summaryrefslogtreecommitdiffstats
path: root/services/inputflinger/InputDispatcher.h
blob: 70b0a34b0a9db22754adf15531afa30ad9ee5885 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef _UI_INPUT_DISPATCHER_H
#define _UI_INPUT_DISPATCHER_H

#include <input/Input.h>
#include <input/InputTransport.h>
#include <utils/KeyedVector.h>
#include <utils/Vector.h>
#include <utils/threads.h>
#include <utils/Timers.h>
#include <utils/RefBase.h>
#include <utils/String8.h>
#include <utils/Looper.h>
#include <utils/BitSet.h>
#include <cutils/atomic.h>

#include <stddef.h>
#include <unistd.h>
#include <limits.h>

#include "InputWindow.h"
#include "InputApplication.h"
#include "InputListener.h"


namespace android {

/*
 * Constants used to report the outcome of input event injection.
 */
enum {
    /* (INTERNAL USE ONLY) Specifies that injection is pending and its outcome is unknown. */
    INPUT_EVENT_INJECTION_PENDING = -1,

    /* Injection succeeded. */
    INPUT_EVENT_INJECTION_SUCCEEDED = 0,

    /* Injection failed because the injector did not have permission to inject
     * into the application with input focus. */
    INPUT_EVENT_INJECTION_PERMISSION_DENIED = 1,

    /* Injection failed because there were no available input targets. */
    INPUT_EVENT_INJECTION_FAILED = 2,

    /* Injection failed due to a timeout. */
    INPUT_EVENT_INJECTION_TIMED_OUT = 3
};

/*
 * Constants used to determine the input event injection synchronization mode.
 */
enum {
    /* Injection is asynchronous and is assumed always to be successful. */
    INPUT_EVENT_INJECTION_SYNC_NONE = 0,

    /* Waits for previous events to be dispatched so that the input dispatcher can determine
     * whether input event injection willbe permitted based on the current input focus.
     * Does not wait for the input event to finish processing. */
    INPUT_EVENT_INJECTION_SYNC_WAIT_FOR_RESULT = 1,

    /* Waits for the input event to be completely processed. */
    INPUT_EVENT_INJECTION_SYNC_WAIT_FOR_FINISHED = 2,
};


/*
 * An input target specifies how an input event is to be dispatched to a particular window
 * including the window's input channel, control flags, a timeout, and an X / Y offset to
 * be added to input event coordinates to compensate for the absolute position of the
 * window area.
 */
struct InputTarget {
    enum {
        /* This flag indicates that the event is being delivered to a foreground application. */
        FLAG_FOREGROUND = 1 << 0,

        /* This flag indicates that the target of a MotionEvent is partly or wholly
         * obscured by another visible window above it.  The motion event should be
         * delivered with flag AMOTION_EVENT_FLAG_WINDOW_IS_OBSCURED. */
        FLAG_WINDOW_IS_OBSCURED = 1 << 1,

        /* This flag indicates that a motion event is being split across multiple windows. */
        FLAG_SPLIT = 1 << 2,

        /* This flag indicates that the pointer coordinates dispatched to the application
         * will be zeroed out to avoid revealing information to an application. This is
         * used in conjunction with FLAG_DISPATCH_AS_OUTSIDE to prevent apps not sharing
         * the same UID from watching all touches. */
        FLAG_ZERO_COORDS = 1 << 3,

        /* This flag indicates that the event should be sent as is.
         * Should always be set unless the event is to be transmuted. */
        FLAG_DISPATCH_AS_IS = 1 << 8,

        /* This flag indicates that a MotionEvent with AMOTION_EVENT_ACTION_DOWN falls outside
         * of the area of this target and so should instead be delivered as an
         * AMOTION_EVENT_ACTION_OUTSIDE to this target. */
        FLAG_DISPATCH_AS_OUTSIDE = 1 << 9,

        /* This flag indicates that a hover sequence is starting in the given window.
         * The event is transmuted into ACTION_HOVER_ENTER. */
        FLAG_DISPATCH_AS_HOVER_ENTER = 1 << 10,

        /* This flag indicates that a hover event happened outside of a window which handled
         * previous hover events, signifying the end of the current hover sequence for that
         * window.
         * The event is transmuted into ACTION_HOVER_ENTER. */
        FLAG_DISPATCH_AS_HOVER_EXIT = 1 << 11,

        /* This flag indicates that the event should be canceled.
         * It is used to transmute ACTION_MOVE into ACTION_CANCEL when a touch slips
         * outside of a window. */
        FLAG_DISPATCH_AS_SLIPPERY_EXIT = 1 << 12,

        /* This flag indicates that the event should be dispatched as an initial down.
         * It is used to transmute ACTION_MOVE into ACTION_DOWN when a touch slips
         * into a new window. */
        FLAG_DISPATCH_AS_SLIPPERY_ENTER = 1 << 13,

        /* Mask for all dispatch modes. */
        FLAG_DISPATCH_MASK = FLAG_DISPATCH_AS_IS
                | FLAG_DISPATCH_AS_OUTSIDE
                | FLAG_DISPATCH_AS_HOVER_ENTER
                | FLAG_DISPATCH_AS_HOVER_EXIT
                | FLAG_DISPATCH_AS_SLIPPERY_EXIT
                | FLAG_DISPATCH_AS_SLIPPERY_ENTER,
    };

    // The input channel to be targeted.
    sp<InputChannel> inputChannel;

