91 lines
2.2 KiB
Go
91 lines
2.2 KiB
Go
// Copyright 2015 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package structure
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import (
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"github.com/juju/errors"
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"github.com/pingcap/tidb/kv"
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)
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// ErrTxDone is the error returned after transaction has already been committed or rolled back.
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var ErrTxDone = errors.New("Transaction has already been committed or rolled back")
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// TStore is the storage for data structure.
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type TStore struct {
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store kv.Storage
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prefix []byte
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}
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// NewStore creates a TStore with kv storage and special key prefix.
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func NewStore(store kv.Storage, prefix []byte) *TStore {
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s := &TStore{
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store: store,
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prefix: prefix,
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}
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return s
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}
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// Begin creates a TxStructure for calling structure APIs in a transaction later.
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func (s *TStore) Begin() (*TxStructure, error) {
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t := &TxStructure{done: false, prefix: s.prefix}
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var err error
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t.txn, err = s.store.Begin()
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if err != nil {
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return nil, errors.Trace(err)
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}
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return t, nil
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}
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// RunInNewTxn runs f in a new transaction
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func (s *TStore) RunInNewTxn(retryable bool, f func(t *TxStructure) error) error {
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fn := func(txn kv.Transaction) error {
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t := &TxStructure{done: false, prefix: s.prefix, txn: txn}
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return errors.Trace(f(t))
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}
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err := kv.RunInNewTxn(s.store, retryable, fn)
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return errors.Trace(err)
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}
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// TxStructure supports some simple data structures like string, hash, list, etc... and
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// you can use these in a transaction.
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type TxStructure struct {
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txn kv.Transaction
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done bool
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prefix []byte
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}
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// Commit commits the transaction.
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func (t *TxStructure) Commit() error {
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if t.done {
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return ErrTxDone
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}
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t.done = true
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return errors.Trace(t.txn.Commit())
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}
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// Rollback rolls back the transaction.
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func (t *TxStructure) Rollback() error {
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if t.done {
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return ErrTxDone
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}
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t.done = true
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return errors.Trace(t.txn.Rollback())
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}
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