--- loncom/xml/run.pm	2002/05/23 21:15:34	1.29
+++ loncom/xml/run.pm	2004/07/13 19:12:46	1.47
@@ -1,6 +1,6 @@
 package Apache::run;
 #
-# $Id: run.pm,v 1.29 2002/05/23 21:15:34 albertel Exp $
+# $Id: run.pm,v 1.47 2004/07/13 19:12:46 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -27,88 +27,158 @@ package Apache::run;
 
 use HTML::Entities;
 
-$Apache::run::EVALUATE_STRING=<<'ENDEVALUATE';  
-  my %_LONCAPA_INTERNAL_oldexpressions=();
-  my $i=0;
-  while (!$_LONCAPA_INTERNAL_oldexpressions{$_}) {
+$Apache::run::EVALUATE_STRING=<<'ENDEVALUATE';
+my %_LONCAPA_INTERNAL_oldexpressions=();
+while (!$_LONCAPA_INTERNAL_oldexpressions{$_}) {
     $_LONCAPA_INTERNAL_oldexpressions{$_}=1;
-    $_ =~s/((?:\$|\&)(?:[\#|\$]*[A-Za-z][\w]*|\{[A-Za-z][\w]*\}))([\[\{][^\$\&\]\}]+[\]\}])*?(\([^\$\&\)]+\))*?(?=[^\[\{\(]|$)/eval(defined(eval($1.$2))?eval('$1.$2.$3'):'$1.$2.$3')/seg;
-    if ($i++ > 10 ) { last; }
-  }
+    $_ =~s/  # $1 will be the variable reference or subroutine name
+            ((?:\$|\&) #look for a starting $ or &
+             (?:[\#|\$]* #support $$ or $#$ etc.
+              [A-Za-z][\w]*| # get variable name
+              \{[A-Za-z][\w]*\})) # for ${a}
+             # $2 is 0 or more array dereferences []
+             #             or  hash dereferences {}
+             # the ^$ and ^& is because we do this iteratively
+             #    $a[$c] becomes $a[3] which then evaluates
+             ([\[\{][^\$\&\]\}]+[\]\}])*?
+             # $3 is the list of arguments
+             (\([^\$\&\)]+\))*?
+                # only match the above if there is not { [ ( coming up
+                # Why? (I.e. this fails &a(1)[2]
+                (?=[^\[\{\(]|$)/
+		 my ($__LC__a,$__LC__b,$__LC__c)=($1,$2,$3);
+		 my $__LC__prefix;
+		 my $result;
+		 while (1) {
+		     { 
+			 use strict;
+			 no strict "vars";
+			 if (eval(defined(eval($__LC__a.$__LC__b)))) {
+			     $result= $__LC__prefix.eval($__LC__a.$__LC__b.$__LC__c);
+			     last;
+			 }
+		     }
+		     $__LC__prefix.=substr($__LC__a,0,1,"");
+		     if ($__LC__a!~m-^(\$|&|\#)-) { last; }
+		 }
+		 if (!defined($result)) {
+		     $result=$__LC__prefix.$__LC__a.$__LC__b.$__LC__c;
+		 }
+		 $result;
+                  /sexg;
+    if (scalar(values(%_LONCAPA_INTERNAL_oldexpressions))>10) {last;}
+}
 ENDEVALUATE
 
 sub evaluate {
-  my ($expression,$safeeval,$decls) = @_;
-  unless (defined($expression)) { return ''; }
-  if (!$Apache::lonxml::evaluate) { return $expression; }
-  my $result = '';
-  $@='';
-  if ($Apache::lonxml::request) {
-    $Apache::lonxml::request->hard_timeout("Apache::run::run, evaluation $code");
-  }
-  $safeeval->reval('{'.$decls.';$_=<<\'EXPRESSION\';'."\n".$expression.
-		   "\n".'EXPRESSION'."\n".$EVALUATE_STRING.'}');
-  if ($Apache::lonxml::request) { $Apache::lonxml::request->kill_timeout; }
-#  $safeeval->reval('{'.$decls.';<< &evaluate(q|'.$expression.'|);}');
-  my $error=$@;
-  if ($@ eq '') {
-    $result = $safeeval->reval('return $_;');
-    chomp $result;
-  } else {
-    &Apache::lonxml::error('substitution on <pre>'.$expression.
-			   '</pre> with <pre>'.$decls.
-			   '</pre> caused <pre>'.$error);
-  }  
-  return $result
+    my ($expression,$safeeval,$decls) = @_;
+    unless (defined($expression)) { return ''; }
+    if ($Apache::lonxml::evaluate < 1) { return $expression; }
+    my $result = '';
+    $@='';
+    $Apache::run::timeout=0;
+    $main::SIG{'ALRM'} = sub {
+	$Apache::run::timeout=1;
+	die("timeout");
+    };
+    my $innererror;
+    $safeeval->permit("require");
+    eval {
+	alarm($Apache::lonnet::perlvar{'lonScriptTimeout'});
+	$safeeval->reval('{'.$decls.';$_=<<\'EXPRESSION\';'."\n".$expression.
+			 "\n".'EXPRESSION'."\n".$EVALUATE_STRING.'}');
+	$innererror=$@;
+	alarm(0);
+    };
+    $safeeval->deny("require");
+    my $error=$@;
+    if ($error eq '' && $innererror eq '' && !$Apache::run::timeout) {
+	$result = $safeeval->reval('return $_;');
+	chomp $result;
+    } else {
+	if ($Apache::run::timeout) {
+	    $error = 'Code ran too long. It ran for more than '.
+		$Apache::lonnet::perlvar{'lonScriptTimeout'}.' seconds';
+	}
+	&Apache::lonxml::error('substitution on <pre>'.
+			       &HTML::Entities::encode($expression,'<>&"').
+			       '</pre> with <pre>'.
+			       &HTML::Entities::encode($decls,'<>&"').
+			       '</pre> caused <pre>'.
+			       &HTML::Entities::encode($error,'<>&"').' '.
+			       &HTML::Entities::encode($innererror,'<>&"').
+			       '</pre>');
+    }
+    return $result
 }
 
