64 lines
1.4 KiB
Go
64 lines
1.4 KiB
Go
package db0103
|
|
|
|
import "bytes"
|
|
|
|
type KV struct {
|
|
log Log
|
|
mem map[string][]byte
|
|
}
|
|
|
|
func (kv *KV) Open() error {
|
|
if err := kv.log.Open(); err != nil {
|
|
return err
|
|
}
|
|
kv.mem = map[string][]byte{}
|
|
for {
|
|
entry := Entry{}
|
|
eof, err := kv.log.Read(&entry)
|
|
if err != nil {
|
|
return err
|
|
} else if eof {
|
|
break
|
|
}
|
|
|
|
if entry.deleted {
|
|
delete(kv.mem, string(entry.key))
|
|
} else {
|
|
kv.mem[string(entry.key)] = entry.val
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (kv *KV) Close() error { return kv.log.Close() }
|
|
|
|
func (kv *KV) Get(key []byte) (val []byte, ok bool, err error) {
|
|
val, ok = kv.mem[string(key)]
|
|
return
|
|
}
|
|
|
|
func (kv *KV) Set(key []byte, val []byte) (updated bool, err error) {
|
|
prev, exist := kv.mem[string(key)]
|
|
updated = !exist || !bytes.Equal(prev, val)
|
|
if updated {
|
|
if err = kv.log.Write(&Entry{key: key, val: val, deleted: false}); err != nil {
|
|
return false, err
|
|
}
|
|
kv.mem[string(key)] = val
|
|
}
|
|
return
|
|
}
|
|
|
|
func (kv *KV) Del(key []byte) (deleted bool, err error) {
|
|
_, deleted = kv.mem[string(key)]
|
|
if deleted {
|
|
if err = kv.log.Write(&Entry{key: key, val: nil, deleted: true}); err != nil {
|
|
return false, err
|
|
}
|
|
delete(kv.mem, string(key))
|
|
}
|
|
return
|
|
}
|
|
|
|
// QzBQWVJJOUhU https://trialofcode.org/
|