+=item makesourceversions
+
+ @{$cgi_var{found}} = makesourceversions($cgi_var{package},undef,@{$cgi_var{found}});
+
+Canonicalize versions into source versions, which have an explicitly
+named source package. This is used to cope with source packages whose
+names have changed during their history, and with cases where source
+version numbers differ from binary version numbers.
+
+=cut
+
+our %_sourceversioncache = ();
+sub makesourceversions {
+ my $pkg = shift;
+ my $arch = shift;
+ my %sourceversions;
+
+ for my $version (@_) {
+ if ($version =~ m[/]) {
+ # Already a source version.
+ $sourceversions{$version} = 1;
+ } else {
+ my $cachearch = (defined $arch) ? $arch : '';
+ my $cachekey = "$pkg/$cachearch/$version";
+ if (exists($_sourceversioncache{$cachekey})) {
+ for my $v (@{$_sourceversioncache{$cachekey}}) {
+ $sourceversions{$v} = 1;
+ }
+ next;
+ }
+
+ my @srcinfo = binarytosource($pkg, $version, $arch);
+ unless (@srcinfo) {
+ # We don't have explicit information about the
+ # binary-to-source mapping for this version (yet). Since
+ # this is a CGI script and our output is transient, we can
+ # get away with just looking in the unversioned map; if it's
+ # wrong (as it will be when binary and source package
+ # versions differ), too bad.
+ my $pkgsrc = getpkgsrc();
+ if (exists $pkgsrc->{$pkg}) {
+ @srcinfo = ([$pkgsrc->{$pkg}, $version]);
+ } elsif (getsrcpkgs($pkg)) {
+ # If we're looking at a source package that doesn't have
+ # a binary of the same name, just try the same version.
+ @srcinfo = ([$pkg, $version]);
+ } else {
+ next;
+ }
+ }
+ $sourceversions{"$_->[0]/$_->[1]"} = 1 foreach @srcinfo;
+ $_sourceversioncache{$cachekey} = [ map { "$_->[0]/$_->[1]" } @srcinfo ];
+ }
+ }
+
+ return sort keys %sourceversions;
+}
+
+