concurrency-test.p6

#!/usr/bin/env perl6

# I run this in a directory with 30k files.
# I suggest using a SSD if you have one, for your sanity.

use v6;

sub gather-files(Str $start-path --> List) {
	# Gather a list of all files. Run this is a huge directory.
	my $files = Channel.new;
	my IO @dirs = ($start-path.IO);
	while (@dirs)
	{
		@dirs = @dirs.race.map(-> $dir {
		#@dirs = @dirs.map(-> $dir {
			|$dir.dir.race.map( -> IO $path {
			#|$dir.dir.map( -> IO $path {
				if ($path.d) {
					$path;
				} else {
					if (!$path.l) {
						$files.send: $path.Str;
					}
					|(); # slip nothing into the list
				}
			});
		});
	}
	$files.close;
	return $files.list;
}

sub MAIN(Str $start-path='.') {
	my @files = gather-files($start-path);

	my $stop = False;
	await do for @files -> $file-path {
		last if $stop;
		start {
			$file-path.IO.slurp;
			#my $fh = $file-path.IO.open: :r;
			#$fh.lines.cache;
			#$fh.close;

			CATCH {
				when / 'UTF-8' / { } # we don't care about UTF-8 exceptions
				default {
					note "Got exception: $_"~.backtrace.full;
					$stop = True;
				}
			}
		}
	}
	die if $stop;
}