modules/File/UseList.pm

   1 package File::UseList;
   2
   3 #
   4 # File::UseList 1.1.1
   5 #
   6 # Run a list with files that are currently in use
   7 # (bases on Filing::UseList by Roland Bluethgen <calocybe@web.de>)
   8 #
   9 # Author:        Patrick Canterino <patshaping@gmx.net>
  10 # Last modified: 2003-10-17
  11 #
  12
  13 use strict;
  14
  15 use Carp qw(croak);
  16
  17 # new()
  18 #
  19 # Constructor
  20 #
  21 # Params: Hash: listfile => File with list of files in use
  22 #               lockfile => Lock file (Default: List file + .lock)
  23 #               timeout  => Lock timeout in seconds (Default: 10)
  24 #
  25 # Return: File::UseList object (Blessed Reference)
  26
  27 sub new(%)
  28 {
  29  my ($class,%args) = @_;
  30
  31  # Check if we got all the necessary information
  32
  33  croak "Missing path to list file"             unless($args{'listfile'});
  34  $args{'lockfile'} = $args{'listfile'}.".lock" unless($args{'lockfile'}); # Default filename of lock file
  35  $args{'timeout'}  = 10                        unless($args{'timeout'});  # Default timeout
  36
  37  # Add some other information
  38
  39  $args{'files'}  = [];
  40  $args{'locked'} = 0;
  41
  42  return bless(\%args,$class);
  43 }
  44
  45 # lock()
  46 #
  47 # Lock list with files
  48 # (delete lock file)
  49 #
  50 # Params: -nothing-
  51 #
  52 # Return: Status code (Boolean)
  53
  54 sub lock
  55 {
  56  my $self     = shift;
  57  my $lockfile = $self->{'lockfile'};
  58  my $timeout  = $self->{'timeout'};
  59
  60  return 1 if($self->{'locked'});
  61
  62  # Try to delete the lock file one time per second
  63  # until the timeout is reached
  64
  65  for(my $x=$timeout;$x>=0;$x--)
  66  {
  67   if(unlink($lockfile))
  68   {
  69    $self->{'locked'} = 1;
  70    return 1;
  71   }
  72
  73   sleep(1);
  74  }
  75
  76  # Timeout
  77
  78  return;
  79 }
  80
  81 # unlock()
  82 #
  83 # Unlock list with files, but only if _we_ locked it
  84 # (create lock file)
  85 #
  86 # Params: -nothing-
  87 #
  88 # Return: Status code (Boolean)
  89
  90 sub unlock
  91 {
  92  my $self     = shift;
  93  my $lockfile = $self->{'lockfile'};
  94  local *LOCKFILE;
  95
  96  if($self->{'locked'})
  97  {
  98   unless(-f $lockfile)
  99   {
 100    open(LOCKFILE,">",$lockfile) or return;
 101    close(LOCKFILE)              or return;
 102   }
 103
 104   $self->{'locked'} = 0;
 105   return 1;
 106  }
 107
 108  # The list wasn't lock by us or it isn't locked at all
 109
 110  return;
 111 }
 112
 113 # load()
 114 #
 115 # Load the list with files from the list file
 116 #
 117 # Params: -nothing-
 118 #
 119 # Return: Status code (Boolean)
 120
 121 sub load
 122 {
 123  my $self = shift;
 124  my $file = $self->{'listfile'};
 125  local *FILE;
 126
 127  # Read out the file and split the content line-per-line
 128
 129  open(FILE,"<",$file) or return;
 130  read(FILE, my $content, -s $file);
 131  close(FILE)          or return;
 132
 133  my @files = split(/\015\012|\012|\015/,$content);
 134
 135  # Remove useless lines
 136
 137  for(my $x=0;$x<@files;$x++)
 138  {
 139   if($files[$x] eq "" || $files[$x] =~ /^\s+$/)
 140   {
 141    splice(@files,$x,1);
 142    $x--; # <-- very important!
 143   }
 144  }
 145
 146  $self->{'files'} = \@files;
 147  return 1;
 148 }
 149
 150 # save()
 151 #
 152 # Write the list with files back to the list file
 153 #
 154 # Params: -nothing-
 155 #
 156 # Return: Status code (Boolean)
 157
 158 sub save
 159 {
 160  my $self  = shift;
 161  my $file  = $self->{'listfile'};
 162  my $temp  = $file.".temp";
 163  my $files = $self->{'files'};
 164  local *FILE;
 165
 166  my $data = (@$files) ? join("\n",@$files) : '';
 167
 168  open(FILE,">",$temp) or return;
 169  print FILE $data     or do { close(FILE); return };
 170  close(FILE)          or return;
 171
 172  rename($temp,$file)  or return;
 173
 174  return 1;
 175 }
 176
 177 # add_file()
 178 #
 179 # Add a file to the list
 180 #
 181 # Params: File
 182
 183 sub add_file($)
 184 {
 185  my ($self,$file) = @_;
 186  my $files = $self->{'files'};
 187
 188  # Check if the file is already in the list
 189
 190  return if($self->in_use($file));
 191
 192  push(@$files,$file);
 193 }
 194
 195 # remove_file()
 196 #
 197 # Remove a file from the list
 198 #
 199 # Params: File
 200
 201 sub remove_file($)
 202 {
 203  my ($self,$file) = @_;
 204  my $files = $self->{'files'};
 205
 206  # Check if the file is really in the list
 207
 208  return if($self->unused($file));
 209
 210  # Remove the file from the list
 211
 212  for(my $x=0;$x<@$files;$x++)
 213  {
 214   if($files->[$x] eq $file)
 215   {
 216    splice(@$files,$x,1);
 217    last;
 218   }
 219  }
 220 }
 221
 222 # in_use()
 223 #
 224 # Check if a file is in the list
 225 #
 226 # Params: File to check
 227 #
 228 # Return: Status code (Boolean)
 229
 230 sub in_use($)
 231 {
 232  my ($self,$file) = @_;
 233  my $files = $self->{'files'};
 234
 235  foreach(@$files)
 236  {
 237   return 1 if($_ eq $file);
 238  }
 239
 240  return;
 241 }
 242
 243 # unused()
 244 #
 245 # Check if a file is not in the list
 246 #
 247 # Params: File to check
 248 #
 249 # Return: Status code (Boolean)
 250
 251 sub unused($)
 252 {
 253  return not shift->in_use(shift);
 254 }
 255
 256 # it's true, baby ;-)
 257
 258 1;
 259
 260 #
 261 ### End ###