PERF: editor could be crashed if you entered huge inline blocks

app/assets/javascripts/discourse/dialects/html.js

@@ -25,12 +25,15 @@ var blockTags = ['address', 'article', 'aside', 'audio', 'blockquote', 'canvas',
     };
 
 Discourse.Dialect.registerBlock('html', function(block, next) {
-  var split;
+  var split, pos;
 
   // Fix manual blockquote paragraphing even though it's not strictly correct
-  if (block.search(/[^\s]+<blockquote/) === 0) {
-    split = splitAtLast('blockquote', block, next, true);
-    if (split) { return this.processInline(split[0]); }
+  // PERF NOTE: /\S+<blockquote/ is a perf hog for search, try on huge string
+  if (pos = block.search(/<blockquote/) >= 0) {
+    if(block.substring(0, pos).search(/\s/) === -1) {
+      split = splitAtLast('blockquote', block, next, true);
+      if (split) { return this.processInline(split[0]); }
+    }
   }
 
   var m = /^<([^>]+)\>/.exec(block);

vendor/assets/javascripts/better_markdown.js

@@ -1155,28 +1155,38 @@
     inline: {
 
       __oneElement__: function oneElement( text, patterns_or_re, previous_nodes ) {
-        var m, res;
+        var m, res, pos, search_re, match_re;
+
+        // PERF NOTE: rewritten to avoid greedy match regex \([\s\S]*?)(...)\
+        // greedy match performs horribly with large inline blocks, it can be so
+        // slow it will crash chrome
 
         patterns_or_re = patterns_or_re || this.dialect.inline.__patterns__;
-        var re = new RegExp( "([\\s\\S]*?)(" + (patterns_or_re.source || patterns_or_re) + ")" );
+        search_re = new RegExp(patterns_or_re.source || patterns_or_re);
+
+        pos = text.search(search_re);
 
-        m = re.exec( text );
-        if (!m) {
-          // Just boring text
+        // Just boring text
+        if (pos === -1) {
           return [ text.length, text ];
         }
-        else if ( m[1] ) {
+
+        if (pos !== 0) {
           // Some un-interesting text matched. Return that first
-          return [ m[1].length, m[1] ];
+          return [pos, text.substring(0,pos)];
         }
 
-        if ( m[2] in this.dialect.inline ) {
-          res = this.dialect.inline[ m[2] ].call(
+        match_re = new RegExp( "^(" + (patterns_or_re.source || patterns_or_re) + ")" );
+        m = match_re.exec( text );
+
+        if ( m[1] in this.dialect.inline ) {
+          res = this.dialect.inline[ m[1] ].call(
                     this,
                     text.substr( m.index ), m, previous_nodes || [] );
         }
+
         // Default for now to make dev easier. just slurp special and output it.
-        res = res || [ m[2].length, m[2] ];
+        res = res || [ m[1].length, m[1] ];
         return res;
       },