diff options
Diffstat (limited to 'cmd/sklad/db.go')
| -rw-r--r-- | cmd/sklad/db.go | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/cmd/sklad/db.go b/cmd/sklad/db.go index a6cdda8..262a164 100644 --- a/cmd/sklad/db.go +++ b/cmd/sklad/db.go @@ -163,6 +163,7 @@ var errNoSuchContainer = errors.New("no such container") var errCannotChangeSeriesNotEmpty = errors.New( "cannot change the series of a non-empty container") var errCannotChangeNumber = errors.New("cannot change the number") +var errWouldContainItself = errors.New("container would contain itself") var errContainerInUse = errors.New("container is in use") // Find and filter out the container in O(n). @@ -204,19 +205,27 @@ func dbContainerCreate(c *Container) error { } func dbContainerUpdate(c *Container, updated Container) error { - newId := updated.Id() + newID := updated.Id() if updated.Series != c.Series && len(c.Children()) > 0 { return errCannotChangeSeriesNotEmpty } if updated.Number != c.Number { return errCannotChangeNumber } - if _, ok := indexContainer[newId]; ok && newId != c.Id() { + if _, ok := indexContainer[newID]; ok && newID != c.Id() { return errContainerAlreadyExists } if updated.Parent != c.Parent { + // Relying on the invariant that we can't change the ID + // of a non-empty container. + for pv := &updated; pv.Parent != ""; pv = indexContainer[pv.Parent] { + if pv.Parent == updated.Id() { + return errWouldContainItself + } + } + indexChildren[c.Parent] = filterContainer(indexChildren[c.Parent], c) - indexChildren[newId] = append(indexChildren[newId], c) + indexChildren[newID] = append(indexChildren[newID], c) } *c = updated return dbCommit() |