// Open opens a database at the provided path.
// If the file does not exist then it will be created automatically.
func Open(path string) (*DB, error) {
db := &DB{}
db.keys = btree.New(16, nil)
db.exps = btree.New(16, &exctx{db})
db.idxs = make(map[string]*index)
db.config = Config{
SyncPolicy: EverySecond,
AutoShrinkPercentage: 100,
AutoShrinkMinSize: 32 * 1024 * 1024,
}
db.persist = path != ":memory:"
if db.persist {
var err error
// Hardcoding 0666 as the default mode.
db.file, err = os.OpenFile(path, os.O_CREATE|os.O_RDWR, 0666)
if err != nil {
return nil, err
}
if err := db.load(); err != nil {
_ = db.file.Close()
return nil, err
}
db.bufw = bufio.NewWriter(db.file)
}
// start the background manager.
go db.backgroundManager()
return db, nil
}
// createIndex is called by CreateIndex() and CreateSpatialIndex()
func (db *DB) createIndex(
name string,
pattern string,
less func(a, b string) bool,
rect func(item string) (min, max []float64),
) error {
db.mu.Lock()
defer db.mu.Unlock()
if db.closed {
return ErrDatabaseClosed
}
if name == "" {
return ErrIndexExists
}
if _, ok := db.idxs[name]; ok {
return ErrIndexExists
}
idx := &index{
name: name,
pattern: pattern,
less: less,
rect: rect,
db: db,
}
if less != nil {
idx.btr = btree.New(16, idx)
}
if rect != nil {
idx.rtr = rtree.New(idx)
}
db.keys.Ascend(func(item btree.Item) bool {
dbi := item.(*dbItem)
if !wildcardMatch(dbi.key, idx.pattern) {
return true
}
if less != nil {
idx.btr.ReplaceOrInsert(dbi)
}
if rect != nil {
idx.rtr.Insert(dbi)
}
return true
})
db.idxs[name] = idx
return nil
}