Persistent problem data - modify to retrieve from $envir

and to allow update and get operations. The webwork2 side
will now store this in a special field.
Includes changes and suggestions from Dr. Glenn Rice.
See: openwebwork#809

lib/PGcore.pm

@@ -73,10 +73,14 @@ sub new {
 		POST_HEADER_ARRAY => [],
 		#		PG_ANSWERS                => [],  # holds answers with labels # deprecated
 		#		PG_UNLABELED_ANSWERS      => [],  # holds unlabeled ans. #deprecated -replaced by PG_ANSWERS_HASH
-		PG_ANSWERS_HASH    => {},    # holds label=>answer pairs
-		PERSISTENCE_HASH   => {},    # holds other data, besides answers, which persists during a session and beyond
-		answer_eval_count  => 0,
-		answer_blank_count => 0,
+		PG_ANSWERS_HASH => {},    # holds label=>answer pairs
+
+		# Holds other data, besides answers, which persists during a session and beyond.
+		PERSISTENCE_HASH         => $envir->{PERSISTENCE_HASH} // {},    # Main data, received from DB
+		PERSISTENCE_HASH_UPDATED => {},    # Keys whose updated values should be saved by the DB
+
+		answer_eval_count            => 0,
+		answer_blank_count           => 0,
 		unlabeled_answer_blank_count => 0,
 		unlabeled_answer_eval_count  => 0,
 		KEPT_EXTRA_ANSWERS           => [],
@@ -538,17 +542,27 @@ sub record_unlabeled_array_name {
 }
 
 sub store_persistent_data {    # will store strings only (so far)
-	my $self    = shift;
-	my $label   = shift;
-	my @content = @_;
+	my ($self, $label, @values) = @_;
 	if (defined($self->{PERSISTENCE_HASH}->{$label})) {
 		warn "can' overwrite $label in persistent data";
 	} else {
-		$self->{PERSISTENCE_HASH}->{$label} = join("", @content);    #need base64 encoding?
+		$self->{PERSISTENCE_HASH_UPDATED}->{$label} = 1;
+		$self->{PERSISTENCE_HASH}->{$label}         = join("", @values);
 	}
 	$label;
 }
 
+sub update_persistent_data {    # will store strings only (so far)
+	my ($self, $label, @values) = @_;
+	$self->{PERSISTENCE_HASH_UPDATED}->{$label} = 1;
+	$self->{PERSISTENCE_HASH}->{$label}         = join("", @values);
+}
+
+sub get_persistent_data {
+	my ($self, $label) = @_;
+	return $self->{PERSISTENCE_HASH}->{$label};
+}
+
 sub check_answer_hash {
 	my $self = shift;
 	foreach my $key (keys %{ $self->{PG_ANSWERS_HASH} }) {

lib/WeBWorK/PG.pm

@@ -242,6 +242,11 @@ sub defineProblemEnvironment ($pg_envir, $options = {}, $image_generator = undef
 		pastDue            => $options->{pastDue}            // 0,
 		answersAvailable   => $options->{answersAvailable}   // 0,
 		isInstructor       => $options->{isInstructor}       // 0,
+		PERSISTENCE_HASH   => $options->{PERSISTENCE_HASH}   // {},
+
+		# The next has marks what data was updated and needs to be saved
+		# by the front end.
+		PERSISTENCE_HASH_UPDATED => {},
 
 		inputs_ref => $options->{inputs_ref},
 

macros/PG.pl

@@ -307,7 +307,18 @@ sub ANS_NUM_TO_NAME {
 }
 
 sub store_persistent_data {
-	$PG->store_persistent_data(@_);    #needs testing
+	my ($label, @values) = @_;
+	$PG->store_persistent_data($label, @values);
+}
+
+sub update_persistent_data {
+	my ($label, @values) = @_;
+	$PG->update_persistent_data($label, @values);
+}
+
+sub get_persistent_data {
+	my ($label) = @_;
+	return $PG->get_persistent_data($label);
 }
 
 sub RECORD_FORM_LABEL {    # this stores form data (such as sticky answers), but does nothing more
@@ -600,8 +611,7 @@ sub ENDDOCUMENT {
 			warn "$key is ", join("|", %{ $PG->{PG_ANSWERS_HASH}->{$key} });
 		}
 	}
-	push @KEPT_EXTRA_ANSWERS, keys %{ $PG->{PERSISTENCE_HASH} };
-	#Hackish way to store other persistence data
+
 	$PG->{flags}->{KEPT_EXTRA_ANSWERS} = \@KEPT_EXTRA_ANSWERS;
 	$PG->{flags}->{ANSWER_ENTRY_ORDER} = \@PG_ANSWER_ENTRY_ORDER;