LibWeb: Add support for cursor movement and delete.

Author: https://github.com/asynts
Commit: 78558c9f30
Pull-request: https://github.com/SerenityOS/serenity/pull/4318
Reviewed-by: https://github.com/Lubrsi
Reviewed-by: https://github.com/awesomekling
Reviewed-by: https://github.com/linusg

Libraries/LibWeb/Page/EditEventHandler.cpp

@@ -40,13 +40,13 @@ namespace Web {
 
 void EditEventHandler::handle_delete(DOM::Range range)
 {
-    // FIXME: Find a better way of updating the selection and cursor position.
+    // FIXME: Deleting nodes seems to mess up the layout tree. Not sure if this is not entirely
+    //        my fault or not my fault at all.
+
+    dump_tree(*m_frame.document());
 
     if (range.start().node() != range.end().node()) {
         if (range.start().node()->parent() == range.end().node()->parent()) {
-            m_frame.document()->layout_node()->set_selection({});
-            m_frame.cursor_position().set_offset(range.start().offset());
-
             // Remove all intermediate nodes.
             auto* current = range.start().node()->next_sibling();
             while (current != range.end().node()) {
@@ -55,9 +55,6 @@ void EditEventHandler::handle_delete(DOM::Range range)
                 current = next;
             }
 
-            if (!is<DOM::Text>(*range.start().node()) || !is<DOM::Text>(*range.end().node()))
-                TODO();
-
             // Join remaining text together.
             StringBuilder builder;
             builder.append(downcast<DOM::Text>(range.start().node())->data().substring_view(0, range.start().offset()));
@@ -73,7 +70,6 @@ void EditEventHandler::handle_delete(DOM::Range range)
     } else {
         if (is<DOM::Text>(*range.start().node())) {
             m_frame.document()->layout_node()->set_selection({});
-            m_frame.cursor_position().set_offset(range.start().offset());
 
             auto& node = downcast<DOM::Text>(*range.start().node());
 
@@ -89,24 +85,8 @@ void EditEventHandler::handle_delete(DOM::Range range)
     // FIXME: We need to remove stale layout nodes when nodes are removed from the DOM. Currently,
     //        this is the only way to get these to disappear.
     m_frame.document()->force_layout();
-}
 
-void EditEventHandler::handle_delete(DOM::Position position)
+    dump_tree(*m_frame.document());
-{
-    if (position.offset() == 0)
-        TODO();
-
-    if (is<DOM::Text>(*position.node())) {
-        auto& node = downcast<DOM::Text>(*position.node());
-
-        StringBuilder builder;
-        builder.append(node.data().substring_view(0, position.offset() - 1));
-        builder.append(node.data().substring_view(position.offset()));
-        node.set_data(builder.to_string());
-
-        m_frame.cursor_position().set_offset(m_frame.cursor_position().offset() - 1);
-        node.invalidate_style();
-    }
 }
 
 void EditEventHandler::handle_insert(DOM::Position position, u32 code_point)
@@ -120,9 +100,12 @@ void EditEventHandler::handle_insert(DOM::Position position, u32 code_point)
         builder.append(node.data().substring_view(position.offset()));
         node.set_data(builder.to_string());
 
-        m_frame.cursor_position().set_offset(m_frame.cursor_position().offset() + 1);
         node.invalidate_style();
     }
+
+    // FIXME: We need to remove stale layout nodes when nodes are removed from the DOM. Currently,
+    //        this is the only way to get these to disappear.
+    m_frame.document()->force_layout();
 }
 
 }

Libraries/LibWeb/Page/EditEventHandler.h

@@ -39,7 +39,6 @@ public:
 
     virtual ~EditEventHandler() = default;
 
-    virtual void handle_delete(DOM::Position);
     virtual void handle_delete(DOM::Range);
     virtual void handle_insert(DOM::Position, u32 code_point);
 

Libraries/LibWeb/Page/EventHandler.cpp

@@ -348,6 +348,9 @@ bool EventHandler::handle_keydown(KeyCode key, unsigned modifiers, u32 code_poin
     if (layout_root()->selection().is_valid()) {
         auto range = layout_root()->selection().to_dom_range();
 
+        m_frame.document()->layout_node()->set_selection({});
+        m_frame.set_cursor_position(range.start());
+
         if (key == KeyCode::Key_Backspace) {
             if (range.start().node()->is_editable()) {
                 m_edit_event_handler->handle_delete(range);
@@ -355,17 +358,54 @@ bool EventHandler::handle_keydown(KeyCode key, unsigned modifiers, u32 code_poin
             }
         } else {
             m_edit_event_handler->handle_delete(range);
+
             m_edit_event_handler->handle_insert(m_frame.cursor_position(), code_point);
+            m_frame.cursor_position().set_offset(m_frame.cursor_position().offset() + 1);
             return true;
         }
     }
 
     if (m_frame.cursor_position().is_valid() && m_frame.cursor_position().node()->is_editable()) {
         if (key == KeyCode::Key_Backspace) {
-            m_edit_event_handler->handle_delete(m_frame.cursor_position());
+            auto position = m_frame.cursor_position();
+
+            if (position.offset() == 0)
+                TODO();
+
+            m_frame.cursor_position().set_offset(position.offset() - 1);
+            m_edit_event_handler->handle_delete({ { *position.node(), position.offset() - 1 }, position });
+
+            return true;
+        } else if (key == KeyCode::Key_Delete) {
+            auto position = m_frame.cursor_position();
+
+            if (position.offset() >= downcast<DOM::Text>(position.node())->data().length())
+                TODO();
+
+            m_edit_event_handler->handle_delete({ position, { *position.node(), position.offset() + 1 } });
+
+            return true;
+        } else if (key == KeyCode::Key_Right) {
+            auto position = m_frame.cursor_position();
+
+            if (position.offset() >= downcast<DOM::Text>(position.node())->data().length())
+                TODO();
+
+            m_frame.cursor_position().set_offset(position.offset() + 1);
+
+            return true;
+        } else if (key == KeyCode::Key_Left) {
+            auto position = m_frame.cursor_position();
+
+            if (position.offset() == 0)
+                TODO();
+
+            m_frame.cursor_position().set_offset(position.offset() - 1);
+
             return true;
         } else {
             m_edit_event_handler->handle_insert(m_frame.cursor_position(), code_point);
+            m_frame.cursor_position().set_offset(m_frame.cursor_position().offset() + 1);
             return true;
         }
     }
@@ -380,5 +420,4 @@ void EventHandler::set_mouse_event_tracking_layout_node(Layout::Node* layout_nod
     else
         m_mouse_event_tracking_layout_node = nullptr;
 }
-
 }