ds: support add unique timers

A common pattern we use is to arm a timer once and prevent
it from being armed until it fires.  We'll be using it more
to do polling for saved searches and imports.

diff --git a/lib/PublicInbox/DS.pm b/lib/PublicInbox/DS.pm
index d804792bfd0cafbf13c5cb55853e73092e1c3a93..c89c7b8b40f4ddb4f9f89825e0c8a0c9f2e7edd6 100644 (file)
--- a/lib/PublicInbox/DS.pm
+++ b/lib/PublicInbox/DS.pm
@@ -32,7 +32,7 @@ use PublicInbox::Syscall qw(:epoll);
 use PublicInbox::Tmpfile;
 use Errno qw(EAGAIN EINVAL);
 use Carp qw(carp croak);
-our @EXPORT_OK = qw(now msg_more dwaitpid add_timer);
+our @EXPORT_OK = qw(now msg_more dwaitpid add_timer add_uniq_timer);
 
 my %Stack;
 my $nextq; # queue for next_tick
@@ -40,7 +40,7 @@ my $wait_pids; # list of [ pid, callback, callback_arg ]
 my $later_q; # list of callbacks to run at some later interval
 my $EXPMAP; # fd -> idle_time
 our $EXPTIME = 180; # 3 minutes
-my ($later_timer, $reap_armed, $exp_timer);
+my ($reap_armed, $exp_timer);
 my $ToClose; # sockets to close when event loop is done
 our (
      %DescriptorMap,             # fd (num) -> PublicInbox::DS object
@@ -51,6 +51,7 @@ our (
 
      $LoopTimeout,               # timeout of event loop in milliseconds
      @Timers,                    # timers
+     %UniqTimer,
      $in_loop,
      );
 
@@ -70,6 +71,7 @@ sub Reset {
                $in_loop = undef; # first in case DESTROY callbacks use this
                %DescriptorMap = ();
                @Timers = ();
+               %UniqTimer = ();
                $PostLoopCallback = undef;
 
                # we may be iterating inside one of these on our stack
@@ -81,9 +83,9 @@ sub Reset {
                $Epoll = undef; # may call DSKQXS::DESTROY
        } while (@Timers || keys(%Stack) || $nextq || $wait_pids ||
                $later_q || $ToClose || keys(%DescriptorMap) ||
-               $PostLoopCallback);
+               $PostLoopCallback || keys(%UniqTimer));
 
-       $reap_armed = $later_timer = $exp_timer = undef;
+       $reap_armed = $exp_timer = undef;
        $LoopTimeout = -1;  # no timeout by default
 }
 
@@ -97,36 +99,33 @@ immediately.
 =cut
 sub SetLoopTimeout { $LoopTimeout = $_[1] + 0 }
 
-=head2 C<< PublicInbox::DS::add_timer( $seconds, $coderef, $arg) >>
+sub _add_named_timer {
+       my ($name, $secs, $coderef, @args) = @_;
+       my $fire_time = now() + $secs;
+       my $timer = [$fire_time, $name, $coderef, @args];
 
-Add a timer to occur $seconds from now. $seconds may be fractional, but timers
-are not guaranteed to fire at the exact time you ask for.
-
-=cut
-sub add_timer ($$;@) {
-    my ($secs, $coderef, @args) = @_;
-
-    my $fire_time = now() + $secs;
-
-    my $timer = [$fire_time, $coderef, @args];
+       if (!@Timers || $fire_time >= $Timers[-1][0]) {
+               push @Timers, $timer;
+               return $timer;
+       }
 
-    if (!@Timers || $fire_time >= $Timers[-1][0]) {
-        push @Timers, $timer;
-        return $timer;
-    }
+       # Now, where do we insert?  (NOTE: this appears slow, algorithm-wise,
+       # but it was compared against calendar queues, heaps, naive push/sort,
+       # and a bunch of other versions, and found to be fastest with a large
+       # variety of datasets.)
+       for (my $i = 0; $i < @Timers; $i++) {
+               if ($Timers[$i][0] > $fire_time) {
+                       splice(@Timers, $i, 0, $timer);
+                       return $timer;
+               }
+       }
+       die "Shouldn't get here.";
+}
 
-    # Now, where do we insert?  (NOTE: this appears slow, algorithm-wise,
-    # but it was compared against calendar queues, heaps, naive push/sort,
-    # and a bunch of other versions, and found to be fastest with a large
-    # variety of datasets.)
-    for (my $i = 0; $i < @Timers; $i++) {
-        if ($Timers[$i][0] > $fire_time) {
-            splice(@Timers, $i, 0, $timer);
-            return $timer;
-        }
-    }
+sub add_timer { _add_named_timer(undef, @_) }
 
