ui/base/ime/chromeos/character_composer.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_BASE_IME_CHROMEOS_CHARACTER_COMPOSER_H_
   6 #define UI_BASE_IME_CHROMEOS_CHARACTER_COMPOSER_H_
   7
   8 #include <vector>
   9
  10 #include "base/strings/string_util.h"
  11 #include "ui/base/ui_base_export.h"
  12
  13 namespace ui {
  14 class KeyEvent;
  15
  16 // A class to recognize compose and dead key sequence.
  17 // Outputs composed character.
  18 class UI_BASE_EXPORT CharacterComposer {
  19  public:
  20   CharacterComposer();
  21   ~CharacterComposer();
  22
  23   void Reset();
  24
  25   // Filters keypress.
  26   // Returns true if the keypress is recognized as a part of composition
  27   // sequence.
  28   // Fabricated events which don't have the native event, are not supported.
  29   bool FilterKeyPress(const ui::KeyEvent& event);
  30
  31   // Returns a string consisting of composed character.
  32   // Empty string is returned when there is no composition result.
  33   const base::string16& composed_character() const {
  34     return composed_character_;
  35   }
  36
  37   // Returns the preedit string.
  38   const base::string16& preedit_string() const { return preedit_string_; }
  39
  40  private:
  41   friend class CharacterComposerTest;
  42
  43   // An enum to describe composition mode.
  44   enum CompositionMode {
  45     // This is the initial state.
  46     // Composite a character with dead-keys and compose-key.
  47     KEY_SEQUENCE_MODE,
  48     // Composite a character with a hexadecimal unicode sequence.
  49     HEX_MODE,
  50   };
  51
  52   // Filters keypress using IBus defined value.
  53   // Returns true if the keypress is recognized as a part of composition
  54   // sequence.
  55   // |keyval| must be a GDK_KEY_* constant.
  56   // |keycode| must be a X key code.
  57   // |flags| must be a combination of ui::EF_* flags.
  58   //
  59   // composed_character() returns non empty string when there is a character
  60   // composed after this method returns true.
  61   // preedit_string() returns non empty string when there is a preedit string
  62   // after this method returns true.
  63   // Return values of preedit_string() is empty after this method returns false.
  64   // composed_character() may have some characters which are consumed in this
  65   // composing session.
  66   //
  67   //
  68   // TODO(nona): Actually a X KeySym is passed to |keyval|, so we should use
  69   // XK_* rather than GDK_KEY_*.
  70   bool FilterKeyPressInternal(unsigned int keyval, unsigned int keycode,
  71                               int flags);
  72
  73   // Filters keypress in key sequence mode.
  74   bool FilterKeyPressSequenceMode(unsigned int keyval, int flags);
  75
  76   // Filters keypress in hexadecimal mode.
  77   bool FilterKeyPressHexMode(unsigned int keyval, unsigned int keycode,
  78                              int flags);
  79
  80   // Commit a character composed from hexadecimal uncode sequence
  81   void CommitHex();
  82
  83   // Updates preedit string in hexadecimal mode.
  84   void UpdatePreeditStringHexMode();
  85
  86   // Remembers keypresses previously filtered.
  87   std::vector<unsigned int> compose_buffer_;
  88
  89   // A string representing the composed character.
  90   base::string16 composed_character_;
  91
  92   // Preedit string.
  93   base::string16 preedit_string_;
  94
  95   // Composition mode which this instance is in.
  96   CompositionMode composition_mode_;
  97
  98   DISALLOW_COPY_AND_ASSIGN(CharacterComposer);
  99 };
 100
 101 }  // namespace ui
 102
 103 #endif  // UI_BASE_IME_CHROMEOS_CHARACTER_COMPOSER_H_