templates.go

@@ -0,0 +1,146 @@
+package main
+
+import (
+	"html/template"
+	"io"
+	"io/fs"
+	"path/filepath"
+	"strings"
+	txttmpl "text/template"
+)
+
+// Options for getting a template tree
+type Options struct {
+	Globs  []string
+	Prefix string
+	Suffix string
+	Root   string
+	Funcs  map[string]interface{}
+}
+
+func (o Options) getRoot() string {
+	if o.Root == "" {
+		return "."
+	}
+	return o.Root
+}
+
+func (o Options) matchesGlob(path string) (bool, error) {
+	if len(o.Globs) == 0 {
+		return true, nil
+	}
+	for _, glob := range o.Globs {
+		ok, err := filepath.Match(glob, path)
+		if err != nil {
+			return false, err
+		}
+		if ok {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
+func (o Options) trim(path string) string {
+	return strings.TrimSuffix(strings.TrimPrefix(path, o.Prefix), o.Suffix)
+}
+
+// Templates returns templates based on a filesystem
+func Templates(files fs.FS, opts Options) (*template.Template, error) {
+	var ret *template.Template
+	parseTemplates := func(name string, body []byte) error {
+		var tmpl *template.Template
+		if ret == nil {
+			tmpl = template.New(name)
+			if opts.Funcs != nil {
+				tmpl = tmpl.Funcs(template.FuncMap(opts.Funcs))
+			}
+		} else {
+			tmpl = ret.New(name)
+		}
+		tmpl, err := tmpl.Parse(string(body))
+		if err != nil {
+			return err
+		}
+		ret = tmpl
+		return nil
+	}
+
+	if err := walk(files, opts, parseTemplates); err != nil {
+		return nil, err
+	}
+	return ret, nil
+}
+
+// TextTemplates returns templates based on a filesystem
+func TextTemplates(files fs.FS, opts Options) (*txttmpl.Template, error) {
+	var ret *txttmpl.Template
+	parseTemplates := func(name string, body []byte) error {
+		var tmpl *txttmpl.Template
+		if ret == nil {
+			tmpl = txttmpl.New(name)
+			if opts.Funcs != nil {
+				tmpl = tmpl.Funcs(txttmpl.FuncMap(opts.Funcs))
+			}
+		} else {
+			tmpl = ret.New(name)
+		}
+		tmpl, err := tmpl.Parse(string(body))
+		if err != nil {
+			return err
+		}
+		ret = tmpl
+		return nil
+	}
+
+	if err := walk(files, opts, parseTemplates); err != nil {
+		return nil, err
+	}
+	return ret, nil
+}
+
+func walk(files fs.FS, opts Options, handle func(string, []byte) error) error {
+	walker := func(path string, d fs.DirEntry, er error) (err error) {
+		if er != nil {
+			return er
+		}
+		matches, err := opts.matchesGlob(path)
+		if err != nil {
+			return err
+		}
+		if !matches {
+			return nil
+		}
+		body, err := readfile(files, path)
+		if err != nil {
+			return err
+		}
+		if err := handle(opts.trim(path), body); err != nil {
+			return err
+		}
+		return nil
+	}
+
+	if err := fs.WalkDir(files, opts.getRoot(), walker); err != nil {
+		return err
+	}
+	return nil
+}
+
+func readfile(files fs.FS, path string) ([]byte, error) {
+	f, err := files.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	body, err := io.ReadAll(f)
+	if err != nil {
+		if err := f.Close(); err != nil {
+			return nil, err
+		}
+		return nil, err
+	}
+	if err := f.Close(); err != nil {
+		return nil, err
+	}
+	return body, nil
+}