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1 /*
2  * Copyright (C) 2008 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef _LIBINPUT_KEY_CHARACTER_MAP_H
18 #define _LIBINPUT_KEY_CHARACTER_MAP_H
19 
20 #include <stdint.h>
21 
22 #ifdef __linux__
23 #include <binder/IBinder.h>
24 #endif
25 
26 #include <android-base/result.h>
27 #include <input/Input.h>
28 #include <utils/Errors.h>
29 #include <utils/KeyedVector.h>
30 #include <utils/Tokenizer.h>
31 #include <utils/Unicode.h>
32 
33 // Maximum number of keys supported by KeyCharacterMaps
34 #define MAX_KEYS 8192
35 
36 namespace android {
37 
38 /**
39  * Describes a mapping from Android key codes to characters.
40  * Also specifies other functions of the keyboard such as the keyboard type
41  * and key modifier semantics.
42  *
43  * This object is immutable after it has been loaded.
44  */
45 class KeyCharacterMap {
46 public:
47     enum class KeyboardType : int32_t {
48         UNKNOWN = 0,
49         NUMERIC = 1,
50         PREDICTIVE = 2,
51         ALPHA = 3,
52         FULL = 4,
53         /**
54          * Deprecated. Set 'keyboard.specialFunction' to '1' in the device's IDC file instead.
55          */
56         SPECIAL_FUNCTION = 5,
57         OVERLAY = 6,
58     };
59 
60     enum class Format {
61         // Base keyboard layout, may contain device-specific options, such as "type" declaration.
62         BASE = 0,
63         // Overlay keyboard layout, more restrictive, may be published by applications,
64         // cannot override device-specific options.
65         OVERLAY = 1,
66         // Either base or overlay layout ok.
67         ANY = 2,
68     };
69 
70     // Substitute key code and meta state for fallback action.
71     struct FallbackAction {
72         int32_t keyCode;
73         int32_t metaState;
74     };
75 
76     /* Loads a key character map from a file. */
77     static base::Result<std::shared_ptr<KeyCharacterMap>> load(const std::string& filename,
78                                                                Format format);
79 
80     /* Loads a key character map from its string contents. */
81     static base::Result<std::shared_ptr<KeyCharacterMap>> loadContents(const std::string& filename,
82                                                                        const char* contents,
83                                                                        Format format);
84 
85     const std::string getLoadFileName() const;
86 
87     /* Combines this key character map with an overlay. */
88     void combine(const KeyCharacterMap& overlay);
89 
90     /* Gets the keyboard type. */
91     KeyboardType getKeyboardType() const;
92 
93     /* Gets the primary character for this key as in the label physically printed on it.
94      * Returns 0 if none (eg. for non-printing keys). */
95     char16_t getDisplayLabel(int32_t keyCode) const;
96 
97     /* Gets the Unicode character for the number or symbol generated by the key
98      * when the keyboard is used as a dialing pad.
99      * Returns 0 if no number or symbol is generated.
100      */
101     char16_t getNumber(int32_t keyCode) const;
102 
103     /* Gets the Unicode character generated by the key and meta key modifiers.
104      * Returns 0 if no character is generated.
105      */
106     char16_t getCharacter(int32_t keyCode, int32_t metaState) const;
107 
108     /* Gets the fallback action to use by default if the application does not
109      * handle the specified key.
110      * Returns true if an action was available, false if none.
111      */
112     bool getFallbackAction(int32_t keyCode, int32_t metaState,
113             FallbackAction* outFallbackAction) const;
114 
115     /* Gets the first matching Unicode character that can be generated by the key,
116      * preferring the one with the specified meta key modifiers.
117      * Returns 0 if no matching character is generated.
118      */
119     char16_t getMatch(int32_t keyCode, const char16_t* chars,
120             size_t numChars, int32_t metaState) const;
121 
122     /* Gets a sequence of key events that could plausibly generate the specified
123      * character sequence.  Returns false if some of the characters cannot be generated.
