-# Lock.pm
-
-# ====================================================
-# Autor: n.d.p. / 2001-01-04
-# lm : n.d.p. / 2000-01-05
-# ====================================================
-# Funktion:
-# Sperren einer Datei
-# ====================================================
-
-use strict;
-
package Lock;
-use vars qw(@ISA @EXPORT_OK %EXPORT_TAGS $Timeout $violentTimeout $masterTimeout $iAmMaster);
-
-# ====================================================
-# Funktionsexport
-# ====================================================
+################################################################################
+# #
+# File: shared/Lock.pm #
+# #
+# Authors: Andre Malo <nd@o3media.de>, 2001-04-01 #
+# #
+# Description: file locking #
+# #
+################################################################################
-require Exporter;
-@ISA = qw(Exporter);
-
-@EXPORT_OK = qw(lock_file unlock_file write_lock_file write_unlock_file
- violent_unlock_file set_master_lock release_file);
-
-%EXPORT_TAGS = (READ => [qw(lock_file unlock_file violent_unlock_file)],
- WRITE => [qw(write_lock_file write_unlock_file violent_unlock_file)],
- ALL => [qw(lock_file unlock_file write_lock_file write_unlock_file
- violent_unlock_file set_master_lock release_file)]);
-
-# ====================================================
+use strict;
+use Carp;
+use vars qw(
+ @EXPORT_OK
+ %EXPORT_TAGS
+ $Timeout
+ $violentTimeout
+ $masterTimeout
+ $iAmMaster
+);
+
+################################################################################
+#
+# Export
+#
+use base qw(Exporter);
+
+@EXPORT_OK = qw(
+ lock_file
+ unlock_file
+ write_lock_file
+ write_unlock_file
+ violent_unlock_file
+ set_master_lock
+ release_file
+);
+
+%EXPORT_TAGS = (
+ READ => [qw(
+ lock_file
+ unlock_file
+ violent_unlock_file
+ )],
+ WRITE => [qw(
+ write_lock_file
+ write_unlock_file
+ violent_unlock_file
+ )],
+ ALL => [qw(
+ lock_file
+ unlock_file
+ write_lock_file
+ write_unlock_file
+ violent_unlock_file
+ set_master_lock
+ release_file
+ )]
+);
+
+################################################################################
+#
# Windows section (no symlinks)
-# ====================================================
-
-################################
-# sub w_lock_file
#
-# Schreibsperre setzen
-################################
+### sub w_lock_file ($;$) ######################################################
+#
+# set read lock (shared lock)
+# (for no-symlink-systems)
+#
+# Params: $filename - file to lock
+# $timeout - Lock Timeout (sec.)
+#
+# Return: Status Code (Bool)
+#
sub w_lock_file ($;$) {
- my $filename=shift;
- my ($timeout)=(shift (@_) or $Timeout);
- my $i;
+ my $filename = shift;
+ my $timeout = +shift || $Timeout;
if (-f &masterlockfile($filename)) {
+ for (0..$timeout) {
- for ($i=0 ; $i<=$timeout ; $i++) {
- # Referenzzaehler um eins erhoehen
+ # try to increment the reference counter
+ #
&set_ref($filename,1,$timeout) and return 1;
- sleep (1);}}
+ sleep (1);
+ }
+ }
else {
- # Mastersperre
- return undef;}
-
- 0; # Mist
+ # master lock is set
+ # or file has not been realeased yet
+ #
+ return;
+ }
+
+ # time out
+ # maybe the system is occupied
+ 0;
}
-################################
-# sub w_unlock_file
+### sub w_unlock_file ($;$) ####################################################
+#
+# remove read lock (shared lock)
+# (for no-symlink-systems)
+#
+# Params: $filename - locked file
+# $timeout - timeout (sec.)
