# Copyright (C) 2018-2021 all contributors # License: AGPL-3.0+ # Base class for per-inbox locking package PublicInbox::Lock; use strict; use v5.10.1; use Fcntl qw(:flock :DEFAULT); use Carp qw(croak); use PublicInbox::OnDestroy; use File::Temp (); # we only acquire the flock if creating or reindexing; # PublicInbox::Import already has the lock on its own. sub lock_acquire { my ($self) = @_; 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_WRONLY|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, $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) = @_; $self->lock_acquire; PublicInbox::OnDestroy->new(@single_pid, \&lock_release, $self); } sub new_tmp { my ($cls, $ident) = @_; my $tmp = File::Temp->new("$ident.lock-XXXXXX", TMPDIR => 1); bless { lock_path => $tmp->filename, tmp => $tmp }, $cls; } 1;