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=head1 NAME |
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|
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Coro::Select - a (slow but coro-aware) replacement for CORE::select |
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|
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=head1 SYNOPSIS |
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|
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use Coro::Select; # replace select globally (be careful, see below) |
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use Core::Select 'select'; # only in this module |
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use Coro::Select (); # use Coro::Select::select |
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|
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=head1 DESCRIPTION |
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|
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This module tries to create a fully working replacement for perl's |
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C<select> built-in, using C<AnyEvent> watchers to do the job, so other |
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threads can run in parallel to any select user. As many libraries that |
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only have a blocking API do not use global variables and often use select |
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(or IO::Select), this effectively makes most such libraries "somewhat" |
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non-blocking w.r.t. other threads. |
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|
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This implementation works fastest when only very few bits are set in the |
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fd set(s). |
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|
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To be effective globally, this module must be C<use>'d before any other |
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module that uses C<select>, so it should generally be the first module |
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C<use>'d in the main program. Note that overriding C<select> globally |
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might actually cause problems, as some C<AnyEvent> backends use C<select> |
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themselves, and asking AnyEvent to use Coro::Select, which in turn asks |
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AnyEvent will not quite work. |
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|
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You can also invoke it from the commandline as C<perl -MCoro::Select>. |
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|
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To override select only for a single module (e.g. C<Net::DBus::Reactor>), |
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use a code fragment like this to load it: |
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|
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{ |
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package Net::DBus::Reactor; |
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use Coro::Select qw(select); |
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use Net::DBus::Reactor; |
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} |
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|
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Some modules (notably L<POE::Loop::Select>) directly call |
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C<CORE::select>. For these modules, we need to patch the opcode table by |
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sandwiching it between calls to C<Coro::Select::patch_pp_sselect> and |
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C<Coro::Select::unpatch_pp_sselect>: |
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|
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BEGIN { |
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use Coro::Select (); |
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Coro::Select::patch_pp_sselect; |
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require evil_poe_module_using_CORE::SELECT; |
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Coro::Select::unpatch_pp_sselect; |
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} |
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|
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=over 4 |
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|
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=cut |
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|
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package Coro::Select; |
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|
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use common::sense; |
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|
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use Errno; |
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|
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use Coro (); |
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use Coro::State (); |
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use AnyEvent 4.800001 (); |
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use Coro::AnyEvent (); |
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|
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use base Exporter::; |
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|
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our $VERSION = 6.57; |
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our @EXPORT_OK = "select"; |
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|
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sub import { |
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my $pkg = shift; |
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if (@_) { |
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$pkg->export (scalar caller 0, @_); |
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} else { |
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$pkg->export ("CORE::GLOBAL", "select"); |
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} |
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} |
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|
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sub select(;*$$$) { |
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if (@_ == 0) { |
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return CORE::select |
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} elsif (@_ == 1) { |
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return CORE::select $_[0] |
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} elsif (defined $_[3] && !$_[3]) { |
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return CORE::select $_[0], $_[1], $_[2], $_[3] |
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} else { |
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my $nfound = 0; |
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my @w; |
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my $wakeup = Coro::rouse_cb; |
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|
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# AnyEvent does not do 'e', so replace it by 'r' |
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for ([0, 0], [1, 1], [2, 0]) { |
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my ($i, $poll) = @$_; |
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if (defined $_[$i]) { |
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my $rvec = \$_[$i]; |
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|
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# we parse the bitmask by first expanding it into |
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# a string of bits |
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for (unpack "b*", $$rvec) { |
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# and then repeatedly matching a regex against it |
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while (/1/g) { |
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my $fd = (pos) - 1; |
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|
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push @w, |
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AE::io $fd, $poll, sub { |
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(vec $$rvec, $fd, 1) = 1; |
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++$nfound; |
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$wakeup->(); |
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}; |
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} |
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} |
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|
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$$rvec ^= $$rvec; # clear all bits |
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} |
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} |
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|
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push @w, |
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AE::timer $_[3], 0, $wakeup |
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if defined $_[3]; |
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|
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Coro::rouse_wait; |
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|
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return $nfound |
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} |
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} |
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|
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1; |
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|
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=back |
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|
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=head1 BUGS |
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|
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For performance reasons, Coro::Select's select function might not |
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properly detect bad file descriptors (but relying on EBADF is inherently |
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non-portable). |
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|
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=head1 SEE ALSO |
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|
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L<Coro::LWP>. |
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|
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=head1 AUTHOR/SUPPORT/CONTACT |
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|
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Marc A. Lehmann <schmorp@schmorp.de> |
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http://software.schmorp.de/pkg/Coro.html |
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|
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=cut |
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|
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