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andyedinborough / aenetmail

C# POP/IMAP Mail Client
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Race condition in TextClient.Disconnect #20

Closed petersondrew closed 12 years ago

petersondrew commented 12 years ago

I've discovered a race condition in TextClient.Disconnect and TextClient.SendCommand that is happening about once a day (program runs 24/7). Turns out the idle code (or something) must be calling the SendCommand function while disconnect is disposing of the SSL stream, resulting in a ThreadException being raised when it attempts to write to the stream. I'm not really sure of the best way to handle this so I've just attempted to hack around it for now by catching an ObjectDisposedException and carrying on like nothing happened. Here are the exception details

Cannot access a disposed object.
Object name: 'SslStream'.
   at System.Net.Security.SslState.CheckThrow(Boolean authSucessCheck)
   at System.Net.Security.SslState.get_SecureStream()
   at System.Net.Security.SslStream.Write(Byte[] buffer, Int32 offset, Int32 count)
   at AE.Net.Mail.TextClient.SendCommand(String command) in D:\Documents\CODE\aenetmail\TextClient.cs:line 98
   at AE.Net.Mail.ImapClient.OnLogout() in D:\Documents\CODE\aenetmail\ImapClient.cs:line 481
   at AE.Net.Mail.TextClient.Logout() in D:\Documents\CODE\aenetmail\TextClient.cs:line 43
   at AE.Net.Mail.TextClient.Disconnect() in D:\Documents\CODE\aenetmail\TextClient.cs:line 119
   at AE.Net.Mail.TextClient.Dispose() in D:\Documents\CODE\aenetmail\TextClient.cs:line 134
andyedinborough commented 12 years ago

Looks like the order of operations was wrong in the Dispose() method. The connections were being shutdown before Disconnect() and Logout() had run. Fixed in commit #50f0959d80.