Better handling of interrupted PDF printing

- Document the fact Stop WebAction can interrupt the in-progress PDF
generation.

- Update PrintViewManagerQt::PrintPreviewDone(): Normally
IsPrintRenderFrameConnected() implies IsRenderFrameLive(), but we have
to check both to avoid crash when render process exits. (Like Chrome
does.)

- Update PrintViewManagerQt::RequestPrintPreview(): Handle that case when
print preview params were sent between processes at the beginning, but it
was interrupted before RequestPrintPreview() could start PDF generation.

- Add a simple auto test to catch crashes

Pick-to: 6.5
Task-number: QTBUG-108154
Change-Id: I8a4f9cc97ddcf9a165d66a5981d93a023858fbc1
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

1 files changed, 14 insertions, 0 deletions

diff --git a/tests/auto/widgets/printing/tst_printing.cpp b/tests/auto/widgets/printing/tst_printing.cpp
index 1c1e0615e..1f9b5059c 100644
--- a/tests/auto/widgets/printing/tst_printing.cpp
+++ b/tests/auto/widgets/printing/tst_printing.cpp
@@ -23,6 +23,7 @@ private slots:
 #if QT_CONFIG(webengine_system_poppler)
     void printToPdfPoppler();
 #endif
+    void interruptPrinting();
 };
 
 void tst_Printing::printToPdfBasic()
@@ -117,6 +118,19 @@ void tst_Printing::printToPdfPoppler()
 }
 #endif
 
+void tst_Printing::interruptPrinting()
+{
+    QWebEngineView view;
+    QSignalSpy spy(&view, &QWebEngineView::loadFinished);
+    view.load(QUrl("qrc:///resources/basic_printing_page.html"));
+    QTRY_VERIFY(spy.size() == 1);
+
+    QTemporaryDir tempDir(QDir::tempPath() + "/tst_qwebengineview-XXXXXX");
+    QVERIFY(tempDir.isValid());
+    view.page()->printToPdf(tempDir.path() + "/file.pdf");
+    // Navigation stop interrupts print job, preferably do this without crash/assert
+    view.page()->triggerAction(QWebEnginePage::Stop);
+}
 
 QTEST_MAIN(tst_Printing)
 #include "tst_printing.moc"