Acme-Sort-Sleep
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local/lib/perl5/IO/Async/Loop.pm view on Meta::CPAN
# Undocumented; used only by the test scripts.
# Setting this value true will avoid the IO::Async::Loop::$^O candidate in the
# magic constructor
our $LOOP_NO_OS;
# SIGALRM handler for watchdog
$SIG{ALRM} = sub {
# There are two extra frames here; this one and the signal handler itself
local $Carp::CarpLevel = $Carp::CarpLevel + 2;
if( WATCHDOG_SIGABRT ) {
print STDERR Carp::longmess( "Watchdog timeout" );
kill ABRT => $$;
}
else {
Carp::confess( "Watchdog timeout" );
}
} if WATCHDOG_ENABLE;
$SIG{PIPE} = "IGNORE" if ( $SIG{PIPE} || "" ) eq "DEFAULT";
=head1 NAME
C<IO::Async::Loop> - core loop of the C<IO::Async> framework
=head1 SYNOPSIS
use IO::Async::Stream;
use IO::Async::Timer::Countdown;
use IO::Async::Loop;
my $loop = IO::Async::Loop->new;
$loop->add( IO::Async::Timer::Countdown->new(
delay => 10,
on_expire => sub { print "10 seconds have passed\n" },
)->start );
$loop->add( IO::Async::Stream->new_for_stdin(
on_read => sub {
my ( $self, $buffref, $eof ) = @_;
while( $$buffref =~ s/^(.*)\n// ) {
print "You typed a line $1\n";
}
return 0;
},
) );
$loop->run;
=head1 DESCRIPTION
This module provides an abstract class which implements the core loop of the
L<IO::Async> framework. Its primary purpose is to store a set of
L<IO::Async::Notifier> objects or subclasses of them. It handles all of the
lower-level set manipulation actions, and leaves the actual IO readiness
testing/notification to the concrete class that implements it. It also
provides other functionality such as signal handling, child process managing,
and timers.
See also the two bundled Loop subclasses:
=over 4
=item L<IO::Async::Loop::Select>
=item L<IO::Async::Loop::Poll>
=back
Or other subclasses that may appear on CPAN which are not part of the core
L<IO::Async> distribution.
=head2 Ignoring SIGPIPE
Since version I<0.66> loading this module automatically ignores C<SIGPIPE>, as
it is highly unlikely that the default-terminate action is the best course of
action for an L<IO::Async>-based program to take. If at load time the handler
disposition is still set as C<DEFAULT>, it is set to ignore. If already
another handler has been placed there by the program code, it will be left
undisturbed.
=cut
# Internal constructor used by subclasses
sub __new
{
my $class = shift;
# Detect if the API version provided by the subclass is sufficient
$class->can( "API_VERSION" ) or
die "$class is too old for IO::Async $VERSION; it does not provide \->API_VERSION\n";
$class->API_VERSION >= NEED_API_VERSION or
die "$class is too old for IO::Async $VERSION; we need API version >= ".NEED_API_VERSION.", it provides ".$class->API_VERSION."\n";
WATCHDOG_ENABLE and !$class->_CAN_WATCHDOG and
warn "$class cannot implement IO_ASYNC_WATCHDOG\n";
my $self = bless {
notifiers => {}, # {nkey} = notifier
iowatches => {}, # {fd} = [ $on_read_ready, $on_write_ready, $on_hangup ]
sigattaches => {}, # {sig} => \@callbacks
childmanager => undef,
childwatches => {}, # {pid} => $code
threadwatches => {}, # {tid} => $code
timequeue => undef,
deferrals => [],
os => {}, # A generic scratchpad for IO::Async::OS to store whatever it wants
}, $class;
# It's possible this is a specific subclass constructor. We still want the
# magic IO::Async::Loop->new constructor to yield this if it's the first
# one
our $ONE_TRUE_LOOP ||= $self;
# Legacy support - temporary until all CPAN classes are updated; bump NEEDAPI version at that point
my $old_timer = $self->can( "enqueue_timer" ) != \&enqueue_timer;
local/lib/perl5/IO/Async/Loop.pm view on Meta::CPAN
}
return wantarray ? @{ $self->{result} } : $self->{result}[0];
}
=head2 stop
$loop->stop( @result )
Stops the inner-most C<run> method currently in progress, causing it to return
the given C<@result>.
