Make copy/paste work for source code

Fix regression casued by go-gitea#12047 so copy/paste works properly in all browsers.

Fixes go-gitea#12184

Also while looking at this I saw a small display issue for blame view. I think go-gitea#12023 was merged into original PR through an update branch before go-gitea#12047 was merged and made one of the css ruules not apply anymore.

modules/highlight/highlight.go

@@ -133,7 +133,12 @@ func File(numLines int, fileName string, code []byte) map[int]string {
 	m := make(map[int]string, numLines)
 	for k, v := range strings.SplitN(htmlbuf.String(), "\n", numLines) {
 		line := k + 1
-		m[line] = string(v)
+		content := string(v)
+		//need to keep lines that are only \n so copy/paste works properly in browser
+		if content == "" {
+			content = "\n"
+		}
+		m[line] = content
 	}
 	return m
 }
@@ -143,7 +148,12 @@ func plainText(code string, numLines int) map[int]string {
 	m := make(map[int]string, numLines)
 	for k, v := range strings.SplitN(string(code), "\n", numLines) {
 		line := k + 1
-		m[line] = string(v)
+		content := string(v)
+		//need to keep lines that are only \n so copy/paste works properly in browser
+		if content == "" {
+			content = "\n"
+		}
+		m[line] = content
 	}
 	return m
 }

templates/repo/home.tmpl

@@ -1,5 +1,5 @@
 {{template "base/head" .}}
-<div class="repository file list">
+<div class="repository file list {{if .IsBlame}}blame{{end}}">
 	{{template "repo/header" .}}
 	<div class="ui container {{if .IsBlame}}fluid padded{{end}}">
 		{{template "base/alert" .}}

templates/repo/view_file.tmpl

@@ -105,7 +105,7 @@
 								<span id="L{{$line}}" data-line-number="{{$line}}"></span>
 							</td>
 							<td rel="L{{$line}}" class="lines-code chroma">
-								<pre><code>{{$code | Safe}}</code></pre>
+								<code>{{$code | Safe}}</code>
 							</td>
 						</tr>
 						{{end}}

web_src/less/_base.less

@@ -1039,6 +1039,10 @@ i.icon.centerlock {
     }
 }
 
+.lines-code code {
+    white-space: pre;
+}
+
 .blame .lines-num {
     padding: 0 !important;
     background-color: #f5f5f5;