#!/usr/local/bin/perl

# PERL program to remove archived Strike probabilities.

@ARCHIVE = ("/data1/WWW/Tropical/StrikeProb/Archive","/data1/WWW/Tropical/StrikeProb/Archive/.Clip","/data1/WWW/Tropical/StrikeProb/Archive/.WML");  # Archive directories
$MaxTries = 10;     # Each try is .1 second.

$UseLocking = 1;
$LOCK_SH =  1;    # shared lock 
$LOCK_EX =  2;    # exclusive lock 
$LOCK_NB =  4;    # don't block when locking
$LOCK_UN =  8;    # unlock

foreach $ARCHIVE (@ARCHIVE) {

   opendir(ARCHDIR,"$ARCHIVE");  # Read Directory
   @archfiles = readdir(ARCHDIR);
   closedir(ARCHDIR);
   @archfiles = grep(/(\.html|\.wml)$/i,@archfiles);
   grep($_ = "$ARCHIVE/".$_,@archfiles);       # Add root to file names

   for ($nrepeat=0; $nrepeat<=0; ++$nrepeat) {
      if (scalar(@archfiles) >= 1) {
         $narch = $#archfiles;
         for ($i=0; $i<=$narch; $i++) {
            $file = shift(@archfiles);
            if (open(AFILE,"+>>$file")) {
               $lockerror = &LockFile(AFILE,$LOCK_EX);
               if ($lockerror) {   # can't get lock, probably writing which is OK
                  close(AFILE);
                  push(@archfiles,$file);  # Save to try again later
               } else {
                  close(AFILE);
                  unlink("$file");   # go ahead and delete
               }
            }
         }
      }
      if (scalar(@archfiles) >= 1) {sleep(1);} # Wait
   } 
}

exit(0);


sub LockFile {

    local(*FILE,$locktype) = @_;
    local($TrysLeft) = $MaxTries;

    if ($UseLocking) {
	# Try to get a lock on the file
	while ($TrysLeft--) {
	    
	    # Try to use locking, if it doesn't use locking, the eval would
	    # die.  Catch that, and don't use locking.

	    # Try to grab the lock with a non-blocking (4) exclusive (2) lock.
	    # (4 | 2 = 6)
	    $lockresult = eval("flock(FILE,$LOCK_NB|$locktype)");

	    if ($@) {
		#$UseLocking = 0;
		last;
	    }

	    if (!$lockresult) {
		select(undef,undef,undef,0.1); # Wait for 1/10 sec.
	    } else {
		last;		# We have gotten the lock.
	    }
	}
    } else {return -1;}

    if ($TrysLeft >= 0) {
	# Success!
	return 0;
    } else {
	return -1;
    }
}

sub UnlockFile {
    local(*FILE) = @_;

    if ($UseLocking) {
	flock(FILE,$LOCK_UN);			# Unlock the file.
    }
}