mirror of https://github.com/ledisdb/ledisdb.git
93 lines
1.9 KiB
Go
93 lines
1.9 KiB
Go
package ledis
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import (
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"errors"
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"github.com/siddontang/ledisdb/store"
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)
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var errDataType = errors.New("error data type")
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var errMetaKey = errors.New("error meta key")
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func (db *DB) scan(dataType byte, key []byte, count int, inclusive bool) ([][]byte, error) {
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var minKey, maxKey []byte
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var err error
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if key != nil {
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if err = checkKeySize(key); err != nil {
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return nil, err
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}
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if minKey, err = db.encodeMetaKey(dataType, key); err != nil {
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return nil, err
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}
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} else {
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if minKey, err = db.encodeMinKey(dataType); err != nil {
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return nil, err
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}
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}
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if maxKey, err = db.encodeMaxKey(dataType); err != nil {
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return nil, err
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}
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if count <= 0 {
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count = defaultScanCount
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}
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v := make([][]byte, 0, count)
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rangeType := store.RangeROpen
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if !inclusive {
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rangeType = store.RangeOpen
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}
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it := db.bucket.RangeLimitIterator(minKey, maxKey, rangeType, 0, count)
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for ; it.Valid(); it.Next() {
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if k, err := db.decodeMetaKey(dataType, it.Key()); err != nil {
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continue
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} else {
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v = append(v, k)
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}
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}
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it.Close()
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return v, nil
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}
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func (db *DB) encodeMinKey(dataType byte) ([]byte, error) {
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return db.encodeMetaKey(dataType, nil)
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}
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func (db *DB) encodeMaxKey(dataType byte) ([]byte, error) {
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k, err := db.encodeMetaKey(dataType, nil)
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if err != nil {
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return nil, err
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}
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k[len(k)-1] = dataType + 1
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return k, nil
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}
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func (db *DB) encodeMetaKey(dataType byte, key []byte) ([]byte, error) {
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switch dataType {
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case KVType:
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return db.encodeKVKey(key), nil
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case LMetaType:
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return db.lEncodeMetaKey(key), nil
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case HSizeType:
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return db.hEncodeSizeKey(key), nil
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case ZSizeType:
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return db.zEncodeSizeKey(key), nil
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case BitMetaType:
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return db.bEncodeMetaKey(key), nil
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case SSizeType:
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return db.sEncodeSizeKey(key), nil
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default:
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return nil, errDataType
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}
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}
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func (db *DB) decodeMetaKey(dataType byte, ek []byte) ([]byte, error) {
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if len(ek) < 2 || ek[0] != db.index || ek[1] != dataType {
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return nil, errMetaKey
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}
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return ek[2:], nil
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}
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