    // Flags for the input target.
    int32_t flags;

    // The x and y offset to add to a MotionEvent as it is delivered.
    // (ignored for KeyEvents)
    float xOffset, yOffset;

    // Scaling factor to apply to MotionEvent as it is delivered.
    // (ignored for KeyEvents)
    float scaleFactor;

    // The subset of pointer ids to include in motion events dispatched to this input target
    // if FLAG_SPLIT is set.
    BitSet32 pointerIds;
};


/*
 * Input dispatcher configuration.
 *
 * Specifies various options that modify the behavior of the input dispatcher.
 * The values provided here are merely defaults. The actual values will come from ViewConfiguration
 * and are passed into the dispatcher during initialization.
 */
struct InputDispatcherConfiguration {
    // The key repeat initial timeout.
    nsecs_t keyRepeatTimeout;

    // The key repeat inter-key delay.
    nsecs_t keyRepeatDelay;

    InputDispatcherConfiguration() :
            keyRepeatTimeout(500 * 1000000LL),
            keyRepeatDelay(50 * 1000000LL) { }
};


/*
 * Input dispatcher policy interface.
 *
 * The input reader policy is used by the input reader to interact with the Window Manager
 * and other system components.
 *
 * The actual implementation is partially supported by callbacks into the DVM
 * via JNI.  This interface is also mocked in the unit tests.
 */
class InputDispatcherPolicyInterface : public virtual RefBase {
protected:
    InputDispatcherPolicyInterface() { }
    virtual ~InputDispatcherPolicyInterface() { }

public:
    /* Notifies the system that a configuration change has occurred. */
    virtual void notifyConfigurationChanged(nsecs_t when) = 0;

    /* Notifies the system that an application is not responding.
     * Returns a new timeout to continue waiting, or 0 to abort dispatch. */
    virtual nsecs_t notifyANR(const sp<InputApplicationHandle>& inputApplicationHandle,
            const sp<InputWindowHandle>& inputWindowHandle,
            const String8& reason) = 0;

    /* Notifies the system that an input channel is unrecoverably broken. */
    virtual void notifyInputChannelBroken(const sp<InputWindowHandle>& inputWindowHandle) = 0;

    /* Gets the input dispatcher configuration. */
    virtual void getDispatcherConfiguration(InputDispatcherConfiguration* outConfig) = 0;

    /* Filters an input event.
     * Return true to dispatch the event unmodified, false to consume the event.
     * A filter can also transform and inject events later by passing POLICY_FLAG_FILTERED
     * to injectInputEvent.
     */
    virtual bool filterInputEvent(const InputEvent* inputEvent, uint32_t policyFlags) = 0;

    /* Intercepts a key event immediately before queueing it.
     * The policy can use this method as an opportunity to perform power management functions
     * and early event preprocessing such as updating policy flags.
     *
     * This method is expected to set the POLICY_FLAG_PASS_TO_USER policy flag if the event
     * should be dispatched to applications.
     */
    virtual void interceptKeyBeforeQueueing(const KeyEvent* keyEvent, uint32_t& policyFlags) = 0;

    /* Intercepts a touch, trackball or other motion event before queueing it.
     * The policy can use this method as an opportunity to perform power management functions
     * and early event preprocessing such as updating policy flags.
     *
     * This method is expected to set the POLICY_FLAG_PASS_TO_USER policy flag if the event
     * should be dispatched to applications.
     */
    virtual void interceptMotionBeforeQueueing(nsecs_t when, uint32_t& policyFlags) = 0;

    /* Allows the policy a chance to intercept a key before dispatching. */
    virtual nsecs_t interceptKeyBeforeDispatching(const sp<InputWindowHandle>& inputWindowHandle,
            const KeyEvent* keyEvent, uint32_t policyFlags) = 0;

    /* Allows the policy a chance to perform default processing for an unhandled key.
     * Returns an alternate keycode to redispatch as a fallback, or 0 to give up. */
    virtual bool dispatchUnhandledKey(const sp<InputWindowHandle>& inputWindowHandle,
            const KeyEvent* keyEvent, uint32_t policyFlags, KeyEvent* outFallbackKeyEvent) = 0;

    /* Notifies the policy about switch events.
     */
    virtual void notifySwitch(nsecs_t when,
            uint32_t switchValues, uint32_t switchMask, uint32_t policyFlags) = 0;

    /* Poke user activity for an event dispatched to a window. */
    virtual void pokeUserActivity(nsecs_t eventTime, int32_t eventType) = 0;

    /* Checks whether a given application pid/uid has permission to inject input events
     * into other applications.
     *
     * This method is special in that its implementation promises to be non-reentrant and
     * is safe to call while holding other locks.  (Most other methods make no such guarantees!)
     */
    virtual bool checkInjectEventsPermissionNonReentrant(
            int32_t injectorPid, int32_t injectorUid) = 0;
};


/* Notifies the system about input events generated by the input reader.
 * The dispatcher is expected to be mostly asynchronous. */
class InputDispatcherInterface : public virtual RefBase, public InputListenerInterface {
protected:
    InputDispatcherInterface() { }
    virtual ~InputDispatcherInterface() { }

public:
    /* Dumps the state of the input dispatcher.
     *
     * This method may be called on any thread (usually by the input manager). */
    virtual void dump(String8& dump) = 0;

    /* Called by the heatbeat to ensures that the dispatcher has not deadlocked. */
    virtual void monitor() = 0;

