Add experimental V2 client.

v2/multi.go

@@ -0,0 +1,134 @@
+package redis
+
+import (
+	"fmt"
+	"sync"
+)
+
+type MultiClient struct {
+	*Client
+	execMtx sync.Mutex
+}
+
+func (c *Client) MultiClient() (*MultiClient, error) {
+	return &MultiClient{
+		Client: &Client{
+			baseClient: &baseClient{
+				connPool: newSingleConnPool(c.connPool, nil, true),
+
+				password: c.password,
+				db:       c.db,
+			},
+		},
+	}, nil
+}
+
+func (c *MultiClient) Close() error {
+	c.Unwatch()
+	return c.Client.Close()
+}
+
+func (c *MultiClient) Watch(keys ...string) *StatusReq {
+	args := append([]string{"WATCH"}, keys...)
+	req := NewStatusReq(args...)
+	c.Process(req)
+	return req
+}
+
+func (c *MultiClient) Unwatch(keys ...string) *StatusReq {
+	args := append([]string{"UNWATCH"}, keys...)
+	req := NewStatusReq(args...)
+	c.Process(req)
+	return req
+}
+
+func (c *MultiClient) Discard() {
+	c.reqsMtx.Lock()
+	if c.reqs == nil {
+		panic("Discard can be used only inside Exec")
+	}
+	c.reqs = c.reqs[:1]
+	c.reqsMtx.Unlock()
+}
+
+func (c *MultiClient) Exec(do func()) ([]Req, error) {
+	c.reqsMtx.Lock()
+	c.reqs = []Req{NewStatusReq("MULTI")}
+	c.reqsMtx.Unlock()
+
+	do()
+
+	c.queue(NewIfaceSliceReq("EXEC"))
+
+	c.reqsMtx.Lock()
+	reqs := c.reqs
+	c.reqs = nil
+	c.reqsMtx.Unlock()
+
+	if len(reqs) == 2 {
+		return []Req{}, nil
+	}
+
+	cn, err := c.conn()
+	if err != nil {
+		return nil, err
+	}
+
+	// Synchronize writes and reads to the connection using mutex.
+	c.execMtx.Lock()
+	err = c.execReqs(reqs, cn)
+	c.execMtx.Unlock()
+	if err != nil {
+		c.removeConn(cn)
+		return nil, err
+	}
+
+	c.putConn(cn)
+	return reqs[1 : len(reqs)-1], nil
+}
+
+func (c *MultiClient) execReqs(reqs []Req, cn *conn) error {
+	err := c.writeReq(cn, reqs...)
+	if err != nil {
+		return err
+	}
+
+	statusReq := NewStatusReq()
+
+	// Omit last request (EXEC).
+	reqsLen := len(reqs) - 1
+
+	// Parse queued replies.
+	for i := 0; i < reqsLen; i++ {
+		_, err = statusReq.ParseReply(cn.Rd)
+		if err != nil {
+			return err
+		}
+	}
+
+	// Parse number of replies.
+	line, err := readLine(cn.Rd)
+	if err != nil {
+		return err
+	}
+	if line[0] != '*' {
+		return fmt.Errorf("Expected '*', but got line %q", line)
+	}
+	if len(line) == 3 && line[1] == '-' && line[2] == '1' {
+		return Nil
+	}
+
+	// Parse replies.
+	// Loop starts from 1 to omit first request (MULTI).
+	for i := 1; i < reqsLen; i++ {
+		req := reqs[i]
+		val, err := req.ParseReply(cn.Rd)
+		if err != nil {
+			req.SetErr(err)
+		} else {
+			req.SetVal(val)
+		}
+	}
+
+	return nil
+}