talent-plan-tinykv/raft/log.go

100 lines
3.0 KiB
Go

// Copyright 2015 The etcd Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package raft
import pb "github.com/pingcap-incubator/tinykv/proto/pkg/eraftpb"
// RaftLog manage the log entries, its struct look like:
//
// snapshot/first.....applied....committed....stabled.....last
// --------|------------------------------------------------|
// log entries
//
// for simplify the RaftLog implement should manage all log entries
// that not truncated
type RaftLog struct {
// storage contains all stable entries since the last snapshot.
storage Storage
// committed is the highest log position that is known to be in
// stable storage on a quorum of nodes.
committed uint64
// applied is the highest log position that the application has
// been instructed to apply to its state machine.
// Invariant: applied <= committed
applied uint64
// log entries with index <= stabled are persisted to storage.
// It is used to record the logs that are not persisted by storage yet.
// Everytime handling `Ready`, the unstabled logs will be included.
stabled uint64
// all entries that have not yet compact.
entries []pb.Entry
// the incoming unstable snapshot, if any.
// (Used in 2C)
pendingSnapshot *pb.Snapshot
// Your Data Here (2A).
}
// newLog returns log using the given storage. It recovers the log
// to the state that it just commits and applies the latest snapshot.
func newLog(storage Storage) *RaftLog {
// Your Code Here (2A).
return nil
}
// We need to compact the log entries in some point of time like
// storage compact stabled log entries prevent the log entries
// grow unlimitedly in memory
func (l *RaftLog) maybeCompact() {
// Your Code Here (2C).
}
// allEntries return all the entries not compacted.
// note, exclude any dummy entries from the return value.
// note, this is one of the test stub functions you need to implement.
func (l *RaftLog) allEntries() []pb.Entry {
// Your Code Here (2A).
return nil
}
// unstableEntries return all the unstable entries
func (l *RaftLog) unstableEntries() []pb.Entry {
// Your Code Here (2A).
return nil
}
// nextEnts returns all the committed but not applied entries
func (l *RaftLog) nextEnts() (ents []pb.Entry) {
// Your Code Here (2A).
return nil
}
// LastIndex return the last index of the log entries
func (l *RaftLog) LastIndex() uint64 {
// Your Code Here (2A).
return 0
}
// Term return the term of the entry in the given index
func (l *RaftLog) Term(i uint64) (uint64, error) {
// Your Code Here (2A).
return 0, nil
}