Revert "Do not wait in QWindowsPipe{Reader|Writer}::stop()"

This reverts commit c7ec07d40115bef849574c81d619b629af9434a9.

Reason for revert: This causes a memory leak on program termination.

The initial commit was an attempt to fix a deadlock where the user
destroys object from a thread that does not own the object. This is
an unsupported case and should be treated as an invalid report.

Pick-to: 5.15
Change-Id: I4957784b86a0361adb65b9d023542f96480f00ba
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>

4 files changed, 14 insertions, 30 deletions

diff --git a/src/corelib/io/qwindowspipereader.cpp b/src/corelib/io/qwindowspipereader.cpp
index 1f03ac5d5a..c20909766d 100644
--- a/src/corelib/io/qwindowspipereader.cpp
+++ b/src/corelib/io/qwindowspipereader.cpp
@@ -58,7 +58,7 @@ void QWindowsPipeReader::Overlapped::clear()
 QWindowsPipeReader::QWindowsPipeReader(QObject *parent)
     : QObject(parent),
       handle(INVALID_HANDLE_VALUE),
-      overlapped(nullptr),
+      overlapped(this),
       readBufferMaxSize(0),
       actualReadBufferSize(0),
       stopped(true),
@@ -75,7 +75,6 @@ QWindowsPipeReader::QWindowsPipeReader(QObject *parent)
 QWindowsPipeReader::~QWindowsPipeReader()
 {
     stop();
-    delete overlapped;
 }
 
 /*!
@@ -97,16 +96,14 @@ void QWindowsPipeReader::stop()
 {
     stopped = true;
     if (readSequenceStarted) {
-        overlapped->pipeReader = nullptr;
-        if (!CancelIoEx(handle, overlapped)) {
+        if (!CancelIoEx(handle, &overlapped)) {
             const DWORD dwError = GetLastError();
             if (dwError != ERROR_NOT_FOUND) {
                 qErrnoWarning(dwError, "QWindowsPipeReader: CancelIoEx on handle %p failed.",
                               handle);
             }
         }
-        overlapped = nullptr;       // The object will be deleted in the I/O callback.
-        readSequenceStarted = false;
+        waitForNotification(-1);
     }
 }
 
@@ -227,10 +224,8 @@ void QWindowsPipeReader::startAsyncRead()
 
     stopped = false;
     readSequenceStarted = true;
-    if (!overlapped)
-        overlapped = new Overlapped(this);
-    overlapped->clear();
-    if (!ReadFileEx(handle, ptr, bytesToRead, overlapped, &readFileCompleted)) {
+    overlapped.clear();
+    if (!ReadFileEx(handle, ptr, bytesToRead, &overlapped, &readFileCompleted)) {
         readSequenceStarted = false;
 
         const DWORD dwError = GetLastError();
@@ -257,10 +252,7 @@ void QWindowsPipeReader::readFileCompleted(DWORD errorCode, DWORD numberOfBytesT
                                            OVERLAPPED *overlappedBase)
 {
     Overlapped *overlapped = static_cast<Overlapped *>(overlappedBase);
-    if (overlapped->pipeReader)
-        overlapped->pipeReader->notified(errorCode, numberOfBytesTransfered);
-    else
-        delete overlapped;
+    overlapped->pipeReader->notified(errorCode, numberOfBytesTransfered);
 }
 
 /*!
diff --git a/src/corelib/io/qwindowspipereader_p.h b/src/corelib/io/qwindowspipereader_p.h
index c757753c9c..5ec9dc379c 100644
--- a/src/corelib/io/qwindowspipereader_p.h
+++ b/src/corelib/io/qwindowspipereader_p.h
@@ -105,7 +105,7 @@ private:
     };
 
     HANDLE handle;
-    Overlapped *overlapped;
+    Overlapped overlapped;
     qint64 readBufferMaxSize;
     QRingBuffer readBuffer;
     qint64 actualReadBufferSize;
diff --git a/src/corelib/io/qwindowspipewriter.cpp b/src/corelib/io/qwindowspipewriter.cpp
index 32536f495b..e374034a06 100644
--- a/src/corelib/io/qwindowspipewriter.cpp
+++ b/src/corelib/io/qwindowspipewriter.cpp
@@ -57,7 +57,7 @@ void QWindowsPipeWriter::Overlapped::clear()
 QWindowsPipeWriter::QWindowsPipeWriter(HANDLE pipeWriteEnd, QObject *parent)
     : QObject(parent),
       handle(pipeWriteEnd),
-      overlapped(nullptr),
+      overlapped(this),
       pendingBytesWrittenValue(0),
       stopped(true),
       writeSequenceStarted(false),
@@ -72,7 +72,6 @@ QWindowsPipeWriter::QWindowsPipeWriter(HANDLE pipeWriteEnd, QObject *parent)
 QWindowsPipeWriter::~QWindowsPipeWriter()
 {
     stop();
-    delete overlapped;
 }
 
 bool QWindowsPipeWriter::waitForWrite(int msecs)
@@ -122,10 +121,7 @@ void QWindowsPipeWriter::writeFileCompleted(DWORD errorCode, DWORD numberOfBytes
                                             OVERLAPPED *overlappedBase)
 {
     Overlapped *overlapped = static_cast<Overlapped *>(overlappedBase);
-    if (overlapped->pipeWriter)
-        overlapped->pipeWriter->notified(errorCode, numberOfBytesTransfered);
-    else
-        delete overlapped;
+    overlapped->pipeWriter->notified(errorCode, numberOfBytesTransfered);
 }
 
 /*!
@@ -187,14 +183,12 @@ bool QWindowsPipeWriter::write(const QByteArray &ba)
     if (writeSequenceStarted)
         return false;
 
-    if (!overlapped)
-        overlapped = new Overlapped(this);
-    overlapped->clear();
+    overlapped.clear();
     buffer = ba;
     stopped = false;
     writeSequenceStarted = true;
     if (!WriteFileEx(handle, buffer.constData(), buffer.size(),
-                     overlapped, &writeFileCompleted)) {
+                     &overlapped, &writeFileCompleted)) {
         writeSequenceStarted = false;
         buffer.clear();
 
@@ -218,16 +212,14 @@ void QWindowsPipeWriter::stop()
     bytesWrittenPending = false;
     pendingBytesWrittenValue = 0;
     if (writeSequenceStarted) {
-        overlapped->pipeWriter = nullptr;
-        if (!CancelIoEx(handle, overlapped)) {
+        if (!CancelIoEx(handle, &overlapped)) {
             const DWORD dwError = GetLastError();
             if (dwError != ERROR_NOT_FOUND) {
                 qErrnoWarning(dwError, "QWindowsPipeWriter: CancelIoEx on handle %p failed.",
                               handle);
             }
         }
-        overlapped = nullptr;       // The object will be deleted in the I/O callback.
-        writeSequenceStarted = false;
+        waitForNotification(-1);
     }
 }
 
diff --git a/src/corelib/io/qwindowspipewriter_p.h b/src/corelib/io/qwindowspipewriter_p.h
index 6c269e86b7..f7f68b688c 100644
--- a/src/corelib/io/qwindowspipewriter_p.h
+++ b/src/corelib/io/qwindowspipewriter_p.h
@@ -143,7 +143,7 @@ private:
     };
 
     HANDLE handle;
-    Overlapped *overlapped;
+    Overlapped overlapped;
     QByteArray buffer;
     qint64 pendingBytesWrittenValue;
     bool stopped;