Add gitea-vet (#121)

Close #119

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: jolheiser <john.olheiser@gmail.com>
Reviewed-on: https://gitea.com/gitea/tea/pulls/121
Reviewed-by: John Olheiser <john.olheiser@gmail.com>
Reviewed-by: Andrew Thornton <art27@cantab.net>

vendor/gitea.com/jolheiser/gitea-vet/checks/imports.go

@@ -0,0 +1,54 @@
+// 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.
+
+package checks
+
+import (
+	"strings"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+var Imports = &analysis.Analyzer{
+	Name: "imports",
+	Doc:  "check for import order.",
+	Run:  runImports,
+}
+
+func runImports(pass *analysis.Pass) (interface{}, error) {
+	for _, file := range pass.Files {
+		level := 0
+		for _, im := range file.Imports {
+			var lvl int
+			val := im.Path.Value
+			if importHasPrefix(val, "code.gitea.io") {
+				lvl = 2
+			} else if strings.Contains(val, ".") {
+				lvl = 3
+			} else {
+				lvl = 1
+			}
+
+			if lvl < level {
+				pass.Reportf(file.Pos(), "Imports are sorted wrong")
+				break
+			}
+			level = lvl
+		}
+	}
+	return nil, nil
+}
+
+func importHasPrefix(s, p string) bool {
+	return strings.HasPrefix(s, "\""+p)
+}
+
+func sliceHasPrefix(s string, prefixes ...string) bool {
+	for _, p := range prefixes {
+		if importHasPrefix(s, p) {
+			return true
+		}
+	}
+	return false
+}