This method is a recent addition and may not be supported by all the
C<IO::Async::Loop> subclasses currently available on CPAN.
=cut
sub stop
{
my $self = shift;
@{ $self->{result} } = @_;
undef $self->{running};
}
=head2 loop_forever
$loop->loop_forever
A synonym for C<run>, though this method does not return a result.
=cut
sub loop_forever
{
my $self = shift;
$self->run;
return;
}
=head2 loop_stop
$loop->loop_stop
A synonym for C<stop>, though this method does not pass any results.
=cut
sub loop_stop
{
my $self = shift;
$self->stop;
}
=head2 post_fork
$loop->post_fork
The base implementation of this method does nothing. It is provided in case
some Loop subclasses should take special measures after a C<fork()> system
call if the main body of the program should survive in both running processes.
This may be required, for example, in a long-running server daemon that forks
multiple copies on startup after opening initial listening sockets. A loop
implementation that uses some in-kernel resource that becomes shared after
forking (for example, a Linux C<epoll> or a BSD C<kqueue> filehandle) would
need recreating in the new child process before the program can continue.
=cut
sub post_fork
{
# empty
}
###########
# Futures #
###########
=head1 FUTURE SUPPORT
The following methods relate to L<IO::Async::Future> objects.
=cut
=head2 new_future
$future = $loop->new_future
Returns a new L<IO::Async::Future> instance with a reference to the Loop.
=cut
sub new_future
{
my $self = shift;
require IO::Async::Future;
return IO::Async::Future->new( $self );
}
=head2 await
$loop->await( $future )
Blocks until the given future is ready, as indicated by its C<is_ready> method.
As a convenience it returns the future, to simplify code:
my @result = $loop->await( $future )->get;
=cut
sub await
{
my $self = shift;
my ( $future ) = @_;
$self->loop_once until $future->is_ready;
return $future;
}
=head2 await_all
$loop->await_all( @futures )
Blocks until all the given futures are ready, as indicated by the C<is_ready>
method. Equivalent to calling C<await> on a C<< Future->wait_all >> except
local/lib/perl5/IO/Async/Loop.pm view on Meta::CPAN
}
############
# Features #
############
=head1 FEATURES
Most of the following methods are higher-level wrappers around base
functionality provided by the low-level API documented below. They may be
used by L<IO::Async::Notifier> subclasses or called directly by the program.
The following methods documented with a trailing call to C<< ->get >> return
L<Future> instances.
=cut
sub __new_feature
{
my $self = shift;
my ( $classname ) = @_;
( my $filename = "$classname.pm" ) =~ s{::}{/}g;
require $filename;
# These features aren't supposed to be "user visible", so if methods called
# on it carp or croak, the shortmess line ought to skip IO::Async::Loop and
# go on report its caller. To make this work, add the feature class to our
# @CARP_NOT list.
push our(@CARP_NOT), $classname;
return $classname->new( loop => $self );
}
=head2 attach_signal
$id = $loop->attach_signal( $signal, $code )
This method adds a new signal handler to watch the given signal. The same
signal can be attached to multiple times; its callback functions will all be
invoked, in no particular order.
The returned C<$id> value can be used to identify the signal handler in case
it needs to be removed by the C<detach_signal> method. Note that this value
may be an object reference, so if it is stored, it should be released after it
cancelled, so the object itself can be freed.
=over 8
=item $signal
The name of the signal to attach to. This should be a bare name like C<TERM>.
=item $code
A CODE reference to the handling callback.
=back
Attaching to C<SIGCHLD> is not recommended because of the way all child
processes use it to report their termination. Instead, the C<watch_child>
method should be used to watch for termination of a given child process. A
warning will be printed if C<SIGCHLD> is passed here, but in future versions
of L<IO::Async> this behaviour may be disallowed altogether.
See also L<POSIX> for the C<SIGI<name>> constants.
For a more flexible way to use signals from within Notifiers, see instead the
L<IO::Async::Signal> object.
