vendor files

vendor/k8s.io/apimachinery/pkg/watch/streamwatcher.go

@@ -0,0 +1,119 @@
+/*
+Copyright 2014 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package watch
+
+import (
+	"io"
+	"sync"
+
+	"github.com/golang/glog"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/util/net"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+)
+
+// Decoder allows StreamWatcher to watch any stream for which a Decoder can be written.
+type Decoder interface {
+	// Decode should return the type of event, the decoded object, or an error.
+	// An error will cause StreamWatcher to call Close(). Decode should block until
+	// it has data or an error occurs.
+	Decode() (action EventType, object runtime.Object, err error)
+
+	// Close should close the underlying io.Reader, signalling to the source of
+	// the stream that it is no longer being watched. Close() must cause any
+	// outstanding call to Decode() to return with an error of some sort.
+	Close()
+}
+
+// StreamWatcher turns any stream for which you can write a Decoder interface
+// into a watch.Interface.
+type StreamWatcher struct {
+	sync.Mutex
+	source  Decoder
+	result  chan Event
+	stopped bool
+}
+
+// NewStreamWatcher creates a StreamWatcher from the given decoder.
+func NewStreamWatcher(d Decoder) *StreamWatcher {
+	sw := &StreamWatcher{
+		source: d,
+		// It's easy for a consumer to add buffering via an extra
+		// goroutine/channel, but impossible for them to remove it,
+		// so nonbuffered is better.
+		result: make(chan Event),
+	}
+	go sw.receive()
+	return sw
+}
+
+// ResultChan implements Interface.
+func (sw *StreamWatcher) ResultChan() <-chan Event {
+	return sw.result
+}
+
+// Stop implements Interface.
+func (sw *StreamWatcher) Stop() {
+	// Call Close() exactly once by locking and setting a flag.
+	sw.Lock()
+	defer sw.Unlock()
+	if !sw.stopped {
+		sw.stopped = true
+		sw.source.Close()
+	}
+}
+
+// stopping returns true if Stop() was called previously.
+func (sw *StreamWatcher) stopping() bool {
+	sw.Lock()
+	defer sw.Unlock()
+	return sw.stopped
+}
+
+// receive reads result from the decoder in a loop and sends down the result channel.
+func (sw *StreamWatcher) receive() {
+	defer close(sw.result)
+	defer sw.Stop()
+	defer utilruntime.HandleCrash()
+	for {
+		action, obj, err := sw.source.Decode()
+		if err != nil {
+			// Ignore expected error.
+			if sw.stopping() {
+				return
+			}
+			switch err {
+			case io.EOF:
+				// watch closed normally
+			case io.ErrUnexpectedEOF:
+				glog.V(1).Infof("Unexpected EOF during watch stream event decoding: %v", err)
+			default:
+				msg := "Unable to decode an event from the watch stream: %v"
+				if net.IsProbableEOF(err) {
+					glog.V(5).Infof(msg, err)
+				} else {
+					glog.Errorf(msg, err)
+				}
+			}
+			return
+		}
+		sw.result <- Event{
+			Type:   action,
+			Object: obj,
+		}
+	}
+}