+=cut
+
+sub AddShare {
+ my ($shelfnumber, $key)= @_;
+ return if !$shelfnumber || !$key;
+
+ my $dbh = C4::Context->dbh;
+ my $sql = "INSERT INTO virtualshelfshares (shelfnumber, invitekey, sharedate) VALUES (?, ?, NOW())";
+ $dbh->do($sql, undef, ($shelfnumber, $key));
+ return !$dbh->err;
+}
+
+=head2 AcceptShare
+
+ my $result= AcceptShare($shelfnumber, $key, $borrowernumber);
+
+Checks acceptation of a share request.
+Key must be found for this shelf. Invitation must not have expired.
+Returns true when accepted, false otherwise.
+
+=cut
+
+sub AcceptShare {
+ my ($shelfnumber, $key, $borrowernumber)= @_;
+ return if !$shelfnumber || !$key || !$borrowernumber;
+
+ my $sql;
+ my $dbh = C4::Context->dbh;
+ $sql="
+UPDATE virtualshelfshares
+SET invitekey=NULL, sharedate=NOW(), borrowernumber=?
+WHERE shelfnumber=? AND invitekey=? AND (sharedate + INTERVAL ? DAY) >NOW()
+ ";
+ my $i= $dbh->do($sql, undef, ($borrowernumber, $shelfnumber, $key, SHARE_INVITATION_EXPIRY_DAYS));
+ return if !defined($i) || !$i || $i eq '0E0'; #not found
+ return 1;
+}
+
+=head2 IsSharedList
+
+ my $bool= IsSharedList( $shelfnumber );
+
+IsSharedList checks if a (private) list has shares.
+Note that such a check would not be useful for public lists. A public list has
+no shares, but is visible for anyone by nature..
+Used to determine the list type in the display of Your lists (all private).
+Returns boolean value.
+
+=cut
+
+sub IsSharedList {
+ my ($shelfnumber) = @_;
+ my $dbh = C4::Context->dbh;
+ my $sql="SELECT id FROM virtualshelfshares WHERE shelfnumber=? AND borrowernumber IS NOT NULL";
+ my $sth = $dbh->prepare($sql);
+ $sth->execute($shelfnumber);
+ my ($rv)= $sth->fetchrow_array;
+ return defined($rv);
+}
+
+=head2 RemoveShare
+
+ RemoveShare( $user, $shelfnumber );
+
+RemoveShare removes a share for specific shelf and borrower.
+Returns true if a record could be deleted.
+
+=cut
+
+sub RemoveShare {
+ my ($user, $shelfnumber)= @_;
+ my $dbh = C4::Context->dbh;
+ my $sql="
+DELETE FROM virtualshelfshares
+WHERE borrowernumber=? AND shelfnumber=?
+ ";
+ my $n= $dbh->do($sql,undef,($user, $shelfnumber));
+ return if !defined($n) || !$n || $n eq '0E0'; #nothing removed
+ return 1;