1 package Object::Remote::MiniLoop;
4 use Time::HiRes qw(time);
5 use Object::Remote::Logging qw( :log :dlog );
8 # this is ro because we only actually set it using local in sub run
10 has is_running => (is => 'ro', clearer => 'stop');
12 has _read_watches => (is => 'ro', default => sub { {} });
13 has _read_select => (is => 'ro', default => sub { IO::Select->new });
15 has _write_watches => (is => 'ro', default => sub { {} });
16 has _write_select => (is => 'ro', default => sub { IO::Select->new });
18 has _timers => (is => 'ro', default => sub { [] });
21 my ($self, $new_loop) = @_;
22 log_debug { "passing watches to new run loop" };
23 foreach my $fh ($self->_read_select->handles) {
26 on_read_ready => $self->_read_watches->{$fh}
29 foreach my $fh ($self->_write_select->handles) {
32 on_write_ready => $self->_write_watches->{$fh}
38 my ($self, %watch) = @_;
39 my $fh = $watch{handle};
40 Dlog_debug { "Adding IO watch for $_" } $fh;
42 #TODO if this works out non-blocking support
43 #will need to be integrated in a way that
44 #is compatible with Windows which has no
45 #non-blocking support - see also ::ReadChannel
47 Dlog_warn { "setting file handle to be non-blocking: $_" } $fh;
48 use Fcntl qw(F_GETFL F_SETFL O_NONBLOCK);
49 my $flags = fcntl($fh, F_GETFL, 0)
50 or die "Can't get flags for the socket: $!\n";
51 $flags = fcntl($fh, F_SETFL, $flags | O_NONBLOCK)
52 or die "Can't set flags for the socket: $!\n";
55 if (my $cb = $watch{on_read_ready}) {
56 log_trace { "IO watcher is registering with select for reading" };
57 $self->_read_select->add($fh);
58 $self->_read_watches->{$fh} = $cb;
60 if (my $cb = $watch{on_write_ready}) {
61 log_trace { "IO watcher is registering with select for writing" };
62 $self->_write_select->add($fh);
63 $self->_write_watches->{$fh} = $cb;
69 my ($self, %watch) = @_;
70 my $fh = $watch{handle};
71 Dlog_debug { "Removing IO watch for $_" } $fh;
72 if ($watch{on_read_ready}) {
73 log_trace { "IO watcher is removing read from select()" };
74 $self->_read_select->remove($fh);
75 delete $self->_read_watches->{$fh};
77 if ($watch{on_write_ready}) {
78 log_trace { "IO watcher is removing write from select()" };
79 $self->_write_select->remove($fh);
80 delete $self->_write_watches->{$fh};
86 my ($self, %watch) = @_;
87 my $at = $watch{at} || do {
88 die "watch_time requires at or after" unless my $after = $watch{after};
91 die "watch_time requires code" unless my $code = $watch{code};
92 my $timers = $self->_timers;
93 my $new = [ $at => $code ];
94 @{$timers} = sort { $a->[0] <=> $b->[0] } @{$timers}, $new;
95 log_debug { "Created new timer that expires at '$at'" };
100 my ($self, $id) = @_;
101 log_debug { "Removing timer with id of '$id'" };
102 @$_ = grep !($_ eq $id), @$_ for $self->_timers;
106 sub _next_timer_expires_delay {
108 my $timers = $self->_timers;
109 #undef means no timeout, select only returns
110 #when data is ready - when the system
111 #deadlocks the chatter from the timeout in
112 #select clogs up the logs
113 #TODO should make this an attribute
114 my $delay_max = undef;
116 return $delay_max unless @$timers;
117 my $duration = $timers->[0]->[0] - time;
119 log_trace { "next timer fires in '$duration' seconds " };
123 } elsif (defined $delay_max && $duration > $delay_max) {
124 $duration = $delay_max;
132 my $read = $self->_read_watches;
133 my $write = $self->_write_watches;
134 our $Loop_Entered = 1;
138 my $wait_time = $self->_next_timer_expires_delay;
139 log_trace { sprintf("Run loop: loop_once() has been invoked by $c[1]:$c[2] with read:%i write:%i select timeout:%s",
140 scalar(keys(%$read)), scalar(keys(%$write)), defined $wait_time ? $wait_time : 'indefinite' ) };
141 #TODO The docs state that select() in some instances can return a socket as ready to
142 #read data even if reading from it would block and the recomendation is to set
143 #handles used with select() as non-blocking but Perl on Windows can not set a
144 #handle to use non-blocking IO - If Windows is not one of the operating
145 #systems where select() returns a handle that could block it would work to
146 #enable non-blocking mode only under Posix - the non-blocking sysread()
147 #logic would work unmodified for both blocking and non-blocking handles
148 #under Posix and Windows.
149 my ($readable, $writeable) = IO::Select->select(
150 #TODO how come select() isn't used to identify handles with errors on them?
151 #TODO is there a specific reason for a half second maximum wait duration?
152 #The two places I've found for the runloop to be invoked don't return control
153 #to the caller until a controlling variable interrupts the loop that invokes
154 #loop_once() - is this to allow that variable to be polled and exit the
155 #run loop? If so why isn't that behavior event driven and causes select() to
157 $self->_read_select, $self->_write_select, undef, $wait_time
160 my $readable_count = defined $readable ? scalar(@$readable) : 0;
161 my $writable_count = defined $writeable ? scalar(@$writeable) : 0;
162 "Run loop: select returned readable:$readable_count writeable:$writable_count";
164 # I would love to trap errors in the select call but IO::Select doesn't
165 # differentiate between an error and a timeout.
170 log_trace { "Reading from all ready filehandles" };
171 foreach my $fh (@$readable) {
172 next unless $read->{$fh};
175 last if $Loop_Entered;
177 log_trace { "Writing to all ready filehandles" };
178 foreach my $fh (@$writeable) {
179 next unless $write->{$fh};
182 last if $Loop_Entered;
185 log_trace { "Read from $read_count filehandles; wrote to $write_count filehandles" };
186 my $timers = $self->_timers;
188 log_trace { "Checking timers" };
189 while (@$timers and $timers->[0][0] <= $now) {
190 Dlog_debug { "Found timer that needs to be executed: $_" } $timers->[0];
191 (shift @$timers)->[1]->();
192 last if $Loop_Entered;
194 log_trace { "Run loop: single loop is completed" };
198 #::Node and ::ConnectionServer use the want_run() / want_stop()
199 #counter to cause a run-loop to execute while something is active;
200 #the futures do this via a different mechanism
203 Dlog_debug { "Run loop: Incrimenting want_running, is now $_" }
204 ++$self->{want_running};
207 sub run_while_wanted {
209 log_debug { my $wr = $self->{want_running}; "Run loop: run_while_wanted() invoked; want_running: $wr" };
210 $self->loop_once while $self->{want_running};
211 log_debug { "Run loop: run_while_wanted() completed" };
217 if (! $self->{want_running}) {
218 log_debug { "Run loop: want_stop() was called but want_running was not true" };
221 Dlog_debug { "Run loop: decrimenting want_running, is now $_" }
222 --$self->{want_running};
225 #TODO Hypothesis: Futures invoke run() which gives that future
226 #it's own localized is_running attribute - any adjustment to the
227 #is_running attribute outside of that future will not effect that
228 #future so each future winds up able to call run() and stop() at
229 #will with out interfering with each other - how about having
230 #run loop until the future becomes ready?
233 log_trace { "Run loop: run() invoked" };
234 local $self->{is_running} = 1;
235 while ($self->is_running) {
238 log_trace { "Run loop: run() completed" };