QProcess: refine 'Channel' structure

- exclude unused notifier pointer on Windows;
- use default initialization for members;
- avoid bit fields in declarations as there are extra
  padding bytes anyway.

Change-Id: I2e03c4c269c885c90c0a6d18b8a935885f4b3feb
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>

src/corelib/io/qprocess.cpp

@@ -391,6 +391,8 @@ void QProcessPrivate::Channel::clear()
         process->stdoutChannel.type = Normal;
         process->stdoutChannel.process = nullptr;
         break;
+    default:
+        break;
     }
 
     type = Normal;

src/corelib/io/qprocess_p.h

@@ -231,23 +231,13 @@ public:
     Q_DECLARE_PUBLIC(QProcess)
 
     struct Channel {
-        enum ProcessChannelType {
+        enum ProcessChannelType : char {
             Normal = 0,
             PipeSource = 1,
             PipeSink = 2,
             Redirect = 3
-            // if you add "= 4" here, increase the number of bits below
         };
 
-        Channel() : process(nullptr), notifier(nullptr), type(Normal), closed(false), append(false)
-        {
-            pipe[0] = INVALID_Q_PIPE;
-            pipe[1] = INVALID_Q_PIPE;
-#ifdef Q_OS_WIN
-            reader = 0;
-#endif
-        }
-
         void clear();
 
         Channel &operator=(const QString &fileName)
@@ -273,19 +263,20 @@ public:
         }
 
         QString file;
-        QProcessPrivate *process;
-        QSocketNotifier *notifier;
-#ifdef Q_OS_WIN
+        QProcessPrivate *process = nullptr;
+#ifdef Q_OS_UNIX
+        QSocketNotifier *notifier = nullptr;
+#else
         union {
-            QWindowsPipeReader *reader;
+            QWindowsPipeReader *reader = nullptr;
             QWindowsPipeWriter *writer;
         };
 #endif
-        Q_PIPE pipe[2];
+        Q_PIPE pipe[2] = {INVALID_Q_PIPE, INVALID_Q_PIPE};
 
-        unsigned type : 2;
-        bool closed : 1;
-        bool append : 1;
+        ProcessChannelType type = Normal;
+        bool closed = false;
+        bool append = false;
     };
 
     QProcessPrivate();