    /* Runs a single iteration of the dispatch loop.
     * Nominally processes one queued event, a timeout, or a response from an input consumer.
     *
     * This method should only be called on the input dispatcher thread.
     */
    virtual void dispatchOnce() = 0;

    /* Injects an input event and optionally waits for sync.
     * The synchronization mode determines whether the method blocks while waiting for
     * input injection to proceed.
     * Returns one of the INPUT_EVENT_INJECTION_XXX constants.
     *
     * This method may be called on any thread (usually by the input manager).
     */
    virtual int32_t injectInputEvent(const InputEvent* event, int32_t displayId,
            int32_t injectorPid, int32_t injectorUid, int32_t syncMode, int32_t timeoutMillis,
            uint32_t policyFlags) = 0;

    /* Sets the list of input windows.
     *
     * This method may be called on any thread (usually by the input manager).
     */
    virtual void setInputWindows(const Vector<sp<InputWindowHandle> >& inputWindowHandles) = 0;

    /* Sets the focused application.
     *
     * This method may be called on any thread (usually by the input manager).
     */
    virtual void setFocusedApplication(
            const sp<InputApplicationHandle>& inputApplicationHandle) = 0;

    /* Sets the input dispatching mode.
     *
     * This method may be called on any thread (usually by the input manager).
     */
    virtual void setInputDispatchMode(bool enabled, bool frozen) = 0;

    /* Sets whether input event filtering is enabled.
     * When enabled, incoming input events are sent to the policy's filterInputEvent
     * method instead of being dispatched.  The filter is expected to use
     * injectInputEvent to inject the events it would like to have dispatched.
     * It should include POLICY_FLAG_FILTERED in the policy flags during injection.
     */
    virtual void setInputFilterEnabled(bool enabled) = 0;

    /* Transfers touch focus from the window associated with one channel to the
     * window associated with the other channel.
     *
     * Returns true on success.  False if the window did not actually have touch focus.
     */
    virtual bool transferTouchFocus(const sp<InputChannel>& fromChannel,
            const sp<InputChannel>& toChannel) = 0;

    /* Registers or unregister input channels that may be used as targets for input events.
     * If monitor is true, the channel will receive a copy of all input events.
     *
     * These methods may be called on any thread (usually by the input manager).
     */
    virtual status_t registerInputChannel(const sp<InputChannel>& inputChannel,
            const sp<InputWindowHandle>& inputWindowHandle, bool monitor) = 0;
    virtual status_t unregisterInputChannel(const sp<InputChannel>& inputChannel) = 0;
};

/* Dispatches events to input targets.  Some functions of the input dispatcher, such as
 * identifying input targets, are controlled by a separate policy object.
 *
 * IMPORTANT INVARIANT:
 *     Because the policy can potentially block or cause re-entrance into the input dispatcher,
 *     the input dispatcher never calls into the policy while holding its internal locks.
 *     The implementation is also carefully designed to recover from scenarios such as an
 *     input channel becoming unregistered while identifying input targets or processing timeouts.
 *
 *     Methods marked 'Locked' must be called with the lock acquired.
 *
 *     Methods marked 'LockedInterruptible' must be called with the lock acquired but
 *     may during the course of their execution release the lock, call into the policy, and
 *     then reacquire the lock.  The caller is responsible for recovering gracefully.
 *
 *     A 'LockedInterruptible' method may called a 'Locked' method, but NOT vice-versa.
 */
class InputDispatcher : public InputDispatcherInterface {
protected:
    virtual ~InputDispatcher();

public:
    explicit InputDispatcher(const sp<InputDispatcherPolicyInterface>& policy);

    virtual void dump(String8& dump);
    virtual void monitor();

    virtual void dispatchOnce();

    virtual void notifyConfigurationChanged(const NotifyConfigurationChangedArgs* args);
    virtual void notifyKey(const NotifyKeyArgs* args);
    virtual void notifyMotion(const NotifyMotionArgs* args);
    virtual void notifySwitch(const NotifySwitchArgs* args);
    virtual void notifyDeviceReset(const NotifyDeviceResetArgs* args);

    virtual int32_t injectInputEvent(const InputEvent* event, int32_t displayId,
            int32_t injectorPid, int32_t injectorUid, int32_t syncMode, int32_t timeoutMillis,
            uint32_t policyFlags);

    virtual void setInputWindows(const Vector<sp<InputWindowHandle> >& inputWindowHandles);
    virtual void setFocusedApplication(const sp<InputApplicationHandle>& inputApplicationHandle);
    virtual void setInputDispatchMode(bool enabled, bool frozen);
    virtual void setInputFilterEnabled(bool enabled);

    virtual bool transferTouchFocus(const sp<InputChannel>& fromChannel,
            const sp<InputChannel>& toChannel);

    virtual status_t registerInputChannel(const sp<InputChannel>& inputChannel,
            const sp<InputWindowHandle>& inputWindowHandle, bool monitor);
    virtual status_t unregisterInputChannel(const sp<InputChannel>& inputChannel);

private:
    template <typename T>
    struct Link {
        T* next;
        T* prev;

    protected:
        inline Link() : next(NULL), prev(NULL) { }
    };

    struct InjectionState {
        mutable int32_t refCount;

        int32_t injectorPid;
        int32_t injectorUid;
        int32_t injectionResult;  // initially INPUT_EVENT_INJECTION_PENDING
        bool injectionIsAsync; // set to true if injection is not waiting for the result
        int32_t pendingForegroundDispatches; // the number of foreground dispatches in progress

