[GTK] Crash when dragging an account node above WebView

https://bugs.webkit.org/show_bug.cgi?id=226811

Patch by Michael Catanzaro <mcatanzaro@gnome.org> on 2021-06-11
Reviewed by Adrian Perez de Castro.

When we receive empty drag data, this is indicated by length -1, not by 0.

* UIProcess/API/gtk/DropTargetGtk3.cpp:
(WebKit::DropTarget::dataReceived):

Canonical link: https://commits.webkit.org/238721@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@278761 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebKit/ChangeLog

@@ -1,3 +1,15 @@
+2021-06-11  Michael Catanzaro  <mcatanzaro@gnome.org>
+
+        [GTK] Crash when dragging an account node above WebView
+        https://bugs.webkit.org/show_bug.cgi?id=226811
+
+        Reviewed by Adrian Perez de Castro.
+
+        When we receive empty drag data, this is indicated by length -1, not by 0.
+
+        * UIProcess/API/gtk/DropTargetGtk3.cpp:
+        (WebKit::DropTarget::dataReceived):
+
 2021-06-11  Adrian Perez de Castro  <aperez@igalia.com>
 
         Unreviewed. Update OptionsWPE.cmake and NEWS for the 2.33.2 release

Source/WebKit/UIProcess/API/gtk/DropTargetGtk3.cpp

@@ -177,7 +177,7 @@ void DropTarget::dataReceived(IntPoint&& position, GtkSelectionData* data, unsig
     case DropTargetType::Markup: {
         gint length;
         const auto* markupData = gtk_selection_data_get_data_with_length(data, &length);
-        if (length) {
+        if (length > 0) {
             // If data starts with UTF-16 BOM assume it's UTF-16, otherwise assume UTF-8.
             if (length >= 2 && reinterpret_cast<const UChar*>(markupData)[0] == 0xFEFF)
                 m_selectionData->setMarkup(String(reinterpret_cast<const UChar*>(markupData) + 1, (length / 2) - 1));
@@ -189,14 +189,14 @@ void DropTarget::dataReceived(IntPoint&& position, GtkSelectionData* data, unsig
     case DropTargetType::URIList: {
         gint length;
         const auto* uriListData = gtk_selection_data_get_data_with_length(data, &length);
-        if (length)
+        if (length > 0)
             m_selectionData->setURIList(String::fromUTF8(uriListData, length));
         break;
     }
     case DropTargetType::NetscapeURL: {
         gint length;
         const auto* urlData = gtk_selection_data_get_data_with_length(data, &length);
-        if (length) {
+        if (length > 0) {
             Vector<String> tokens = String::fromUTF8(urlData, length).split('\n');
             URL url({ }, tokens[0]);
             if (url.isValid())
@@ -210,7 +210,7 @@ void DropTarget::dataReceived(IntPoint&& position, GtkSelectionData* data, unsig
     case DropTargetType::Custom: {
         int length;
         const auto* customData = gtk_selection_data_get_data_with_length(data, &length);
-        if (length)
+        if (length > 0)
             m_selectionData->setCustomData(SharedBuffer::create(customData, static_cast<size_t>(length)));
         break;
     }