Move api/client -> cli/command

Using
  gomvpkg
     -from github.com/docker/docker/api/client
     -to github.com/docker/docker/cli/command
     -vcs_mv_cmd 'git mv {{.Src}} {{.Dst}}'

Signed-off-by: Daniel Nephin <dnephin@docker.com>
Upstream-commit: 0640a14b4fcba3715f7cc3bc9444f3c7f4827edd
Component: engine

components/engine/cli/command/system/events_utils.go

@@ -0,0 +1,66 @@
+package system
+
+import (
+	"encoding/json"
+	"io"
+	"sync"
+
+	"github.com/Sirupsen/logrus"
+	eventtypes "github.com/docker/docker/api/types/events"
+)
+
+// EventHandler is abstract interface for user to customize
+// own handle functions of each type of events
+type EventHandler interface {
+	Handle(action string, h func(eventtypes.Message))
+	Watch(c <-chan eventtypes.Message)
+}
+
+// InitEventHandler initializes and returns an EventHandler
+func InitEventHandler() EventHandler {
+	return &eventHandler{handlers: make(map[string]func(eventtypes.Message))}
+}
+
+type eventHandler struct {
+	handlers map[string]func(eventtypes.Message)
+	mu       sync.Mutex
+}
+
+func (w *eventHandler) Handle(action string, h func(eventtypes.Message)) {
+	w.mu.Lock()
+	w.handlers[action] = h
+	w.mu.Unlock()
+}
+
+// Watch ranges over the passed in event chan and processes the events based on the
+// handlers created for a given action.
+// To stop watching, close the event chan.
+func (w *eventHandler) Watch(c <-chan eventtypes.Message) {
+	for e := range c {
+		w.mu.Lock()
+		h, exists := w.handlers[e.Action]
+		w.mu.Unlock()
+		if !exists {
+			continue
+		}
+		logrus.Debugf("event handler: received event: %v", e)
+		go h(e)
+	}
+}
+
+// DecodeEvents decodes event from input stream
+func DecodeEvents(input io.Reader, ep eventProcessor) error {
+	dec := json.NewDecoder(input)
+	for {
+		var event eventtypes.Message
+		err := dec.Decode(&event)
+		if err != nil && err == io.EOF {
+			break
+		}
+
+		if procErr := ep(event, err); procErr != nil {
+			return procErr
+		}
+	}
+	return nil
+}