// key顺序扫描，常用于数据导出、附近搜索
// 返回的key是面向用户的key，而非内部结构的raw_key
func (l *LevelRedis) KeyEnumerate(seek []byte, direction IterDirection, fn func(i int, key, keytype, value []byte, quit *bool)) {
var iter *gorocks.Iterator
if l.snap != nil {
iter = l.db.NewIterator(l.ro)
} else {
ro := gorocks.NewReadOptions()
ro.SetFillCache(false)
defer ro.Close()
iter = l.db.NewIterator(ro)
}
defer iter.Close()
minkey := joinStringBytes(KEY_PREFIX, SEP_LEFT, string(seek))
maxkey := []byte{MAXBYTE}
prefix := joinStringBytes(KEY_PREFIX, SEP_LEFT)
l.Enumerate(iter, minkey, maxkey, direction, func(i int, key, value []byte, quit *bool) {
if !bytes.HasPrefix(key, prefix) {
*quit = true
return
}
left := bytes.Index(key, []byte(SEP_LEFT))
right := bytes.LastIndex(key, []byte(SEP_RIGHT))
if left == -1 || right == -1 {
return // just skip
}
fn(i, key[left+1:right], key[right+1:], value, quit)
})
}
func (l *LevelRedis) RangeEnumerate(min, max []byte, direction IterDirection, fn func(i int, key, value []byte, quit *bool)) {
var iter *gorocks.Iterator
if l.snap != nil {
iter = l.db.NewIterator(l.ro)
} else {
ro := gorocks.NewReadOptions()
ro.SetFillCache(false)
defer ro.Close()
iter = l.db.NewIterator(ro)
}
defer iter.Close()
l.Enumerate(iter, min, max, direction, fn)
}
// 范围扫描
func (l *LevelRedis) Enumerate(iter *gorocks.Iterator, min, max []byte, direction IterDirection, fn func(i int, key, value []byte, quit *bool)) {
l.incrCounter("enum")
found := false
if direction == IterBackward {
if len(max) == 0 {
iter.SeekToLast()
} else {
iter.Seek(max)
}
} else {
if len(min) == 0 {
iter.SeekToFirst()
} else {
iter.Seek(min)
}
}
found = iter.Valid()
if !found {
return
}
i := -1
// 范围判断
if found && between(iter.Key(), min, max) {
i++
quit := false
fn(i, copyBytes(iter.Key()), copyBytes(iter.Value()), &quit)
if quit {
return
}
}
for {
found = false
if direction == IterBackward {
iter.Prev()
} else {
iter.Next()
}
found = iter.Valid()
if found && between(iter.Key(), min, max) {
i++
quit := false
fn(i, copyBytes(iter.Key()), copyBytes(iter.Value()), &quit)
if quit {
return
}
} else {
break
}
}
return
}