From 4b947adb56b6939fc2dc8a3f7e14c1dedc026041 Mon Sep 17 00:00:00 2001
From: Nathan Wallach <tani@technion.ac.il>
Date: Thu, 13 Apr 2023 18:42:22 +0300
Subject: [PATCH] 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:
 https://github.com/openwebwork/pg/pull/809

---
 lib/PGcore.pm     | 30 ++++++++++++++++++++++--------
 lib/WeBWorK/PG.pm |  5 +++++
 macros/PG.pl      | 16 +++++++++++++---
 3 files changed, 40 insertions(+), 11 deletions(-)

diff --git a/lib/PGcore.pm b/lib/PGcore.pm
index f711cc3686..88cfa015be 100755
--- a/lib/PGcore.pm
+++ b/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 %{ $self->{PG_ANSWERS_HASH} }) {
diff --git a/lib/WeBWorK/PG.pm b/lib/WeBWorK/PG.pm
index 662925b53e..2d2e8c519f 100644
--- a/lib/WeBWorK/PG.pm
+++ b/lib/WeBWorK/PG.pm
@@ -242,6 +242,11 @@ sub defineProblemEnvironment ($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},
 
diff --git a/macros/PG.pl b/macros/PG.pl
index 7fe996013b..a9e530eeb6 100644
--- a/macros/PG.pl
+++ b/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;