Cocoa integration - fix a crash in QMacPasteboard

QMacPasteboard's dtor skips LazyRequest promises and this leaves pasteboard
manager in broken state, since we release the pasteboard itself
of the next step in destructor. As a result, not only Qt's app doing D & D
(and thus via QCocoaDrag creating a stack-allocated QMacPasteboard) can die
suddenly when somebody inspects a pasteboard, this 'somebody' ... can also
die amazingly. So now we DO resolve promises using PasteboardResolvePromises
(but we also preserve the original intent of not providing or providing empty
data for lazy requests).

Task-number: QTBUG-54663
Task-number: QTBUG-54832
Change-Id: I3ce90bd0a012dd3cbb30c93b2b17dce9473acb28
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

2 files changed, 7 insertions, 13 deletions

diff --git a/src/plugins/platforms/cocoa/qmacclipboard.h b/src/plugins/platforms/cocoa/qmacclipboard.h
index 0d1f195f48..6989a44a0e 100644
--- a/src/plugins/platforms/cocoa/qmacclipboard.h
+++ b/src/plugins/platforms/cocoa/qmacclipboard.h
@@ -69,6 +69,7 @@ private:
     uchar mime_type;
     mutable QPointer<QMimeData> mime;
     mutable bool mac_mime_source;
+    bool resolvingBeforeDestruction;
     static OSStatus promiseKeeper(PasteboardRef, PasteboardItemID, CFStringRef, void *);
     void clear_helper();
 public:
diff --git a/src/plugins/platforms/cocoa/qmacclipboard.mm b/src/plugins/platforms/cocoa/qmacclipboard.mm
index f4fd32ffd1..d0e2c39895 100644
--- a/src/plugins/platforms/cocoa/qmacclipboard.mm
+++ b/src/plugins/platforms/cocoa/qmacclipboard.mm
@@ -81,6 +81,7 @@ QMacPasteboard::QMacPasteboard(PasteboardRef p, uchar mt)
     mime_type = mt ? mt : uchar(QMacInternalPasteboardMime::MIME_ALL);
     paste = p;
     CFRetain(paste);
+    resolvingBeforeDestruction = false;
 }
 
 QMacPasteboard::QMacPasteboard(uchar mt)
@@ -94,6 +95,7 @@ QMacPasteboard::QMacPasteboard(uchar mt)
     } else {
         qDebug("PasteBoard: Error creating pasteboard: [%d]", (int)err);
     }
+    resolvingBeforeDestruction = false;
 }
 
 QMacPasteboard::QMacPasteboard(CFStringRef name, uchar mt)
@@ -107,23 +109,14 @@ QMacPasteboard::QMacPasteboard(CFStringRef name, uchar mt)
     } else {
         qDebug("PasteBoard: Error creating pasteboard: %s [%d]", QCFString::toQString(name).toLatin1().constData(), (int)err);
     }
+    resolvingBeforeDestruction = false;
 }
 
 QMacPasteboard::~QMacPasteboard()
 {
     // commit all promises for paste after exit close
-    for (int i = 0; i < promises.count(); ++i) {
-        const Promise &promise = promises.at(i);
-        // At this point app teardown has started and control is somewhere in the Q[Core]Application
-        // destructor. Skip "lazy" promises where the application has not provided data;
-        // the application will generally not be in a state to provide it.
-        if (promise.dataRequestType == LazyRequest)
-            continue;
-        QCFString flavor = QCFString(promise.convertor->flavorFor(promise.mime));
-        NSInteger pbItemId = promise.itemId;
-        promiseKeeper(paste, reinterpret_cast<PasteboardItemID>(pbItemId), flavor, this);
-    }
-
+    resolvingBeforeDestruction = true;
+    PasteboardResolvePromises(paste);
     if (paste)
         CFRelease(paste);
 }
@@ -175,7 +168,7 @@ OSStatus QMacPasteboard::promiseKeeper(PasteboardRef paste, PasteboardItemID id,
     // to request the data from the application.
     QVariant promiseData;
     if (promise.dataRequestType == LazyRequest) {
-        if (!promise.mimeData.isNull())
+        if (!qpaste->resolvingBeforeDestruction && !promise.mimeData.isNull())
             promiseData = promise.mimeData->variantData(promise.mime);
     } else {
         promiseData = promise.variantData;