-    die "Shouldn't get here.";
+sub add_uniq_timer { # ($name, $secs, $coderef, @args) = @_;
+       $UniqTimer{$_[0]} //= _add_named_timer(@_);
 }
 
 # keeping this around in case we support other FD types for now,
@@ -184,31 +183,32 @@ sub next_tick () {
 
 # runs timers and returns milliseconds for next one, or next event loop
 sub RunTimers {
-    next_tick();
+       next_tick();
 
-    return (($nextq || $ToClose) ? 0 : $LoopTimeout) unless @Timers;
+       return (($nextq || $ToClose) ? 0 : $LoopTimeout) unless @Timers;
 
-    my $now = now();
+       my $now = now();
 
-    # Run expired timers
-    while (@Timers && $Timers[0][0] <= $now) {
-        my $to_run = shift(@Timers);
-        $to_run->[1]->(@$to_run[2..$#$to_run]);
-    }
+       # Run expired timers
+       while (@Timers && $Timers[0][0] <= $now) {
+               my $to_run = shift(@Timers);
+               delete $UniqTimer{$to_run->[1] // ''};
+               $to_run->[2]->(@$to_run[3..$#$to_run]);
+       }
 
-    # timers may enqueue into nextq:
-    return 0 if ($nextq || $ToClose);
+       # timers may enqueue into nextq:
+       return 0 if ($nextq || $ToClose);
 
-    return $LoopTimeout unless @Timers;
+       return $LoopTimeout unless @Timers;
 
-    # convert time to an even number of milliseconds, adding 1
-    # extra, otherwise floating point fun can occur and we'll
-    # call RunTimers like 20-30 times, each returning a timeout
-    # of 0.0000212 seconds
-    my $timeout = int(($Timers[0][0] - $now) * 1000) + 1;
+       # convert time to an even number of milliseconds, adding 1
+       # extra, otherwise floating point fun can occur and we'll
+       # call RunTimers like 20-30 times, each returning a timeout
+       # of 0.0000212 seconds
+       my $timeout = int(($Timers[0][0] - $now) * 1000) + 1;
 
-    # -1 is an infinite timeout, so prefer a real timeout
-    ($LoopTimeout < 0 || $LoopTimeout >= $timeout) ? $timeout : $LoopTimeout;
+       # -1 is an infinite timeout, so prefer a real timeout
+       ($LoopTimeout < 0 || $LoopTimeout >= $timeout) ? $timeout : $LoopTimeout
 }
 
 sub sig_setmask { sigprocmask(SIG_SETMASK, @_) or die "sigprocmask: $!" }
@@ -660,7 +660,7 @@ sub dwaitpid ($;$$) {
 
 sub _run_later () {
        my $q = $later_q or return;
-       $later_timer = $later_q = undef;
+       $later_q = undef;
        $Stack{later_q} = $q;
        $_->() for @$q;
        delete $Stack{later_q};
@@ -668,7 +668,7 @@ sub _run_later () {
 
 sub later ($) {
        push @$later_q, $_[0]; # autovivifies @$later_q
-       $later_timer //= add_timer(60, \&_run_later);
+       add_uniq_timer('later', 60, \&_run_later);
 }
 
 sub expire_old () {

diff --git a/lib/PublicInbox/LeiNoteEvent.pm b/lib/PublicInbox/LeiNoteEvent.pm
index c03c53193b032297da2d9abee056c3892a9844ab..18313359378d0bc79bc6406b28d4265947214a43 100644 (file)
--- a/lib/PublicInbox/LeiNoteEvent.pm
+++ b/lib/PublicInbox/LeiNoteEvent.pm
@@ -7,8 +7,8 @@ package PublicInbox::LeiNoteEvent;
 use strict;
 use v5.10.1;
 use parent qw(PublicInbox::IPC);
+use PublicInbox::DS;
 
-my $flush_timer;
 our $to_flush; # { cfgpath => $lei }
 
 sub flush_lei ($) {
@@ -20,7 +20,6 @@ sub flush_lei ($) {
 # we batch up writes and flush every 5s (matching Linux default
 # writeback behavior) since MUAs can trigger a storm of inotify events
 sub flush_task { # PublicInbox::DS timer callback
-       undef $flush_timer;
        my $todo = $to_flush // return;
        $to_flush = undef;
        for my $lei (values %$todo) { flush_lei($lei) }
@@ -29,7 +28,7 @@ sub flush_task { # PublicInbox::DS timer callback
 # sets a timer to flush
 sub note_event_arm_done ($) {
        my ($lei) = @_;
-       $flush_timer //= PublicInbox::DS::add_timer(5, \&flush_task);
+       PublicInbox::DS::add_uniq_timer('flush_timer', 5, \&flush_task);
        $to_flush->{$lei->{cfg}->{'-f'}} //= $lei;
 }