UI/Qt: Avoid stale autocomplete activation

Remember which query produced the visible autocomplete popup rows, and
only activate selected rows when the visible popup still belongs to the
current query.

When Enter is pressed while fresh results are pending, rerun
autocomplete for the current query and activate once matching results
arrive. Ignore late completions after focus leaves. Avoid canceling
autocomplete while its completion callback activates the pending result.

UI/Qt/LocationEdit.cpp

@@ -253,6 +253,10 @@ LocationEdit::LocationEdit(QWidget* parent)
     update_location_icon();
 
     m_autocomplete->on_query_complete = [this](auto suggestions, WebView::AutocompleteResultKind result_kind) {
+        if (!hasFocus())
+            return;
+
+        auto query = current_query();
         int selected_row = -1;
         if (!m_autocomplete_query_without_inline.isNull() && text() == m_autocomplete_query_without_inline)
             selected_row = 0;
@@ -263,10 +267,22 @@ LocationEdit::LocationEdit(QWidget* parent)
         // Intermediate updates are triggered on every keystroke and would
         // cause visible flicker in the suggestion list.
         // Only final results are used to refresh the UI.
-        if (result_kind == WebView::AutocompleteResultKind::Intermediate && m_autocomplete->is_visible())
+        bool should_activate_pending_query = !m_pending_autocomplete_activation_query.isNull()
+            && m_pending_autocomplete_activation_query == query;
+        if (result_kind == WebView::AutocompleteResultKind::Intermediate && m_autocomplete->is_visible() && !should_activate_pending_query)
             return;
 
+        m_autocomplete_popup_query = query;
         m_autocomplete->show_with_suggestions(AK::move(suggestions), selected_row);
+        if (should_activate_pending_query) {
+            auto selected = m_autocomplete->selected_suggestion();
+            if (result_kind == WebView::AutocompleteResultKind::Final
+                || (selected.has_value() && qstring_from_ak_string(*selected) != query)) {
+                m_pending_autocomplete_activation_query = QString();
+                m_should_skip_autocomplete_cancel_on_focus_out = true;
+                activate_selected_autocomplete_suggestion();
+            }
+        }
     };
 
     connect(m_autocomplete, &Autocomplete::suggestion_activated, this, [this](QString const& text) {
@@ -285,6 +301,8 @@ LocationEdit::LocationEdit(QWidget* parent)
     connect(m_autocomplete, &Autocomplete::did_close, this, [this] {
         m_current_inline_autocomplete_suggestion.clear();
         if (!m_autocomplete_query_without_inline.isNull()) {
+            if (hasSelectedText())
+                restore_query();
             m_autocomplete_query_without_inline = QString();
             return;
         }
@@ -317,6 +335,8 @@ LocationEdit::LocationEdit(QWidget* parent)
             m_has_user_edited_hidden_url = true;
 
         auto query = current_query();
+        if (!m_pending_autocomplete_activation_query.isNull() && m_pending_autocomplete_activation_query != query)
+            m_pending_autocomplete_activation_query = QString();
 
         if (m_should_suppress_inline_autocomplete_on_next_change) {
             m_suppressed_inline_autocomplete_query = query;
@@ -394,6 +414,7 @@ void LocationEdit::show_autocomplete()
         return;
 
     auto query = text();
+    m_autocomplete_popup_query = QString();
     m_autocomplete_query_without_inline = query;
     m_autocomplete->query_autocomplete_engine(ak_string_from_qstring(query));
 }
@@ -439,8 +460,18 @@ void LocationEdit::focusOutEvent(QFocusEvent* event)
 
     animate_focus_glow(0);
 
+    if (hasSelectedText()) {
+        auto query = current_query();
+        m_is_applying_inline_autocomplete = true;
+        setText(query);
+        setCursorPosition(query.length());
+        m_is_applying_inline_autocomplete = false;
+    }
+
+    auto should_cancel_pending_query = !m_should_skip_autocomplete_cancel_on_focus_out;
     reset_autocomplete_state();
-    m_autocomplete->cancel_pending_query();
+    if (should_cancel_pending_query)
+        m_autocomplete->cancel_pending_query();
     m_autocomplete->close();
     m_should_show_full_url_on_mouse_release = false;
 
@@ -501,15 +532,17 @@ void LocationEdit::keyPressEvent(QKeyEvent* event)
     }
 
     if ((event->key() == Qt::Key_Return || event->key() == Qt::Key_Enter) && m_autocomplete->is_visible()) {
-        if (auto selected = m_autocomplete->selected_suggestion(); selected.has_value()) {
+        auto query = current_query();
-            m_is_applying_inline_autocomplete = true;
+        if (m_autocomplete_popup_query == query) {
-            setText(qstring_from_ak_string(*selected));
+            activate_selected_autocomplete_suggestion();
-            m_is_applying_inline_autocomplete = false;
+            event->accept();
+            return;
+        } else {
+            m_pending_autocomplete_activation_query = query;
+            m_autocomplete->query_autocomplete_engine(ak_string_from_qstring(query));
+            event->accept();
+            return;
         }
-        m_autocomplete->close();
-        emit returnPressed();
-        event->accept();
-        return;
     }
 
     if (should_suppress_inline_autocomplete_for_key(event))
@@ -1075,6 +1108,17 @@ void LocationEdit::apply_inline_autocomplete_text(QString const& inline_text, QS
     m_is_applying_inline_autocomplete = false;
 }
 
+void LocationEdit::activate_selected_autocomplete_suggestion()
+{
+    if (auto selected = m_autocomplete->selected_suggestion(); selected.has_value()) {
+        m_is_applying_inline_autocomplete = true;
+        setText(qstring_from_ak_string(*selected));
+        m_is_applying_inline_autocomplete = false;
+    }
+    m_autocomplete->close();
+    emit returnPressed();
+}
+
 void LocationEdit::restore_query()
 {
     if (!hasFocus())
@@ -1092,8 +1136,11 @@ void LocationEdit::restore_query()
 
 void LocationEdit::reset_autocomplete_state()
 {
+    m_autocomplete_popup_query = QString();
     m_autocomplete_query_without_inline = QString();
     m_current_inline_autocomplete_suggestion.clear();
+    m_should_skip_autocomplete_cancel_on_focus_out = false;
+    m_pending_autocomplete_activation_query = QString();
     m_suppressed_inline_autocomplete_query = QString();
     m_should_suppress_inline_autocomplete_on_next_change = false;
 }

UI/Qt/LocationEdit.h

@@ -75,6 +75,7 @@ private:
     int apply_inline_autocomplete(Vector<WebView::AutocompleteSuggestion> const&);
     bool apply_inline_autocomplete_suggestion_text(QString const& suggestion_text, QString const& query);
     void apply_inline_autocomplete_text(QString const& inline_text, QString const& query);
+    void activate_selected_autocomplete_suggestion();
     void restore_query();
     QString current_query() const;
     void reset_autocomplete_state();
@@ -98,8 +99,11 @@ private:
 
     bool m_is_applying_inline_autocomplete { false };
     bool m_should_suppress_inline_autocomplete_on_next_change { false };
+    bool m_should_skip_autocomplete_cancel_on_focus_out { false };
+    QString m_autocomplete_popup_query;
     QString m_autocomplete_query_without_inline;
     QString m_current_inline_autocomplete_suggestion;
+    QString m_pending_autocomplete_activation_query;
     QString m_suppressed_inline_autocomplete_query;
 };