+#
+# Return: Status Code (Bool)
#
-# Schreibsperre aufheben
-################################
-
sub w_unlock_file ($;$) {
- my $filename=shift;
- my ($timeout)=(shift (@_) or $Timeout);
+ my $filename = shift;
+ my $timeout = shift || $Timeout;
if (-f &masterlockfile($filename)) {
- # Referenzzaehler um eins erniedrigen
- &set_ref($filename,-1,$timeout) and return 1;}
- 0; # Mist
+ # try do decrement the reference counter
+ #
+ &set_ref($filename,-1,$timeout) and return 1;
+ }
+
+ # time out
+ # maybe the system is occupied
+ # or file has not been released yet
+ #
+ return;
}
-################################
-# sub w_write_lock_file
+### sub w_write_lock_file ($;$) ################################################
+#
+# set write lock (exclusive lock)
+# (for no-symlink-systems)
+#
+# Params: $filename - file to lock
+# $timeout - timeout (sec.)
+#
+# Return: Status Code (Bool)
#
-# Lese- und Schreibsperre
-# setzen
-################################
-
sub w_write_lock_file ($;$) {
my $filename=shift;
- my ($timeout)=(shift (@_) or $Timeout);
+ my $timeout= shift || $Timeout;
if (-f &masterlockfile($filename) or $iAmMaster) {
- # bevorstehenden Schreibzugriff anmelden
- &simple_lock ($filename,$timeout) or return 0;
-
- my $i;
- for ($i=0 ; $i<=$timeout ; $i++) {
- # Referenzdatei sperren
- &simple_lock (&reffile($filename),$timeout) or (return &simple_unlock($filename,$timeout) and 0);
- # Referenzzaehler = 0 ? => okay
+ # announce the write lock
+ # and wait $timeout seconds for
+ # references == 0 (no shared locks set)
+ #
+ &simple_lock ($filename,$timeout) or return;
+ for (0..$timeout) {
+ # lock reference counter
+ # or fail
+ #
+ unless (&simple_lock (&reffile($filename),$timeout)) {
+ &simple_unlock($filename,$timeout);
+ return;
+ }
+
+ # ready if we have no shared locks
+ #
return 1 if (&get_ref ($filename) == 0);
- # Referenzdatei wieder freigeben
- &simple_unlock (&reffile($filename),$timeout) or (return &simple_unlock($filename,$timeout) and 0);
- sleep(1);}
-
+ # release reference counter
+ # shared locks get the chance to be removed
+ #
+ unless (&simple_unlock (&reffile($filename),$timeout)) {
+ &simple_unlock($filename,$timeout);
+ return;
+ }
+ sleep(1);
+ }
+
+ # write lock failed
+ # remove the announcement
+ #
&simple_unlock ($filename);}
else {
- # Mastersperre gesetzt
- return undef;}
-
- 0; # Mist
+ # master lock is set
+ # or file has not been released yet
+ #
+ return;}
+
+ # time out
+ # maybe the system is occupied
+ #
+ 0;
}
-################################
-# sub w_write_unlock_file
+### sub w_write_unlock_file ($;$) ##############################################
+#
+# remove write lock (exclusive lock)
+# (for no-symlink-systems)
+#
+# Params: $filename - locked file
+# $timeout - timeout (sec.)
+#
+# Return: Status Code (Bool)
#
-# Lese- und Schreibsperre
-# aufheben
-################################
-
sub w_write_unlock_file ($;$) {
- my $filename=shift;
- my ($timeout)=(shift (@_) or $Timeout);
+ my $filename = shift;
+ my $timeout = shift || $Timeout;
if (-f &masterlockfile($filename) or $iAmMaster) {
- &simple_unlock (&reffile($filename),$timeout) or return 0; # Referenzdatei freigeben
- &simple_unlock ($filename,$timeout) or return 0;} # Lesesperre aufheben
- 1; # jawoll!
