Fix crash when triggereing the "Compare files" action via D-Bus

If the number of selected items is not two, Dolphin disables this
action. However, it is still possible to trigger it via D-Bus, and this
could cause a crash in DolphinMainWindow::compareFiles() because this
function did not test at all if there are really two items selected.

This patch adds such a check and simplifies the code in that function.

BUG: 325517
FIXED-IN: 4.11.3

1 files changed, 12 insertions, 39 deletions

diff --git a/src/dolphinmainwindow.cpp b/src/dolphinmainwindow.cpp
index a11fb0c5b..ccef356ea 100644
--- a/src/dolphinmainwindow.cpp
+++ b/src/dolphinmainwindow.cpp
@@ -999,50 +999,23 @@ void DolphinMainWindow::goHome(Qt::MouseButtons buttons)
 
 void DolphinMainWindow::compareFiles()
 {
-    // The method is only invoked if exactly 2 files have
-    // been selected. The selected files may be:
-    // - both in the primary view
-    // - both in the secondary view
-    // - one in the primary view and the other in the secondary
-    //   view
-    Q_ASSERT(m_viewTab[m_tabIndex].primaryView);
-
-    KUrl urlA;
-    KUrl urlB;
-
-    KFileItemList items = m_viewTab[m_tabIndex].primaryView->view()->selectedItems();
+    const DolphinViewContainer* primaryViewContainer = m_viewTab[m_tabIndex].primaryView;
+    Q_ASSERT(primaryViewContainer);
+    KFileItemList items = primaryViewContainer->view()->selectedItems();
 
-    switch (items.count()) {
-    case 0: {
-        Q_ASSERT(m_viewTab[m_tabIndex].secondaryView);
-        items = m_viewTab[m_tabIndex].secondaryView->view()->selectedItems();
-        Q_ASSERT(items.count() == 2);
-        urlA = items[0].url();
-        urlB = items[1].url();
-        break;
+    const DolphinViewContainer* secondaryViewContainer = m_viewTab[m_tabIndex].secondaryView;
+    if (secondaryViewContainer) {
+        items.append(secondaryViewContainer->view()->selectedItems());
     }
 
-    case 1: {
-        urlA = items[0].url();
-        Q_ASSERT(m_viewTab[m_tabIndex].secondaryView);
-        items = m_viewTab[m_tabIndex].secondaryView->view()->selectedItems();
-        Q_ASSERT(items.count() == 1);
-        urlB = items[0].url();
-        break;
-    }
-
-    case 2: {
-        urlA = items[0].url();
-        urlB = items[1].url();
-        break;
+    if (items.count() != 2) {
+        // The action is disabled in this case, but it could have been triggered
+        // via D-Bus, see https://bugs.kde.org/show_bug.cgi?id=325517
+        return;
     }
 
-    default: {
-        // may not happen: compareFiles may only get invoked if 2
-        // files are selected
-        Q_ASSERT(false);
-    }
-    }
+    KUrl urlA = items.at(0).url();
+    KUrl urlB = items.at(1).url();
 
     QString command("kompare -c \"");
     command.append(urlA.pathOrUrl());