=cut
sub attach_signal
{
my $self = shift;
my ( $signal, $code ) = @_;
HAVE_SIGNALS or croak "This OS cannot ->attach_signal";
if( $signal eq "CHLD" ) {
# We make special exception to allow $self->watch_child to do this
caller eq "IO::Async::Loop" or
carp "Attaching to SIGCHLD is not advised - use ->watch_child instead";
}
if( not $self->{sigattaches}->{$signal} ) {
my @attaches;
$self->watch_signal( $signal, sub {
foreach my $attachment ( @attaches ) {
$attachment->();
}
} );
$self->{sigattaches}->{$signal} = \@attaches;
}
push @{ $self->{sigattaches}->{$signal} }, $code;
return \$self->{sigattaches}->{$signal}->[-1];
}
=head2 detach_signal
$loop->detach_signal( $signal, $id )
Removes a previously-attached signal handler.
=over 8
=item $signal
The name of the signal to remove from. This should be a bare name like
C<TERM>.
=item $id
The value returned by the C<attach_signal> method.
=back
=cut
sub detach_signal
{
my $self = shift;
my ( $signal, $id ) = @_;
HAVE_SIGNALS or croak "This OS cannot ->detach_signal";
# Can't use grep because we have to preserve the addresses
my $attaches = $self->{sigattaches}->{$signal} or return;
for (my $i = 0; $i < @$attaches; ) {
$i++, next unless \$attaches->[$i] == $id;
splice @$attaches, $i, 1, ();
}
if( !@$attaches ) {
$self->unwatch_signal( $signal );
delete $self->{sigattaches}->{$signal};
}
}
=head2 later
$loop->later( $code )
Schedules a code reference to be invoked as soon as the current round of IO
operations is complete.
The code reference is never invoked immediately, though the loop will not
perform any blocking operations between when it is installed and when it is
invoked. It may call C<select>, C<poll> or equivalent with a zero-second
timeout, and process any currently-pending IO conditions before the code is
invoked, but it will not block for a non-zero amount of time.
This method is implemented using the C<watch_idle> method, with the C<when>
parameter set to C<later>. It will return an ID value that can be passed to
C<unwatch_idle> if required.
=cut
sub later
{
my $self = shift;
my ( $code ) = @_;
return $self->watch_idle( when => 'later', code => $code );
}
=head2 spawn_child
$loop->spawn_child( %params )
This method creates a new child process to run a given code block or command.
For more detail, see the C<spawn_child> method on the
L<IO::Async::ChildManager> class.
=cut
sub spawn_child
{
my $self = shift;
my %params = @_;
my $childmanager = $self->{childmanager} ||=
$self->__new_feature( "IO::Async::ChildManager" );
$childmanager->spawn_child( %params );
}
=head2 open_child
$pid = $loop->open_child( %params )
This creates a new child process to run the given code block or command, and
attaches filehandles to it that the parent will watch. This method is a light
wrapper around constructing a new L<IO::Async::Process> object, provided
largely for backward compatibility. New code ought to construct such an object
directly, as it may provide more features than are available here.
The C<%params> hash takes the following keys:
=over 8
=item command => ARRAY or STRING
=item code => CODE
The command or code to run in the child process (as per the C<spawn> method)
=item on_finish => CODE
A continuation to be called when the child process exits and has closed all of
the filehandles that were set up for it. It will be invoked in the following
way:
$on_finish->( $pid, $exitcode )
The second argument is passed the plain perl C<$?> value.
=item on_error => CODE
Optional continuation to be called when the child code block throws an
exception, or the command could not be C<exec(2)>ed. It will be invoked in the
following way (as per C<spawn>)
$on_error->( $pid, $exitcode, $dollarbang, $dollarat )
If this continuation is not supplied, then C<on_finish> is used instead. The
value of C<$!> and C<$@> will not be reported.
=item setup => ARRAY
Optional reference to an array to pass to the underlying C<spawn> method.
=back
In addition, the hash takes keys that define how to set up file descriptors in
the child process. (If the C<setup> array is also given, these operations will
be performed after those specified by C<setup>.)
=over 8
=item fdI<n> => HASH
A hash describing how to set up file descriptor I<n>. The hash may contain one
of the following sets of keys:
=over 4
=item on_read => CODE
The child will be given the writing end of a pipe. The reading end will be
wrapped by an L<IO::Async::Stream> using this C<on_read> callback function.
=item from => STRING
The child will be given the reading end of a pipe. The string given by the
C<from> parameter will be written to the child. When all of the data has been
written the pipe will be closed.
=back
=item stdin => ...