+ # remove reference counter lock
+ #
+ &simple_unlock (&reffile($filename),$timeout) or return;
+
+ # remove the write lock announce
+ #
+ &simple_unlock ($filename,$timeout) or return;}
+
+ # done
+ 1;
}
-################################
-# sub w_violent_unlock_file
+### sub w_violent_unlock_file ($) ##############################################
+#
+# remove any lock violent (excl. master lock)
+# (for no-symlink-systems)
+#
+# Params: $filename - locked file
+#
+# Return: -none- (the success is not defined)
#
-# Sperre brutal aufheben
-################################
-
sub w_violent_unlock_file ($) {
- my $filename=shift;
+ my $filename = shift;
if (-f &masterlockfile($filename)) {
- # Zeit der letzten Modifikation feststellen
- # und abbrechen, wenn meine Zeit noch nicht gekommen ist
+ # find out last modification time
+ # and do nothing unless 'violent-timout' is over
+ #
my $reffile;
if (-f ($reffile = $filename) or -f ($reffile = &lockfile($filename))) {
my $time = (stat $reffile)[9];
return if ((time - $time) < $violentTimeout);}
- write_lock_file ($filename,1); # letzter Versuch, exklusiven Zugriff zu bekommen
- unlink (&reffile($filename)); # Referenzzaehler auf null
- simple_unlock (&reffile($filename)); # Referenzdatei freigeben
- simple_unlock ($filename);} # Datei freigeben (Lesesperre aufheben)
+ write_lock_file ($filename,1); # last try, to set an exclusive lock on $filename
+ unlink (&reffile($filename)); # reference counter = 0
+ simple_unlock (&reffile($filename)); # release reference counter file
+ simple_unlock ($filename);} # release file
+
+ return;
}
-################################
-# sub w_set_master_lock
+### sub w_set_master_lock ($;$) ################################################
+#
+# set master lock
+# (for no-symlink-systems)
+#
+# Params: $filename - file to lock
+# $timeout - timeout (sec.)
+#
+# Return: Status Code (Bool)
#
-# Mastersperre setzen
-################################
-
sub w_set_master_lock ($;$) {
- my $filename=shift;
- my $timeout=(shift @_ or $masterTimeout);
+ my $filename = shift;
+ my $timeout = shift || $masterTimeout;
- # exklusiven Zugriff erlangen...oder abbrechen
- return 0 unless (&write_lock_file ($filename,$timeout));
+ # set exclusive lock or fail
+ #
+ return unless (&write_lock_file ($filename,$timeout));
- # Mastersperre setzen und Erfolg melden
+ # set master lock
+ #
unlink &masterlockfile($filename) and return 1;
- 0; # Mist
+ # no chance (occupied?, master lock set yet?)
+ return;
}
-################################
-# sub w_release_file
+### sub w_release_file ($) #####################################################
+#
+# remove any locks (incl. master lock)
+# (for no-symlink-systems)
+#
+# Params: $filename - file to lock
+# $timeout - timeout (sec.)
+#
+# Return: Status Code (Bool)
#
-# Alle Sperren inkl. Master-
-# sperre aufheben
-################################
-
sub w_release_file ($) {
my $filename=shift;
- unlink (&reffile($filename)); # Referenzzaehler auf null
- return 0 if (-f &reffile($filename)); # wirklich?
- return 0 unless (simple_unlock (&reffile($filename))); # Referenzzaehler freigeben
- return 0 unless (&simple_unlock ($filename)); # Datei selbst freigeben (Lesesperre)
- return 0 unless (&simple_unlock (&masterfile($filename))); # Mastersperre aufheben
+ unlink (&reffile($filename)); # reference counter = 0
+ return if (-f &reffile($filename)); # really?
