QProcess: simplify the logic around _q_processDied()

Both on Unix and Windows, _q_processDied() unconditionally releases all
resources associated with the terminated child process, resets QProcess
to the initial state, and emits finished() signal. Thus, we can omit
reporting success, which also eliminates the related checks from
callers.

Change-Id: I40e32d1a9ccc8d488be6badba934355d734a8abd
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>

src/corelib/io/qprocess.cpp

@@ -1057,15 +1057,14 @@ bool QProcessPrivate::_q_canWrite()
 /*!
     \internal
 */
-bool QProcessPrivate::_q_processDied()
+void QProcessPrivate::_q_processDied()
 {
     Q_Q(QProcess);
 #if defined QPROCESS_DEBUG
     qDebug("QProcessPrivate::_q_processDied()");
 #endif
 #ifdef Q_OS_UNIX
-    if (!waitForDeadChild())
-        return false;
+    waitForDeadChild();
 #endif
 #ifdef Q_OS_WIN
     if (processFinishedNotifier)
@@ -1078,7 +1077,7 @@ bool QProcessPrivate::_q_processDied()
     // give it a chance to emit started() or errorOccurred(FailedToStart).
     if (processState == QProcess::Starting) {
         if (!_q_startupNotification())
-            return true;
+            return;
     }
 
     if (dying) {
@@ -1086,7 +1085,7 @@ bool QProcessPrivate::_q_processDied()
         // reentering this slot recursively by calling waitForFinished()
         // or opening a dialog inside slots connected to the readyRead
         // signals emitted below.
-        return true;
+        return;
     }
     dying = true;
 
@@ -1119,7 +1118,6 @@ bool QProcessPrivate::_q_processDied()
 #if defined QPROCESS_DEBUG
     qDebug("QProcessPrivate::_q_processDied() process is dead");
 #endif
-    return true;
 }
 
 /*!

src/corelib/io/qprocess.h

@@ -283,7 +283,7 @@ private:
     Q_PRIVATE_SLOT(d_func(), bool _q_canReadStandardError())
     Q_PRIVATE_SLOT(d_func(), bool _q_canWrite())
     Q_PRIVATE_SLOT(d_func(), bool _q_startupNotification())
-    Q_PRIVATE_SLOT(d_func(), bool _q_processDied())
+    Q_PRIVATE_SLOT(d_func(), void _q_processDied())
     friend class QProcessManager;
 };
 

src/corelib/io/qprocess_p.h

@@ -295,7 +295,7 @@ public:
     bool _q_canReadStandardError();
     bool _q_canWrite();
     bool _q_startupNotification();
-    bool _q_processDied();
+    void _q_processDied();
 
     QProcess::ProcessChannelMode processChannelMode = QProcess::SeparateChannels;
     QProcess::InputChannelMode inputChannelMode = QProcess::ManagedInputChannel;
@@ -354,7 +354,7 @@ public:
     void killProcess();
     void findExitCode();
 #ifdef Q_OS_UNIX
-    bool waitForDeadChild();
+    void waitForDeadChild();
 #endif
 #ifdef Q_OS_WIN
     bool callCreateProcess(QProcess::CreateProcessArguments *cpargs);

src/corelib/io/qprocess_unix.cpp

@@ -768,8 +768,8 @@ bool QProcessPrivate::waitForReadyRead(int msecs)
             return false;
 
         if (qt_pollfd_check(poller.forkfd(), POLLIN)) {
-            if (_q_processDied())
-                return false;
+            _q_processDied();
+            return false;
         }
     }
     return false;
@@ -818,8 +818,8 @@ bool QProcessPrivate::waitForBytesWritten(int msecs)
             return false;
 
         if (qt_pollfd_check(poller.forkfd(), POLLIN)) {
-            if (_q_processDied())
-                return false;
+            _q_processDied();
+            return false;
         }
     }
 
@@ -867,8 +867,8 @@ bool QProcessPrivate::waitForFinished(int msecs)
             return true;
 
         if (qt_pollfd_check(poller.forkfd(), POLLIN)) {
-            if (_q_processDied())
-                return true;
+            _q_processDied();
+            return true;
         }
     }
     return false;
@@ -878,10 +878,10 @@ void QProcessPrivate::findExitCode()
 {
 }
 
-bool QProcessPrivate::waitForDeadChild()
+void QProcessPrivate::waitForDeadChild()
 {
     if (forkfd == -1)
-        return true; // child has already exited
+        return; // child has already been reaped
 
     // read the process information from our fd
     forkfd_info info;
@@ -901,7 +901,6 @@ bool QProcessPrivate::waitForDeadChild()
     qDebug() << "QProcessPrivate::waitForDeadChild() dead with exitCode"
              << exitCode << ", crashed?" << crashed;
 #endif
-    return true;
 }
 
 bool QProcessPrivate::startDetached(qint64 *pid)