        InjectionState(int32_t injectorPid, int32_t injectorUid);
        void release();

    private:
        ~InjectionState();
    };

    struct EventEntry : Link<EventEntry> {
        enum {
            TYPE_CONFIGURATION_CHANGED,
            TYPE_DEVICE_RESET,
            TYPE_KEY,
            TYPE_MOTION
        };

        mutable int32_t refCount;
        int32_t type;
        nsecs_t eventTime;
        uint32_t policyFlags;
        InjectionState* injectionState;

        bool dispatchInProgress; // initially false, set to true while dispatching

        inline bool isInjected() const { return injectionState != NULL; }

        void release();

        virtual void appendDescription(String8& msg) const = 0;

    protected:
        EventEntry(int32_t type, nsecs_t eventTime, uint32_t policyFlags);
        virtual ~EventEntry();
        void releaseInjectionState();
    };

    struct ConfigurationChangedEntry : EventEntry {
        ConfigurationChangedEntry(nsecs_t eventTime);
        virtual void appendDescription(String8& msg) const;

    protected:
        virtual ~ConfigurationChangedEntry();
    };

    struct DeviceResetEntry : EventEntry {
        int32_t deviceId;

        DeviceResetEntry(nsecs_t eventTime, int32_t deviceId);
        virtual void appendDescription(String8& msg) const;

    protected:
        virtual ~DeviceResetEntry();
    };

    struct KeyEntry : EventEntry {
        int32_t deviceId;
        uint32_t source;
        int32_t action;
        int32_t flags;
        int32_t keyCode;
        int32_t scanCode;
        int32_t metaState;
        int32_t repeatCount;
        nsecs_t downTime;

        bool syntheticRepeat; // set to true for synthetic key repeats

        enum InterceptKeyResult {
            INTERCEPT_KEY_RESULT_UNKNOWN,
            INTERCEPT_KEY_RESULT_SKIP,
            INTERCEPT_KEY_RESULT_CONTINUE,
            INTERCEPT_KEY_RESULT_TRY_AGAIN_LATER,
        };
        InterceptKeyResult interceptKeyResult; // set based on the interception result
        nsecs_t interceptKeyWakeupTime; // used with INTERCEPT_KEY_RESULT_TRY_AGAIN_LATER

        KeyEntry(nsecs_t eventTime,
                int32_t deviceId, uint32_t source, uint32_t policyFlags, int32_t action,
                int32_t flags, int32_t keyCode, int32_t scanCode, int32_t metaState,
                int32_t repeatCount, nsecs_t downTime);
        virtual void appendDescription(String8& msg) const;
        void recycle();

    protected:
        virtual ~KeyEntry();
    };

    struct MotionEntry : EventEntry {
        nsecs_t eventTime;
        int32_t deviceId;
        uint32_t source;
        int32_t action;
        int32_t flags;
        int32_t metaState;
        int32_t buttonState;
        int32_t edgeFlags;
        float xPrecision;
        float yPrecision;
        nsecs_t downTime;
        int32_t displayId;
        uint32_t pointerCount;
        PointerProperties pointerProperties[MAX_POINTERS];
        PointerCoords pointerCoords[MAX_POINTERS];

        MotionEntry(nsecs_t eventTime,
                int32_t deviceId, uint32_t source, uint32_t policyFlags,
                int32_t action, int32_t flags,
                int32_t metaState, int32_t buttonState, int32_t edgeFlags,
                float xPrecision, float yPrecision,
                nsecs_t downTime, int32_t displayId, uint32_t pointerCount,
                const PointerProperties* pointerProperties, const PointerCoords* pointerCoords,
                float xOffset, float yOffset);
        virtual void appendDescription(String8& msg) const;

    protected:
        virtual ~MotionEntry();
    };

    // Tracks the progress of dispatching a particular event to a particular connection.
    struct DispatchEntry : Link<DispatchEntry> {
        const uint32_t seq; // unique sequence number, never 0

        EventEntry* eventEntry; // the event to dispatch
        int32_t targetFlags;
        float xOffset;
        float yOffset;
        float scaleFactor;
        nsecs_t deliveryTime; // time when the event was actually delivered

        // Set to the resolved action and flags when the event is enqueued.
        int32_t resolvedAction;
        int32_t resolvedFlags;

        DispatchEntry(EventEntry* eventEntry,
                int32_t targetFlags, float xOffset, float yOffset, float scaleFactor);
        ~DispatchEntry();

        inline bool hasForegroundTarget() const {
            return targetFlags & InputTarget::FLAG_FOREGROUND;
        }

        inline bool isSplit() const {
            return targetFlags & InputTarget::FLAG_SPLIT;
        }

    private:
        static volatile int32_t sNextSeqAtomic;

        static uint32_t nextSeq();
    };

    // A command entry captures state and behavior for an action to be performed in the
    // dispatch loop after the initial processing has taken place.  It is essentially
    // a kind of continuation used to postpone sensitive policy interactions to a point
    // in the dispatch loop where it is safe to release the lock (generally after finishing
    // the critical parts of the dispatch cycle).
    //
    // The special thing about commands is that they can voluntarily release and reacquire
    // the dispatcher lock at will.  Initially when the command starts running, the
    // dispatcher lock is held.  However, if the command needs to call into the policy to
    // do some work, it can release the lock, do the work, then reacquire the lock again
    // before returning.
    //
    // This mechanism is a bit clunky but it helps to preserve the invariant that the dispatch
    // never calls into the policy while holding its lock.
    //
    // Commands are implicitly 'LockedInterruptible'.
    struct CommandEntry;
    typedef void (InputDispatcher::*Command)(CommandEntry* commandEntry);

    class Connection;
    struct CommandEntry : Link<CommandEntry> {
        CommandEntry(Command command);
        ~CommandEntry();