+ return unless (simple_unlock (&reffile($filename))); # release reference counter
+ return unless (&simple_unlock ($filename)); # remove any write lock announce
+ return unless (&simple_unlock (&masterfile($filename))); # remove master lock
- 1; # jup
+ # done
+ 1;
}
-# ====================================================
+################################################################################
+#
# *n*x section (symlinks possible)
-# ====================================================
-
-################################
-# sub x_lock_file
#
-# Schreibsperre setzen
-################################
+### sub x_lock_file ($;$) ######################################################
+#
+# set read lock (shared lock)
+# (symlinks possible)
+#
+# Params: $filename - file to lock
+# $timeout - Lock Timeout (sec.)
+#
+# Return: Status Code (Bool)
+#
sub x_lock_file ($;$) {
- my $filename=shift;
- my ($timeout)=(shift (@_) or $Timeout);
- my $i;
+ my $filename = shift;
+ my $timeout = shift || $Timeout;
unless (-l &masterlockfile($filename)) {
+ for (0..$timeout) {
- for ($i=0 ; $i<=$timeout ; $i++) {
- # Referenzzaehler um eins erhoehen
+ # try to increment the reference counter
+ #
&set_ref($filename,1,$timeout) and return 1;
- sleep (1);}}
+ sleep (1);
+ }
+ }
else {
- # Mastersperre
- return undef;}
-
- 0; # Mist
+ # master lock is set
+ # or file has not been realeased yet
+ #
+ return;
+ }
+
+ # time out
+ # maybe the system is occupied
+ 0;
}
-################################
-# sub x_unlock_file
+### sub x_unlock_file ($;$) ####################################################
+#
+# remove read lock (shared lock)
+# (symlinks possible)
+#
+# Params: $filename - locked file
+# $timeout - timeout (sec.)
+#
+# Return: Status Code (Bool)
#
-# Schreibsperre aufheben
-################################
-
sub x_unlock_file ($;$) {
my $filename=shift;
my ($timeout)=(shift (@_) or $Timeout);
unless (-l &masterlockfile($filename)) {
- # Referenzzaehler um eins erniedrigen
+ # try do decrement the reference counter
+ #
&set_ref($filename,-1,$timeout) and return 1;}
- 0; # Mist
+ # time out
+ # maybe the system is occupied
+ # or file has not been released yet
+ #
+ return;
}
-################################
-# sub x_write_lock_file
+### sub x_write_lock_file ($;$) ################################################
+#
+# set write lock (exclusive lock)
+# (symlinks possible)
+#
+# Params: $filename - file to lock
+# $timeout - timeout (sec.)
+#
+# Return: Status Code (Bool)
#
-# Lese- und Schreibsperre
-# setzen
-################################
-
sub x_write_lock_file ($;$) {
- my $filename=shift;
- my ($timeout)=(shift (@_) or $Timeout);
+ my $filename = shift;
+ my $timeout = shift || $Timeout;
unless (-l &masterlockfile($filename) and not $iAmMaster) {
- # bevorstehenden Schreibzugriff anmelden
- &simple_lock ($filename,$timeout) or return 0;
-
- my $i;
- for ($i=0 ; $i<=$timeout ; $i++) {
- # Referenzdatei sperren
- &simple_lock (&reffile($filename),$timeout) or (return &simple_unlock($filename,$timeout) and 0);
-
- # Referenzzaehler = 0 ? => okay
+ # announce the write lock
+ # and wait $timeout seconds for
+ # references == 0 (no shared locks set)
+ #
+ &simple_lock ($filename,$timeout) or return;
+ for (0..$timeout) {
+
+ # lock reference counter
+ # or fail
+ #
+ unless (&simple_lock (&reffile($filename),$timeout)) {
+ &simple_unlock($filename,$timeout);
+ return;
+ }
+
+ # ready if we have no shared locks
+ #
return 1 if (&get_ref ($filename) == 0);
- # Referenzdatei wieder freigeben
- &simple_unlock (&reffile($filename),$timeout) or (return &simple_unlock($filename,$timeout) and 0);
- sleep(1);}
-
+ # release reference counter
+ # shared locks get the chance to be removed
+ #
+ unless (&simple_unlock (&reffile($filename),$timeout)) {
+ &simple_unlock($filename,$timeout);
+ return;
+ }
+ sleep(1);
+ }
+
+ # write lock failed
+ # remove the announcement
+ #
&simple_unlock ($filename);}
else {
- # Mastersperre gesetzt
- return undef;}
-
- 0; # Mist
+ # master lock is set
+ # or file has not been released yet
+ #
+ return;
+ }
+
+ # time out
+ # maybe the system is occupied
+ #
+ 0;
}
-################################
-# sub x_write_unlock_file
+### sub x_write_unlock_file ($;$) ##############################################
+#
+# remove write lock (exclusive lock)
+# (symlinks possible)
+#
+# Params: $filename - locked file
+# $timeout - timeout (sec.)
