# Copyright (C) 2020-2021 all contributors
# License: AGPL-3.0+
# for systems lacking Linux::Inotify2 or IO::KQueue, just emulates
# enough of Linux::Inotify2
package PublicInbox::FakeInotify;
use strict;
use v5.10.1;
use parent qw(Exporter);
use Time::HiRes qw(stat);
use PublicInbox::DS qw(add_timer);
sub IN_MODIFY () { 0x02 } # match Linux inotify
# my $IN_MOVED_FROM 0x00000040 /* File was moved from X. */
# my $IN_MOVED_TO = 0x80;
# my $IN_CREATE = 0x100;
sub MOVED_TO_OR_CREATE () { 0x80 | 0x100 }
sub IN_DELETE () { 0x200 }
sub IN_DELETE_SELF () { 0x400 }
sub IN_MOVE_SELF () { 0x800 }
our @EXPORT_OK = qw(fill_dirlist on_dir_change);
my $poll_intvl = 2; # same as Filesys::Notify::Simple
sub new { bless { watch => {}, dirlist => {} }, __PACKAGE__ }
sub fill_dirlist ($$$) {
my ($self, $path, $dh) = @_;
my $dirlist = $self->{dirlist}->{$path} = {};
while (defined(my $n = readdir($dh))) {
$dirlist->{$n} = undef if $n !~ /\A\.\.?\z/;
}
}
# behaves like Linux::Inotify2->watch
sub watch {
my ($self, $path, $mask) = @_;
my @st = stat($path) or return;
my $k = "$path\0$mask";
$self->{watch}->{$k} = $st[10]; # 10 - ctime
if ($mask & IN_DELETE) {
opendir(my $dh, $path) or return;
fill_dirlist($self, $path, $dh);
}
bless [ $self->{watch}, $k ], 'PublicInbox::FakeInotify::Watch';
}
# also used by KQNotify since it kevent requires readdir on st_nlink
# count changes.
sub on_dir_change ($$$$$) {
my ($events, $dh, $path, $old_ctime, $dirlist) = @_;
my $oldlist = $dirlist->{$path};
my $newlist = $oldlist ? {} : undef;
while (defined(my $base = readdir($dh))) {
next if $base =~ /\A\.\.?\z/;
my $full = "$path/$base";
my @st = stat($full);
if (@st && $st[10] > $old_ctime) {
push @$events,
bless(\$full, 'PublicInbox::FakeInotify::Event')
}
if (!@st) {
# ignore ENOENT due to race
warn "unhandled stat($full) error: $!\n" if !$!{ENOENT};
} elsif ($newlist) {
$newlist->{$base} = undef;
}
}
return if !$newlist;
delete @$oldlist{keys %$newlist};
$dirlist->{$path} = $newlist;
push(@$events, map {
bless \"$path/$_", 'PublicInbox::FakeInotify::GoneEvent'
} keys %$oldlist);
}
# behaves like non-blocking Linux::Inotify2->read
sub read {
my ($self) = @_;
my $watch = $self->{watch} or return ();
my $events = [];
my @watch_gone;
for my $x (keys %$watch) {
my ($path, $mask) = split(/\0/, $x, 2);
my @now = stat($path);
if (!@now && $!{ENOENT} && ($mask & IN_DELETE_SELF)) {
push @$events, bless(\$path,
'PublicInbox::FakeInotify::SelfGoneEvent');
push @watch_gone, $x;
delete $self->{dirlist}->{$path};
}
next if !@now;
my $old_ctime = $watch->{$x};
$watch->{$x} = $now[10];
next if $old_ctime == $now[10];
if ($mask & IN_MODIFY) {
push @$events,
bless(\$path, 'PublicInbox::FakeInotify::Event')
} elsif ($mask & (MOVED_TO_OR_CREATE | IN_DELETE)) {
if (opendir(my $dh, $path)) {
on_dir_change($events, $dh, $path, $old_ctime,
$self->{dirlist});
} elsif ($!{ENOENT}) {
push @watch_gone, $x;
delete $self->{dirlist}->{$path};
} else {
warn "W: opendir $path: $!\n";
}
}
}
delete @$watch{@watch_gone};
@$events;
}
sub poll_once {
my ($obj) = @_;
$obj->event_step; # PublicInbox::InboxIdle::event_step
add_timer($poll_intvl, \&poll_once, $obj);
}
package PublicInbox::FakeInotify::Watch;
use strict;
sub cancel {
my ($self) = @_;
delete $self->[0]->{$self->[1]};
}
sub name {
my ($self) = @_;
(split(/\0/, $self->[1], 2))[0];
}
package PublicInbox::FakeInotify::Event;
use strict;
sub fullname { ${$_[0]} }
sub IN_DELETE { 0 }
sub IN_MOVED_FROM { 0 }
sub IN_DELETE_SELF { 0 }
package PublicInbox::FakeInotify::GoneEvent;
use strict;
our @ISA = qw(PublicInbox::FakeInotify::Event);
sub IN_DELETE { 1 }
sub IN_MOVED_FROM { 0 }
package PublicInbox::FakeInotify::SelfGoneEvent;
use strict;
our @ISA = qw(PublicInbox::FakeInotify::GoneEvent);
sub IN_DELETE_SELF { 1 }
1;