=item stdout => ...
=item stderr => ...
Shortcuts for C<fd0>, C<fd1> and C<fd2> respectively.
=back
=cut
sub open_child
{
my $self = shift;
my %params = @_;
my $on_finish = delete $params{on_finish};
ref $on_finish or croak "Expected 'on_finish' to be a reference";
$params{on_finish} = sub {
my ( $process, $exitcode ) = @_;
$on_finish->( $process->pid, $exitcode );
};
if( my $on_error = delete $params{on_error} ) {
ref $on_error or croak "Expected 'on_error' to be a reference";
$params{on_exception} = sub {
my ( $process, $exception, $errno, $exitcode ) = @_;
# Swap order
$on_error->( $process->pid, $exitcode, $errno, $exception );
};
}
$params{on_exit} and croak "Cannot pass 'on_exit' parameter through ChildManager->open";
require IO::Async::Process;
my $process = IO::Async::Process->new( %params );
$self->add( $process );
return $process->pid;
}
=head2 run_child
$pid = $loop->run_child( %params )
This creates a new child process to run the given code block or command,
capturing its STDOUT and STDERR streams. When the process exits, a
continuation is invoked being passed the exitcode, and content of the streams.
=over 8
=item command => ARRAY or STRING
=item code => CODE
The command or code to run in the child process (as per the C<spawn_child>
method)
=item on_finish => CODE
A continuation to be called when the child process exits and closed its STDOUT
and STDERR streams. It will be invoked in the following way:
$on_finish->( $pid, $exitcode, $stdout, $stderr )
The second argument is passed the plain perl C<$?> value.
=item stdin => STRING
Optional. String to pass in to the child process's STDIN stream.
=item setup => ARRAY
Optional reference to an array to pass to the underlying C<spawn> method.
=back
This method is intended mainly as an IO::Async-compatible replacement for the
perl C<readpipe> function (`backticks`), allowing it to replace
my $output = `command here`;
with
$loop->run_child(
command => "command here",
on_finish => sub {
my ( undef, $exitcode, $output ) = @_;
...
}
);
=cut
sub run_child
{
my $self = shift;
my %params = @_;
my $on_finish = delete $params{on_finish};
ref $on_finish or croak "Expected 'on_finish' to be a reference";
my $stdout;
my $stderr;
my %subparams;
if( my $child_stdin = delete $params{stdin} ) {
ref $child_stdin and croak "Expected 'stdin' not to be a reference";
$subparams{stdin} = { from => $child_stdin };
}
$subparams{code} = delete $params{code};
$subparams{command} = delete $params{command};
$subparams{setup} = delete $params{setup};
croak "Unrecognised parameters " . join( ", ", keys %params ) if keys %params;
require IO::Async::Process;
my $process = IO::Async::Process->new(
%subparams,
stdout => { into => \$stdout },
stderr => { into => \$stderr },
on_finish => sub {
my ( $process, $exitcode ) = @_;
$on_finish->( $process->pid, $exitcode, $stdout, $stderr );
},
);
$self->add( $process );
return $process->pid;
}
=head2 resolver
$loop->resolver
Returns the internally-stored L<IO::Async::Resolver> object, used for name
resolution operations by the C<resolve>, C<connect> and C<listen> methods.
=cut
sub resolver
{
my $self = shift;
return $self->{resolver} ||= do {
require IO::Async::Resolver;
my $resolver = IO::Async::Resolver->new;
$self->add( $resolver );
$resolver;
}
}
=head2 set_resolver
$loop->set_resolver( $resolver )
Sets the internally-stored L<IO::Async::Resolver> object. In most cases this
method should not be required, but it may be used to provide an alternative
resolver for special use-cases.
=cut
sub set_resolver
{
my $self = shift;
my ( $resolver ) = @_;
$resolver->can( $_ ) or croak "Resolver is unsuitable as it does not implement $_"
for qw( resolve getaddrinfo getnameinfo );
$self->{resolver} = $resolver;
$self->add( $resolver );
}
=head2 resolve
@result = $loop->resolve( %params )->get
This method performs a single name resolution operation. It uses an
internally-stored L<IO::Async::Resolver> object. For more detail, see the
C<resolve> method on the L<IO::Async::Resolver> class.
