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wakaba |
1.1 |
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package Yuki::YukiWikiDB_Lock; |
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wakaba |
1.2 |
($VERSION) = q($Revision: 1.1 $) =~ m/\x20([\d.]+)\x20/; |
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wakaba |
1.1 |
use strict; |
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sub _make_lock_file_name ($$) { |
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my ($self, $o) = @_; |
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return sprintf '%s.%d.%d.%d.lock', $o->{prefix}, $o->{seq}, |
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$o->{time}, $o->{creation}; |
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} |
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sub _match_lock_file_name ($$%) { |
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my ($self, $fname, %o) = @_; |
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if ($fname =~ /^\Q$o{prefix}\E\.([0-9]+)\.([0-9]+)\.([0-9]+)\.lock$/) { |
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return {prefix => $o{prefix}, seq => $1, time => $2, |
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creation => $3}; |
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} |
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return undef; |
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} |
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## Lock |
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## Returns 1 if lock successed and 0 otherwise. |
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sub _lock ($$$;%) { |
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my ($self, $old_lock_name, $status, %opt) = @_; |
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## Share lock |
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if ($self->{-share}) { |
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if ($opt{force}) { # force lock |
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$status->{seq} = 0; |
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$status->{time} = time; |
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$status->{creation} = time; |
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} elsif ( # normal lock |
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($status->{seq} == 0 && $status->{time} == 0) # not locked |
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|| ($status->{seq} && $status->{time})) { # share locked |
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$status->{seq}++; ## Increase lock count |
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$status->{time} = time; ## Update locked date |
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$status->{creation} = time if $status->{seq} == 1; |
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} else { # Exclusively locked or unknown error |
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return 0; |
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} |
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## Exclusive lock |
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} else { |
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if ($opt{force} # force lock |
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|| ($status->{seq} == 0 && $status->{time} == 0)) { # not locked |
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$status->{seq} = 0; |
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$status->{time} = time; ## Locked date |
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$status->{creation} = time; |
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} else { # Already locked |
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return 0; |
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} |
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} |
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my $newname = $self->{-directory}.$self->_make_lock_file_name |
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($status); |
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if (rename $self->{-directory}.$old_lock_name => $newname) { |
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&{$self->{-error_handler}} ($self, level => 'detaillog', |
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msg => qq(_lock: $self->{-directory}$old_lock_name => $newname: locking successd)); |
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return 1; |
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} else { |
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&{$self->{-error_handler}} ($self, level => 'log', |
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msg => qq(_lock: $self->{-directory}$old_lock_name => $newname: $!)); |
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return 0; |
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} |
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} |
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sub _unlock ($$$) { |
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my ($self, $old_lock_name, $status) = @_; |
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## Share lock |
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if ($self->{-share}) { |
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if ($status->{seq} && $status->{time}) { |
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## I'm the last lock owner |
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if ($status->{seq} == 1) { |
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$status->{seq} = 0; |
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$status->{time} = 0; |
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$status->{creation} = 0; |
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} else { |
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$status->{seq}--; |
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#$status->{time} unchanged |
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} |
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} else { |
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return 0; |
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} |
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## Exclusive lock |
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} else { |
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if ($status->{seq} == 0 && $status->{time}) { |
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$status->{time} = 0; |
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$status->{creation} = 0; |
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} else { |
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return 0; |
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} |
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} |
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my $newname = $self->{-directory}.$self->_make_lock_file_name |
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($status); |
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if (rename $self->{-directory}.$old_lock_name => $newname) { |
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&{$self->{-error_handler}} ($self, level => 'detaillog', |
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msg => qq(_unlock: $self->{-directory}$old_lock_name => $newname: unlocking successed)); |
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return 1; |
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} else { |
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&{$self->{-error_handler}} ($self, level => 'log', |
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msg => qq(_unlock: $self->{-directory}$old_lock_name => $newname: $!)); |
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return 0; |
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} |
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} |
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## -directory => path Lock files' directory |
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## -name => 1*filename-char Base name of lock file |
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## -share => 0/1 |
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## - 1: Share lock |
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## - 0: Exclusive lock (default) |
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## -retry => -1/0/1.. |
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## - -1: No retry |
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## - 0: Infinite times of retries |
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## - n (n > 0): n times of retries (default 8) |
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## -timeout => n (second) (default 20) |
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## -error_handler => CODE : Error handler (default: die) |
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## |
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sub new ($%) { |
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my $class = shift; |
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my $self = bless {@_}, $class; |
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$self->{-retry} = 8 unless defined $self->{-retry}; |
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$self->{-timeout} ||= 20; |
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$self->{-error_handler} ||= sub { |
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my (undef, %o) = @_; |
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if ($o{level} eq 'fatal') { |
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die sprintf '%d: %s', scalar time, $o{msg}; |
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} else { |
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warn sprintf '%d: %s', scalar time, $o{msg}; |
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} |
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}; |
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$self->{-directory} .= '/' |
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unless substr ($self->{-directory}, -1) eq '/'; |
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return $self; |
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} |
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sub lock ($) { |
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my $self = shift; |
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return if $self->{locked}; |
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## Get lock file |
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my ($lockfile, $status) = $self->_make_new_lock (); |
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## Try locking |
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if ($self->_lock ($lockfile, $status)) { |
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## Success |
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$self->{creation} = $status->{creation}; |
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$self->{locked} = 1; |
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return 1; |
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} else { ## Failure |
