This also means that plain text templates can only include plain text partials.
* Shortcode templates are, by definition, currently HTML templates only.

Fixes #3221

1 files changed, 7 insertions, 9 deletions

diff --git a/hugolib/shortcode.go b/hugolib/shortcode.go
index d165c778b..d72a96faa 100644
--- a/hugolib/shortcode.go
+++ b/hugolib/shortcode.go
@@ -177,7 +177,7 @@ var isInnerShortcodeCache = struct {
 // to avoid potential costly look-aheads for closing tags we look inside the template itself
 // we could change the syntax to self-closing tags, but that would make users cry
 // the value found is cached
-func isInnerShortcode(t *template.Template) (bool, error) {
+func isInnerShortcode(t tpl.TemplateExecutor) (bool, error) {
 	isInnerShortcodeCache.RLock()
 	m, ok := isInnerShortcodeCache.m[t.Name()]
 	isInnerShortcodeCache.RUnlock()
@@ -188,10 +188,7 @@ func isInnerShortcode(t *template.Template) (bool, error) {
 
 	isInnerShortcodeCache.Lock()
 	defer isInnerShortcodeCache.Unlock()
-	if t.Tree == nil {
-		return false, errors.New("Template failed to compile")
-	}
-	match, _ := regexp.MatchString("{{.*?\\.Inner.*?}}", t.Tree.Root.String())
+	match, _ := regexp.MatchString("{{.*?\\.Inner.*?}}", t.Tree())
 	isInnerShortcodeCache.m[t.Name()] = match
 
 	return match, nil
@@ -398,8 +395,6 @@ Loop:
 		case tScName:
 			sc.name = currItem.val
 			tmpl := getShortcodeTemplate(sc.name, p.s.Tmpl)
-			{
-			}
 			if tmpl == nil {
 				return sc, fmt.Errorf("Unable to locate template for shortcode %q in page %q", sc.name, p.Path())
 			}
@@ -570,7 +565,10 @@ func replaceShortcodeTokens(source []byte, prefix string, replacements map[strin
 	return source, nil
 }
 
-func getShortcodeTemplate(name string, t tpl.Template) *template.Template {
+func getShortcodeTemplate(name string, t tpl.TemplateHandler) *tpl.TemplateAdapter {
+	isInnerShortcodeCache.RLock()
+	defer isInnerShortcodeCache.RUnlock()
+
 	if x := t.Lookup("shortcodes/" + name + ".html"); x != nil {
 		return x
 	}
@@ -580,7 +578,7 @@ func getShortcodeTemplate(name string, t tpl.Template) *template.Template {
 	return t.Lookup("_internal/shortcodes/" + name + ".html")
 }
 
-func renderShortcodeWithPage(tmpl *template.Template, data *ShortcodeWithPage) string {
+func renderShortcodeWithPage(tmpl tpl.Template, data *ShortcodeWithPage) string {
 	buffer := bp.GetBuffer()
 	defer bp.PutBuffer(buffer)