perf(serverHandler): prevent assemble string in template

BREAKING CHANGE:

Getting HTML formatted sub items in template changed.

Before:

```
{{range .SubItemsHtml}}
<li class="{{if .IsDir}}dir{{else}}file{{end}}">
  <a href="{{$subItemPrefix}}{{.Link}}{{if .IsDir}}/{{end}}">
    <span class="name">{{.Name}}{{if .IsDir}}/{{end}}</span>
    <span class="size">{{if not .IsDir}}{{.Size}}{{end}}</span>
    <span class="time">{{.ModTime}}</span>
  </a>
</li>
{{end}}
```

After:

```
{{range .SubItemsHtml}}
<li class="{{.Type}}">
  <a href="{{.Url}}">
    <span class="name">{{.DisplayName}}</span>
    <span class="size">{{.DisplaySize}}</span>
    <span class="time">{{.DisplayTime}}</span>
  </a>
</li>
{{end}}
```

Author: marjune163

src/serverHandler/page.go

@@ -2,24 +2,42 @@ package serverHandler
 
 import (
 	tplutil "../tpl/util"
+	"html/template"
 	"net/http"
 )
 
+const TypeDir = template.HTML("dir")
+const TypeFile = template.HTML("file")
+
 func updateSubItemsHtml(data *responseData) {
 	length := len(data.SubItems)
 
 	data.SubItemsHtml = make([]*itemHtml, length)
 
-	for i := 0; i < length; i++ {
-		info := data.SubItems[i]
+	for i, info := range data.SubItems {
 		name := info.Name()
+		displayName := tplutil.FormatFilename(name)
+
+		var typ template.HTML
+		var url string
+		var readableSize template.HTML
+
+		if info.IsDir() {
+			typ = TypeDir
+			url = data.SubItemPrefix + name + "/"
+			displayName += "/"
+		} else {
+			typ = TypeFile
+			url = data.SubItemPrefix + name
+			readableSize = tplutil.FormatSize(info.Size())
+		}
 
 		data.SubItemsHtml[i] = &itemHtml{
-			IsDir:   info.IsDir(),
-			Link:    name,
-			Name:    tplutil.FormatFilename(name),
-			Size:    tplutil.FormatSize(info.Size()),
-			ModTime: tplutil.FormatTime(info.ModTime()),
+			Type:        typ,
+			Url:         url,
+			DisplayName: displayName,
+			DisplaySize: readableSize,
+			DisplayTime: tplutil.FormatTime(info.ModTime()),
 		}
 	}
 }

src/serverHandler/responseData.go

@@ -17,11 +17,11 @@ type pathEntry struct {
 }
 
 type itemHtml struct {
-	IsDir   bool
-	Link    string
-	Name    template.HTML
-	Size    template.HTML
-	ModTime template.HTML
+	Type        template.HTML
+	Url         string
+	DisplayName template.HTML
+	DisplaySize template.HTML
+	DisplayTime template.HTML
 }
 
 type responseData struct {

src/tpl/page.html

@@ -46,11 +46,11 @@
 		</a>
 	</li>
 	{{range .SubItemsHtml}}
-		<li class="{{if .IsDir}}dir{{else}}file{{end}}">
-			<a href="{{$subItemPrefix}}{{.Link}}{{if .IsDir}}/{{end}}">
-				<span class="name">{{.Name}}{{if .IsDir}}/{{end}}</span>
-				<span class="size">{{if not .IsDir}}{{.Size}}{{end}}</span>
-				<span class="time">{{.ModTime}}</span>
+		<li class="{{.Type}}">
+			<a href="{{.Url}}">
+				<span class="name">{{.DisplayName}}</span>
+				<span class="size">{{.DisplaySize}}</span>
+				<span class="time">{{.DisplayTime}}</span>
 			</a>
 		</li>
 	{{end}}

src/tpl/page.html.go

@@ -51,11 +51,11 @@ const pageTplStr = `
 </a>
 </li>
 {{range .SubItemsHtml}}
-<li class="{{if .IsDir}}dir{{else}}file{{end}}">
-<a href="{{$subItemPrefix}}{{.Link}}{{if .IsDir}}/{{end}}">
-<span class="name">{{.Name}}{{if .IsDir}}/{{end}}</span>
-<span class="size">{{if not .IsDir}}{{.Size}}{{end}}</span>
-<span class="time">{{.ModTime}}</span>
+<li class="{{.Type}}">
+<a href="{{.Url}}">
+<span class="name">{{.DisplayName}}</span>
+<span class="size">{{.DisplaySize}}</span>
+<span class="time">{{.DisplayTime}}</span>
 </a>
 </li>
 {{end}}