        Command command;

        // parameters for the command (usage varies by command)
        sp<Connection> connection;
        nsecs_t eventTime;
        KeyEntry* keyEntry;
        sp<InputApplicationHandle> inputApplicationHandle;
        sp<InputWindowHandle> inputWindowHandle;
        String8 reason;
        int32_t userActivityEventType;
        uint32_t seq;
        bool handled;
    };

    // Generic queue implementation.
    template <typename T>
    struct Queue {
        T* head;
        T* tail;

        inline Queue() : head(NULL), tail(NULL) {
        }

        inline bool isEmpty() const {
            return !head;
        }

        inline void enqueueAtTail(T* entry) {
            entry->prev = tail;
            if (tail) {
                tail->next = entry;
            } else {
                head = entry;
            }
            entry->next = NULL;
            tail = entry;
        }

        inline void enqueueAtHead(T* entry) {
            entry->next = head;
            if (head) {
                head->prev = entry;
            } else {
                tail = entry;
            }
            entry->prev = NULL;
            head = entry;
        }

        inline void dequeue(T* entry) {
            if (entry->prev) {
                entry->prev->next = entry->next;
            } else {
                head = entry->next;
            }
            if (entry->next) {
                entry->next->prev = entry->prev;
            } else {
                tail = entry->prev;
            }
        }

        inline T* dequeueAtHead() {
            T* entry = head;
            head = entry->next;
            if (head) {
                head->prev = NULL;
            } else {
                tail = NULL;
            }
            return entry;
        }

        uint32_t count() const;
    };

    /* Specifies which events are to be canceled and why. */
    struct CancelationOptions {
        enum Mode {
            CANCEL_ALL_EVENTS = 0,
            CANCEL_POINTER_EVENTS = 1,
            CANCEL_NON_POINTER_EVENTS = 2,
            CANCEL_FALLBACK_EVENTS = 3,
        };

        // The criterion to use to determine which events should be canceled.
        Mode mode;

        // Descriptive reason for the cancelation.
        const char* reason;

        // The specific keycode of the key event to cancel, or -1 to cancel any key event.
        int32_t keyCode;

        // The specific device id of events to cancel, or -1 to cancel events from any device.
        int32_t deviceId;

        CancelationOptions(Mode mode, const char* reason) :
                mode(mode), reason(reason), keyCode(-1), deviceId(-1) { }
    };

    /* Tracks dispatched key and motion event state so that cancelation events can be
     * synthesized when events are dropped. */
    class InputState {
    public:
        InputState();
        ~InputState();

        // Returns true if there is no state to be canceled.
        bool isNeutral() const;

        // Returns true if the specified source is known to have received a hover enter
        // motion event.
        bool isHovering(int32_t deviceId, uint32_t source, int32_t displayId) const;

        // Records tracking information for a key event that has just been published.
        // Returns true if the event should be delivered, false if it is inconsistent
        // and should be skipped.
        bool trackKey(const KeyEntry* entry, int32_t action, int32_t flags);

        // Records tracking information for a motion event that has just been published.
        // Returns true if the event should be delivered, false if it is inconsistent
        // and should be skipped.
        bool trackMotion(const MotionEntry* entry, int32_t action, int32_t flags);

        // Synthesizes cancelation events for the current state and resets the tracked state.
        void synthesizeCancelationEvents(nsecs_t currentTime,
                Vector<EventEntry*>& outEvents, const CancelationOptions& options);

        // Clears the current state.
        void clear();

        // Copies pointer-related parts of the input state to another instance.
        void copyPointerStateTo(InputState& other) const;

        // Gets the fallback key associated with a keycode.
        // Returns -1 if none.
        // Returns AKEYCODE_UNKNOWN if we are only dispatching the unhandled key to the policy.
        int32_t getFallbackKey(int32_t originalKeyCode);

        // Sets the fallback key for a particular keycode.
        void setFallbackKey(int32_t originalKeyCode, int32_t fallbackKeyCode);

        // Removes the fallback key for a particular keycode.
        void removeFallbackKey(int32_t originalKeyCode);

        inline const KeyedVector<int32_t, int32_t>& getFallbackKeys() const {
            return mFallbackKeys;
        }

    private:
        struct KeyMemento {
            int32_t deviceId;
            uint32_t source;
            int32_t keyCode;
            int32_t scanCode;
            int32_t metaState;
            int32_t flags;
            nsecs_t downTime;
            uint32_t policyFlags;
        };

        struct MotionMemento {
            int32_t deviceId;
            uint32_t source;
            int32_t flags;
            float xPrecision;
            float yPrecision;
            nsecs_t downTime;
            int32_t displayId;
            uint32_t pointerCount;
            PointerProperties pointerProperties[MAX_POINTERS];
            PointerCoords pointerCoords[MAX_POINTERS];
            bool hovering;
            uint32_t policyFlags;

            void setPointers(const MotionEntry* entry);
        };

