+sub check_content (@) {
+ my %params=@_;
+
+ return 1 if ! exists $hooks{checkcontent}; # optimisation
+
+ if (exists $pagesources{$params{page}}) {
+ my @diff;
+ my %old=map { $_ => 1 }
+ split("\n", readfile(srcfile($pagesources{$params{page}})));
+ foreach my $line (split("\n", $params{content})) {
+ push @diff, $line if ! exists $old{$_};
+ }
+ $params{diff}=join("\n", @diff);
+ }