1 files changed, 21 insertions, 40 deletions

diff --git a/vendor/github.com/Microsoft/hcsshim/internal/queue/mq.go b/vendor/github.com/Microsoft/hcsshim/internal/queue/mq.go
index e177c9a62..4eb9bb9f1 100644
--- a/vendor/github.com/Microsoft/hcsshim/internal/queue/mq.go
+++ b/vendor/github.com/Microsoft/hcsshim/internal/queue/mq.go
@@ -5,10 +5,7 @@ import (
 	"sync"
 )
 
-var (
-	ErrQueueClosed = errors.New("the queue is closed for reading and writing")
-	ErrQueueEmpty  = errors.New("the queue is empty")
-)
+var ErrQueueClosed = errors.New("the queue is closed for reading and writing")
 
 // MessageQueue represents a threadsafe message queue to be used to retrieve or
 // write messages to.
@@ -29,8 +26,8 @@ func NewMessageQueue() *MessageQueue {
 	}
 }
 
-// Write writes `msg` to the queue.
-func (mq *MessageQueue) Write(msg interface{}) error {
+// Enqueue writes `msg` to the queue.
+func (mq *MessageQueue) Enqueue(msg interface{}) error {
 	mq.m.Lock()
 	defer mq.m.Unlock()
 
@@ -43,55 +40,37 @@ func (mq *MessageQueue) Write(msg interface{}) error {
 	return nil
 }
 
-// Read will read a value from the queue if available, otherwise return an error.
-func (mq *MessageQueue) Read() (interface{}, error) {
+// Dequeue will read a value from the queue and remove it. If the queue
+// is empty, this will block until the queue is closed or a value gets enqueued.
+func (mq *MessageQueue) Dequeue() (interface{}, error) {
 	mq.m.Lock()
 	defer mq.m.Unlock()
-	if mq.closed {
-		return nil, ErrQueueClosed
-	}
-	if mq.isEmpty() {
-		return nil, ErrQueueEmpty
+
+	for !mq.closed && mq.size() == 0 {
+		mq.c.Wait()
 	}
-	val := mq.messages[0]
-	mq.messages[0] = nil
-	mq.messages = mq.messages[1:]
-	return val, nil
-}
 
-// ReadOrWait will read a value from the queue if available, else it will wait for a
-// value to become available. This will block forever if nothing gets written or until
-// the queue gets closed.
-func (mq *MessageQueue) ReadOrWait() (interface{}, error) {
-	mq.m.Lock()
+	// We got woken up, check if it's because the queue got closed.
 	if mq.closed {
-		mq.m.Unlock()
 		return nil, ErrQueueClosed
 	}
-	if mq.isEmpty() {
-		for !mq.closed && mq.isEmpty() {
-			mq.c.Wait()
-		}
-		mq.m.Unlock()
-		return mq.Read()
-	}
+
 	val := mq.messages[0]
 	mq.messages[0] = nil
 	mq.messages = mq.messages[1:]
-	mq.m.Unlock()
 	return val, nil
 }
 
-// IsEmpty returns if the queue is empty
-func (mq *MessageQueue) IsEmpty() bool {
+// Size returns the size of the queue.
+func (mq *MessageQueue) Size() int {
 	mq.m.RLock()
 	defer mq.m.RUnlock()
-	return len(mq.messages) == 0
+	return mq.size()
 }
 
-// Nonexported empty check that doesn't lock so we can call this in Read and Write.
-func (mq *MessageQueue) isEmpty() bool {
-	return len(mq.messages) == 0
+// Nonexported size check to check if the queue is empty inside already locked functions.
+func (mq *MessageQueue) size() int {
+	return len(mq.messages)
 }
 
 // Close closes the queue for future writes or reads. Any attempts to read or write from the
@@ -99,13 +78,15 @@ func (mq *MessageQueue) isEmpty() bool {
 func (mq *MessageQueue) Close() {
 	mq.m.Lock()
 	defer mq.m.Unlock()
-	// Already closed
+
+	// Already closed, noop
 	if mq.closed {
 		return
 	}
+
 	mq.messages = nil
 	mq.closed = true
-	// If there's anybody currently waiting on a value from ReadOrWait, we need to
+	// If there's anybody currently waiting on a value from Dequeue, we need to
 	// broadcast so the read(s) can return ErrQueueClosed.
 	mq.c.Broadcast()
 }