        Vector<KeyMemento> mKeyMementos;
        Vector<MotionMemento> mMotionMementos;
        KeyedVector<int32_t, int32_t> mFallbackKeys;

        ssize_t findKeyMemento(const KeyEntry* entry) const;
        ssize_t findMotionMemento(const MotionEntry* entry, bool hovering) const;

        void addKeyMemento(const KeyEntry* entry, int32_t flags);
        void addMotionMemento(const MotionEntry* entry, int32_t flags, bool hovering);

        static bool shouldCancelKey(const KeyMemento& memento,
                const CancelationOptions& options);
        static bool shouldCancelMotion(const MotionMemento& memento,
                const CancelationOptions& options);
    };

    /* Manages the dispatch state associated with a single input channel. */
    class Connection : public RefBase {
    protected:
        virtual ~Connection();

    public:
        enum Status {
            // Everything is peachy.
            STATUS_NORMAL,
            // An unrecoverable communication error has occurred.
            STATUS_BROKEN,
            // The input channel has been unregistered.
            STATUS_ZOMBIE
        };

        Status status;
        sp<InputChannel> inputChannel; // never null
        sp<InputWindowHandle> inputWindowHandle; // may be null
        bool monitor;
        InputPublisher inputPublisher;
        InputState inputState;

        // True if the socket is full and no further events can be published until
        // the application consumes some of the input.
        bool inputPublisherBlocked;

        // Queue of events that need to be published to the connection.
        Queue<DispatchEntry> outboundQueue;

        // Queue of events that have been published to the connection but that have not
        // yet received a "finished" response from the application.
        Queue<DispatchEntry> waitQueue;

        explicit Connection(const sp<InputChannel>& inputChannel,
                const sp<InputWindowHandle>& inputWindowHandle, bool monitor);

        inline const char* getInputChannelName() const { return inputChannel->getName().string(); }

        const char* getWindowName() const;
        const char* getStatusLabel() const;

        DispatchEntry* findWaitQueueEntry(uint32_t seq);
    };

    enum DropReason {
        DROP_REASON_NOT_DROPPED = 0,
        DROP_REASON_POLICY = 1,
        DROP_REASON_APP_SWITCH = 2,
        DROP_REASON_DISABLED = 3,
        DROP_REASON_BLOCKED = 4,
        DROP_REASON_STALE = 5,
    };

    sp<InputDispatcherPolicyInterface> mPolicy;
    InputDispatcherConfiguration mConfig;

    Mutex mLock;

    Condition mDispatcherIsAliveCondition;

    sp<Looper> mLooper;

    EventEntry* mPendingEvent;
    Queue<EventEntry> mInboundQueue;
    Queue<EventEntry> mRecentQueue;
    Queue<CommandEntry> mCommandQueue;

    void dispatchOnceInnerLocked(nsecs_t* nextWakeupTime);

    // Enqueues an inbound event.  Returns true if mLooper->wake() should be called.
    bool enqueueInboundEventLocked(EventEntry* entry);

    // Cleans up input state when dropping an inbound event.
    void dropInboundEventLocked(EventEntry* entry, DropReason dropReason);

    // Adds an event to a queue of recent events for debugging purposes.
    void addRecentEventLocked(EventEntry* entry);

    // App switch latency optimization.
    bool mAppSwitchSawKeyDown;
    nsecs_t mAppSwitchDueTime;

    static bool isAppSwitchKeyCode(int32_t keyCode);
    bool isAppSwitchKeyEventLocked(KeyEntry* keyEntry);
    bool isAppSwitchPendingLocked();
    void resetPendingAppSwitchLocked(bool handled);

    // Stale event latency optimization.
    static bool isStaleEventLocked(nsecs_t currentTime, EventEntry* entry);

    // Blocked event latency optimization.  Drops old events when the user intends
    // to transfer focus to a new application.
    EventEntry* mNextUnblockedEvent;

    sp<InputWindowHandle> findTouchedWindowAtLocked(int32_t displayId, int32_t x, int32_t y);

    // All registered connections mapped by channel file descriptor.
    KeyedVector<int, sp<Connection> > mConnectionsByFd;

    ssize_t getConnectionIndexLocked(const sp<InputChannel>& inputChannel);

    // Input channels that will receive a copy of all input events.
    Vector<sp<InputChannel> > mMonitoringChannels;

    // Event injection and synchronization.
    Condition mInjectionResultAvailableCondition;
    bool hasInjectionPermission(int32_t injectorPid, int32_t injectorUid);
    void setInjectionResultLocked(EventEntry* entry, int32_t injectionResult);

    Condition mInjectionSyncFinishedCondition;
    void incrementPendingForegroundDispatchesLocked(EventEntry* entry);
    void decrementPendingForegroundDispatchesLocked(EventEntry* entry);

    // Key repeat tracking.
    struct KeyRepeatState {
        KeyEntry* lastKeyEntry; // or null if no repeat
        nsecs_t nextRepeatTime;
    } mKeyRepeatState;

    void resetKeyRepeatLocked();
    KeyEntry* synthesizeKeyRepeatLocked(nsecs_t currentTime);

    // Key replacement tracking
    struct KeyReplacement {
        int32_t keyCode;
        int32_t deviceId;
        bool operator==(const KeyReplacement& rhs) const {
            return keyCode == rhs.keyCode && deviceId == rhs.deviceId;
        }
        bool operator<(const KeyReplacement& rhs) const {
            return keyCode != rhs.keyCode ? keyCode < rhs.keyCode : deviceId < rhs.deviceId;
        }
    };
    // Maps the key code replaced, device id tuple to the key code it was replaced with
    KeyedVector<KeyReplacement, int32_t> mReplacedKeys;

