| // Copyright 2013 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_BASE_IME_CHARACTER_COMPOSER_H_ |
| #define UI_BASE_IME_CHARACTER_COMPOSER_H_ |
| |
| #include <stddef.h> |
| #include <stdint.h> |
| |
| #include <vector> |
| |
| #include "base/component_export.h" |
| #include "base/macros.h" |
| #include "base/strings/string_util.h" |
| #include "ui/events/keycodes/dom/dom_key.h" |
| |
| namespace ui { |
| class KeyEvent; |
| |
| // A class to recognize compose and dead key sequence. |
| // Outputs composed character. |
| class COMPONENT_EXPORT(UI_BASE_IME_TYPES) CharacterComposer { |
| public: |
| using ComposeBuffer = std::vector<DomKey>; |
| |
| CharacterComposer(); |
| ~CharacterComposer(); |
| |
| void Reset(); |
| |
| // Filters keypress. |
| // Returns true if the keypress is recognized as a part of composition |
| // sequence. |
| // Fabricated events which don't have the native event, are not supported. |
| bool FilterKeyPress(const ui::KeyEvent& event); |
| |
| // Returns a string consisting of composed character. |
| // Empty string is returned when there is no composition result. |
| const base::string16& composed_character() const { |
| return composed_character_; |
| } |
| |
| // Returns the preedit string. |
| const base::string16& preedit_string() const { return preedit_string_; } |
| |
| private: |
| // An enum to describe composition mode. |
| enum CompositionMode { |
| // This is the initial state. |
| // Composite a character with dead-keys and compose-key. |
| KEY_SEQUENCE_MODE, |
| // Composite a character with a hexadecimal unicode sequence. |
| HEX_MODE, |
| }; |
| |
| // Filters keypress in key sequence mode. |
| bool FilterKeyPressSequenceMode(const ui::KeyEvent& event); |
| |
| // Filters keypress in hexadecimal mode. |
| bool FilterKeyPressHexMode(const ui::KeyEvent& event); |
| |
| // Commit a character composed from hexadecimal uncode sequence |
| void CommitHex(); |
| |
| // Updates preedit string in hexadecimal mode. |
| void UpdatePreeditStringHexMode(); |
| |
| // Remembers keypresses previously filtered. |
| std::vector<DomKey> compose_buffer_; |
| |
| // Records hexadecimal digits previously filtered. |
| std::vector<unsigned int> hex_buffer_; |
| |
| // A string representing the composed character. |
| base::string16 composed_character_; |
| |
| // Preedit string. |
| base::string16 preedit_string_; |
| |
| // Composition mode which this instance is in. |
| CompositionMode composition_mode_; |
| |
| DISALLOW_COPY_AND_ASSIGN(CharacterComposer); |
| }; |
| |
| // Abstract class for determining whether a ComposeBuffer forms a valid |
| // character composition sequence. |
| class ComposeChecker { |
| public: |
| enum class CheckSequenceResult { |
| // The sequence is not a composition sequence or the prefix of any |
| // composition sequence. |
| NO_MATCH, |
| // The sequence is a prefix of one or more composition sequences. |
| PREFIX_MATCH, |
| // The sequence matches a composition sequence. |
| FULL_MATCH |
| }; |
| ComposeChecker() {} |
| virtual ~ComposeChecker() {} |
| virtual CheckSequenceResult CheckSequence( |
| const ui::CharacterComposer::ComposeBuffer& sequence, |
| uint32_t* composed_character) const = 0; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(ComposeChecker); |
| }; |
| |
| // Implementation of |ComposeChecker| using a compact generated tree. |
| class TreeComposeChecker : public ComposeChecker { |
| public: |
| struct CompositionData { |
| size_t maximum_sequence_length; |
| int tree_entries; |
| const uint16_t* tree; |
| }; |
| |
| explicit TreeComposeChecker(const CompositionData& data) : data_(data) {} |
| CheckSequenceResult CheckSequence( |
| const ui::CharacterComposer::ComposeBuffer& sequence, |
| uint32_t* composed_character) const override; |
| |
| private: |
| bool Find(uint16_t index, uint16_t size, uint16_t key, uint16_t* value) const; |
| const CompositionData& data_; |
| }; |
| |
| } // namespace ui |
| |
| #endif // UI_BASE_IME_CHARACTER_COMPOSER_H_ |