[
https://issues.apache.org/jira/browse/QPID-3193?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Chuck Rolke updated QPID-3193:
------------------------------
Attachment: QPID-3694_lock-and-throw-preview.patch
This patch, soon to be on Review Board, is what I suggest makes sense for a
single class in the .NET Binding. It fixes the 'Message' class as that has most
of the variations. The highlights are:
1. A common file with a macro in it. This macro blocks entry into disposed
objects.
2. An IsDisposed property to tell if your underlying object is still there.
Consider it a diagnostic.
3. A mess of THROW_IF_DISPOSED calls to block access to disposed objects.
4. Some changes to object destructor and finalizer. Destructors called (C#
Dispose, C++ delete) deliberately suppress GC finalization.
WRT lock(this), I think it is the best choice. The entire Message class storage
consists of a single pointer into unmanaged space. There is no finer-grained
object on which to lock than 'this'.
This patch and the Review Board show one class. The intent is to do the same to
all the binding classes.
> .NET Binding for Messaging classes need a test to check that binding is still
> in effect
> ---------------------------------------------------------------------------------------
>
> Key: QPID-3193
> URL: https://issues.apache.org/jira/browse/QPID-3193
> Project: Qpid
> Issue Type: Improvement
> Affects Versions: 0.11
> Reporter: Chuck Rolke
> Assignee: Chuck Rolke
> Attachments: QPID-3694_lock-and-throw-preview.patch
>
>
> The .NET Binding for Messaging could be made more user-friendly with the
> addition of a property that indicates whether or not the underlying binding
> is still available. A C# coder may innocently write:
> (1) Message mA = new Message("a");
> (2) Message mB = mA;
> ...
> (N) mB.Dispose();
> After disposing of message mB then message mA is clobbered. 'Message' is a
> 'ref class' type and messages mA and mB refer to the same object on managed
> heap. When message mB is disposed then the bound C++ Messaging object is
> deleted [1]. Any reference to the bound message part of mA will result in an
> illegal memory reference (to 0) and a process exit. The .NET runtime can't
> catch this fault.
> The obvious answer is not to do that. If the second line of code was 'Message
> mB = new Message(mA)' then mA and mB would have been completely separate and
> disposing of either would have no effect on the other.
> Another answer is to have the binding check for a null binding reference on
> each and every access and then to throw if the underlying binding is gone.
> This is not very appealing from a performance standpoint.
> As a compromise I would like to add a property isBound to each class. Users
> then have a fighting chance to check that the binding is still in effect and
> that function calls on the object shouldn't blow up. This property would be
> useful in Assert statements or in debugging.
> [1] If anyone knows how to have my binding library intercept example code
> line (2) and create reference counts, please let me know.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
---------------------------------------------------------------------
Apache Qpid - AMQP Messaging Implementation
Project: http://qpid.apache.org
Use/Interact: mailto:[email protected]
