X-Git-Url: http://www.git.stargrave.org/?a=blobdiff_plain;f=lib%2FPublicInbox%2FLock.pm;h=0ee2a8bd60bd964a13c0c24f958f43e0ca9a6b5b;hb=HEAD;hp=693a37949a651f7935df09d6c58a785dc2322140;hpb=34c1a6c16733adee3acfe5861096692f3ea55378;p=public-inbox.git

diff --git a/lib/PublicInbox/Lock.pm b/lib/PublicInbox/Lock.pm
index 693a3794..0ee2a8bd 100644
--- a/lib/PublicInbox/Lock.pm
+++ b/lib/PublicInbox/Lock.pm
@@ -1,38 +1,60 @@
-# Copyright (C) 2018-2020 all contributors <meta@public-inbox.org>
+# Copyright (C) 2018-2021 all contributors <meta@public-inbox.org>
 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 
 # Base class for per-inbox locking
 package PublicInbox::Lock;
 use strict;
-use warnings;
+use v5.10.1;
 use Fcntl qw(:flock :DEFAULT);
 use Carp qw(croak);
+use PublicInbox::OnDestroy;
 
 # we only acquire the flock if creating or reindexing;
 # PublicInbox::Import already has the lock on its own.
 sub lock_acquire {
 	my ($self) = @_;
-	croak 'already locked' if $self->{lockfh};
-	my $lock_path = $self->{lock_path} or return;
-	sysopen(my $lockfh, $lock_path, O_WRONLY|O_CREAT) or
-		die "failed to open lock $lock_path: $!\n";
-	flock($lockfh, LOCK_EX) or die "lock failed: $!\n";
+	my $lock_path = $self->{lock_path};
+	croak 'already locked '.($lock_path // '(undef)') if $self->{lockfh};
+	return unless defined($lock_path);
+	sysopen(my $lockfh, $lock_path, O_RDWR|O_CREAT) or
+		croak "failed to open $lock_path: $!\n";
+	flock($lockfh, LOCK_EX) or croak "lock $lock_path failed: $!\n";
 	$self->{lockfh} = $lockfh;
 }
 
 sub lock_release {
-	my ($self) = @_;
-	return unless $self->{lock_path};
-	my $lockfh = delete $self->{lockfh} or croak 'not locked';
-
-	# NetBSD 8.1 and OpenBSD 6.5 (and maybe other versions/*BSDs) lack
-	# NOTE_CLOSE_WRITE from FreeBSD 11+, so trigger NOTE_WRITE, instead.
-	# We also need to change the ctime on Linux systems w/o inotify
-	if ($^O ne 'linux' || !eval { require Linux::Inotify2; 1 }) {
-		syswrite($lockfh, '.');
-	}
-	flock($lockfh, LOCK_UN) or die "unlock failed: $!\n";
-	close $lockfh or die "close failed: $!\n";
+	my ($self, $wake) = @_;
+	defined(my $lock_path = $self->{lock_path}) or return;
+	my $lockfh = delete $self->{lockfh} or croak "not locked: $lock_path";
+
+	syswrite($lockfh, '.') if $wake;
+
+	flock($lockfh, LOCK_UN) or croak "unlock $lock_path failed: $!\n";
+	close $lockfh or croak "close $lock_path failed: $!\n";
+}
+
+# caller must use return value
+sub lock_for_scope {
+	my ($self, @single_pid) = @_;
+	lock_acquire($self) or return; # lock_path not set
+	PublicInbox::OnDestroy->new(@single_pid, \&lock_release, $self);
+}
+
+sub lock_acquire_fast {
+	$_[0]->{lockfh} or return lock_acquire($_[0]);
+	flock($_[0]->{lockfh}, LOCK_EX) or croak "lock (fast) failed: $!";
+}
+
+sub lock_release_fast {
+	flock($_[0]->{lockfh} // return, LOCK_UN) or
+			croak "unlock (fast) $_[0]->{lock_path}: $!";
+}
+
+# caller must use return value
+sub lock_for_scope_fast {
+	my ($self, @single_pid) = @_;
+	lock_acquire_fast($self) or return; # lock_path not set
+	PublicInbox::OnDestroy->new(@single_pid, \&lock_release_fast, $self);
 }
 
 1;