update github.com/ncw/swift package in vendor to avoid potential memory leaks

Signed-off-by: mlmhl <409107750@qq.com>

vendor/github.com/ncw/swift/watchdog_reader.go

@@ -5,29 +5,50 @@ import (
 	"time"
 )
 
+var watchdogChunkSize = 1 << 20 // 1 MiB
+
 // An io.Reader which resets a watchdog timer whenever data is read
 type watchdogReader struct {
-	timeout time.Duration
-	reader  io.Reader
-	timer   *time.Timer
+	timeout   time.Duration
+	reader    io.Reader
+	timer     *time.Timer
+	chunkSize int
 }
 
 // Returns a new reader which will kick the watchdog timer whenever data is read
 func newWatchdogReader(reader io.Reader, timeout time.Duration, timer *time.Timer) *watchdogReader {
 	return &watchdogReader{
-		timeout: timeout,
-		reader:  reader,
-		timer:   timer,
+		timeout:   timeout,
+		reader:    reader,
+		timer:     timer,
+		chunkSize: watchdogChunkSize,
 	}
 }
 
 // Read reads up to len(p) bytes into p
-func (t *watchdogReader) Read(p []byte) (n int, err error) {
-	// FIXME limit the amount of data read in one chunk so as to not exceed the timeout?
+func (t *watchdogReader) Read(p []byte) (int, error) {
+	//read from underlying reader in chunks not larger than t.chunkSize
+	//while resetting the watchdog timer before every read; the small chunk
+	//size ensures that the timer does not fire when reading a large amount of
+	//data from a slow connection
+	start := 0
+	end := len(p)
+	for start < end {
+		length := end - start
+		if length > t.chunkSize {
+			length = t.chunkSize
+		}
+
+		resetTimer(t.timer, t.timeout)
+		n, err := t.reader.Read(p[start : start+length])
+		start += n
+		if n == 0 || err != nil {
+			return start, err
+		}
+	}
+
 	resetTimer(t.timer, t.timeout)
-	n, err = t.reader.Read(p)
-	resetTimer(t.timer, t.timeout)
-	return
+	return start, nil
 }
 
 // Check it satisfies the interface