+#
+# Return: Status Code (Bool)
#
-# Lese- und Schreibsperre
-# aufheben
-################################
-
sub x_write_unlock_file ($;$) {
- my $filename=shift;
- my ($timeout)=(shift (@_) or $Timeout);
+ my $filename = shift;
+ my $timeout = shift || $Timeout;
unless (-l &masterlockfile($filename) and not $iAmMaster) {
- &simple_unlock (&reffile($filename),$timeout) or return 0; # Referenzdatei freigeben
- &simple_unlock ($filename,$timeout) or return 0;} # Lesesperre aufheben
+ # remove reference counter lock
+ #
+ &simple_unlock (&reffile($filename),$timeout) or return;
+
+ # remove the write lock announce
+ #
+ &simple_unlock ($filename,$timeout) or return;
+ }
- 1; # jawoll!
+ # done
+ 1;
}
-################################
-# sub x_violent_unlock_file
+### sub x_violent_unlock_file ($) ##############################################
+#
+# remove any lock violent (excl. master lock)
+# (symlinks possible)
+#
+# Params: $filename - locked file
+#
+# Return: -none- (the success is not defined)
#
-# Sperre brutal aufheben
-################################
-
sub x_violent_unlock_file ($) {
my $filename=shift;
unless (-l &masterlockfile($filename)) {
- # Zeit der letzten Modifikation feststellen
- # und abbrechen, wenn meine Zeit noch nicht gekommen ist
+ # find out last modification time
+ # and do nothing unless 'violent-timout' is over
+ #
my ($reffile,$time);
if (-f ($reffile = $filename)) {
if ($reffile) {
return if ((time - $time) < $violentTimeout);}
- write_lock_file ($filename,1); # letzter Versuch, exklusiven Zugriff zu bekommen
- unlink (&reffile($filename)); # Referenzzaehler auf null
- simple_unlock (&reffile($filename)); # Referenzdatei freigeben
- simple_unlock ($filename);} # Datei freigeben (Lesesperre aufheben)
+ write_lock_file ($filename,1); # last try, to set an exclusive lock on $filename
+ unlink (&reffile($filename)); # reference counter = 0
+ simple_unlock (&reffile($filename)); # release reference counter file
+ simple_unlock ($filename);} # release file
}
-################################
-# sub x_set_master_lock
+### sub x_set_master_lock ($;$) ################################################
+#
+# set master lock
+# (symlinks possible)
+#
+# Params: $filename - file to lock
+# $timeout - timeout (sec.)
+#
+# Return: Status Code (Bool)
#
-# Mastersperre setzen
-################################
-
sub x_set_master_lock ($;$) {
- my $filename=shift;
- my $timeout=(shift @_ or $masterTimeout);
+ my $filename = shift;
+ my $timeout = shift || $masterTimeout;
- # exklusiven Zugriff erlangen...oder abbrechen
- return 0 unless (&write_lock_file ($filename,$timeout));
+ # set exclusive lock or fail
+ #
+ return unless (&write_lock_file ($filename,$timeout));
- # Mastersperre setzen und Erfolg melden
+ # set master lock
+ #
symlink $filename, &masterlockfile($filename) and return 1;
- 0; # Mist
+ # no chance (occupied?, master lock set yet?)
