Add detected file language to code search (#10256)

Move langauge detection to separate module to be more reusable

Add option to disable vendored file exclusion from file search

Allways show all language stats for search

modules/analyze/code_langauge.go

@@ -0,0 +1,36 @@
+// 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 analyze
+
+import (
+	"path/filepath"
+
+	"github.com/src-d/enry/v2"
+)
+
+// GetCodeLanguageWithCallback detects code language based on file name and content using callback
+func GetCodeLanguageWithCallback(filename string, contentFunc func() ([]byte, error)) string {
+	if language, ok := enry.GetLanguageByExtension(filename); ok {
+		return language
+	}
+
+	if language, ok := enry.GetLanguageByFilename(filename); ok {
+		return language
+	}
+
+	content, err := contentFunc()
+	if err != nil {
+		return enry.OtherLanguage
+	}
+
+	return enry.GetLanguage(filepath.Base(filename), content)
+}
+
+// GetCodeLanguage detects code language based on file name and content
+func GetCodeLanguage(filename string, content []byte) string {
+	return GetCodeLanguageWithCallback(filename, func() ([]byte, error) {
+		return content, nil
+	})
+}