- 实现Redis的database层(核心层:处理命令并返回)
- https://github.com/csgopher/go-redis
- 本文涉及以下文件:
dict:定义字典的一些方法
sync_dict:实现dict
db:分数据库
command:定义指令
ping,keys,string:指令的具体处理逻辑
database:单机版数据库
datastruct/dict/dict.go
// 遍历字典所有的键值对,返回值是布尔,true继续遍历,false停止遍历
type Consumer func(key string, val interface{}) bool
type Dict interface {
Get(key string) (val interface{}, exists bool)
Len() int
Put(key string, val interface{}) (result int)
PutIfAbsent(key string, val interface{}) (result int)
PutIfExists(key string, val interface{}) (result int)
Remove(key string) (result int)
ForEach(consumer Consumer)
Keys() []string
RandomKeys(limit int) []string
RandomDistinctKeys(limit int) []string
Clear()
}
Consumer:遍历字典所有的键值对,返回值是布尔,true继续遍历,false停止遍历
Dict接口:Redis数据结构的接口。这里使用sync.Map作为字典的实现,如果想用别的数据结构,换一个实现即可
datastruct/dict/sync_dict.go
// 使用sync.Map实现Dict接口
type SyncDict struct {
m sync.Map
}
func MakeSyncDict() *SyncDict {
return &SyncDict{}
}
func (dict *SyncDict) Get(key string) (val interface{}, exists bool) {
val, ok := dict.m.Load(key)
return val, ok
}
func (dict *SyncDict) Len() int {
length := 0
dict.m.Range(func(k, v interface{}) bool {
length++
return true
})
return length
}
func (dict *SyncDict) Put(key string, val interface{}) (result int) {
_, existed := dict.m.Load(key)
dict.m.Store(key, val)
if existed {
return 0
}
return 1
}
func (dict *SyncDict) PutIfAbsent(key string, val interface{}) (result int) {
_, existed := dict.m.Load(key)
if existed {
return 0
}
dict.m.Store(key, val)
return 1
}
func (dict *SyncDict) PutIfExists(key string, val interface{}) (result int) {
_, existed := dict.m.Load(key)
if existed {
dict.m.Store(key, val)
return 1
}
return 0
}
func (dict *SyncDict) Remove(key string) (result int) {
_, existed := dict.m.Load(key)
dict.m.Delete(key)
if existed {
return 1
}
return 0
}
func (dict *SyncDict) ForEach(consumer Consumer) {
dict.m.Range(func(key, value interface{}) bool {
consumer(key.(string), value)
return true
})
}
func (dict *SyncDict) Keys() []string {
result := make([]string, dict.Len())
i := 0
dict.m.Range(func(key, value interface{}) bool {
result[i] = key.(string)
i++
return true
})
return result
}
func (dict *SyncDict) RandomKeys(limit int) []string {
result := make([]string, limit)
for i := 0; i < limit; i++ {
dict.m.Range(func(key, value interface{}) bool {
result[i] = key.(string)
return false
})
}
return result
}
func (dict *SyncDict) RandomDistinctKeys(limit int) []string {
result := make([]string, limit)
i := 0
dict.m.Range(func(key, value interface{}) bool {
result[i] = key.(string)
i++
if i == limit {
return false
}
return true
})
return result
}
func (dict *SyncDict) Clear() {
*dict = *MakeSyncDict()
}
使用sync.Map实现Dict接口
database/db.go
// Redis中的分数据库
type DB struct {
index int
data dict.Dict
}
// 所有Redis的指令都写成这样的类型
type ExecFunc func(db *DB, args [][]byte) resp.Reply
type CmdLine = [][]byte
func makeDB() *DB {
db := &DB{
data: dict.MakeSyncDict(),
}
return db
}
func (db *DB) Exec(c resp.Connection, cmdLine [][]byte) resp.Reply {
cmdName := strings.ToLower(string(cmdLine[0]))
cmd, ok := cmdTable[cmdName]
if !ok {
return reply.MakeErrReply("ERR unknown command '" + cmdName + "'")
}
if !validateArity(cmd.arity, cmdLine) {
return reply.Make