Add support for LMPOP (#2440)

* feat: add lmpop command

Author: SoulPancake

command.go

@@ -3690,3 +3690,65 @@ func (cmd *MapStringStringSliceCmd) readReply(rd *proto.Reader) error {
 	}
 	return nil
 }
+
+//------------------------------------------------------------------------------
+
+type ListElementCmd struct {
+	baseCmd
+
+	key string
+	val []string
+}
+
+var _ Cmder = (*ListElementCmd)(nil)
+
+func NewListElementCmd(ctx context.Context, args ...interface{}) *ListElementCmd {
+	return &ListElementCmd{
+		baseCmd: baseCmd{
+			ctx:  ctx,
+			args: args,
+		},
+	}
+}
+
+func (cmd *ListElementCmd) SetVal(key string, val []string) {
+	cmd.key = key
+	cmd.val = val
+}
+
+func (cmd *ListElementCmd) Val() (string, []string) {
+	return cmd.key, cmd.val
+}
+
+func (cmd *ListElementCmd) Result() (string, []string, error) {
+	return cmd.key, cmd.val, cmd.err
+}
+
+func (cmd *ListElementCmd) String() string {
+	return cmdString(cmd, cmd.val)
+}
+
+func (cmd *ListElementCmd) readReply(rd *proto.Reader) (err error) {
+	if err = rd.ReadFixedArrayLen(2); err != nil {
+		return err
+	}
+
+	cmd.key, err = rd.ReadString()
+	if err != nil {
+		return err
+	}
+
+	n, err := rd.ReadArrayLen()
+	if err != nil {
+		return err
+	}
+	cmd.val = make([]string, n)
+	for i := 0; i < n; i++ {
+		cmd.val[i], err = rd.ReadString()
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}

commands.go

@@ -225,6 +225,7 @@ type Cmdable interface {
 	LInsertBefore(ctx context.Context, key string, pivot, value interface{}) *IntCmd
 	LInsertAfter(ctx context.Context, key string, pivot, value interface{}) *IntCmd
 	LLen(ctx context.Context, key string) *IntCmd
+	LMPop(ctx context.Context, direction string, count int64, keys ...string) *ListElementCmd
 	LPop(ctx context.Context, key string) *StringCmd
 	LPopCount(ctx context.Context, key string, count int) *StringSliceCmd
 	LPos(ctx context.Context, key string, value string, args LPosArgs) *IntCmd
@@ -1463,6 +1464,22 @@ func (c cmdable) LIndex(ctx context.Context, key string, index int64) *StringCmd
 	return cmd
 }
 
+// LMPop Pops one or more elements from the first non-empty list key from the list of provided key names.
+// direction: left or right, count: > 0
+// example: client.LMPop(ctx, "left", 3, "key1", "key2")
+func (c cmdable) LMPop(ctx context.Context, direction string, count int64, keys ...string) *ListElementCmd {
+	args := make([]interface{}, 2+len(keys), 5+len(keys))
+	args[0] = "lmpop"
+	args[1] = len(keys)
+	for i, key := range keys {
+		args[2+i] = key
+	}
+	args = append(args, strings.ToLower(direction), "count", count)
+	cmd := NewListElementCmd(ctx, args...)
+	_ = c(ctx, cmd)
+	return cmd
+}
+
 func (c cmdable) LInsert(ctx context.Context, key, op string, pivot, value interface{}) *IntCmd {
 	cmd := NewIntCmd(ctx, "linsert", key, op, pivot, value)
 	_ = c(ctx, cmd)

commands_test.go

@@ -2272,6 +2272,46 @@ var _ = Describe("Commands", func() {
 			Expect(lRange.Val()).To(Equal([]string{"Hello", "There", "World"}))
 		})
 
+		It("should LMPop", func() {
+			err := client.LPush(ctx, "list1", "one", "two", "three", "four", "five").Err()
+			Expect(err).NotTo(HaveOccurred())
+
+			err = client.LPush(ctx, "list2", "a", "b", "c", "d", "e").Err()
+			Expect(err).NotTo(HaveOccurred())
+
+			key, elems, err := client.LMPop(ctx, "left", 3, "list1", "list2").Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(key).To(Equal("list1"))
+			Expect(elems).To(Equal([]string{"five", "four", "three"}))
+
+			key, elems, err = client.LMPop(ctx, "right", 3, "list1", "list2").Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(key).To(Equal("list1"))
+			Expect(elems).To(Equal([]string{"one", "two"}))
+
+			key, elems, err = client.LMPop(ctx, "left", 1, "list1", "list2").Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(key).To(Equal("list2"))
+			Expect(elems).To(Equal([]string{"e"}))
+
+			key, elems, err = client.LMPop(ctx, "right", 10, "list1", "list2").Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(key).To(Equal("list2"))
+			Expect(elems).To(Equal([]string{"a", "b", "c", "d"}))
+
+			err = client.LMPop(ctx, "left", 10, "list1", "list2").Err()
+			Expect(err).To(Equal(redis.Nil))
+
+			err = client.Set(ctx, "list3", 1024, 0).Err()
+			Expect(err).NotTo(HaveOccurred())
+
+			err = client.LMPop(ctx, "left", 10, "list1", "list2", "list3").Err()
+			Expect(err.Error()).To(Equal("WRONGTYPE Operation against a key holding the wrong kind of value"))
+
+			err = client.LMPop(ctx, "right", 0, "list1", "list2").Err()
+			Expect(err).To(HaveOccurred())
+		})
+
 		It("should LLen", func() {
 			lPush := client.LPush(ctx, "list", "World")
 			Expect(lPush.Err()).NotTo(HaveOccurred())