[smuxi] Frontend-GNOME: fix opening URLs on Mono/Linux

[Mirco M. M. Bauer <mmmbauer src gnome org>]

commit a29efabca298c18b54dabcabd989044d37dd0cf2
Author: Mirco Bauer <meebey meebey net>
Date:   Thu Feb 4 00:34:49 2021 +0800

    Frontend-GNOME: fix opening URLs on Mono/Linux
    
    Mono >= 6.6 has a regression where Process.Start() can no longer open URLs on
    Linux and just throws a Win32Exception.
    
    To workaround this issue we have to call xdg-open directly :(
    
    For the bug in Mono see:
    
https://github.com/mono/mono/commit/5d088cf0de7f3e50e3547dba361af4401e938dd4#diff-c1ecca7d198c8f4922767c6c350edb3d1f7bbd59524f36f73d34f973d2f42a2eR2069

 src/Frontend-GNOME/Frontend.cs | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)
---
diff --git a/src/Frontend-GNOME/Frontend.cs b/src/Frontend-GNOME/Frontend.cs
index 8085b1ce..ebac6ed8 100644
--- a/src/Frontend-GNOME/Frontend.cs
+++ b/src/Frontend-GNOME/Frontend.cs
@@ -1,7 +1,7 @@
 /*
  * Smuxi - Smart MUltipleXed Irc
  *
- * Copyright (c) 2005-2015 Mirco Bauer <meebey meebey net>
+ * Copyright (c) 2005-2015, 2021 Mirco Bauer <meebey meebey net>
  *
  * Full GPL License: <http://www.gnu.org/licenses/gpl.txt>
  *
@@ -938,18 +938,34 @@ namespace Smuxi.Frontend.Gnome
             if (TryOpenChatLink(link)) {
                 return;
             }
-
+            var escapedUrl = Uri.EscapeUriString(link.ToString());
             // hopefully MS .NET / Mono finds some way to handle the URL
             ThreadPool.QueueUserWorkItem(delegate {
                 try {
-                    var url = link.ToString();
-                    using (var process = SysDiag.Process.Start(url)) {
+                    using (var process = SysDiag.Process.Start(escapedUrl)) {
                         // Start() might return null in case it re-used a
                         // process instead of starting one
                         if (process != null) {
                             process.WaitForExit();
                         }
                     }
+                } catch (System.ComponentModel.Win32Exception ex) when (IsMono && IsLinux) {
+                    // HACK: Mono >= 6.6 has a regression where Process.Start() can
+                    // no longer open URLs on Linux and just throws a Win32Exception.
+                    // To workaround this issue we call xdg-open directly :(
+                    // For the bug in Mono see:
+                    // 
https://github.com/mono/mono/commit/5d088cf0de7f3e50e3547dba361af4401e938dd4#diff-c1ecca7d198c8f4922767c6c350edb3d1f7bbd59524f36f73d34f973d2f42a2eR2069
+#if LOG4NET
+                    _Logger.Warn("OpenLink(): buggy Mono version detected, failing back to xdg-open. 
Exception:", ex);
+#endif
+                    var info = new SysDiag.ProcessStartInfo("xdg-open", escapedUrl) {
+                        UseShellExecute = false
+                    };
+                    using (var process = SysDiag.Process.Start(info)) {
+                        if (process != null) {
+                            process.WaitForExit ();
+                        }
+                    }
                 } catch (Exception ex) {
                     // exceptions in the thread pool would kill the process, see:
                     // http://msdn.microsoft.com/en-us/library/0ka9477y.aspx