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Re: Cancelling Subversion operations

From: Garrett Rooney <rooneg_at_electricjellyfish.net>
Date: 2002-09-18 16:01:16 CEST

Bill Tutt wrote:
>
>>From: Philip Martin [mailto:philip@codematters.co.uk]
>>
>>"Bill Tutt" <rassilon@lyra.org> writes:
>>
>>
>>>Oh yeah, and what are you thinking having only one user cancellation
>>>handler?
>>>i.e. Why is this state global?
>>
>>The simple answer is that it handles a global condition, namely an
>>asynchronous signal.
>
>
> No, it doesn't. The user of it might only need a global condition, but
> it's incorrect of an API to assume that it's really a global condition.
>
> The command line client's use of the API is a global use of course, esp.
> since logic gets invoked via a signal handler, but that doesn't mean
> that another user application would do the same thing.

FWIW, the fact that a GUI client might have more complex needs than the
command line client is the reason the proposed solution uses a client
specified callback. the previous proposals had just a simple volatile
sig_atomic_t with a 'svn_async_cancel' function that would twiddle it.
then SVN_ERR would check that variable. this would ONLY be useful for a
signal handler type situation (or a single threaded client app), which
was why i pushed for the callback. this way if the client has more
complex needs, they can provide a callback function which takes that
into account. they still have to go through a single callback function,
but it is certainly possible to write that function to handle a complex
multithreaded app.

-garrett

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Received on Wed Sep 18 16:01:56 2002

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