templates: Parse all templates in the directory

To allow for specifying custom templates in frontmatter in the future.

templates.go

@@ -10,11 +10,48 @@ import (
 	"path/filepath"
 	"strings"
 	"text/template"
+	"text/template/parse"
 )
 
 // Template represents a template.
 type Template interface {
+	AddParseTree(*parse.Tree) error
 	Execute(io.Writer, interface{}) error
+	Tree() *parse.Tree
+}
+
+type textTemplate struct {
+	tmpl *template.Template
+}
+
+func (t textTemplate) AddParseTree(tree *parse.Tree) error {
+	_, err := t.tmpl.AddParseTree(t.tmpl.Name(), tree)
+	return err
+}
+
+func (t textTemplate) Execute(w io.Writer, data interface{}) error {
+	return t.tmpl.Execute(w, data)
+}
+
+func (t textTemplate) Tree() *parse.Tree {
+	return t.tmpl.Tree
+}
+
+type htmlTemplate struct {
+	tmpl *htemplate.Template
+}
+
+func (t htmlTemplate) AddParseTree(tree *parse.Tree) error {
+	_, err := t.tmpl.AddParseTree(t.tmpl.Name(), tree)
+	return err
+}
+
+func (t htmlTemplate) Execute(w io.Writer, data interface{}) error {
+	return t.tmpl.Execute(w, data)
+}
+
+func (t htmlTemplate) Tree() *parse.Tree {
+	return t.tmpl.Tree
 }
 
 // Templates contains site templates.
@@ -38,7 +75,7 @@ func (t *Templates) Funcs(funcs map[string]interface{}) {
 
 // LoadTemplate loads a template from the provided filenames.
 func (t *Templates) LoadTemplate(name string, filenames ...string) error {
-	if pathpkg.Ext(name) == ".html" {
+	if ext := pathpkg.Ext(name); ext == ".html" || ext == ".xml" {
 		return t.loadHTMLTemplate(name, filenames...)
 	}
 	return t.loadTextTemplate(name, filenames...)
@@ -55,7 +92,7 @@ func (t *Templates) loadTextTemplate(name string, filenames ...string) error {
 			return err
 		}
 	}
-	t.tmpls[name] = tmpl
+	t.tmpls[name] = textTemplate{tmpl}
 	return nil
 }
 
@@ -70,60 +107,13 @@ func (t *Templates) loadHTMLTemplate(name string, filenames ...string) error {
 			return err
 		}
 	}
-	t.tmpls[name] = tmpl
+	t.tmpls[name] = htmlTemplate{tmpl}
 	return nil
 }
 
 // Load loads templates from the provided directory.
 func (t *Templates) Load(dir string, exts []string) error {
 	err := filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
-		if err != nil {
-			return err
-		}
-		if d.IsDir() {
-			name := d.Name()
-			if strings.HasPrefix(name, "_") && name != "_default" {
-				return fs.SkipDir
-			}
-
-			// Load atom.xml template
-			atom := pathpkg.Join(path, "atom.xml")
-			if _, err := os.Stat(atom); err == nil {
-				name := strings.TrimPrefix(atom, dir)
-				t.loadHTMLTemplate(name, atom)
-			}
-
-			// Load page templates
-			for _, ext := range exts {
-				for _, name := range []string{"index" + ext, "page" + ext} {
-					filename := pathpkg.Join(path, name)
-					if _, err := os.Stat(filename); err != nil {
-						// Template does not exist
-						continue
-					}
-
-					filenames := []string{filename}
-					base := pathpkg.Join(path, "base"+ext)
-					if _, err := os.Stat(base); err == nil {
-						filenames = append(filenames, base)
-					}
-
-					name := strings.TrimPrefix(filename, dir)
-					if err := t.LoadTemplate(name, filenames...); err != nil {
-						return err
-					}
-				}
-			}
-		}
-		return nil
-	})
-	if err != nil && !os.IsNotExist(err) {
-		return err
-	}
-
-	// Load partial templates
-	partials := pathpkg.Join(dir, "_partials")
-	err = filepath.WalkDir(partials, func(path string, d fs.DirEntry, err error) error {
 		if err != nil {
 			return err
 		}
@@ -136,6 +126,25 @@ func (t *Templates) Load(dir string, exts []string) error {
 	if err != nil && !os.IsNotExist(err) {
 		return err
 	}
+
+	// Add base templates
+	var extsMap = map[string]struct{}{}
+	for _, ext := range exts {
+		extsMap[ext] = struct{}{}
+	}
+	for path := range t.tmpls {
+		ext := pathpkg.Ext(path)
+		if _, ok := extsMap[ext]; !ok {
+			continue
+		}
+		base := pathpkg.Join(pathpkg.Dir(path), "base"+ext)
+		if tmpl, ok := t.tmpls[base]; ok {
+			err := t.tmpls[path].AddParseTree(tmpl.Tree())
+			if err != nil {
+				return err
+			}
+		}
+	}
 	return nil
 }