throw error on "optimistic locking" failure detection

git-svn-id: svn://svn.open-ils.org/ILS/trunk@1836 dcc99617-32d9-48b4-a31d-7c20da2025e4

diff --git a/Open-ILS/src/perlmods/OpenILS/Application/Storage/CDBI.pm b/Open-ILS/src/perlmods/OpenILS/Application/Storage/CDBI.pm
index 7ec18e0..0155c96 100644 (file)
--- a/Open-ILS/src/perlmods/OpenILS/Application/Storage/CDBI.pm
+++ b/Open-ILS/src/perlmods/OpenILS/Application/Storage/CDBI.pm
@@ -245,6 +245,7 @@ sub create_from_fieldmapper {
 sub delete {
        my $self = shift;
        my $arg = shift;
+       my $orig = $self;
 
        my $class = ref($self) || $self;
 
@@ -258,7 +259,13 @@ sub delete {
 
        if ($class->find_column( 'last_xact_id' )) {
                my $xact_id = $self->current_xact_id;
-               throw Error unless ($xact_id);
+               
+               throw Error ("Deleting from $class requires a transaction be established")
+                       unless ($xact_id);
+               
+               throw Error ("The row you are attempting to delete has been changed since you read it")
+                       unless ( $orig->last_xact_id eq $self->last_xact_id);
+
                $self->last_xact_id( $class->current_xact_id );
                $self->SUPER::update;
        }
@@ -287,6 +294,7 @@ sub update {
 sub modify_from_fieldmapper {
        my $obj = shift;
        my $fm = shift;
+       my $orig = $obj;
 
        $log->debug("Modifying object using fieldmapper", DEBUG);
 
@@ -322,7 +330,10 @@ sub modify_from_fieldmapper {
 
        if ($class->find_column( 'last_xact_id' ) and $obj->is_changed) {
                my $xact_id = $obj->current_xact_id;
-               throw Error unless ($xact_id);
+               throw Error ("Updating $class requires a transaction be established")
+                       unless ($xact_id);
+               throw Error ("The row you are attempting to delete has been changed since you read it")
+                       unless ( $orig->last_xact_id eq $self->last_xact_id);
                $obj->last_xact_id( $xact_id );
        } else {
                $obj->autoupdate($au)