+ return;
}
-################################
-# sub x_release_file
+### sub x_release_file ($) #####################################################
+#
+# remove any locks (incl. master lock)
+# (symlinks possible)
+#
+# Params: $filename - file to lock
+# $timeout - timeout (sec.)
+#
+# Return: Status Code (Bool)
#
-# Alle Sperren inkl. Master-
-# sperre aufheben
-################################
-
sub x_release_file ($) {
my $filename=shift;
- unlink (&reffile($filename)); # Referenzzaehler auf null
- return 0 if (-f &reffile($filename)); # wirklich?
- return 0 unless (simple_unlock (&reffile($filename))); # Referenzzaehler freigeben
- return 0 unless (&simple_unlock ($filename)); # Datei selbst freigeben (Lesesperre)
- return 0 unless (&simple_unlock (&masterfile($filename))); # Mastersperre aufheben
+ unlink (&reffile($filename)); # reference counter = 0
+ return if (-f &reffile($filename)); # really?
+ return unless (simple_unlock (&reffile($filename))); # release reference counter
+ return unless (&simple_unlock ($filename)); # remove any write lock announce
+ return unless (&simple_unlock (&masterfile($filename))); # remove master lock
- 1; # jup
+ # done
+ 1;
}
-# ====================================================
+################################################################################
+#
# private subs
-# ====================================================
-
-################################
-# Dateinamen
-################################
+#
+### sub ~file ($) ##############################################################
+#
+# create lock file names
+#
sub reffile ($) {
"$_[0].lock.ref";
}
&lockfile(&masterfile($_[0]));
}
sub masterfile ($) {
+ confess unless defined $_[0];
"$_[0].master";
}
-################################
-# einfaches Sperren/Entsperren
-# Windows
+### sub w_simple_lock ($;$) ####################################################
+### sub w_simple_unlock ($) ####################################################
+#
+# simple file lock/unlock
+# (for no-symlink-systems: kill/create lockfile)
+#
+# Params: $filename - file to lock
+# [ $timeout - Lock time out (sec.) ]
+#
+# Return: Status Code (Bool)
#
-# (Lockdatei loeschen)
-################################
-
sub w_simple_lock ($;$) {
- my $filename=shift;
- my ($timeout)=(shift (@_) or $Timeout);
- my $lockfile=&lockfile($filename);
-
- my $i;
- for ($i=$timeout; $i>=0; $i--) {
- unlink("$lockfile") and return 1;
- sleep(1);}
-
- 0; # Mist
+ my $filename = shift;
+ my $timeout = shift || $Timeout;
+ my $lockfile = lockfile $filename;
+
+ for (0..$timeout) {
+ unlink $lockfile and return 1;
+ sleep(1);
+ }
+
+ # timeout
+ # occupied?
+ return;
}
sub w_simple_unlock ($) {
- my $filename=shift;
- my $lockfile=&lockfile($filename);
- my $flag=1;
+ my $filename = shift;
+ my $lockfile = lockfile $filename;
local *LF;
- open(LF, ">$lockfile") or $flag=0;
- close(LF) or $flag=0;
+ if (open(LF, "> $lockfile")) {
+ return 1 if close (LF);
+ }
- # Rueckgabe
- $flag;
+ # not able to create lockfile, hmmm...
