Revert "Support more than 62 instances of QWinEventNotifier"

It breaks sth in QLocalSocket which is used in QtRemoteObject.

This reverts commit 5c6210e3452f78cab2f58887e747eb5cb2501f70.

Task-number: QTBUG-61668
Change-Id: Ib11890923773496e5d998b7709ef93b0a839a759
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

1 files changed, 26 insertions, 41 deletions

diff --git a/src/corelib/kernel/qeventdispatcher_win.cpp b/src/corelib/kernel/qeventdispatcher_win.cpp
index fc34dd0a6b..0952464f53 100644
--- a/src/corelib/kernel/qeventdispatcher_win.cpp
+++ b/src/corelib/kernel/qeventdispatcher_win.cpp
@@ -53,7 +53,6 @@
 #include "qcoreapplication_p.h"
 #include <private/qthread_p.h>
 #include <private/qmutexpool_p.h>
-#include <private/qwineventnotifier_p.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -97,14 +96,13 @@ LRESULT QT_WIN_CALLBACK qt_internal_proc(HWND hwnd, UINT message, WPARAM wp, LPA
 QEventDispatcherWin32Private::QEventDispatcherWin32Private()
     : threadId(GetCurrentThreadId()), interrupt(false), closingDown(false), internalHwnd(0),
       getMessageHook(0), serialNumber(0), lastSerialNumber(0), sendPostedEventsWindowsTimerId(0),
-      wakeUps(0), activateNotifiersPosted(false), winEventNotifierActivatedEvent(NULL)
+      wakeUps(0)
+    , activateNotifiersPosted(false)
 {
 }
 
 QEventDispatcherWin32Private::~QEventDispatcherWin32Private()
 {
-    if (winEventNotifierActivatedEvent)
-        CloseHandle(winEventNotifierActivatedEvent);
     if (internalHwnd)
         DestroyWindow(internalHwnd);
 }
@@ -539,14 +537,12 @@ bool QEventDispatcherWin32::processEvents(QEventLoop::ProcessEventsFlags flags)
     bool needWM_QT_SENDPOSTEDEVENTS = false;
     do {
         DWORD waitRet = 0;
-        DWORD nCount = 0;
-        HANDLE *pHandles = nullptr;
-        if (d->winEventNotifierActivatedEvent) {
-            nCount = 1;
-            pHandles = &d->winEventNotifierActivatedEvent;
-        }
+        HANDLE pHandles[MAXIMUM_WAIT_OBJECTS - 1];
         QVarLengthArray<MSG> processedTimers;
         while (!d->interrupt) {
+            DWORD nCount = d->winEventNotifierList.count();
+            Q_ASSERT(nCount < MAXIMUM_WAIT_OBJECTS - 1);
+
             MSG msg;
             bool haveMessage;
 
@@ -588,6 +584,8 @@ bool QEventDispatcherWin32::processEvents(QEventLoop::ProcessEventsFlags flags)
             }
             if (!haveMessage) {
                 // no message - check for signalled objects
+                for (int i=0; i<(int)nCount; i++)
+                    pHandles[i] = d->winEventNotifierList.at(i)->handle();
                 waitRet = MsgWaitForMultipleObjectsEx(nCount, pHandles, 0, QS_ALLINPUT, MWMO_ALERTABLE);
                 if ((haveMessage = (waitRet == WAIT_OBJECT_0 + nCount))) {
                     // a new message has arrived, process it
@@ -628,7 +626,7 @@ bool QEventDispatcherWin32::processEvents(QEventLoop::ProcessEventsFlags flags)
                     DispatchMessage(&msg);
                 }
             } else if (waitRet - WAIT_OBJECT_0 < nCount) {
-                activateEventNotifiers();
+                d->activateEventNotifier(d->winEventNotifierList.at(waitRet - WAIT_OBJECT_0));
             } else {
                 // nothing todo so break
                 break;
@@ -641,11 +639,16 @@ bool QEventDispatcherWin32::processEvents(QEventLoop::ProcessEventsFlags flags)
                    && !d->interrupt
                    && (flags & QEventLoop::WaitForMoreEvents));
         if (canWait) {
+            DWORD nCount = d->winEventNotifierList.count();
+            Q_ASSERT(nCount < MAXIMUM_WAIT_OBJECTS - 1);
+            for (int i=0; i<(int)nCount; i++)
+                pHandles[i] = d->winEventNotifierList.at(i)->handle();
+
             emit aboutToBlock();
             waitRet = MsgWaitForMultipleObjectsEx(nCount, pHandles, INFINITE, QS_ALLINPUT, MWMO_ALERTABLE | MWMO_INPUTAVAILABLE);
             emit awake();
             if (waitRet - WAIT_OBJECT_0 < nCount) {
-                activateEventNotifiers();
+                d->activateEventNotifier(d->winEventNotifierList.at(waitRet - WAIT_OBJECT_0));
                 retVal = true;
             }
         }
@@ -903,12 +906,12 @@ bool QEventDispatcherWin32::registerEventNotifier(QWinEventNotifier *notifier)
     if (d->winEventNotifierList.contains(notifier))
         return true;
 
