add XLExists cmd

ledis/t_list.go

@@ -506,6 +506,18 @@ func (db *DB) BRPop(keys [][]byte, timeout time.Duration) ([]interface{}, error)
 	return db.lblockPop(keys, listTailSeq, timeout)
 }
 
+func (db *DB) XLExists(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+	sk := db.lEncodeMetaKey(key)
+	v, err := db.bucket.Get(sk)
+	if v != nil && err == nil {
+		return 1, nil
+	}
+	return 0, err
+}
+
 func (db *DB) lblockPop(keys [][]byte, whereSeq int32, timeout time.Duration) ([]interface{}, error) {
 	ch := make(chan []byte)
 

ledis/t_list_test.go

@@ -163,3 +163,19 @@ func TestLFlush(t *testing.T) {
 		t.Fatal("invalid value length ", len(v))
 	}
 }
+
+func TestXLExists(t *testing.T) {
+	db := getTestDB()
+	key := []byte("xlexists_test")
+	if n, err := db.XLExists(key); err != nil {
+		t.Fatal(err.Error())
+	} else if n != 0 {
+		t.Fatal("invalid value ", n)
+	}
+	db.LPush(key, []byte("hello"), []byte("world"))
+	if n, err := db.XLExists(key); err != nil {
+		t.Fatal(err.Error())
+	} else if n != 1 {
+		t.Fatal("invalid value ", n)
+	}
+}

server/cmd_hash.go

@@ -300,7 +300,7 @@ func hxrevscanCommand(c *client) error {
 	return xscanGeneric(c, c.db.HRevScan)
 }
 
-func hxexistsCommand(c *client) error {
+func xhexistsCommand(c *client) error {
 	args := c.args
 	if len(args) != 1 {
 		return ErrCmdParams
@@ -338,5 +338,5 @@ func init() {
 	register("hxrevscan", hxrevscanCommand)
 	register("xhscan", hxscanCommand)
 	register("xhrevscan", hxrevscanCommand)
-	register("xhexists", hxexistsCommand)
+	register("xhexists", xhexistsCommand)
 }

server/cmd_list.go

@@ -285,6 +285,18 @@ func lParseBPopArgs(c *client) (keys [][]byte, timeout time.Duration, err error)
 	keys = args[0 : len(args)-1]
 	return
 }
+func xlexistsCommand(c *client) error {
+	args := c.args
+	if len(args) != 1 {
+		return ErrCmdParams
+	}
+	if n, err := c.db.XLExists(args[0]); err != nil {
+		return err
+	} else {
+		c.resp.writeInteger(n)
+	}
+	return nil
+}
 
 func init() {
 	register("blpop", blpopCommand)
@@ -309,4 +321,5 @@ func init() {
 	register("lxrevscan", lxrevscanCommand)
 	register("xlscan", lxscanCommand)
 	register("xlrevscan", lxrevscanCommand)
+	register("xlexists", xlexistsCommand)
 }

server/cmd_list_test.go

@@ -58,6 +58,11 @@ func TestList(t *testing.T) {
 	defer c.Close()
 
 	key := []byte("a")
+	if n, err := ledis.Int(c.Do("xlexists", key)); err != nil {
+		t.Fatal(err)
+	} else if n != 0 {
+		t.Fatal(n)
+	}
 
 	if n, err := ledis.Int(c.Do("lpush", key, 1)); err != nil {
 		t.Fatal(err)
@@ -65,6 +70,12 @@ func TestList(t *testing.T) {
 		t.Fatal(n)
 	}
 
+	if n, err := ledis.Int(c.Do("xlexists", key)); err != nil {
+		t.Fatal(err)
+	} else if n != 1 {
+		t.Fatal(1)
+	}
+
 	if n, err := ledis.Int(c.Do("rpush", key, 2)); err != nil {
 		t.Fatal(err)
 	} else if n != 2 {