=cut
sub resolve
{
my $self = shift;
my ( %params ) = @_;
local/lib/perl5/IO/Async/Loop.pm view on Meta::CPAN
$host ||= "";
defined $service or $service = ""; # might be 0
my %gai_hints;
exists $params{$_} and $gai_hints{$_} = $params{$_} for qw( family socktype protocol flags );
defined $gai_hints{socktype} or defined $gai_hints{protocol} or
carp "Attempting to ->listen without either 'socktype' or 'protocol' hint is not portable";
$self->resolver->getaddrinfo(
host => $host,
service => $service,
passive => 1,
%gai_hints,
)->then( sub {
my @addrs = @_;
$self->_listen_addrs( $listener, \@addrs, %params );
});
}
=head1 OS ABSTRACTIONS
Because the Magic Constructor searches for OS-specific subclasses of the Loop,
several abstractions of OS services are provided, in case specific OSes need
to give different implementations on that OS.
=cut
=head2 signame2num
$signum = $loop->signame2num( $signame )
Legacy wrappers around L<IO::Async::OS> functions.
=cut
sub signame2num { shift; IO::Async::OS->signame2num( @_ ) }
=head2 time
$time = $loop->time
Returns the current UNIX time in fractional seconds. This is currently
equivalent to C<Time::HiRes::time> but provided here as a utility for
programs to obtain the time current used by L<IO::Async> for its own timing
purposes.
=cut
sub time
{
my $self = shift;
return Time::HiRes::time;
}
=head2 fork
$pid = $loop->fork( %params )
This method creates a new child process to run a given code block, returning
its process ID.
=over 8
=item code => CODE
A block of code to execute in the child process. It will be called in scalar
context inside an C<eval> block. The return value will be used as the
C<exit(2)> code from the child if it returns (or 255 if it returned C<undef> or
thows an exception).
=item on_exit => CODE
A optional continuation to be called when the child processes exits. It will
be invoked in the following way:
$on_exit->( $pid, $exitcode )
The second argument is passed the plain perl C<$?> value.
This key is optional; if not supplied, the calling code should install a
handler using the C<watch_child> method.
=item keep_signals => BOOL
Optional boolean. If missing or false, any CODE references in the C<%SIG> hash
will be removed and restored back to C<DEFAULT> in the child process. If true,
no adjustment of the C<%SIG> hash will be performed.
=back
=cut
sub fork
{
my $self = shift;
my %params = @_;
HAVE_POSIX_FORK or croak "POSIX fork() is not available";
my $code = $params{code} or croak "Expected 'code' as a CODE reference";
my $kid = fork;
defined $kid or croak "Cannot fork() - $!";
if( $kid == 0 ) {
unless( $params{keep_signals} ) {
foreach( keys %SIG ) {
next if m/^__(WARN|DIE)__$/;
$SIG{$_} = "DEFAULT" if ref $SIG{$_} eq "CODE";
}
}
my $exitvalue = eval { $code->() };
defined $exitvalue or $exitvalue = -1;
POSIX::_exit( $exitvalue );
}
if( defined $params{on_exit} ) {
$self->watch_child( $kid => $params{on_exit} );
}
return $kid;
}
=head2 create_thread
$tid = $loop->create_thread( %params )
This method creates a new (non-detached) thread to run the given code block,
returning its thread ID.
=over 8
=item code => CODE
A block of code to execute in the thread. It is called in the context given by
the C<context> argument, and its return value will be available to the
C<on_joined> callback. It is called inside an C<eval> block; if it fails the
exception will be caught.
=item context => "scalar" | "list" | "void"
Optional. Gives the calling context that C<code> is invoked in. Defaults to
C<scalar> if not supplied.
local/lib/perl5/IO/Async/Loop.pm view on Meta::CPAN
$self->unwatch_time( $id->[0] );
}
=head2 requeue_timer
$newid = $loop->requeue_timer( $id, %params )
Reschedule an existing timer, moving it to a new time. The old timer is
removed and will not be invoked.
The C<%params> hash takes the same keys as C<enqueue_timer>, except for the
C<code> argument.
The requeue operation may be implemented as a cancel + enqueue, which may
mean the ID changes. Be sure to store the returned C<$newid> value if it is
required.
This method should not be used in new code but is retained for legacy
purposes. For requeueable, consider using an L<IO::Async::Timer::Countdown> or
L<IO::Async::Timer::Absolute> instead.
