package index import ( "bytes" "github.com/asdine/storm/internal" "github.com/boltdb/bolt" ) // NewUniqueIndex loads a UniqueIndex func NewUniqueIndex(parent *bolt.Bucket, indexName []byte) (*UniqueIndex, error) { var err error b := parent.Bucket(indexName) if b == nil { if !parent.Writable() { return nil, ErrNotFound } b, err = parent.CreateBucket(indexName) if err != nil { return nil, err } } return &UniqueIndex{ IndexBucket: b, Parent: parent, }, nil } // UniqueIndex is an index that references unique values and the corresponding ID. type UniqueIndex struct { Parent *bolt.Bucket IndexBucket *bolt.Bucket } // Add a value to the unique index func (idx *UniqueIndex) Add(value []byte, targetID []byte) error { if value == nil || len(value) == 0 { return ErrNilParam } if targetID == nil || len(targetID) == 0 { return ErrNilParam } exists := idx.IndexBucket.Get(value) if exists != nil { if bytes.Equal(exists, targetID) { return nil } return ErrAlreadyExists } return idx.IndexBucket.Put(value, targetID) } // Remove a value from the unique index func (idx *UniqueIndex) Remove(value []byte) error { return idx.IndexBucket.Delete(value) } // RemoveID removes an ID from the unique index func (idx *UniqueIndex) RemoveID(id []byte) error { c := idx.IndexBucket.Cursor() for val, ident := c.First(); val != nil; val, ident = c.Next() { if bytes.Equal(ident, id) { return idx.Remove(val) } } return nil } // Get the id corresponding to the given value func (idx *UniqueIndex) Get(value []byte) []byte { return idx.IndexBucket.Get(value) } // All returns all the ids corresponding to the given value func (idx *UniqueIndex) All(value []byte, opts *Options) ([][]byte, error) { id := idx.IndexBucket.Get(value) if id != nil { return [][]byte{id}, nil } return nil, nil } // AllRecords returns all the IDs of this index func (idx *UniqueIndex) AllRecords(opts *Options) ([][]byte, error) { var list [][]byte c := internal.Cursor{C: idx.IndexBucket.Cursor(), Reverse: opts != nil && opts.Reverse} for val, ident := c.First(); val != nil; val, ident = c.Next() { if opts != nil && opts.Skip > 0 { opts.Skip-- continue } if opts != nil && opts.Limit == 0 { break } if opts != nil && opts.Limit > 0 { opts.Limit-- } list = append(list, ident) } return list, nil } // Range returns the ids corresponding to the given range of values func (idx *UniqueIndex) Range(min []byte, max []byte, opts *Options) ([][]byte, error) { var list [][]byte c := internal.RangeCursor{ C: idx.IndexBucket.Cursor(), Reverse: opts != nil && opts.Reverse, Min: min, Max: max, CompareFn: func(val, limit []byte) int { return bytes.Compare(val, limit) }, } for val, ident := c.First(); val != nil && c.Continue(val); val, ident = c.Next() { if opts != nil && opts.Skip > 0 { opts.Skip-- continue } if opts != nil && opts.Limit == 0 { break } if opts != nil && opts.Limit > 0 { opts.Limit-- } list = append(list, ident) } return list, nil } // first returns the first ID of this index func (idx *UniqueIndex) first() []byte { c := idx.IndexBucket.Cursor() for val, ident := c.First(); val != nil; val, ident = c.Next() { return ident } return nil }