Untested implementation

1 files changed, 140 insertions, 0 deletions

diff --git a/templates.go b/templates.go
new file mode 100644
index 0000000..30b0301
--- /dev/null
+++ b/templates.go
@@ -0,0 +1,140 @@
+package templates
+
+import (
+	"bytes"
+	"encoding/base64"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+	"text/template"
+)
+
+type Templates struct {
+	base      string
+	pkg       string
+	extension string
+	fName     string
+	sources   map[string]io.ReadCloser
+}
+
+func New(opts ...Option) (*Templates, error) {
+	out := &Templates{
+		pkg:       "main",
+		extension: ".tmpl",
+		base:      "./",
+		fName:     "loadTemplate",
+	}
+	for _, o := range opts {
+		if err := o(out); err != nil {
+			return nil, err
+		}
+	}
+	srcs, err := readTemplates(out.base, "."+out.extension)
+	if err != nil {
+		return nil, err
+	}
+	out.sources = srcs
+	return out, nil
+}
+
+type Option func(*Templates) error
+
+func Base(p string) Option {
+	return func(t *Templates) error {
+		var err error
+		t.base, err = filepath.Abs(p)
+		return err
+	}
+}
+
+func Extension(e string) Option {
+	return func(t *Templates) error {
+		t.extension = e
+		return nil
+	}
+}
+func Package(p string) Option {
+	return func(t *Templates) error {
+		t.pkg = p
+		return nil
+	}
+}
+
+func readTemplates(root, extension string) (map[string]io.ReadCloser, error) {
+	out := make(map[string]io.ReadCloser)
+	filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsDir() {
+			return nil
+		}
+		if !strings.HasSuffix(path, extension) {
+			return nil
+		}
+		varName := strings.TrimPrefix(path, root)
+		varName = strings.TrimSuffix(varName, extension)
+		rc, err := os.Open(path)
+		if err != nil {
+			return err
+		}
+		out[varName] = rc
+		return nil
+	})
+	return out, nil
+}
+
+func (t *Templates) WriteTo(w io.Writer) (int64, error) {
+	tmpl, err := template.New("loader").Parse(loader)
+	if err != nil {
+		return 0, err
+	}
+	data := make(map[string]string, len(t.sources))
+	for k, rc := range t.sources {
+		b, err := ioutil.ReadAll(rc)
+		if err != nil {
+			return 0, err
+		}
+		data[k] = base64.StdEncoding.EncodeToString(b)
+	}
+	var buf bytes.Buffer
+	if err := tmpl.Execute(&buf, struct {
+		Package   string
+		Base      string
+		FName     string
+		Templates map[string]string
+	}{t.pkg, t.base, t.fName, data}); err != nil {
+		return 0, err
+	}
+	return buf.WriteTo(w)
+}
+
+const loader = `package {{ .Package }}
+
+import (
+	"encoding/base64"
+	"fmt"
+	"io/ioutil"
+)
+
+func {{ .FName }}(n string) ([]byte, error) {
+	var templates = map[string]string {
+{{ $name, $data := range .Templates }}
+		"{{ $name }}": ` + "`" + `{{ $data }}` + "`" + `,
+{{ end }}
+	}
+
+	d, ok := templates[n]
+	if !ok {
+		return nil, fmt.Errorf("template not found")
+	}
+	// Check for overriding file
+	b, err := ioutil.ReadFile("{{ .Base }}" + n + "{{ .Extension }}")
+	if err == nil && b != nil {
+		return b, nil
+	}
+	return base64.StdEncoding.DecodeString(d)
+}
+`