more reliable & maintainable extension methods

shadowsocks-csharp/Controller/I18N.cs

@@ -21,7 +21,7 @@ namespace Shadowsocks.Controller
                     string line;
                     while ((line = sr.ReadLine()) != null)
                     {
-                        if (line == "" || line[0] == '#')
+                        if (line.BeginWith('#'))
                             continue;
 
                         var pos = line.IndexOf('=');

shadowsocks-csharp/Controller/Service/GfwListUpdater.cs

@@ -30,6 +30,7 @@ namespace Shadowsocks.Controller
             }
         }
 
+        private static readonly IEnumerable<char> IgnoredLineBegins = new[] { '!', '[' };
         private void http_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
         {
             try
@@ -44,7 +45,7 @@ namespace Shadowsocks.Controller
                         string rule;
                         while ((rule = sr.ReadLine()) != null)
                         {
-                            if (rule == "" || rule[0] == '!' || rule[0] == '[')
+                            if (rule.BeginWithAny(IgnoredLineBegins))
                                 continue;
                             lines.Add(rule);
                         }
@@ -102,7 +103,7 @@ namespace Shadowsocks.Controller
                 string line;
                 while ((line = sr.ReadLine()) != null)
                 {
-                    if (line == "" || line[0] == '!' || line[0] == '[')
+                    if (line.BeginWithAny(IgnoredLineBegins))
                         continue;
                     valid_lines.Add(line);
                 }

shadowsocks-csharp/Controller/ShadowsocksController.cs

@@ -442,6 +442,7 @@ namespace Shadowsocks.Controller
                 UpdatePACFromGFWListError(this, e);
         }
 
+        private static readonly IEnumerable<char> IgnoredLineBegins = new[] { '!', '[' };
         private void pacServer_UserRuleFileChanged(object sender, EventArgs e)
         {
             // TODO: this is a dirty hack. (from code GListUpdater.http_DownloadStringCompleted())
@@ -459,7 +460,7 @@ namespace Shadowsocks.Controller
                     string rule;
                     while ((rule = sr.ReadLine()) != null)
                     {
-                        if (rule == "" || rule[0] == '!' || rule[0] == '[')
+                        if (rule.BeginWithAny(IgnoredLineBegins))
                             continue;
                         lines.Add(rule);
                     }