Fix performance problem in side by side viewer

Inserting "<lf>\n" doesn't work. Prettify leaves the <lf> but
often inserts a <span> tag between <lf> and \n leaving a very
deep tag stack for the DOM to handle. This is really slow to
render and can cause mis-rendering.

Insert a space before LF. Most prettify styles will treat this
as the same as the LF, allowing the trailing space to be removed
before splitting by line.

Change-Id: I85d12c590a8d1bda1b1b66874a0dddb4628a8655

1 files changed, 2 insertions, 2 deletions

diff --git a/gerrit-prettify/src/main/java/com/google/gerrit/prettify/common/PrettyFormatter.java b/gerrit-prettify/src/main/java/com/google/gerrit/prettify/common/PrettyFormatter.java
index 56bd723d93..511b056c86 100644
--- a/gerrit-prettify/src/main/java/com/google/gerrit/prettify/common/PrettyFormatter.java
+++ b/gerrit-prettify/src/main/java/com/google/gerrit/prettify/common/PrettyFormatter.java
@@ -145,9 +145,9 @@ public abstract class PrettyFormatter implements SparseHtmlFile {
       // Drop any '\r' to avoid this problem.
       html = html.replace("\r</span>\n", "</span>\n");
 
-      html = html.replace("\n", "<lf>\n");
+      html = html.replace("\n", " \n");
       html = prettify(html, getFileType());
-      html = html.replace("<lf>\n", "\n");
+      html = html.replace(" \n", "\n");
     } else {
       html = expandTabs(html);
     }