+    if (d->winEventNotifierList.count() >= MAXIMUM_WAIT_OBJECTS - 2) {
+        qWarning("QWinEventNotifier: Cannot have more than %d enabled at one time", MAXIMUM_WAIT_OBJECTS - 2);
+        return false;
+    }
     d->winEventNotifierList.append(notifier);
-
-    if (!d->winEventNotifierActivatedEvent)
-        d->winEventNotifierActivatedEvent = CreateEvent(0, TRUE, FALSE, nullptr);
-
-    return QWinEventNotifierPrivate::get(notifier)->registerWaitObject();
+    return true;
 }
 
 void QEventDispatcherWin32::unregisterEventNotifier(QWinEventNotifier *notifier)
@@ -924,35 +927,17 @@ void QEventDispatcherWin32::unregisterEventNotifier(QWinEventNotifier *notifier)
     Q_D(QEventDispatcherWin32);
 
     int i = d->winEventNotifierList.indexOf(notifier);
-    if (i == -1)
-        return;
-    d->winEventNotifierList.takeAt(i);
-    QWinEventNotifierPrivate *nd = QWinEventNotifierPrivate::get(notifier);
-    if (nd->waitHandle)
-        nd->unregisterWaitObject();
+    if (i != -1)
+        d->winEventNotifierList.takeAt(i);
 }
 
 void QEventDispatcherWin32::activateEventNotifiers()
 {
     Q_D(QEventDispatcherWin32);
-    ResetEvent(d->winEventNotifierActivatedEvent);
-
-    // Iterate backwards, because the notifier might remove itself on activate().
-    for (int i = d->winEventNotifierList.count(); --i >= 0;) {
-        QWinEventNotifier *notifier = d->winEventNotifierList.at(i);
-        QWinEventNotifierPrivate *nd = QWinEventNotifierPrivate::get(notifier);
-        if (WaitForSingleObject(nd->handleToEvent, 0) == WAIT_OBJECT_0) {
-            nd->unregisterWaitObject();
-            d->activateEventNotifier(notifier);
-        }
-    }
-
-    // Re-register the remaining activated notifiers.
-    for (int i = 0; i < d->winEventNotifierList.count(); ++i) {
-        QWinEventNotifier *notifier = d->winEventNotifierList.at(i);
-        QWinEventNotifierPrivate *nd = QWinEventNotifierPrivate::get(notifier);
-        if (nd->waitHandle || !nd->registerWaitObject())
-            return;
+    //### this could break if events are removed/added in the activation
+    for (int i=0; i<d->winEventNotifierList.count(); i++) {
+        if (WaitForSingleObjectEx(d->winEventNotifierList.at(i)->handle(), 0, TRUE) == WAIT_OBJECT_0)
+            d->activateEventNotifier(d->winEventNotifierList.at(i));
     }
 }