--- rat/lonuserstate.pm	2005/07/15 12:29:07	1.95
+++ rat/lonuserstate.pm	2006/02/23 08:38:54	1.99.2.1
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Construct and maintain state and binary representation of course for user
 #
-# $Id: lonuserstate.pm,v 1.95 2005/07/15 12:29:07 www Exp $
+# $Id: lonuserstate.pm,v 1.99.2.1 2006/02/23 08:38:54 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -31,7 +31,6 @@ package Apache::lonuserstate;
 
 # ------------------------------------------------- modules used by this module
 use strict;
-use Apache::Constants qw(:common :http);
 use HTML::TokeParser;
 use Apache::lonnet;
 use Apache::loncommon();
@@ -41,6 +40,7 @@ use Safe;
 use Safe::Hole;
 use Opcode;
 use Apache::lonenc;
+use Fcntl qw(:flock);
 
 # ---------------------------------------------------- Globals for this package
 
@@ -103,7 +103,7 @@ sub processversionfile {
 
 sub loadmap { 
     my $uri=shift;
-    if ($hash{'map_pc_'.$uri}) { return OK; }
+    if ($hash{'map_pc_'.$uri}) { return; }
 
     $pc++;
     my $lpc=$pc;
@@ -118,7 +118,7 @@ sub loadmap {
     unless (($fn=~/\.sequence$/) ||
             ($fn=~/\.page$/)) { 
 	$errtext.="Invalid map: $fn\n";
-	return OK; 
+	return; 
     }
 
     my $instr=&Apache::lonnet::getfile($fn);
@@ -164,7 +164,9 @@ sub loadmap {
                         if ($token->[2]->{'external'} eq 'true') { # external
                             $turi=~s/^http\:\/\//\/adm\/wrapper\/ext\//;
                         } elsif ($turi=~/^\/*uploaded\//) { # uploaded
-			    if (($embstyle eq 'img') || ($embstyle eq 'emb')) {
+			    if (($embstyle eq 'img') 
+				|| ($embstyle eq 'emb')
+				|| ($embstyle eq 'wrp')) {
                                 $turi='/adm/wrapper'.$turi;
 			    } elsif ($embstyle eq 'ssi') {
 				#do nothing with these
@@ -175,7 +177,9 @@ sub loadmap {
 			    my $mapdir=$uri;
 			    $mapdir=~s/[^\/]+$//;
 			    $turi=&Apache::lonnet::hreflocation($mapdir,$turi);
-			    if (($embstyle eq 'img') || ($embstyle eq 'emb')) {
+			    if (($embstyle eq 'img') 
+				|| ($embstyle eq 'emb')
+				|| ($embstyle eq 'wrp')) {
 				$turi='/adm/wrapper'.$turi;
 			    }
                         }
@@ -314,6 +318,8 @@ sub loadmap {
 
 sub simplify {
     my $expression=shift;
+# (0&1) = 1
+    $expression=~s/\(0\&(\d+)\)/$1/g;
 # (8)=8
     $expression=~s/\((\d+)\)/$1/g;
 # 8&8=8
@@ -323,8 +329,8 @@ sub simplify {
 # (5&3)&4=5&3&4
     $expression=~s/\((\d+)((?:\&\d+)+)\)\&(\d+\D)/$1$2\&$3/g;
 # (((5&3)|(4&6)))=((5&3)|(4&6))
-    $expression=~
-	s/\((\(\(\d+(?:\&\d+)*\)(?:\|\(\d+(?:\&\d+)*\))+\))\)/$1/g;
+#    $expression=~
+#	s/\((\(\(\d+(?:\&\d+)*\)(?:\|\(\d+(?:\&\d+)*\))+\))\)/$1/g;
 # ((5&3)|(4&6))|(1&2)=(5&3)|(4&6)|(1&2)
     $expression=~
 	s/\((\(\d+(?:\&\d+)*\))((?:\|\(\d+(?:\&\d+)*\))+)\)\|(\(\d+(?:\&\d+)*\))/\($1$2\|$3\)/g;
@@ -549,15 +555,21 @@ sub readmap {
 	return 'No course data available.';
     }
     @cond=('true:normal');
-    #unlink($fn.'.db');
-    #unlink($fn.'_symb.db');
-    unlink($fn.'.state');
-    unlink($fn.'parms.db');
+
+    open(LOCKFILE,">$fn.db.lock");
+    my $lock=0;
+    if (flock(LOCKFILE,LOCK_EX|LOCK_NB)) {
+	$lock=1;
+	unlink($fn.'.db');
+	unlink($fn.'_symb.db');
+	unlink($fn.'.state');
+	unlink($fn.'parms.db');
+    }
     undef %randompick;
     undef %hiddenurl;
     undef %encurl;
     $retfurl='';
-    if ((tie(%hash,'GDBM_File',"$fn.db",&GDBM_WRCREAT(),0640)) &&
+    if ($lock && (tie(%hash,'GDBM_File',"$fn.db",&GDBM_WRCREAT(),0640)) &&
 	(tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_WRCREAT(),0640))) {
 	%hash=();
 	%parmhash=();
@@ -605,13 +617,19 @@ sub readmap {
 		&Apache::lonnet::logthis("<font color=blue>WARNING: ".
 					 "Could not write statemap $fn for $uri.</font>"); 
 	    }
-	}  
+	}
+	flock(LOCKFILE,LOCK_UN);
+	close(LOCKFILE);
     } else {
 	# if we are here it is likely because we are already trying to 
 	# initialize the course in another child, busy wait trying to 
 	# tie the hashes for the next 90 seconds, if we succeed forward 
 	# them on to navmaps, if we fail, throw up the Could not init 
 	# course screen
+	if ($lock) {
+	    # Got the lock but not the DB files
+	    flock(LOCKFILE,LOCK_UN);
+	}
 	untie(%hash);
 	untie(%parmhash);
 	&Apache::lonnet::logthis("<font color=blue>WARNING: ".
@@ -620,7 +638,8 @@ sub readmap {
 	while($i<90) {
 	    $i++;
 	    sleep(1);
-	    if ((tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER(),0640))) {
+	    if (flock(LOCKFILE,LOCK_EX|LOCK_NB) &&
+		(tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER(),0640))) {
 		if (tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_READER(),0640)) {
 		    $retfurl='/adm/navmaps';
 		    &Apache::lonnet::appenv("request.course.id"  => $short,
@@ -634,6 +653,8 @@ sub readmap {
 	    untie(%hash);
 	    untie(%parmhash);
 	}
+	flock(LOCKFILE,LOCK_UN);
+	close(LOCKFILE);
     }
     &Apache::lonmsg::author_res_msg($env{'request.course.uri'},$errtext);
 # ------------------------------------------------- Check for critical messages