Re: [PATCH v6.1 05/11] libxl_qmp: Implementation of libxl__ev_qmp_*

[Ian Jackson <ian.jackson@citrix.com>]

Anthony PERARD writes ("Re: [PATCH v6.1 05/11] libxl_qmp: Implementation of libxl__ev_qmp_*"):
> The current implementation already cleanup the broken state before the
> control is passed outside ev_qmp implementation. That result in the Idle
> public state. Whenever an internal function throw an error, it lets the
> main function qmp_ev_fd_callback taking care of cleanup the `broken` state
> so that when the control passes outside ev_qmp implementation the state
> is disconnected/Idle.

Ah right.

> An internal `broken` state is just an half-transition toward the
> disconnected/Idle state.
> 
> I guess I could add to the internal state documentation:
> 
>   When an internal function return an error, it can leave ev_qmp in a
>   `broken` state but only if the caller is another internal function.
>   That `broken` needs to be cleaned up, e.i. transitionned to the
>   `disconnected` state, before the control of ev_qmp is released
>   outsides of ev_qmp implementation.

If you do this you need to describe what kinds of states are legal
`broken' states.  This is probably must easily done by making the
`broken' state a proper first-class internal state (giving it an entry
in the state table), but stating, as you do above, that it is not
visible externally because it's always tidied into `disconnected'
before control passes outside ev_qmp.

Ian.

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