LibWeb: Add support for range deletion.

Author: https://github.com/asynts
Commit: https://github.com/SerenityOS/serenity/commit/43dc47a4941
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/DOM/Position.cpp

@@ -39,6 +39,24 @@ Position::~Position()
 {
 }
 
+Range Range::normalized() const
+{
+    if (!is_valid())
+        return {};
+
+    if (m_start.node() == m_end.node()) {
+        if (m_start.offset() <= m_end.offset())
+            return *this;
+
+        return { m_end, m_start };
+    }
+
+    if (m_start.node()->is_before(*m_end.node()))
+        return *this;
+
+    return { m_end, m_start };
+}
+
 const LogStream& operator<<(const LogStream& stream, const Position& position)
 {
     if (!position.node())

Libraries/LibWeb/DOM/Position.h

@@ -62,6 +62,38 @@ private:
     unsigned m_offset { 0 };
 };
 
+class Range {
+public:
+    Range() = default;
+    Range(const Position& start, const Position& end)
+        : m_start(start)
+        , m_end(end)
+    {
+    }
+
+    bool is_valid() const { return m_start.is_valid() && m_end.is_valid(); }
+
+    void set(const Position& start, const Position& end)
+    {
+        m_start = start;
+        m_end = end;
+    }
+
+    void set_start(const Position& start) { m_start = start; }
+    void set_end(const Position& end) { m_end = end; }
+
+    const Position& start() const { return m_start; }
+    Position& start() { return m_start; }
+
+    const Position& end() const { return m_end; }
+    Position& end() { return m_end; }
+
+    Range normalized() const;
+
+private:
+    Position m_start, m_end;
+};
+
 const LogStream& operator<<(const LogStream&, const Position&);
 
 }

Libraries/LibWeb/Forward.h

@@ -51,6 +51,7 @@ class MouseEvent;
 class Node;
 class ParentNode;
 class Position;
+class Range;
 class Text;
 class Timer;
 class Window;

Libraries/LibWeb/Layout/LayoutPosition.cpp

@@ -53,4 +53,12 @@ LayoutRange LayoutRange::normalized() const
     return { m_end, m_start };
 }
 
+DOM::Range LayoutRange::to_dom_range() const
+{
+    if (!is_valid())
+        return {};
+
+    return { m_start.to_dom_position(), m_end.to_dom_position() };
+}
+
 }

Libraries/LibWeb/Layout/LayoutPosition.h

@@ -68,6 +68,8 @@ public:
 
     LayoutRange normalized() const;
 
+    DOM::Range to_dom_range() const;
+
 private:
     LayoutPosition m_start;
     LayoutPosition m_end;

Libraries/LibWeb/Page/EditEventHandler.cpp

@@ -30,10 +30,32 @@
 #include <LibWeb/Layout/LayoutPosition.h>
 #include <LibWeb/Page/Frame.h>
 
+#include <LibWeb/DOM/Document.h>
+#include <LibWeb/Layout/InitialContainingBlockBox.h>
+
 #include "EditEventHandler.h"
 
 namespace Web {
 
+void EditEventHandler::handle_delete(DOM::Range range)
+{
+    if (range.start().node() != range.end().node())
+        TODO();
+
+    if (is<DOM::Text>(*range.start().node())) {
+        auto& node = downcast<DOM::Text>(*range.start().node());
+
+        StringBuilder builder;
+
+        builder.append(node.data().substring_view(0, range.start().offset()));
+        builder.append(node.data().substring_view(range.end().offset()));
+        node.set_data(builder.to_string());
+
+        m_frame.document()->layout_node()->set_selection({});
+        node.invalidate_style();
+    }
+}
+
 void EditEventHandler::handle_delete(DOM::Position position)
 {
     if (position.offset() == 0)
@@ -41,6 +63,7 @@ void EditEventHandler::handle_delete(DOM::Position position)
 
     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()));
@@ -53,10 +76,9 @@ void EditEventHandler::handle_delete(DOM::Position position)
 
 void EditEventHandler::handle_insert(DOM::Position position, u32 code_point)
 {
-    // FIXME: Unicode fiasco.
-
     if (is<DOM::Text>(*position.node())) {
         auto& node = downcast<DOM::Text>(*position.node());
+
         StringBuilder builder;
         builder.append(node.data().substring_view(0, position.offset()));
         builder.append_code_point(code_point);

Libraries/LibWeb/Page/EditEventHandler.h

@@ -40,6 +40,7 @@ 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);
 
 private:

Libraries/LibWeb/Page/EventHandler.cpp

@@ -345,16 +345,33 @@ bool EventHandler::handle_keydown(KeyCode key, unsigned modifiers, u32 code_poin
             return focus_next_element();
     }
 
+    if (layout_root()->selection().is_valid()) {
+        auto range = layout_root()->selection().to_dom_range();
+
+        if (key == KeyCode::Key_Backspace) {
+            if (range.start().node()->is_editable()) {
+                m_edit_event_handler->handle_delete(range);
+                return true;
+            }
+        }
+
+        // FIXME: Check if this code point is in the printable character range.
+
+        m_edit_event_handler->handle_delete(range);
+        m_edit_event_handler->handle_insert(m_frame.cursor_position(), code_point);
+        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());
             return true;
         }
 
-        if (code_point) {
-            m_edit_event_handler->handle_insert(m_frame.cursor_position(), code_point);
-            return true;
-        }
+        // FIXME: Check if this code point is in the printable character range.
+
+        m_edit_event_handler->handle_insert(m_frame.cursor_position(), code_point);
+        return true;
     }
 
     return false;