Model, View and Controller for a Gap Buffer based one line text field in view...

views/controls/textfield/textfield_model.h

+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef VIEWS_CONTROLS_TEXTFIELD_TEXTFIELD_MODEL_H_
+#define VIEWS_CONTROLS_TEXTFIELD_TEXTFIELD_MODEL_H_
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "base/gap_buffer.h"
+#include "views/event.h"
+
+namespace views {
+
+// Model for a single line textfield. It uses a gap buffer under the hood to
+// store data and perform cursor movement.
+class TextfieldModel {
+ public:
+  TextfieldModel();
+  explicit TextfieldModel(const std::wstring& text);
+
+  // Inserts a character at the current cursor position.
+  void Insert(wchar_t c);
+
+  // Deletes the first character after the current cursor position (as if, the
+  // the user has pressed delete key in the textfield).
+  wchar_t InsertDelete();
+
+  // Deletes the first character before the current cursor position (as if, the
+  // the user has pressed backspace key in the textfield).
+  wchar_t InsertBackspace();
+
+  // Returns the current cursor position.
+  int GetCurrentCursorPos();
+
+  // Moves the cursor left by one position (as if, the user has pressed the left
+  // arrow key).
+  void MoveCursorLeft();
+
+  // Moves the cursor right by one position (as if, the user has pressed the
+  // right arrow key).
+  void MoveCursorRight();
+
+  // Moves the cursor left by one word (word boundry is defined by space).
+  void MoveCursorToPreviousWord();
+
+  // Moves the cursor right by one word (word boundry is defined by space).
+  void MoveCursorToNextWord();
+
+  // Moves the cursor to start of the textfield contents.
+  void MoveCursorToStart();
+
+  // Moves the cursor to end of the textfield contents.
+  void MoveCursorToEnd();
+
+  // Returns the current contents of the textfield model.
+  std::wstring text();
+
+ private:
+  // Synchronizes this model's member field "text_" with the contents of the
+  // underlying gap buffer. The need for synchronization is determined by the
+  // "dirty_" flag.
+  void SyncText();
+
+  scoped_ptr<base::GapBuffer<wchar_t> > buffer_;
+  std::wstring text_;
+  bool dirty_;
+};
+
+class TextfieldController {
+ public:
+  virtual ~TextfieldController();
+  virtual void TextChanged(const std::wstring new_text);
+};
+};
+#endif  // VIEWS_CONTROLS_TEXTFIELD_TEXTFIELD_MODEL_H_