    // Deferred command processing.
    bool haveCommandsLocked() const;
    bool runCommandsLockedInterruptible();
    CommandEntry* postCommandLocked(Command command);

    // Input filter processing.
    bool shouldSendKeyToInputFilterLocked(const NotifyKeyArgs* args);
    bool shouldSendMotionToInputFilterLocked(const NotifyMotionArgs* args);

    // Inbound event processing.
    void drainInboundQueueLocked();
    void releasePendingEventLocked();
    void releaseInboundEventLocked(EventEntry* entry);

    // Dispatch state.
    bool mDispatchEnabled;
    bool mDispatchFrozen;
    bool mInputFilterEnabled;

    Vector<sp<InputWindowHandle> > mWindowHandles;

    sp<InputWindowHandle> getWindowHandleLocked(const sp<InputChannel>& inputChannel) const;
    bool hasWindowHandleLocked(const sp<InputWindowHandle>& windowHandle) const;

    // Focus tracking for keys, trackball, etc.
    sp<InputWindowHandle> mFocusedWindowHandle;

    // Focus tracking for touch.
    struct TouchedWindow {
        sp<InputWindowHandle> windowHandle;
        int32_t targetFlags;
        BitSet32 pointerIds;        // zero unless target flag FLAG_SPLIT is set
    };
    struct TouchState {
        bool down;
        bool split;
        int32_t deviceId; // id of the device that is currently down, others are rejected
        uint32_t source;  // source of the device that is current down, others are rejected
        int32_t displayId; // id to the display that currently has a touch, others are rejected
        Vector<TouchedWindow> windows;

        TouchState();
        ~TouchState();
        void reset();
        void copyFrom(const TouchState& other);
        void addOrUpdateWindow(const sp<InputWindowHandle>& windowHandle,
                int32_t targetFlags, BitSet32 pointerIds);
        void removeWindow(const sp<InputWindowHandle>& windowHandle);
        void filterNonAsIsTouchWindows();
        sp<InputWindowHandle> getFirstForegroundWindowHandle() const;
        bool isSlippery() const;
    };

    KeyedVector<int32_t, TouchState> mTouchStatesByDisplay;
    TouchState mTempTouchState;

    // Focused application.
    sp<InputApplicationHandle> mFocusedApplicationHandle;

    // Dispatcher state at time of last ANR.
    String8 mLastANRState;

    // Dispatch inbound events.
    bool dispatchConfigurationChangedLocked(
            nsecs_t currentTime, ConfigurationChangedEntry* entry);
    bool dispatchDeviceResetLocked(
            nsecs_t currentTime, DeviceResetEntry* entry);
    bool dispatchKeyLocked(
            nsecs_t currentTime, KeyEntry* entry,
            DropReason* dropReason, nsecs_t* nextWakeupTime);
    bool dispatchMotionLocked(
            nsecs_t currentTime, MotionEntry* entry,
            DropReason* dropReason, nsecs_t* nextWakeupTime);
    void dispatchEventLocked(nsecs_t currentTime, EventEntry* entry,
            const Vector<InputTarget>& inputTargets);

    void logOutboundKeyDetailsLocked(const char* prefix, const KeyEntry* entry);
    void logOutboundMotionDetailsLocked(const char* prefix, const MotionEntry* entry);

    // Keeping track of ANR timeouts.
    enum InputTargetWaitCause {
        INPUT_TARGET_WAIT_CAUSE_NONE,
        INPUT_TARGET_WAIT_CAUSE_SYSTEM_NOT_READY,
        INPUT_TARGET_WAIT_CAUSE_APPLICATION_NOT_READY,
    };

    InputTargetWaitCause mInputTargetWaitCause;
    nsecs_t mInputTargetWaitStartTime;
    nsecs_t mInputTargetWaitTimeoutTime;
    bool mInputTargetWaitTimeoutExpired;
    sp<InputApplicationHandle> mInputTargetWaitApplicationHandle;

    // Contains the last window which received a hover event.
    sp<InputWindowHandle> mLastHoverWindowHandle;

    // Finding targets for input events.
    int32_t handleTargetsNotReadyLocked(nsecs_t currentTime, const EventEntry* entry,
            const sp<InputApplicationHandle>& applicationHandle,
            const sp<InputWindowHandle>& windowHandle,
            nsecs_t* nextWakeupTime, const char* reason);
    void resumeAfterTargetsNotReadyTimeoutLocked(nsecs_t newTimeout,
            const sp<InputChannel>& inputChannel);
    nsecs_t getTimeSpentWaitingForApplicationLocked(nsecs_t currentTime);
    void resetANRTimeoutsLocked();

    int32_t findFocusedWindowTargetsLocked(nsecs_t currentTime, const EventEntry* entry,
            Vector<InputTarget>& inputTargets, nsecs_t* nextWakeupTime);
    int32_t findTouchedWindowTargetsLocked(nsecs_t currentTime, const MotionEntry* entry,
            Vector<InputTarget>& inputTargets, nsecs_t* nextWakeupTime,
            bool* outConflictingPointerActions);

    void addWindowTargetLocked(const sp<InputWindowHandle>& windowHandle,
            int32_t targetFlags, BitSet32 pointerIds, Vector<InputTarget>& inputTargets);
    void addMonitoringTargetsLocked(Vector<InputTarget>& inputTargets);

    void pokeUserActivityLocked(const EventEntry* eventEntry);
    bool checkInjectionPermission(const sp<InputWindowHandle>& windowHandle,
            const InjectionState* injectionState);
    bool isWindowObscuredAtPointLocked(const sp<InputWindowHandle>& windowHandle,
            int32_t x, int32_t y) const;
    String8 getApplicationWindowLabelLocked(const sp<InputApplicationHandle>& applicationHandle,
            const sp<InputWindowHandle>& windowHandle);