=cut
sub requeue_timer
{
my $self = shift;
my ( $id, %params ) = @_;
$self->unwatch_time( $id->[0] );
return $self->enqueue_timer( %params, code => $id->[1] );
}
=head2 watch_idle
$id = $loop->watch_idle( %params )
This method installs a callback which will be called at some point in the near
future.
The C<%params> hash takes the following keys:
=over 8
=item when => STRING
Specifies the time at which the callback will be invoked. See below.
=item code => CODE
CODE reference to the continuation to run at the allotted time.
=back
The C<when> parameter defines the time at which the callback will later be
invoked. Must be one of the following values:
=over 8
=item later
Callback is invoked after the current round of IO events have been processed
by the loop's underlying C<loop_once> method.
If a new idle watch is installed from within a C<later> callback, the
installed one will not be invoked during this round. It will be deferred for
the next time C<loop_once> is called, after any IO events have been handled.
=back
If there are pending idle handlers, then the C<loop_once> method will use a
zero timeout; it will return immediately, having processed any IO events and
idle handlers.
The returned C<$id> value can be used to identify the idle handler in case it
needs to be removed, by calling the C<unwatch_idle> method. Note this value
may be a reference, so if it is stored it should be released after the
callback has been invoked or cancled, so the referrant itself can be freed.
This and C<unwatch_idle> are optional; a subclass may implement neither, or
both. If it implements neither then idle handling will be performed by the
base class, using the C<_adjust_timeout> and C<_manage_queues> methods.
=cut
sub watch_idle
{
my $self = shift;
my %params = @_;
my $code = delete $params{code};
ref $code or croak "Expected 'code' to be a reference";
my $when = delete $params{when} or croak "Expected 'when'";
# Future-proofing for other idle modes
$when eq "later" or croak "Expected 'when' to be 'later'";
my $deferrals = $self->{deferrals};
push @$deferrals, $code;
return \$deferrals->[-1];
}
=head2 unwatch_idle
$loop->unwatch_idle( $id )
Cancels a previously-installed idle handler.
=cut
sub unwatch_idle
{
my $self = shift;
my ( $id ) = @_;
my $deferrals = $self->{deferrals};
my $idx;
\$deferrals->[$_] == $id and ( $idx = $_ ), last for 0 .. $#$deferrals;
splice @$deferrals, $idx, 1, () if defined $idx;
}
sub _reap_children
{
my ( $childwatches ) = @_;
while( 1 ) {
my $zid = waitpid( -1, WNOHANG );
# PIDs on MSWin32 can be negative
last if !defined $zid or $zid == 0 or $zid == -1;
my $status = $?;
if( defined $childwatches->{$zid} ) {
$childwatches->{$zid}->( $zid, $status );
delete $childwatches->{$zid};
}
if( defined $childwatches->{0} ) {
$childwatches->{0}->( $zid, $status );
# Don't delete it
}
}
}
=head2 watch_child
$loop->watch_child( $pid, $code )
This method adds a new handler for the termination of the given child process
PID, or all child processes.
=over 8
=item $pid
The PID to watch. Will report on all child processes if this is 0.
=item $code
A CODE reference to the exit handler. It will be invoked as
$code->( $pid, $? )
The second argument is passed the plain perl C<$?> value.
=back
After invocation, the handler for a PID-specific watch is automatically
removed. The all-child watch will remain until it is removed by
C<unwatch_child>.
This and C<unwatch_child> are optional; a subclass may implement neither, or
both. If it implements neither then child watching will be performed by using
C<watch_signal> to install a C<SIGCHLD> handler, which will use C<waitpid> to
look for exited child processes.
If both a PID-specific and an all-process watch are installed, there is no
ordering guarantee as to which will be called first.
=cut
sub watch_child
{
my $self = shift;
my ( $pid, $code ) = @_;
my $childwatches = $self->{childwatches};
croak "Already have a handler for $pid" if exists $childwatches->{$pid};
if( HAVE_SIGNALS and !$self->{childwatch_sigid} ) {
$self->{childwatch_sigid} = $self->attach_signal(
CHLD => sub { _reap_children( $childwatches ) }
);
# There's a chance the child has already exited
my $zid = waitpid( $pid, WNOHANG );
if( defined $zid and $zid > 0 ) {
my $exitstatus = $?;
$self->later( sub { $code->( $pid, $exitstatus ) } );
return;
}
}
$childwatches->{$pid} = $code;
}
=head2 unwatch_child
$loop->unwatch_child( $pid )
This method removes a watch on an existing child process PID.
