1 files changed, 473 insertions, 0 deletions
diff --git a/src/dma/vendor/github.com/go-redis/redis/pubsub.go b/src/dma/vendor/github.com/go-redis/redis/pubsub.go
new file mode 100644
index 00000000..0afb47cd
--- /dev/null
+++ b/src/dma/vendor/github.com/go-redis/redis/pubsub.go
@@ -0,0 +1,473 @@
+package redis
+
+import (
+	"errors"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/go-redis/redis/internal"
+	"github.com/go-redis/redis/internal/pool"
+	"github.com/go-redis/redis/internal/proto"
+)
+
+var errPingTimeout = errors.New("redis: ping timeout")
+
+// PubSub implements Pub/Sub commands bas described in
+// http://redis.io/topics/pubsub. Message receiving is NOT safe
+// for concurrent use by multiple goroutines.
+//
+// PubSub automatically reconnects to Redis Server and resubscribes
+// to the channels in case of network errors.
+type PubSub struct {
+	opt *Options
+
+	newConn   func([]string) (*pool.Conn, error)
+	closeConn func(*pool.Conn) error
+
+	mu       sync.Mutex
+	cn       *pool.Conn
+	channels map[string]struct{}
+	patterns map[string]struct{}
+	closed   bool
+	exit     chan struct{}
+
+	cmd *Cmd
+
+	chOnce sync.Once
+	ch     chan *Message
+	ping   chan struct{}
+}
+
+func (c *PubSub) init() {
+	c.exit = make(chan struct{})
+}
+
+func (c *PubSub) conn() (*pool.Conn, error) {
+	c.mu.Lock()
+	cn, err := c._conn(nil)
+	c.mu.Unlock()
+	return cn, err
+}
+
+func (c *PubSub) _conn(newChannels []string) (*pool.Conn, error) {
+	if c.closed {
+		return nil, pool.ErrClosed
+	}
+	if c.cn != nil {
+		return c.cn, nil
+	}
+
+	channels := mapKeys(c.channels)
+	channels = append(channels, newChannels...)
+
+	cn, err := c.newConn(channels)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := c.resubscribe(cn); err != nil {
+		_ = c.closeConn(cn)
+		return nil, err
+	}
+
+	c.cn = cn
+	return cn, nil
+}
+
+func (c *PubSub) writeCmd(cn *pool.Conn, cmd Cmder) error {
+	return cn.WithWriter(c.opt.WriteTimeout, func(wr *proto.Writer) error {
+		return writeCmd(wr, cmd)
+	})
+}
+
+func (c *PubSub) resubscribe(cn *pool.Conn) error {
+	var firstErr error
+
+	if len(c.channels) > 0 {
+		err := c._subscribe(cn, "subscribe", mapKeys(c.channels))
+		if err != nil && firstErr == nil {
+			firstErr = err
+		}
+	}
+
+	if len(c.patterns) > 0 {
+		err := c._subscribe(cn, "psubscribe", mapKeys(c.patterns))
+		if err != nil && firstErr == nil {
+			firstErr = err
+		}
+	}
+
+	return firstErr
+}
+
+func mapKeys(m map[string]struct{}) []string {
+	s := make([]string, len(m))
+	i := 0
+	for k := range m {
+		s[i] = k
+		i++
+	}
+	return s
+}
+
+func (c *PubSub) _subscribe(
+	cn *pool.Conn, redisCmd string, channels []string,
+) error {
+	args := make([]interface{}, 0, 1+len(channels))
+	args = append(args, redisCmd)
+	for _, channel := range channels {
+		args = append(args, channel)
+	}
+	cmd := NewSliceCmd(args...)
+	return c.writeCmd(cn, cmd)
+}
+
+func (c *PubSub) releaseConn(cn *pool.Conn, err error, allowTimeout bool) {
+	c.mu.Lock()
+	c._releaseConn(cn, err, allowTimeout)
+	c.mu.Unlock()
+}
+
+func (c *PubSub) _releaseConn(cn *pool.Conn, err error, allowTimeout bool) {
+	if c.cn != cn {
+		return
+	}
+	if internal.IsBadConn(err, allowTimeout) {
+		c._reconnect(err)
+	}
+}
+
+func (c *PubSub) _reconnect(reason error) {
+	_ = c._closeTheCn(reason)
+	_, _ = c._conn(nil)
+}
+
+func (c *PubSub) _closeTheCn(reason error) error {
+	if c.cn == nil {
+		return nil
+	}
+	if !c.closed {
+		internal.Logf("redis: discarding bad PubSub connection: %s", reason)
+	}
+	err := c.closeConn(c.cn)
+	c.cn = nil
+	return err
+}
+
+func (c *PubSub) Close() error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	if c.closed {
+		return pool.ErrClosed
+	}
+	c.closed = true
+	close(c.exit)
+
+	err := c._closeTheCn(pool.ErrClosed)
+	return err
+}
+
+// Subscribe the client to the specified channels. It returns
+// empty subscription if there are no channels.
