hswg: improve inotify processing

Make sure to read the whole record before checking flags.

.gitignore

@@ -2,6 +2,7 @@
 /hid/hid
 /hnc/hnc
 /hpcu/hpcu
+/hswg/hswg
 /ht/ht
 /prototypes/tls-autodetect
 /prototypes/xgb-draw

hswg/main.go

@@ -334,6 +334,15 @@ func dispatchEvents(dirname string, r io.Reader, ch chan<- *watchEvent) error {
 			return err
 		}
 
+		base := make([]byte, e.Len)
+		if e.Len != 0 {
+			if n, err := r.Read(base); err != nil {
+				return err
+			} else if n < int(e.Len) {
+				return fmt.Errorf("short read")
+			}
+		}
+
 		switch {
 		case e.Mask&syscall.IN_IGNORED != 0:
 			return fmt.Errorf("watch removed by kernel")
@@ -345,13 +354,6 @@ func dispatchEvents(dirname string, r io.Reader, ch chan<- *watchEvent) error {
 			continue
 		}
 
-		base := make([]byte, e.Len)
-		if n, err := r.Read(base); err != nil {
-			return err
-		} else if n < int(e.Len) {
-			return fmt.Errorf("short read")
-		}
-
 		basename, interesting := string(base[:bytes.IndexByte(base, 0)]), false
 		for _, glob := range globs {
 			if matches, _ := filepath.Match(glob, basename); matches {