Normalize strings when they are read from the filesystem, fixes #48

This ensures all characters in string are precomposed.
https://blog.golang.org/normalization

* Normalize first

* Change position of normalization

* Add documentation

* Add dependency for text/unicode/norm

* Add tests for composing title strings

* Fix Year and Format

Gopkg.toml

@@ -56,3 +56,7 @@
 [[constraint]]
   name = "github.com/gorilla/websocket"
   version = "1.2.0"
+
+[[constraint]]
+  name = "golang.org/x/text"
+  version = "0.3.0"

node.go

@@ -20,6 +20,7 @@ import (
 	"time"
 
 	"github.com/fatih/color"
+	"golang.org/x/text/unicode/norm"
 )
 
 var (
@@ -186,11 +187,14 @@ func (n *Node) Order() uint64 {
 }
 
 // The node's computed title with any ordering numbers stripped off, usually for display purposes.
+// We normalize the title string to make sure all special characters are represented in their composed form.
+// Some filesystems store filenames in decomposed form. Using these directly in the frontend led to visual
+// inconsistencies. See: https://blog.golang.org/normalization
 func (n *Node) Title() string {
 	if n.root == n.path {
-		return filepath.Base(n.root)
+		return norm.NFC.String(filepath.Base(n.root))
 	}
-	return removeOrderNumber(filepath.Base(n.path))
+	return removeOrderNumber(norm.NFC.String(filepath.Base(n.path)))
 }
 
 // Returns the full description of the node.

node_doc.go

@@ -13,6 +13,7 @@ import (
 
 	"github.com/russross/blackfriday"
 	"golang.org/x/net/html"
+	"golang.org/x/text/unicode/norm"
 )
 
 // NodeDoc is a document file.
@@ -28,8 +29,11 @@ func (d NodeDoc) Order() uint64 {
 
 // Title of the document and computed with any ordering numbers and the
 // extension stripped off, usually for display purposes.
+// We normalize the title string to make sure all special characters
+// are represented in their composed form. For more on this topic see the
+// docblock of Node.Title().
 func (d NodeDoc) Title() string {
-	base := filepath.Base(d.path)
+	base := norm.NFC.String(filepath.Base(d.path))
 	return removeOrderNumber(strings.TrimSuffix(base, filepath.Ext(base)))
 }
 

node_doc_test.go

@@ -0,0 +1,35 @@
+// Copyright 2018 Atelier Disko. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestDocTitlesWithDecomposedFilenames(t *testing.T) {
+	tmp, _ := ioutil.TempDir("", "tree")
+	defer os.RemoveAll(tmp)
+
+	node0 := filepath.Join(tmp, "foo")
+	os.Mkdir(node0, 0777)
+
+	doc0 := filepath.Join(node0, "01-Cafe\u0301.md")
+	ioutil.WriteFile(doc0, []byte(""), 0666)
+
+	node := &Node{root: tmp, path: filepath.Join(tmp, "foo")}
+
+	docs, err := node.Docs()
+	if err != nil {
+		t.Errorf("can’t read docs")
+	}
+
+	if docs[0].Title() != "Café" {
+		t.Errorf("failed to decode file name, got %v", docs[0].Title())
+	}
+}

node_test.go

@@ -131,3 +131,10 @@ func BenchmarkHashCalculation(b *testing.B) {
 		n.Hash()
 	}
 }
+
+func TestTitlesWithDecomposedFilenames(t *testing.T) {
+  n := &Node{path: "/bar/Cafe\u0301", root: "/bar"}
+  if n.Title() != "Café" {
+    t.Errorf("failed to decode folder name, got %v", n.Title())
+  }
+}