124      */
125     bool getEvents(int32_t deviceId, const char16_t* chars, size_t numChars,
126             Vector<KeyEvent>& outEvents) const;
127 
128     /* Maps a scan code and usage code to a key code, in case this key map overrides
129      * the mapping in some way. */
130     status_t mapKey(int32_t scanCode, int32_t usageCode, int32_t* outKeyCode) const;
131 
132     /* Tries to find a replacement key code for a given key code and meta state
133      * in character map. */
134     void tryRemapKey(int32_t scanCode, int32_t metaState,
135             int32_t* outKeyCode, int32_t* outMetaState) const;
136 
137 #ifdef __linux__
138     /* Reads a key map from a parcel. */
139     static std::shared_ptr<KeyCharacterMap> readFromParcel(Parcel* parcel);
140 
141     /* Writes a key map to a parcel. */
142     void writeToParcel(Parcel* parcel) const;
143 #endif
144 
145     bool operator==(const KeyCharacterMap& other) const;
146 
147     KeyCharacterMap(const KeyCharacterMap& other);
148 
149     virtual ~KeyCharacterMap();
150 
151 private:
152     struct Behavior {
153         Behavior();
154         Behavior(const Behavior& other);
155 
156         /* The next behavior in the list, or NULL if none. */
157         Behavior* next;
158 
159         /* The meta key modifiers for this behavior. */
160         int32_t metaState;
161 
162         /* The character to insert. */
163         char16_t character;
164 
165         /* The fallback keycode if the key is not handled. */
166         int32_t fallbackKeyCode;
167 
168         /* The replacement keycode if the key has to be replaced outright. */
169         int32_t replacementKeyCode;
170     };
171 
172     struct Key {
173         Key();
174         Key(const Key& other);
175         ~Key();
176 
177         /* The single character label printed on the key, or 0 if none. */
178         char16_t label;
179 
180         /* The number or symbol character generated by the key, or 0 if none. */
181         char16_t number;
182 
183         /* The list of key behaviors sorted from most specific to least specific
184          * meta key binding. */
185         Behavior* firstBehavior;
186     };
187 
188     class Parser {
189         enum State {
190             STATE_TOP = 0,
191             STATE_KEY = 1,
192         };
193 
194         enum {
195             PROPERTY_LABEL = 1,
196             PROPERTY_NUMBER = 2,
197             PROPERTY_META = 3,
198         };
199 
200         struct Property {
201             inline explicit Property(int32_t property = 0, int32_t metaState = 0) :
propertyProperty202                     property(property), metaState(metaState) { }
203 
204             int32_t property;
205             int32_t metaState;
206         };
207 
208         KeyCharacterMap* mMap;
209         Tokenizer* mTokenizer;
210         Format mFormat;
211         State mState;
212         int32_t mKeyCode;
213 
214     public:
215         Parser(KeyCharacterMap* map, Tokenizer* tokenizer, Format format);
216         ~Parser();
217         status_t parse();
218 
219     private:
220         status_t parseType();
221         status_t parseMap();
222         status_t parseMapKey();
223         status_t parseKey();
224         status_t parseKeyProperty();
225         status_t finishKey(Key* key);
226         status_t parseModifier(const std::string& token, int32_t* outMetaState);
227         status_t parseCharacterLiteral(char16_t* outCharacter);
228     };
229 
230     KeyedVector<int32_t, Key*> mKeys;
231     KeyboardType mType;
232     std::string mLoadFileName;
233 
234     KeyedVector<int32_t, int32_t> mKeysByScanCode;
235     KeyedVector<int32_t, int32_t> mKeysByUsageCode;
236 
237     KeyCharacterMap();
238 
239     bool getKey(int32_t keyCode, const Key** outKey) const;
240     bool getKeyBehavior(int32_t keyCode, int32_t metaState,
241             const Key** outKey, const Behavior** outBehavior) const;
242     static bool matchesMetaState(int32_t eventMetaState, int32_t behaviorMetaState);
243 
244     bool findKey(char16_t ch, int32_t* outKeyCode, int32_t* outMetaState) const;
245 
246     static base::Result<std::shared_ptr<KeyCharacterMap>> load(Tokenizer* tokenizer, Format format);
247 
248     static void addKey(Vector<KeyEvent>& outEvents,
249             int32_t deviceId, int32_t keyCode, int32_t metaState, bool down, nsecs_t time);
250     static void addMetaKeys(Vector<KeyEvent>& outEvents,
251             int32_t deviceId, int32_t metaState, bool down, nsecs_t time,
252             int32_t* currentMetaState);
253     static bool addSingleEphemeralMetaKey(Vector<KeyEvent>& outEvents,
254             int32_t deviceId, int32_t metaState, bool down, nsecs_t time,
255             int32_t keyCode, int32_t keyMetaState,
256             int32_t* currentMetaState);
257     static void addDoubleEphemeralMetaKey(Vector<KeyEvent>& outEvents,
258             int32_t deviceId, int32_t metaState, bool down, nsecs_t time,
259             int32_t leftKeyCode, int32_t leftKeyMetaState,
260             int32_t rightKeyCode, int32_t rightKeyMetaState,
261             int32_t eitherKeyMetaState,
262             int32_t* currentMetaState);
263     static void addLockedMetaKey(Vector<KeyEvent>& outEvents,
264             int32_t deviceId, int32_t metaState, nsecs_t time,
265             int32_t keyCode, int32_t keyMetaState,
266             int32_t* currentMetaState);
267 };
268 
269 } // namespace android
270 
271 #endif // _LIBINPUT_KEY_CHARACTER_MAP_H
272