Refactor renders (#15175)

* Refactor renders

* Some performance optimization

* Fix comment

* Transform reader

* Fix csv test

* Fix test

* Fix tests

* Improve optimaziation

* Fix test

* Fix test

* Detect file encoding with reader

* Improve optimaziation

* reduce memory usage

* improve code

* fix build

* Fix test

* Fix for go1.15

* Fix render

* Fix comment

* Fix lint

* Fix test

* Don't use NormalEOF when unnecessary

* revert change on util.go

* Apply suggestions from code review

Co-authored-by: zeripath <art27@cantab.net>

* rename function

* Take NormalEOF back

Co-authored-by: zeripath <art27@cantab.net>

modules/markup/renderer_test.go

@@ -0,0 +1,62 @@
+// Copyright 2017 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 markup_test
+
+import (
+	"testing"
+
+	. "code.gitea.io/gitea/modules/markup"
+	_ "code.gitea.io/gitea/modules/markup/markdown"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMisc_IsReadmeFile(t *testing.T) {
+	trueTestCases := []string{
+		"readme",
+		"README",
+		"readME.mdown",
+		"README.md",
+		"readme.i18n.md",
+	}
+	falseTestCases := []string{
+		"test.md",
+		"wow.MARKDOWN",
+		"LOL.mDoWn",
+		"test",
+		"abcdefg",
+		"abcdefghijklmnopqrstuvwxyz",
+		"test.md.test",
+		"readmf",
+	}
+
+	for _, testCase := range trueTestCases {
+		assert.True(t, IsReadmeFile(testCase))
+	}
+	for _, testCase := range falseTestCases {
+		assert.False(t, IsReadmeFile(testCase))
+	}
+
+	trueTestCasesStrict := [][]string{
+		{"readme", ""},
+		{"readme.md", ".md"},
+		{"readme.txt", ".txt"},
+	}
+	falseTestCasesStrict := [][]string{
+		{"readme", ".md"},
+		{"readme.md", ""},
+		{"readme.md", ".txt"},
+		{"readme.md", "md"},
+		{"readmee.md", ".md"},
+		{"readme.i18n.md", ".md"},
+	}
+
+	for _, testCase := range trueTestCasesStrict {
+		assert.True(t, IsReadmeFile(testCase[0], testCase[1]))
+	}
+	for _, testCase := range falseTestCasesStrict {
+		assert.False(t, IsReadmeFile(testCase[0], testCase[1]))
+	}
+}