Support inserting a newline.

Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/d2bb139c461

AK/OwnPtr.h

@@ -94,7 +94,7 @@ private:
 template<class T, class... Args> inline OwnPtr<T>
 make(Args&&... args)
 {
-    return OwnPtr<T>(new T(forward<Args>(args)...));
+    return OwnPtr<T>(new T(AK::forward<Args>(args)...));
 }
 
 template<typename T>

Editor/Document.cpp

@@ -8,7 +8,7 @@ OwnPtr<Document> Document::create_from_file(const std::string& path)
     FileReader reader(path);
     while (reader.can_read()) {
         auto line = reader.read_line();
-        document->m_lines.push_back(Line(line));
+        document->m_lines.push_back(make<Line>(line));
     }
 
     return document;
@@ -17,16 +17,32 @@ OwnPtr<Document> Document::create_from_file(const std::string& path)
 void Document::dump()
 {
     fprintf(stderr, "Document{%p}\n", this);
-    for (size_t i = 0; i < m_lines.size(); ++i) {
-        fprintf(stderr, "[%02zu] %s\n", i, m_lines[i].data().c_str());
+    for (size_t i = 0; i < line_count(); ++i) {
+        fprintf(stderr, "[%02zu] %s\n", i, line(i).data().c_str());
     }
 }
 
-bool Document::backspace_at(Position position)
+bool Document::backspace_at(Position)
 {
     return false;
 }
 
+bool Document::newline_at(Position position)
+{
+    ASSERT(position.is_valid());
+    ASSERT(position.line() < line_count());
+    auto& line = this->line(position.line());
+    if (position.column() > line.length())
+        return false;
+    if (position.column() == line.length()) {
+        m_lines.insert(m_lines.begin() + position.line() + 1, make<Line>(""));
+        return true;
+    }
+    auto chop = line.truncate(position.column());
+    m_lines.insert(m_lines.begin() + position.line() + 1, make<Line>(chop));
+    return true;
+}
+
 bool Document::insert_at(Position position, const std::string& text)
 {
     static FILE* f = fopen("log", "a");
@@ -38,7 +54,7 @@ bool Document::insert_at(Position position, const std::string& text)
     ASSERT(position.line() < line_count());
     if (position.line() >= line_count())
         return false;
-    Line& line = m_lines[position.line()];
+    auto& line = this->line(position.line());
     if (position.column() > line.length())
         return false;
     line.insert(position.column(), text);

Editor/Document.h

@@ -11,17 +11,18 @@ public:
     Document() { }
     ~Document() { }
 
-    const std::deque<Line>& lines() const { return m_lines; }
-    std::deque<Line>& lines() { return m_lines; }
+    Line& line(size_t index) { return *m_lines[index]; }
+    const Line& line(size_t index) const { return *m_lines[index]; }
     size_t line_count() const { return m_lines.size(); }
 
     static OwnPtr<Document> create_from_file(const std::string& path);
 
     bool insert_at(Position, const std::string&);
+    bool newline_at(Position);
     bool backspace_at(Position);
 
     void dump();
 
 private:
-    std::deque<Line> m_lines;
+    std::deque<OwnPtr<Line>> m_lines;
 };

Editor/Editor.cpp

@@ -66,8 +66,8 @@ void Editor::redraw()
             printw("%3d ", current_document_line);
             attroff(ruler_attributes);
             m_ruler_width = 4;
-            size_t line_length = m_document->lines()[current_document_line].data().size();
-            const char* line_data = m_document->lines()[current_document_line].data().c_str();
+            size_t line_length = m_document->line(current_document_line).data().size();
+            const char* line_data = m_document->line(current_document_line).data().c_str();
             if (m_scroll_position.column() < line_length)
                 addnstr(line_data + m_scroll_position.column(), window_width - m_ruler_width);
         }
@@ -182,7 +182,7 @@ void Editor::move_down()
 
 void Editor::coalesce_current_line()
 {
-    m_document->lines()[m_cursor.line()].coalesce();
+    m_document->line(m_cursor.line()).coalesce();
 }
 
 void Editor::move_up()
@@ -212,7 +212,7 @@ size_t Editor::max_line() const
 
 size_t Editor::max_column() const
 {
-    return m_document->lines()[m_cursor.line()].data().size();
+    return m_document->line(m_cursor.line()).data().size();
 }
 
 void Editor::update_scroll_position_if_needed()
@@ -307,6 +307,11 @@ void Editor::insert_at_cursor(int ch)
 bool Editor::insert_text_at_cursor(const std::string& text)
 {
     ASSERT(text.size() == 1);
+    if (text[0] == '\n') {
+        m_document->newline_at(m_cursor);
+        m_cursor.move_to(m_cursor.line() + 1, 0);
+        return true;
+    }
     m_document->insert_at(m_cursor, text);
     m_cursor.move_by(0, text.size());
     return true;

Editor/Line.cpp

@@ -41,6 +41,19 @@ void Line::prepend(const std::string& text)
     m_chunks.push_front(Chunk(text));
 }
 
+std::string Line::truncate(size_t length)
+{
+    coalesce();
+
+    auto remainder = data().substr(0, length);
+    auto chop = data().substr(length, data().length() - length);
+
+    m_chunks.clear();
+    m_chunks.push_back(Chunk{ remainder });
+
+    return chop;
+}
+
 void Line::insert(size_t index, const std::string& text)
 {
     if (index == 0) {

Editor/Line.h

@@ -30,6 +30,8 @@ public:
 
     void insert(size_t index, const std::string&);
 
+    std::string truncate(size_t length);
+
     void coalesce();
 
 private: