Merge pull request #6 from letterbeezps/dev

add example

Author: letterbeezps

README.md

@@ -7,4 +7,36 @@ A simple key-value storage engine in GO. The main purpose of this project is to
 * LSM-tree
 * ... ...
 
-More pratices are still begin planned.
+More pratices are still begin planned.
+
+## example
+
+### GetSet
+
+```go
+package main
+
+import (
+    "fmt"
+    "log"
+
+    mv "github.com/letterbeezps/miniKV/mvcc"
+)
+
+func main() {
+    db := mv.NewMVCC()
+    tx, err := db.Begin()
+    if err != nil {
+    log.Fatal(err)
+    }
+    err = tx.Set("a", []byte("abdc"))
+    if err != nil {
+    log.Fatal(err)
+    }
+    ret, err := tx.Get("a")
+    if err != nil {
+    log.Fatal(err)
+    }
+    fmt.Println(ret)
+}
+```

cmd/example/mvcc/main.go

@@ -0,0 +1,25 @@
+package main
+
+import (
+	"fmt"
+	"log"
+
+	mv "github.com/letterbeezps/miniKV/mvcc"
+)
+
+func main() {
+	db := mv.NewMVCC()
+	tx, err := db.Begin()
+	if err != nil {
+		log.Fatal(err)
+	}
+	err = tx.Set("a", []byte("abdc"))
+	if err != nil {
+		log.Fatal(err)
+	}
+	ret, err := tx.Get("a")
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println(ret)
+}

mvcc/mvcc.go

@@ -4,6 +4,7 @@ import (
 	"sync"
 
 	"github.com/letterbeezps/miniKV/engine"
+	"github.com/letterbeezps/miniKV/engine/memory"
 	"github.com/pkg/errors"
 )
 
@@ -12,6 +13,13 @@ type MVCC struct {
 	Engine engine.Engine
 }
 
+func NewMVCC() *MVCC {
+	return &MVCC{
+		Lock:   &sync.Mutex{},
+		Engine: memory.NewMemory(),
+	}
+}
+
 func (m *MVCC) Begin() (*TX, error) {
 	tx := &TX{
 		Lock:   m.Lock,