mirror of
https://github.com/talent-plan/tinykv.git
synced 2024-12-29 14:31:00 +08:00
99 lines
2.4 KiB
Go
99 lines
2.4 KiB
Go
package mvcc
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import (
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"bytes"
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"encoding/binary"
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"fmt"
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"reflect"
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"github.com/pingcap-incubator/tinykv/kv/util/engine_util"
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"github.com/pingcap-incubator/tinykv/proto/pkg/kvrpcpb"
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)
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const TsMax uint64 = ^uint64(0)
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type Lock struct {
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Primary []byte
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Ts uint64
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Ttl uint64
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Kind WriteKind
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}
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type KlPair struct {
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Key []byte
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Lock *Lock
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}
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// Info creates a LockInfo object from a Lock object for key.
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func (lock *Lock) Info(key []byte) *kvrpcpb.LockInfo {
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info := kvrpcpb.LockInfo{}
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info.Key = key
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info.LockVersion = lock.Ts
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info.PrimaryLock = lock.Primary
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info.LockTtl = lock.Ttl
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return &info
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}
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func (lock *Lock) ToBytes() []byte {
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buf := append(lock.Primary, byte(lock.Kind))
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buf = append(buf, make([]byte, 16)...)
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binary.BigEndian.PutUint64(buf[len(lock.Primary)+1:], lock.Ts)
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binary.BigEndian.PutUint64(buf[len(lock.Primary)+9:], lock.Ttl)
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return buf
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}
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// ParseLock attempts to parse a byte string into a Lock object.
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func ParseLock(input []byte) (*Lock, error) {
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if len(input) <= 16 {
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return nil, fmt.Errorf("mvcc: error parsing lock, not enough input, found %d bytes", len(input))
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}
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primaryLen := len(input) - 17
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primary := input[:primaryLen]
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kind := WriteKind(input[primaryLen])
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ts := binary.BigEndian.Uint64(input[primaryLen+1:])
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ttl := binary.BigEndian.Uint64(input[primaryLen+9:])
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return &Lock{Primary: primary, Ts: ts, Ttl: ttl, Kind: kind}, nil
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}
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// IsLockedFor checks if lock locks key at txnStartTs.
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func (lock *Lock) IsLockedFor(key []byte, txnStartTs uint64, resp interface{}) bool {
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if lock == nil {
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return false
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}
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if txnStartTs == TsMax && bytes.Compare(key, lock.Primary) != 0 {
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return false
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}
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if lock.Ts <= txnStartTs {
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err := &kvrpcpb.KeyError{Locked: lock.Info(key)}
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respValue := reflect.ValueOf(resp)
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reflect.Indirect(respValue).FieldByName("Error").Set(reflect.ValueOf(err))
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return true
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}
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return false
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}
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// AllLocksForTxn returns all locks for the current transaction.
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func AllLocksForTxn(txn *MvccTxn) ([]KlPair, error) {
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var result []KlPair
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iter := txn.Reader.IterCF(engine_util.CfLock)
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defer iter.Close()
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for ; iter.Valid(); iter.Next() {
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item := iter.Item()
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val, err := item.Value()
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if err != nil {
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return nil, err
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}
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lock, err := ParseLock(val)
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if err != nil {
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return nil, err
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}
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if lock.Ts == txn.StartTS() {
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result = append(result, KlPair{item.Key(), lock})
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}
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}
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return result, nil
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}
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