Fix omnibox state for each tab.

ui::Range only saves cursor's logical positions. In order to restore cursor's visual position, need to save and restore gfx::SelectionModel.

BUG=90426
TEST=start chromeos --use-pure-views, type in "abcABC" in omnibox, where "ABC" stands for Hebrew characters. Mouse click on right half of 'c' so that cursor is placed at "abc|CBA". Create a new tab. Click to restore the previous tab page, cursor should be displayed the same as before "abc|CBA", not "abcCBA|".
Review URL: http://codereview.chromium.org/7973007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@103188 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 98 insertions, 0 deletions

diff --git a/ui/gfx/selection_model.h b/ui/gfx/selection_model.h
new file mode 100644
index 0000000..3e7cf9f
--- /dev/null
+++ b/ui/gfx/selection_model.h
@@ -0,0 +1,98 @@
+// Copyright (c) 2011 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_GFX_SELECTION_MODEL_H_
+#define UI_GFX_SELECTION_MODEL_H_
+#pragma once
+
+#include <stdlib.h>
+
+#include "ui/base/ui_export.h"
+
+namespace gfx {
+
+// TODO(xji): publish bidi-editing guide line and replace the place holder.
+// SelectionModel is used to represent the logical selection and visual
+// position of cursor.
+//
+// For bi-directional text, the mapping between visual position and logical
+// position is not one-to-one. For example, logical text "abcDEF" where capital
+// letters stand for Hebrew, the visual display is "abcFED". According to the
+// bidi editing guide (http://bidi-editing-guideline):
+// 1. If pointing to the right half of the cell of a LTR character, the current
+// position must be set after this character and the caret must be displayed
+// after this character.
+// 2. If pointing to the right half of the cell of a RTL character, the current
+// position must be set before this character and the caret must be displayed
+// before this character.
+//
+// Pointing to the right half of 'c' and pointing to the right half of 'D' both
+// set the logical cursor position to 3. But the cursor displayed visually at
+// different places:
+// Pointing to the right half of 'c' displays the cursor right of 'c' as
+// "abc|FED".
+// Pointing to the right half of 'D' displays the cursor right of 'D' as
+// "abcFED|".
+// So, besides the logical selection start point and end point, we need extra
+// information to specify to which character and on which edge of the character
+// the visual cursor is bound to. For example, the visual cursor is bound to
+// the trailing side of the 2nd character 'c' when pointing to right half of
+// 'c'. And it is bound to the leading edge of the 3rd character 'D' when
+// pointing to right of 'D'.
+class UI_EXPORT SelectionModel {
+ public:
+  enum CaretPlacement {
+    LEADING,
+    TRAILING,
+  };
+
+  SelectionModel();
+  explicit SelectionModel(size_t pos);
+  SelectionModel(size_t start, size_t end);
+  SelectionModel(size_t end, size_t pos, CaretPlacement status);
+  SelectionModel(size_t start, size_t end, size_t pos, CaretPlacement status);
+
+  virtual ~SelectionModel();
+
+  size_t selection_start() const { return selection_start_; }
+  void set_selection_start(size_t pos) { selection_start_ = pos; }
+
+  size_t selection_end() const { return selection_end_; }
+  void set_selection_end(size_t pos) { selection_end_ = pos; }
+
+  size_t caret_pos() const { return caret_pos_; }
+  void set_caret_pos(size_t pos) { caret_pos_ = pos; }
+
+  CaretPlacement caret_placement() const { return caret_placement_; }
+  void set_caret_placement(CaretPlacement placement) {
+    caret_placement_ = placement;
+  }
+
+  bool Equals(const SelectionModel& sel) const;
+
+ private:
+  void Init(size_t start, size_t end, size_t pos, CaretPlacement status);
+
+  // Logical selection start. If there is non-empty selection, if
+  // selection_start_ is less than selection_end_, the selection starts visually
+  // at the leading edge of the selection_start_. If selection_start_ is greater
+  // than selection_end_, the selection starts visually at the trailing edge of
+  // selection_start_'s previous grapheme. So, we do not need extra information
+  // for visual bounding.
+  size_t selection_start_;
+
+  // The logical cursor position that next character will be inserted into.
+  // It is also the end of the selection.
+  size_t selection_end_;
+
+  // The following two fields are used to guide cursor visual position.
+  // The index of the character that cursor is visually attached to.
+  size_t caret_pos_;
+  // The visual placement of the cursor, relative to its associated character.
+  CaretPlacement caret_placement_;
+};
+
+}  // namespace gfx
+
+#endif  // UI_GFX_SELECTION_MODEL_H_