Generate Bindata iff TAGS="bindata" and not up-to-date (#10004)

* Only generate bindata if necessary

* Only generate bindata if they are not up-to-date

* generate a hash of the fileinfo and use that to keep up-to-date

* Newer test is redundant

* handle missing bindata and clean

* Only update hash after successful write

* switch to sha1 hash

* Apply suggestions from code review

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

Co-authored-by: guillep2k <18600385+guillep2k@users.noreply.github.com>

modules/options/main.go

@@ -1,23 +0,0 @@
-// +build ignore
-
-package main
-
-import (
-	"log"
-	"net/http"
-
-	"github.com/shurcooL/vfsgen"
-)
-
-func main() {
-	var fsTemplates http.FileSystem = http.Dir("../../options")
-	err := vfsgen.Generate(fsTemplates, vfsgen.Options{
-		PackageName:  "options",
-		BuildTags:    "bindata",
-		VariableName: "Assets",
-		Filename:     "bindata.go",
-	})
-	if err != nil {
-		log.Fatal("%v", err)
-	}
-}

modules/options/options.go

@@ -4,8 +4,6 @@
 
 package options
 
-//go:generate go run -mod=vendor main.go
-
 type directorySet map[string][]string
 
 func (s directorySet) Add(key string, value []string) {

modules/options/options_bindata.go

@@ -0,0 +1,9 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+//+build bindata
+
+package options
+
+//go:generate go run -mod=vendor ../../scripts/generate-bindata.go ../../options options bindata.go