Allow destruction of QWindowsPipeReader in its signal

As a result, we can refrain from using the deleteLater() technique in
QProcess and avoid long-lived soft leaks in blocking applications.

Change-Id: I89e02b02551a668b995ad3d12d3ce9575b2dd9dd
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>

2 files changed, 18 insertions, 19 deletions

diff --git a/src/corelib/io/qprocess_win.cpp b/src/corelib/io/qprocess_win.cpp
index 65422659b0..e557d10453 100644
--- a/src/corelib/io/qprocess_win.cpp
+++ b/src/corelib/io/qprocess_win.cpp
@@ -359,22 +359,15 @@ void QProcessPrivate::destroyPipe(Q_PIPE pipe[2])
     }
 }
 
-template <class T>
-void deleteWorker(T *&worker)
-{
-    if (!worker)
-        return;
-    worker->stop();
-    worker->deleteLater();
-    worker = nullptr;
-}
-
 void QProcessPrivate::closeChannel(Channel *channel)
 {
-    if (channel == &stdinChannel)
-        deleteWorker(channel->writer);
-    else
-        deleteWorker(channel->reader);
+    if (channel == &stdinChannel) {
+        delete channel->writer;
+        channel->writer = nullptr;
+    } else {
+        delete channel->reader;
+        channel->reader = nullptr;
+    }
     destroyPipe(channel->pipe);
 }
 
diff --git a/src/corelib/io/qwindowspipereader.cpp b/src/corelib/io/qwindowspipereader.cpp
index d1a1782529..4d2f008eeb 100644
--- a/src/corelib/io/qwindowspipereader.cpp
+++ b/src/corelib/io/qwindowspipereader.cpp
@@ -41,6 +41,7 @@
 #include "qwindowspipereader_p.h"
 #include <qcoreapplication.h>
 #include <QMutexLocker>
+#include <QPointer>
 
 QT_BEGIN_NAMESPACE
 
@@ -425,12 +426,17 @@ bool QWindowsPipeReader::consumePendingAndEmit(bool allowWinActPosting)
     if (state != Running)
         return false;
 
-    if (emitReadyRead)
-        emit readyRead();
-    if (emitPipeClosed) {
-        if (dwError != ERROR_BROKEN_PIPE && dwError != ERROR_PIPE_NOT_CONNECTED)
+    if (!emitPipeClosed) {
+        if (emitReadyRead)
+            emit readyRead();
+    } else {
+        QPointer<QWindowsPipeReader> alive(this);
+        if (emitReadyRead)
+            emit readyRead();
+        if (alive && dwError != ERROR_BROKEN_PIPE && dwError != ERROR_PIPE_NOT_CONNECTED)
             emit winError(dwError, QLatin1String("QWindowsPipeReader::consumePendingAndEmit"));
-        emit pipeClosed();
+        if (alive)
+            emit pipeClosed();
     }
 
     return emitReadyRead;