+func (c *PubSub) Subscribe(channels ...string) error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	err := c.subscribe("subscribe", channels...)
+	if c.channels == nil {
+		c.channels = make(map[string]struct{})
+	}
+	for _, s := range channels {
+		c.channels[s] = struct{}{}
+	}
+	return err
+}
+
+// PSubscribe the client to the given patterns. It returns
+// empty subscription if there are no patterns.
+func (c *PubSub) PSubscribe(patterns ...string) error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	err := c.subscribe("psubscribe", patterns...)
+	if c.patterns == nil {
+		c.patterns = make(map[string]struct{})
+	}
+	for _, s := range patterns {
+		c.patterns[s] = struct{}{}
+	}
+	return err
+}
+
+// Unsubscribe the client from the given channels, or from all of
+// them if none is given.
+func (c *PubSub) Unsubscribe(channels ...string) error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	for _, channel := range channels {
+		delete(c.channels, channel)
+	}
+	err := c.subscribe("unsubscribe", channels...)
+	return err
+}
+
+// PUnsubscribe the client from the given patterns, or from all of
+// them if none is given.
+func (c *PubSub) PUnsubscribe(patterns ...string) error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	for _, pattern := range patterns {
+		delete(c.patterns, pattern)
+	}
+	err := c.subscribe("punsubscribe", patterns...)
+	return err
+}
+
+func (c *PubSub) subscribe(redisCmd string, channels ...string) error {
+	cn, err := c._conn(channels)
+	if err != nil {
+		return err
+	}
+
+	err = c._subscribe(cn, redisCmd, channels)
+	c._releaseConn(cn, err, false)
+	return err
+}
+
+func (c *PubSub) Ping(payload ...string) error {
+	args := []interface{}{"ping"}
+	if len(payload) == 1 {
+		args = append(args, payload[0])
+	}
+	cmd := NewCmd(args...)
+
+	cn, err := c.conn()
+	if err != nil {
+		return err
+	}
+
+	err = c.writeCmd(cn, cmd)
+	c.releaseConn(cn, err, false)
+	return err
+}
+
+// Subscription received after a successful subscription to channel.
+type Subscription struct {
+	// Can be "subscribe", "unsubscribe", "psubscribe" or "punsubscribe".
+	Kind string
+	// Channel name we have subscribed to.
+	Channel string
+	// Number of channels we are currently subscribed to.
+	Count int
+}
+
+func (m *Subscription) String() string {
+	return fmt.Sprintf("%s: %s", m.Kind, m.Channel)
+}
+
+// Message received as result of a PUBLISH command issued by another client.
+type Message struct {
+	Channel string
+	Pattern string
+	Payload string
+}
+
+func (m *Message) String() string {
+	return fmt.Sprintf("Message<%s: %s>", m.Channel, m.Payload)
+}
+
+// Pong received as result of a PING command issued by another client.
+type Pong struct {
+	Payload string
+}
+
+func (p *Pong) String() string {
+	if p.Payload != "" {
+		return fmt.Sprintf("Pong<%s>", p.Payload)
+	}
+	return "Pong"
+}
+
+func (c *PubSub) newMessage(reply interface{}) (interface{}, error) {
+	switch reply := reply.(type) {
+	case string:
+		return &Pong{
+			Payload: reply,
+		}, nil
+	case []interface{}:
+		switch kind := reply[0].(string); kind {
+		case "subscribe", "unsubscribe", "psubscribe", "punsubscribe":
+			return &Subscription{
+				Kind:    kind,
+				Channel: reply[1].(string),
+				Count:   int(reply[2].(int64)),
+			}, nil
+		case "message":
+			return &Message{
+				Channel: reply[1].(string),
+				Payload: reply[2].(string),
+			}, nil
+		case "pmessage":
+			return &Message{
+				Pattern: reply[1].(string),
+				Channel: reply[2].(string),
+				Payload: reply[3].(string),
+			}, nil
+		case "pong":
+			return &Pong{
+				Payload: reply[1].(string),
+			}, nil
+		default:
+			return nil, fmt.Errorf("redis: unsupported pubsub message: %q", kind)
+		}
+	default:
+		return nil, fmt.Errorf("redis: unsupported pubsub message: %#v", reply)
+	}
+}
+
+// ReceiveTimeout acts like Receive but returns an error if message
+// is not received in time. This is low-level API and in most cases
+// Channel should be used instead.