+ #
+ return;
}
-################################
-# einfaches Sperren/Entsperren
-# *n*x
+### sub w_simple_lock ($;$) ####################################################
+### sub w_simple_unlock ($) ####################################################
+#
+# simple file lock/unlock
+# (symlinks possible: create/unlink symlink)
+#
+# Params: $filename - file to lock
+# [ $timeout - Lock time out (sec.) ]
+#
+# Return: Status Code (Bool)
#
-# (symlink setzen)
-################################
-
sub x_simple_lock ($;$) {
- my $filename=shift;
- my ($timeout)=(shift (@_) or $Timeout);
- my $lockfile=&lockfile($filename);
+ my $filename = shift;
+ my $timeout = shift || $Timeout;
+ my $lockfile = lockfile $filename;
- my $i;
- for ($i=$timeout; $i>=0; $i--) {
+ for (0..$timeout) {
symlink $filename,$lockfile and return 1;
- sleep(1);}
+ sleep(1);
+ }
- 0; # Mist
+ # time out
+ # locking failed (occupied?)
+ #
+ return;
}
sub x_simple_unlock ($) {
unlink (&lockfile($filename)) and return 1;
- 0; # hmmm...
+ # not able to unlink symlink, hmmm...
+ #
+ return;
}
-################################
-# sub w_set_ref
-# Windows
+### sub w_set_ref ($$$) ########################################################
+#
+# add $_[1] to reference counter
+# (may be negative...)
+# (for no-symlink-systems)
+#
+# Params: $filename - file, reference counter belongs to
+# $z - value, added to reference counter
+# $timeout - lock time out
+#
+# Return: Status Code (Bool)
#
-# Referenzzaehler um $_[1]
-# erhoehen
-# (kann auch negativ sein...)
-################################
-
sub w_set_ref ($$$) {
- my ($filename,$z)=@_;
- my $timeout=(shift @_ or $Timeout);
+ my $filename = shift;
+ my $z = shift;
+ my $timeout = shift || $Timeout;
my $old;
- my $reffile=&reffile($filename);
+ my $reffile = reffile $filename;
local *REF;
-
- # runterzaehlen - ja, neue Leseversuche - nein
+ # if write lock announced, only count down allowed
+ #
if ($z > 0) {
- return 0 unless(-e &lockfile($filename));}
+ return unless(-f lockfile($filename));
+ }
- # Referenzdatei locken
- return 0 unless(&simple_lock ($reffile,$timeout));
+ # lock reference counter file
+ #
+ return unless(&simple_lock ($reffile,$timeout));
- # Referenzdatei auslesen
+ # load reference counter
+ #
unless (open REF,"<$reffile") {
- $old=0;}
+ $old=0;
+ }
else {
$old=<REF>;
chomp $old;
- close REF or return 0;}
+ close REF or return;
+ }
- # Neuen Referenzwert schreiben
- $old+=$z;
- $old=0 if ($old < 0);
- open REF,">$reffile" or return 0;
- print REF $old;
- close REF or return 0;
+ # compute and write new ref. counter
+ #
+ $old += $z;
+ $old = 0 if ($old < 0);
- # wieder entsperren
- return 0 unless(&simple_unlock($reffile));
+ # kill reference counter file
+ # if ref. counter == 0
+ #
+ if ($old == 0) {
+ unlink $reffile or return;
+ }
+ else {
+ open REF,">$reffile" or return;
+ print REF $old or return;
+ close REF or return;
+ }
+
+ # release ref. counter file
+ #
+ return unless(&simple_unlock($reffile));
+ # done
1;
}
-################################
-# sub x_set_ref
-# *n*x
+### sub x_set_ref ($$$) ########################################################
+#
+# add $_[1] to reference counter
+# (may be negative...)
+# (symlinks possible)
+#
+# Params: $filename - file, reference counter belongs to
+# $z - value, added to reference counter
+# $timeout - lock time out
+#
+# Return: Status Code (Bool)
#
-# Referenzzaehler um $_[1]
-# erhoehen
-# (kann auch negativ sein...)
