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https://issues.apache.org/jira/browse/ARROW-11841?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17565132#comment-17565132
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Dewey Dunnington commented on ARROW-11841:
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>From the R perspective, you can call {{SafeCallIntoRVoid([]() {
>cpp11::check_user_interrupt(); })}} anywhere in C++ and it will return a
>non-OK status if there's a pending interrupt. That will only work for tasks
>run with {{RunWithCapturedR()}}, although that includes most of the operations
>one would want to cancel (e.g., reading CSV, Feather, and query engine
>execution after ARROW-16444). It also only works for places where the R
>package can insert some kind of cancel callback.
If we have a Future that we can cancel, we could rig something similar, maybe
using our own event loop (currently we use Arrow's RunInSerialExecutor and I
don't know how customizable that is).
In addition to RMonitor, there's also the 'later' package (
https://github.com/r-lib/later ) which can also run event loops although I
don't know how customizable they are.
In the R package we have the {{RMainThread}} singleton which could be an
appropriate place to register a C++ cancel callback (e.g., a {{std::function}}
that calls some Future's cancel callback). In most cases, though, we don't have
a future we can cancel.
> [R][C++] Allow cancelling long-running commands
> -----------------------------------------------
>
> Key: ARROW-11841
> URL: https://issues.apache.org/jira/browse/ARROW-11841
> Project: Apache Arrow
> Issue Type: Improvement
> Components: C++, R
> Reporter: Antoine Pitrou
> Priority: Major
> Fix For: 10.0.0
>
>
> When calling a long-running task (for example reading a CSV file) from the R
> prompt, users may want to interrupt with Ctrl-C.
> Allowing this will require integrating R's user interruption facility with
> the cancellation API that's going to be exposed in C++ (see ARROW-8732).
> Below some information I've gathered on the topic:
> There is some hairy discussion of how to interrupt C++ code from R at
> https://stackoverflow.com/questions/40563522/r-how-to-write-interruptible-c-function-and-recover-partial-results
> and https://stat.ethz.ch/pipermail/r-devel/2011-April/060714.html .
> It seems it may involve polling cpp11::check_user_interrupt() and catching
> any cpp11::unwind_exception that may signal an interruption. A complication
> is that apparently R APIs should only be called from the main thread. There's
> also a small library which claims to make writing all this easier:
> https://github.com/tnagler/RcppThread/blob/master/inst/include/RcppThread/RMonitor.hpp
> But since user interruptions will only be noticed by the R main thread, the
> solution may be to launch heavy computations (e.g. CSV reading) in a separate
> thread and have the main R thread periodically poll for interrupts while
> waiting for the separate thread. This is what this dedicated thread class
> does in its join method:
> https://github.com/tnagler/RcppThread/blob/master/inst/include/RcppThread/Thread.hpp#L79
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