1 files changed, 47 insertions, 0 deletions
diff --git a/lib/PublicInbox/Inotify.pm b/lib/PublicInbox/Inotify.pm
new file mode 100644
index 00000000..c4f1ae84
--- /dev/null
+++ b/lib/PublicInbox/Inotify.pm
@@ -0,0 +1,47 @@
+# Copyright (C) all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+
+# wrap Linux::Inotify2 XS module, support pure Perl via `syscall' someday
+package PublicInbox::Inotify;
+use v5.12;
+our @ISA;
+BEGIN { # prefer pure Perl since it works out-of-the-box
+        my $isa;
+        for my $m (qw(PublicInbox::Inotify3 Linux::Inotify2)) {
+                eval "require $m";
+                next if $@;
+                $isa = $m;
+        }
+        if ($isa) {
+                push @ISA, $isa;
+                my $buf = '';
+                for (qw(IN_MOVED_TO IN_CREATE IN_DELETE IN_DELETE_SELF
+                                IN_MOVE_SELF IN_MOVED_FROM IN_MODIFY)) {
+                        $buf .= "*$_ = \\&PublicInbox::Inotify3::$_;\n";
+                }
+                eval $buf;
+                die $@ if $@;
+        } else {
+                die <<EOM;
+W: inotify syscall numbers unknown on your platform and
+W: Linux::Inotify2 missing: $@
+W: public-inbox hackers welcome the plain-text output of ./devel/sysdefs-list
+W: at meta\@public-inbox.org
+EOM
+        }
+};
+
+sub new {
+        $_[0]->SUPER::new // do {
+                my $msg = $!{EMFILE} ? <<EOM : "$_[0]->new: $!\n";
+inotify_init/inotify_init1: $!
+You may need to raise the `fs.inotify.max_user_instances' sysctl limit.
+Consult your OS documentation and/or sysctl(8) + sysctl.conf(5) manpages.
+EOM
+                $msg =~ s/^/E: /smg;
+                require Carp;
+                Carp::croak($msg);
+        }
+}
+
+1;