-################################
-
sub x_set_ref ($$$) {
- my ($filename,$z)=@_;
- my $timeout=(shift @_ or $Timeout);
+ my $filename = shift;
+ my $z = shift;
+ my $timeout = shift || $Timeout;
my $old;
- my $reffile=&reffile($filename);
+ my $reffile = reffile $filename;
local *REF;
-
- # runterzaehlen - ja, neue Leseversuche - nein
+ # if write lock announced, only count down allowed
+ #
if ($z > 0) {
- return 0 if(-l &lockfile($filename));}
+ return if(-l &lockfile($filename));
+ }
- # Referenzdatei locken
- return 0 unless(&simple_lock ($reffile,$timeout));
+ # lock reference counter file
+ #
+ return unless(&simple_lock ($reffile,$timeout));
- # Referenzdatei auslesen
+ # load reference counter
+ #
unless (open REF,"<$reffile") {
- $old=0;}
+ $old=0;
+ }
else {
$old=<REF>;
chomp $old;
- close REF or return 0;}
+ close REF or return;
+ }
- # Neuen Referenzwert schreiben
+ # compute and write new ref. counter
+ #
$old += $z;
$old = 0 if ($old < 0);
- open REF,">$reffile" or return 0;
- print REF $old;
- close REF or return 0;
+ if ($old == 0) {
+ unlink $reffile or return;
+ }
+ else {
+ open REF,">$reffile" or return;
+ print REF $old or return;
+ close REF or return;
+ }
- # wieder entsperren
- return 0 unless(&simple_unlock($reffile));
+ # release ref. counter file
+ #
+ return unless(&simple_unlock($reffile));
+ # done
1;
}
-################################
-# sub get_ref
+### sub get_ref ($) ############################################################
#
-# Referenzzaehler auslesen
+# read out the reference counter
+# (system independant)
+# no locking here!
+#
+# Params: $filename - file, the ref. counter belongs to
+#
+# Return: reference counter
#
-# Das Locking muss an
-# anderer Stelle ausgefuehrt
-# werden!
-################################
-
sub get_ref ($$) {
- my $filename=shift;
- my $reffile=&reffile($filename);
+ my $filename = shift;
+ my $reffile = reffile $filename;
my $old;
local *REF;
- unless (open REF,"<$reffile") {
- $old=0;}
+ unless (open REF,"< $reffile") {
+ $old = 0;
+ }
else {
$old=<REF>;
chomp $old;
- close REF or return 0;}
+ close REF;
+ }
- # Rueckgabe
+ # return value
$old;
}
-# ====================================================
-# Modulinitialisierung
-# ====================================================
-
+################################################################################
+#
+# initializing the module
+#
BEGIN {
- # Globale Variablen (Zeiten in Sekunden)
- $Timeout = 10; # normaler Timeout
- $violentTimeout = 600; # zum gewaltsamen Entsperren (10 Minuten)
- $masterTimeout = 20; # fuer die Mastersperre
+ # global variables (time in seconds)
+ #
+ $Timeout = 10; # normal timeout
+ $violentTimeout = 600; # violent timeout (10 minutes)
+ $masterTimeout = 20; # master timeout
- $iAmMaster = 0; # erstmal bin ich kein Master :-)
+ $iAmMaster = 0; # default: I am nobody
- # wirkliche Funktionen ihren Bezeichnern zuweisen
+ # assign the aliases to the needed functions
# (perldoc -f symlink)
if ( eval {local $SIG{__DIE__}; symlink('',''); 1 } ) {
*simple_lock = \&x_simple_lock;
*simple_unlock = \&x_simple_unlock;
- *set_ref = \&x_set_ref;}
+ *set_ref = \&x_set_ref;
+ }
else {
*lock_file = \&w_lock_file;
*simple_lock = \&w_simple_lock;
*simple_unlock = \&w_simple_unlock;
- *set_ref = \&w_set_ref;}
+ *set_ref = \&w_set_ref;
+ }
}
-# making require happy
+# keeping require happy
1;
-# ====================================================
-# end of Lock
-# ====================================================
\ No newline at end of file
+#
+#
+### end of Lock ################################################################
\ No newline at end of file
git.p6c8.net / selfforum.git / blobdiff