Views: Extract text selection code from Textfield.

ui/views/selection_controller_host.h

+// Copyright 2016 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 UI_VIEWS_SELECTION_CONTROLLER_HOST_H_
+#define UI_VIEWS_SELECTION_CONTROLLER_HOST_H_
+
+#include "ui/gfx/selection_model.h"
+namespace gfx {
+class RenderText;
+class Point;
+class Range;
+}
+
+namespace views {
+
+class SelectionController;
+
+// An interface implemented/managed by a view which uses a SelectionController.
+class SelectionControllerHost {

[tapted, 2016/10/11 04:42:09]

in views parlance, this would probably be a SelectionFooDelegate  (not a "Host")

[karandeepb, 2016/10/14 09:27:34]

Done. Also made it an inner class of SelectionController to show that they are
tightly coupled.

+ public:
+  // Returns the associated RenderText instance to be used for selection.
+  // Todo(karandeepb): Modify RenderText so that this can return a pointer to a
+  // const RenderText.
+  virtual gfx::RenderText* GetRenderTextForSelection() = 0;
+
+  // Methods related to properties of the associated view
+
+  // Returns true if the associated text view is read only.
+  virtual bool IsReadOnly() const = 0;
+  // Returns whether there is a drag operation originating from the associated
+  // view.
+  virtual bool HasTextBeingDragged() const = 0;
+  // Sets whether text is being dragged from the associated view.
+  virtual void SetTextBeingDragged(bool value) = 0;
+  // Returns the height of the associated view.
+  virtual int GetViewHeight() const = 0;
+  // Returns the width of the associated view.
+  virtual int GetViewWidth() const = 0;
+  // Returns the drag selection timer delay. This is the duration after which a
+  // drag selection is updated when the event location is outside the text
+  // bounds.
+  virtual int GetDragSelectionDelay() const = 0;
+
+  // Methods called to notify a mouse action which may change the associated
+  // view's text and/or selection.
+
+  // Called before performing a mouse action which may change the associated
+  // text or selection. Should not be called in succession and must always be
+  // followed by an OnAfterMouseAction call.
+  virtual void OnBeforeMouseAction() = 0;
+  // Called after the mouse action is performed. |text_changed| and
+  // |selection_changed| can be used by subclasses to make any necessary updates
+  // like redraw the text. Must always be preceeded by a OnBeforeMouseAction
+  // call.
+  virtual void OnAfterMouseAction(bool text_changed,
+                                  bool selection_changed) = 0;
+
+  // Selection related methods. Called only when a mouse action is in progress.
+  // Subclasses can defer making updates till the OnAfterMouseAction call.
+
+  // Select the entire text range. If |reversed| is true, the range will end at
+  // the logical beginning of the text; this generally shows the leading portion
+  // of text that overflows its display area.
+  virtual void SelectAll(bool reversed) = 0;
+  // Selects the word closest to |point|.
+  virtual void SelectWordAt(const gfx::Point& point) = 0;
+  // Selects the word at the current cursor position. If there is a non-empty
+  // selection, the selection bounds are extended to their nearest word
+  // boundaries.
+  virtual void SelectWord() = 0;
+  // Selects the specified logical text range. The range is truncated to lie
+  // within the text range. If the |range| start or end is not a cursorable
+  // position (not on grapheme boundary), it is a NO-OP.
+  virtual void SelectRange(const gfx::Range& range) = 0;
+  // Moves the cursor to the text index corresponding to |point|. |point| is in
+  // the coordinates of the associated view. If |select| is true, a selection is
+  // made with the current selection start index.
+  virtual void MoveCursorTo(const gfx::Point& point, bool select) = 0;
+  // Clears the existing selection keeping the current cursor position and caret
+  // affinity.
+  virtual void ClearSelection() = 0;
+  // Select till the beginning/end of line keeping the current selection start.
+  // Todo should this say something about only supporting single line.
+  virtual void SelectTillEdge(gfx::VisualCursorDirection direction) = 0;
+
+  // Selection clipboard related methods. Called only when a mouse action is in
+  // progress.
+
+  // Pastes the text in the selection clipboard at the current cursor position.
+  // NO-OP if the associated text view is read-only.
+  virtual void PasteSelectionClipboard() = 0;
+  // Updates the selection clipboard with the currently selected text. Should
+  // empty the selection clipboard if no text is currently selected.
+  virtual void UpdateSelectionClipboard() = 0;
+
+ protected:
+  virtual ~SelectionControllerHost() {}
+};
+
+}  // namespace views
+
+#endif  // UI_VIEWS_SELECTION_CONTROLLER_HOST_H_