+func (c *PubSub) ReceiveTimeout(timeout time.Duration) (interface{}, error) {
+	if c.cmd == nil {
+		c.cmd = NewCmd()
+	}
+
+	cn, err := c.conn()
+	if err != nil {
+		return nil, err
+	}
+
+	err = cn.WithReader(timeout, func(rd *proto.Reader) error {
+		return c.cmd.readReply(rd)
+	})
+
+	c.releaseConn(cn, err, timeout > 0)
+	if err != nil {
+		return nil, err
+	}
+
+	return c.newMessage(c.cmd.Val())
+}
+
+// Receive returns a message as a Subscription, Message, Pong or error.
+// See PubSub example for details. This is low-level API and in most cases
+// Channel should be used instead.
+func (c *PubSub) Receive() (interface{}, error) {
+	return c.ReceiveTimeout(0)
+}
+
+// ReceiveMessage returns a Message or error ignoring Subscription and Pong
+// messages. This is low-level API and in most cases Channel should be used
+// instead.
+func (c *PubSub) ReceiveMessage() (*Message, error) {
+	for {
+		msg, err := c.Receive()
+		if err != nil {
+			return nil, err
+		}
+
+		switch msg := msg.(type) {
+		case *Subscription:
+			// Ignore.
+		case *Pong:
+			// Ignore.
+		case *Message:
+			return msg, nil
+		default:
+			err := fmt.Errorf("redis: unknown message: %T", msg)
+			return nil, err
+		}
+	}
+}
+
+// Channel returns a Go channel for concurrently receiving messages.
+// It periodically sends Ping messages to test connection health.
+// The channel is closed with PubSub. Receive* APIs can not be used
+// after channel is created.
+func (c *PubSub) Channel() <-chan *Message {
+	c.chOnce.Do(c.initChannel)
+	return c.ch
+}
+
+func (c *PubSub) initChannel() {
+	c.ch = make(chan *Message, 100)
+	c.ping = make(chan struct{}, 10)
+
+	go func() {
+		var errCount int
+		for {
+			msg, err := c.Receive()
+			if err != nil {
+				if err == pool.ErrClosed {
+					close(c.ch)
+					return
+				}
+				if errCount > 0 {
+					time.Sleep(c.retryBackoff(errCount))
+				}
+				errCount++
+				continue
+			}
+			errCount = 0
+
+			// Any message is as good as a ping.
+			select {
+			case c.ping <- struct{}{}:
+			default:
+			}
+
+			switch msg := msg.(type) {
+			case *Subscription:
+				// Ignore.
+			case *Pong:
+				// Ignore.
+			case *Message:
+				c.ch <- msg
+			default:
+				internal.Logf("redis: unknown message: %T", msg)
+			}
+		}
+	}()
+
+	go func() {
+		const timeout = 5 * time.Second
+
+		timer := time.NewTimer(timeout)
+		timer.Stop()
+
+		healthy := true
+		for {
+			timer.Reset(timeout)
+			select {
+			case <-c.ping:
+				healthy = true
+				if !timer.Stop() {
+					<-timer.C
+				}
+			case <-timer.C:
+				pingErr := c.Ping()
+				if healthy {
+					healthy = false
+				} else {
+					if pingErr == nil {
+						pingErr = errPingTimeout
+					}
+					c.mu.Lock()
+					c._reconnect(pingErr)
+					c.mu.Unlock()
+				}
+			case <-c.exit:
+				return
+			}
+		}
+	}()
+}
+
+func (c *PubSub) retryBackoff(attempt int) time.Duration {
+	return internal.RetryBackoff(attempt, c.opt.MinRetryBackoff, c.opt.MaxRetryBackoff)
+}