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return 0 if $self->{-retry} == -1; # No retry |
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## How many times retry? |
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my $trytime = $self->{-retry} || $self->{-timeout}; |
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$trytime = $self->{-timeout} if $self->{-retry} > $trytime; |
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for (my $try = 0; $try < $trytime; $try++) { |
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my ($lockfile, $status) = $self->_make_new_lock (); |
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my $duration = time - $status->{time}; |
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## Expired lock |
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if ($self->{-timeout} < $duration) { |
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&{$self->{-error_handler}} ($self, level => 'log', |
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msg => qq(lock: $lockfile: lockfile already expired)); |
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if ($self->_lock ($lockfile, $status, force => 1)) { |
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$self->{creation} = $status->{creation}; |
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$self->{locked} = 1; |
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return 1; |
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} else { |
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&{$self->{-error_handler}} ($self, level => 'warn', |
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msg => qq(lock: force lock failed)); |
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# -> retry |
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} |
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## Locked |
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} else { |
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if ($self->_lock ($lockfile, $status)) { |
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$self->{creation} = $status->{creation}; |
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$self->{locked} = 1; |
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return 1; |
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} else { |
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# -> retry |
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} |
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} |
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## Wait |
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&{$self->{-error_handler}} ($self, level => 'log', |
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msg => qq(lock: retry ($try/$trytime) failed)); |
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sleep 1; # 1 second |
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} # for |
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} |
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return 0; |
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} |
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sub unlock ($) { |
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my $self = shift; |
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return unless $self->{locked}; |
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## Get lock file |
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my ($lockfile, $status) = $self->_make_new_lock (); |
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## Current lock file is not same as what was used to lock |
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if ($self->{creation} != $status->{creation}) { |
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&{$self->{-error_handler}} ($self, level => 'log', |
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msg => qq(unlock: $lockfile: original lock ($self->{creation}) was lost)); |
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$self->{creation} = undef; |
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$self->{locked} = 0; |
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return -1; |
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} |
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## Try unlocking |
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if ($self->_unlock ($lockfile, $status)) { |
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## Success |
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$self->{creation} = undef; |
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$self->{locked} = 0; |
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return 1; |
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} else { ## Failure |
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if ($self->{-retry} == -1) { # No retry |
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$self->{creation} = undef; |
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return 0; |
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} |
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## How many times retry? |
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my $trytime = $self->{-retry} || $self->{-timeout}; |
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$trytime = $self->{-timeout} if $self->{-retry} > $trytime; |
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for (my $try = 0; $try < $trytime; $try++) { |
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my ($lockfile, $status) = $self->_make_new_lock (); |
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## Current lock file is not same as what was used to lock |
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if ($self->{creation} != $status->{creation}) { |
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&{$self->{-error_handler}} ($self, level => 'log', |
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msg => qq(unlock: $lockfile: original lock ($self->{creation}) was lost)); |
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$self->{creation} = undef; |
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$self->{locked} = 0; |
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return -1; |
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} elsif ($self->_unlock ($lockfile, $status)) { |
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$self->{creation} = undef; |
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$self->{locked} = 0; |
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return 1; |
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} |
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## Wait |
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&{$self->{-error_handler}} ($self, level => 'log', |
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msg => qq(unlock: retry ($try/$trytime) failed)); |
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#sleep 1; # 1 second |
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} # for |
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} |
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$self->{creation} = undef; |
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return 0; |
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} |
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sub DESTROY ($) { |
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my $self = shift; |
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$self->unlock if $self->{locked}; |
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&{$self->{-error_handler}} ($self, level => 'log', msg => 'DESTROY'); |
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} |
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## Makes new lock file and returns its name. |
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## If already exists, returns its name. |
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sub _make_new_lock ($) { |
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my $self = shift; |
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my @lockfile; |
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opendir LOCKDIR, $self->{-directory} |
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or &{$self->{-error_handler}} |
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($self, msg => qq(_make_new_lock: $self->{-directory}: $!), |
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level => 'fatal'); { |
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my $pfx_length = length $self->{-name}; |
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@lockfile = grep {substr ($_, 0, $pfx_length) |
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eq $self->{-name}} |
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readdir LOCKDIR; |
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} closedir LOCKDIR; |
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my $lockfile; |
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my $status; |
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for (@lockfile) { |
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$status = $self->_match_lock_file_name |
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($_, prefix => $self->{-name}); |
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if ($status) { |
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$lockfile = $_; |
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last; |
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} |
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} |
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## Lock file not exist -- Make new lock file |
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unless ($lockfile) { |
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$status = {prefix => $self->{-name}, seq => 0, time => 0, |
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creation => 0}; |
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$lockfile = $self->_make_lock_file_name ($status); |
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open LOCKFILE, '>', $self->{-directory}.$lockfile |
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or &{$self->{-error_handler}} |
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($self, msg => qq(_make_new_lock: $self->{-directory}.$lockfile: $!), |
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level => 'fatal'); |
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print LOCKFILE scalar localtime; # dummy data |
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close LOCKFILE; |
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} |
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return ($lockfile, $status); |
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} |
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=head1 LICENSE |
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Copyright 2003 Wakaba <w@suika.fam.cx> |
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This program is free software; you can redistribute it and/or |
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modify it under the same terms as Perl itself. |
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=cut |
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wakaba |
1.2 |
1; # $Date: 2003/07/28 08:49:13 $ |
Parent Directory
| 
Revision Log