=cut
sub unwatch_child
{
my $self = shift;
my ( $pid ) = @_;
my $childwatches = $self->{childwatches};
delete $childwatches->{$pid};
if( HAVE_SIGNALS and !keys %$childwatches ) {
$self->detach_signal( CHLD => delete $self->{childwatch_sigid} );
}
}
=head1 METHODS FOR SUBCLASSES
The following methods are provided to access internal features which are
required by specific subclasses to implement the loop functionality. The use
cases of each will be documented in the above section.
=cut
=head2 _adjust_timeout
$loop->_adjust_timeout( \$timeout )
Shortens the timeout value passed in the scalar reference if it is longer in
seconds than the time until the next queued event on the timer queue. If there
are pending idle handlers, the timeout is reduced to zero.
=cut
sub _adjust_timeout
{
my $self = shift;
my ( $timeref, %params ) = @_;
$$timeref = 0, return if @{ $self->{deferrals} };
if( defined $self->{sigproxy} and !$params{no_sigwait} ) {
$$timeref = $MAX_SIGWAIT_TIME if !defined $$timeref or $$timeref > $MAX_SIGWAIT_TIME;
}
if( !HAVE_SIGNALS and keys %{ $self->{childwatches} } ) {
$$timeref = $MAX_CHILDWAIT_TIME if !defined $$timeref or $$timeref > $MAX_CHILDWAIT_TIME;
}
my $timequeue = $self->{timequeue};
return unless defined $timequeue;
my $nexttime = $timequeue->next_time;
return unless defined $nexttime;
my $now = exists $params{now} ? $params{now} : $self->time;
my $timer_delay = $nexttime - $now;
if( $timer_delay < 0 ) {
$$timeref = 0;
local/lib/perl5/IO/Async/Loop.pm view on Meta::CPAN
will become
$loop->FOO_connect(
extensions => [qw( BAR )],
%args
)
This is provided so that extension modules, such as L<IO::Async::SSL> can
easily be invoked indirectly, by passing extra arguments to C<connect> methods
or similar, without needing every module to be aware of the C<SSL> extension.
This functionality is generic and not limited to C<SSL>; other extensions may
also use it.
The following methods take an C<extensions> parameter:
$loop->connect
$loop->listen
If an extension C<listen> method is invoked, it will be passed a C<listener>
parameter even if one was not provided to the original C<< $loop->listen >>
call, and it will not receive any of the C<on_*> event callbacks. It should
use the C<acceptor> parameter on the C<listener> object.
=cut
=head1 STALL WATCHDOG
A well-behaved L<IO::Async> program should spend almost all of its time
blocked on input using the underlying C<IO::Async::Loop> instance. The stall
watchdog is an optional debugging feature to help detect CPU spinlocks and
other bugs, where control is not returned to the loop every so often.
If the watchdog is enabled and an event handler consumes more than a given
amount of real time before returning to the event loop, it will be interrupted
by printing a stack trace and terminating the program. The watchdog is only in
effect while the loop itself is not blocking; it won't fail simply because the
loop instance is waiting for input or timers.
It is implemented using C<SIGALRM>, so if enabled, this signal will no longer
be available to user code. (Though in any case, most uses of C<alarm()> and
C<SIGALRM> are better served by one of the L<IO::Async::Timer> subclasses).
The following environment variables control its behaviour.
=over 4
=item IO_ASYNC_WATCHDOG => BOOL
Enables the stall watchdog if set to a non-zero value.
=item IO_ASYNC_WATCHDOG_INTERVAL => INT
Watchdog interval, in seconds, to pass to the C<alarm(2)> call. Defaults to 10
seconds.
=item IO_ASYNC_WATCHDOG_SIGABRT => BOOL
If enabled, the watchdog signal handler will raise a C<SIGABRT>, which usually
has the effect of breaking out of a running program in debuggers such as
F<gdb>. If not set then the process is terminated by throwing an exception with
C<die>.
=back
=cut
=head1 AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
=cut
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