    String8 checkWindowReadyForMoreInputLocked(nsecs_t currentTime,
            const sp<InputWindowHandle>& windowHandle, const EventEntry* eventEntry,
            const char* targetType);

    // Manage the dispatch cycle for a single connection.
    // These methods are deliberately not Interruptible because doing all of the work
    // with the mutex held makes it easier to ensure that connection invariants are maintained.
    // If needed, the methods post commands to run later once the critical bits are done.
    void prepareDispatchCycleLocked(nsecs_t currentTime, const sp<Connection>& connection,
            EventEntry* eventEntry, const InputTarget* inputTarget);
    void enqueueDispatchEntriesLocked(nsecs_t currentTime, const sp<Connection>& connection,
            EventEntry* eventEntry, const InputTarget* inputTarget);
    void enqueueDispatchEntryLocked(const sp<Connection>& connection,
            EventEntry* eventEntry, const InputTarget* inputTarget, int32_t dispatchMode);
    void startDispatchCycleLocked(nsecs_t currentTime, const sp<Connection>& connection);
    void finishDispatchCycleLocked(nsecs_t currentTime, const sp<Connection>& connection,
            uint32_t seq, bool handled);
    void abortBrokenDispatchCycleLocked(nsecs_t currentTime, const sp<Connection>& connection,
            bool notify);
    void drainDispatchQueueLocked(Queue<DispatchEntry>* queue);
    void releaseDispatchEntryLocked(DispatchEntry* dispatchEntry);
    static int handleReceiveCallback(int fd, int events, void* data);

    void synthesizeCancelationEventsForAllConnectionsLocked(
            const CancelationOptions& options);
    void synthesizeCancelationEventsForInputChannelLocked(const sp<InputChannel>& channel,
            const CancelationOptions& options);
    void synthesizeCancelationEventsForConnectionLocked(const sp<Connection>& connection,
            const CancelationOptions& options);

    // Splitting motion events across windows.
    MotionEntry* splitMotionEvent(const MotionEntry* originalMotionEntry, BitSet32 pointerIds);

    // Reset and drop everything the dispatcher is doing.
    void resetAndDropEverythingLocked(const char* reason);

    // Dump state.
    void dumpDispatchStateLocked(String8& dump);
    void logDispatchStateLocked();

    // Registration.
    void removeMonitorChannelLocked(const sp<InputChannel>& inputChannel);
    status_t unregisterInputChannelLocked(const sp<InputChannel>& inputChannel, bool notify);

    // Add or remove a connection to the mActiveConnections vector.
    void activateConnectionLocked(Connection* connection);
    void deactivateConnectionLocked(Connection* connection);

    // Interesting events that we might like to log or tell the framework about.
    void onDispatchCycleFinishedLocked(
            nsecs_t currentTime, const sp<Connection>& connection, uint32_t seq, bool handled);
    void onDispatchCycleBrokenLocked(
            nsecs_t currentTime, const sp<Connection>& connection);
    void onANRLocked(
            nsecs_t currentTime, const sp<InputApplicationHandle>& applicationHandle,
            const sp<InputWindowHandle>& windowHandle,
            nsecs_t eventTime, nsecs_t waitStartTime, const char* reason);

    // Outbound policy interactions.
    void doNotifyConfigurationChangedInterruptible(CommandEntry* commandEntry);
    void doNotifyInputChannelBrokenLockedInterruptible(CommandEntry* commandEntry);
    void doNotifyANRLockedInterruptible(CommandEntry* commandEntry);
    void doInterceptKeyBeforeDispatchingLockedInterruptible(CommandEntry* commandEntry);
    void doDispatchCycleFinishedLockedInterruptible(CommandEntry* commandEntry);
    bool afterKeyEventLockedInterruptible(const sp<Connection>& connection,
            DispatchEntry* dispatchEntry, KeyEntry* keyEntry, bool handled);
    bool afterMotionEventLockedInterruptible(const sp<Connection>& connection,
            DispatchEntry* dispatchEntry, MotionEntry* motionEntry, bool handled);
    void doPokeUserActivityLockedInterruptible(CommandEntry* commandEntry);
    void initializeKeyEvent(KeyEvent* event, const KeyEntry* entry);

    // Statistics gathering.
    void updateDispatchStatisticsLocked(nsecs_t currentTime, const EventEntry* entry,
            int32_t injectionResult, nsecs_t timeSpentWaitingForApplication);
    void traceInboundQueueLengthLocked();
    void traceOutboundQueueLengthLocked(const sp<Connection>& connection);
    void traceWaitQueueLengthLocked(const sp<Connection>& connection);
};

/* Enqueues and dispatches input events, endlessly. */
class InputDispatcherThread : public Thread {
public:
    explicit InputDispatcherThread(const sp<InputDispatcherInterface>& dispatcher);
    ~InputDispatcherThread();

private:
    virtual bool threadLoop();

    sp<InputDispatcherInterface> mDispatcher;
};

} // namespace android

#endif // _UI_INPUT_DISPATCHER_H