--- loncom/LONCAPA.pm	2006/05/30 19:26:34	1.4
+++ loncom/LONCAPA.pm	2006/07/03 10:26:22	1.12
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Base routines
 #
-# $Id: LONCAPA.pm,v 1.4 2006/05/30 19:26:34 albertel Exp $
+# $Id: LONCAPA.pm,v 1.12 2006/07/03 10:26:22 foxr Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -43,6 +43,8 @@ our @ISA = qw (Exporter);
 our @EXPORT = qw(&add_get_param &escape &unescape &tie_domain_hash &untie_domain_hash &tie_user_hash &untie_user_hash &propath);
 my %perlvar;
 
+
+
 # Inputs are a url, and a hash ref of
 # form name => value pairs
 # takes care of properly adding the form name elements and values to the 
@@ -167,6 +169,27 @@ sub untie_user_hash {
     return &_locking_hash_untie(@_);
 }
 
+# routines if you just have a filename
+# return tied hashref or undef
+
+sub locking_hash_tie {
+    my ($filename,$how)=@_;
+    my ($file_prefix,$namespace)=&db_filename_parts($filename);
+    if ($namespace eq '') { return undef; }
+    return &_locking_hash_tie($file_prefix,$namespace,$how);
+}
+
+sub locking_hash_untie {
+    return &_locking_hash_untie(@_);
+}
+
+sub db_filename_parts {
+    my ($filename)=@_;
+    my ($file_path,$namespace)=($filename=~/^(.*)\/([^\/]+)\.db$/);
+    if ($namespace eq '') { return undef; }
+    return ($file_path.'/'.$namespace,$namespace);
+}
+
 # internal routines that handle the actual tieing and untieing process
 
 sub _do_hash_tie {
@@ -176,11 +199,10 @@ sub _do_hash_tie {
 	# If this is a namespace for which a history is kept,
 	# make the history log entry:    
 	if (($namespace !~/^nohist\_/) && (defined($loghead))) {
-	    my $args = scalar @_;
 	    my $hfh = IO::File->new(">>$file_prefix.hist"); 
 	    if($hfh) {
-		my $now = time;
-		print $hfh "$loghead:$now:$what\n";
+		my $now = time();
+		print $hfh ("$loghead:$now:$what\n");
 	    }
 	    $hfh->close;
 	}
@@ -198,9 +220,32 @@ sub _do_hash_untie {
 
 {
     my $sym;
+    my @pushed_syms;
+
+    sub clean_sym {
+	undef($sym);
+    }
+    sub push_locking_hash_tie {
+	if (!defined($sym)) {
+	    die("Invalid used of push_locking_hash_tie, should only be called after a lock has occurred and before and unlock.");
+	}
+	push(@pushed_syms,$sym);
+	undef($sym);
+    }
+
+    sub pop_locking_hash_tie {
+	if (defined($sym)) {
+	    die("Invalid nested used of pop_locking_hash_tie, should only be called after a unlock has occurred.");
+	}
+	$sym = pop(@pushed_syms);
+    }
 
     sub _locking_hash_tie {
 	my ($file_prefix,$namespace,$how,$loghead,$what) = @_;
+	if (defined($sym)) {
+	    die('Nested locking attempted without proper use of push_locking_hash_tie, this is unsupported');
+	}
+
         my $lock_type=LOCK_SH;
 # Are we reading or writing?
         if ($how eq &GDBM_READER()) {
@@ -212,25 +257,34 @@ sub _do_hash_untie {
                if ((! -e "$file_prefix.db") && (! -e "$file_prefix.db.gz")) {
 # No such file. Forget it.                
                    $! = 2;
+		   &clean_sym();
                    return undef;
                }
 # Apparently just no lock file yet. Make one
                open($sym,">>$file_prefix.db.lock");
            }
 # Do a shared lock
-           if (!&flock_sym(LOCK_SH)) { return undef; } 
+           if (!&flock_sym(LOCK_SH)) { 
+	       &clean_sym();
+	       return undef; 
+	   } 
 # If this is compressed, we will actually need an exclusive lock
 	   if (-e "$file_prefix.db.gz") {
-	       if (!&flock_sym(LOCK_EX)) { return undef; }
+	       if (!&flock_sym(LOCK_EX)) {
+		   &clean_sym();
+		   return undef;
+	       }
 	   }
         } elsif ($how eq &GDBM_WRCREAT()) {
 # We are writing
            open($sym,">>$file_prefix.db.lock");
 # Writing needs exclusive lock
-           if (!&flock_sym(LOCK_EX)) { return undef; }
+           if (!&flock_sym(LOCK_EX)) {
+	       &clean_sym();
+	       return undef;
+	   }
         } else {
-           &logthis("Unknown method $how for $file_prefix");
-           die();
+           die("Unknown method $how for $file_prefix");
         }
 # The file is ours!
 # If it is archived, un-archive it now
@@ -272,7 +326,7 @@ sub _do_hash_untie {
 	my $result = untie(%$hashref);
 	flock($sym,LOCK_UN);
 	close($sym);
-	undef($sym);
+	&clean_sym();
 	return $result;
     }
 }