 sub run {
-  my ($code,$safeeval,$hideerrors) = @_;
-#  print "inside run\n";
-  $@='';
-  if ($Apache::lonxml::request) {
-    $Apache::lonxml::request->hard_timeout("Apache::run::run, evaluation $code");
-  }
-  my (@result)=$safeeval->reval($code);
-  if ($Apache::lonxml::request) { $Apache::lonxml::request->kill_timeout; }
-  my $error=$@;
-  if ($error ne '' && !$hideerrors) {
-    &Apache::lonxml::error('<pre>'.&HTML::Entities::encode($error).
-			   '</pre> occured while running <pre>'.
-			   &HTML::Entities::encode($code).'</pre>');
-  }
-  if ( $#result < '1') {
-    return $result[0];
-  } else {
-    &Apache::lonxml::debug("<b>Got lots results</b>:$#result:");
-    return (@result);
-  }
+    my ($code,$safeeval,$hideerrors) = @_;
+    my @result;
+    $@='';
+    $Apache::run::timeout=0;
+    $main::SIG{'ALRM'} = sub {
+	$Apache::run::timeout=1;
+	die("timeout");
+    };
+    my $innererror;
+    eval {
+	alarm($Apache::lonnet::perlvar{'lonScriptTimeout'});
+	@result=$safeeval->reval($code);
+	$innererror=$@;
+	alarm(0);
+    };
+    my $error=$@;
+    if (($Apache::run::timeout || $error ne '' || $innererror ne '') && !$hideerrors) {
+	if ($Apache::run::timeout) {
+	    $error = 'Code ran too long. It ran for more than '.
+		$Apache::lonnet::perlvar{'lonScriptTimeout'}.' seconds';
+	}
+	my $errormsg='<pre>'.&HTML::Entities::encode($error,'<>&"').' '.
+	    &HTML::Entities::encode($innererror,'<>&"').
+	    '</pre> occured while running <pre>';
+	$code=&HTML::Entities::encode($code,'<>&"');
+	if ($innererror=~/line (\d+)/) {
+	    my $linenumber=$1;
+	    my @code=split("\n",$code);
+	    $code[$linenumber-1]='<b><font color="red">'.
+		$code[$linenumber-1].'</font></b>';
+	    $code=join("\n",@code);
+	}
+	&Apache::lonxml::error($errormsg.$code.'</pre>');
+    }
+    if ( $#result < '1') {
+	return $result[0];
+    } else {
+	&Apache::lonxml::debug("<b>Got lots results</b>:$#result:");
+	return (@result);
+    }
 }
 
 sub dump {
-  my ($target,$safeeval)=@_;
-  my $dump='';
-  foreach my $symname (sort keys %{$safeeval->varglob('main::')}) {
-    if (($symname!~/^\_/) && ($symname!~/\:$/)) {
-      my $line;
-      if ($safeeval->reval('defined($'.$symname.')')) {
-	$line='$'.$symname.'='.$safeeval->reval('$'.$symname);
-      }	
-      if ($safeeval->reval('defined(@'.$symname.')')) {
-	$line='@'.$symname.'=('.
-	  $safeeval->reval('join(",",@'.$symname.')').")";
-      }
-      if ($safeeval->reval('defined(%'.$symname.')')) {
-	$line='%'.$symname.'=(';
-	$line.=$safeeval->reval('join(",",map { $_."=>".$'.
-				$symname.'{$_} } sort keys %'.
-				$symname.')').")"
-      }
-      if ($line ne '') { $dump.=&HTML::Entities::encode($line)."<br />\n"; }
+    my ($target,$safeeval)=@_;
+    my $dump='';
+    foreach my $symname (sort keys %{$safeeval->varglob('main::')}) {
+	if (($symname!~/^\_/) && ($symname!~/\:$/)) {
+	    my $line;
+	    if ($safeeval->reval('defined($'.$symname.')')) {
+		$line='$'.$symname.'='.$safeeval->reval('$'.$symname);
+	    }	
+	    if ($safeeval->reval('defined(@'.$symname.')')) {
+		$line='@'.$symname.'=('.
+		    $safeeval->reval('join(",",@'.$symname.')').")";
+	    }
+	    if ($safeeval->reval('defined(%'.$symname.')')) {
+		$line='%'.$symname.'=(';
+		$line.=$safeeval->reval('join(",",map { $_."=>".$'.
+					$symname.'{$_} } sort keys %'.
+					$symname.')').")"
+				    }
+	    if ($line ne '') {$dump.=&HTML::Entities::encode($line,'<>&"')."<br />";}
+	}
     }
-  }
-  $dump.='';
-  return $dump;
+    $dump.='';
+    return $dump;
 }
 
 1;