Flutter Linux Embedder
fl_key_embedder_responder.cc
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1 // Copyright 2013 The Flutter 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 
6 
7 #include <gtk/gtk.h>
8 #include <cinttypes>
9 
10 #include "flutter/shell/platform/embedder/embedder.h"
13 
14 constexpr uint64_t kMicrosecondsPerMillisecond = 1000;
15 
16 static const FlutterKeyEvent kEmptyEvent{
17  .struct_size = sizeof(FlutterKeyEvent),
18  .timestamp = 0,
19  .type = kFlutterKeyEventTypeDown,
20  .physical = 0,
21  .logical = 0,
22  .character = nullptr,
23  .synthesized = false,
24 };
25 
26 // Look up a hash table that maps a uint64_t to a uint64_t.
27 //
28 // Returns 0 if not found.
29 //
30 // Both key and value should be directly hashed.
31 static uint64_t lookup_hash_table(GHashTable* table, uint64_t key) {
32  return gpointer_to_uint64(
33  g_hash_table_lookup(table, uint64_to_gpointer(key)));
34 }
35 
36 static gboolean hash_table_find_equal_value(gpointer key,
37  gpointer value,
38  gpointer user_data) {
40 }
41 
42 // Look up a hash table that maps a uint64_t to a uint64_t; given its key,
43 // find its value.
44 //
45 // Returns 0 if not found.
46 //
47 // Both key and value should be directly hashed.
48 static uint64_t reverse_lookup_hash_table(GHashTable* table, uint64_t value) {
49  return gpointer_to_uint64(g_hash_table_find(
51 }
52 
53 static uint64_t to_lower(uint64_t n) {
54  constexpr uint64_t lower_a = 0x61;
55  constexpr uint64_t upper_a = 0x41;
56  constexpr uint64_t upper_z = 0x5a;
57 
58  constexpr uint64_t lower_a_grave = 0xe0;
59  constexpr uint64_t upper_a_grave = 0xc0;
60  constexpr uint64_t upper_thorn = 0xde;
61  constexpr uint64_t division = 0xf7;
62 
63  // ASCII range.
64  if (n >= upper_a && n <= upper_z) {
65  return n - upper_a + lower_a;
66  }
67 
68  // EASCII range.
69  if (n >= upper_a_grave && n <= upper_thorn && n != division) {
70  return n - upper_a_grave + lower_a_grave;
71  }
72 
73  return n;
74 }
75 
76 /* Define FlKeyEmbedderUserData */
77 
78 /**
79  * FlKeyEmbedderUserData:
80  * The user_data used when #FlKeyEmbedderResponder sends message through the
81  * embedder.SendKeyEvent API.
82  */
83 #define FL_TYPE_EMBEDDER_USER_DATA fl_key_embedder_user_data_get_type()
84 G_DECLARE_FINAL_TYPE(FlKeyEmbedderUserData,
85  fl_key_embedder_user_data,
86  FL,
87  KEY_EMBEDDER_USER_DATA,
88  GObject);
89 
91  GObject parent_instance;
92 
94  gpointer user_data;
95 };
96 
97 G_DEFINE_TYPE(FlKeyEmbedderUserData, fl_key_embedder_user_data, G_TYPE_OBJECT)
98 
99 static void fl_key_embedder_user_data_dispose(GObject* object);
100 
102  FlKeyEmbedderUserDataClass* klass) {
103  G_OBJECT_CLASS(klass)->dispose = fl_key_embedder_user_data_dispose;
104 }
105 
106 static void fl_key_embedder_user_data_init(FlKeyEmbedderUserData* self) {}
107 
108 static void fl_key_embedder_user_data_dispose(GObject* object) {
109  // The following line suppresses a warning for unused function
110  // FL_IS_KEY_EMBEDDER_USER_DATA.
111  g_return_if_fail(FL_IS_KEY_EMBEDDER_USER_DATA(object));
112 }
113 
114 // Creates a new FlKeyChannelUserData private class with all information.
115 //
116 // The callback and the user_data might be nullptr.
117 static FlKeyEmbedderUserData* fl_key_embedder_user_data_new(
119  gpointer user_data) {
120  FlKeyEmbedderUserData* self = FL_KEY_EMBEDDER_USER_DATA(
121  g_object_new(FL_TYPE_EMBEDDER_USER_DATA, nullptr));
122 
123  self->callback = callback;
124  self->user_data = user_data;
125  return self;
126 }
127 
128 /* Define FlKeyEmbedderResponder */
129 
130 namespace {
131 
132 typedef enum {
133  kStateLogicUndecided,
134  kStateLogicNormal,
135  kStateLogicReversed,
136 } StateLogicInferrence;
137 
138 }
139 
142 
144 
145  // Internal record for states of whether a key is pressed.
146  //
147  // It is a map from Flutter physical key to Flutter logical key. Both keys
148  // and values are directly stored uint64s. This table is freed by the
149  // responder.
150  GHashTable* pressing_records;
151 
152  // Internal record for states of whether a lock mode is enabled.
153  //
154  // It is a bit mask composed of GTK mode bits.
156 
157  // Internal record for the last observed key mapping.
158  //
159  // It stores the physical key last seen during a key down event for a logical
160  // key. It is used to synthesize modifier keys and lock keys.
161  //
162  // It is a map from Flutter logical key to physical key. Both keys and
163  // values are directly stored uint64s. This table is freed by the responder.
164  GHashTable* mapping_records;
165 
166  // The inferred logic type indicating whether the CapsLock state logic is
167  // reversed on this platform.
168  //
169  // For more information, see #update_caps_lock_state_logic_inferrence.
170  StateLogicInferrence caps_lock_state_logic_inferrence;
171 
172  // Record if any events has been sent during a
173  // |fl_key_embedder_responder_handle_event| call.
175 
176  // A static map from GTK modifier bits to #FlKeyEmbedderCheckedKey to
177  // configure the modifier keys that needs to be tracked and kept synchronous
178  // on.
179  //
180  // The keys are directly stored guints. The values must be freed with g_free.
181  // This table is freed by the responder.
183 
184  // A static map from GTK modifier bits to #FlKeyEmbedderCheckedKey to
185  // configure the lock mode bits that needs to be tracked and kept synchronous
186  // on.
187  //
188  // The keys are directly stored guints. The values must be freed with g_free.
189  // This table is freed by the responder.
191 
192  // A static map generated by reverse mapping lock_bit_to_checked_keys.
193  //
194  // It is a map from primary physical keys to lock bits. Both keys and values
195  // are directly stored uint64s. This table is freed by the responder.
197 };
198 
200  FlKeyResponderInterface* iface);
201 static void fl_key_embedder_responder_dispose(GObject* object);
202 
203 #define FL_TYPE_EMBEDDER_RESPONDER_USER_DATA \
204  fl_key_embedder_responder_get_type()
206  FlKeyEmbedderResponder,
207  fl_key_embedder_responder,
208  G_TYPE_OBJECT,
209  G_IMPLEMENT_INTERFACE(FL_TYPE_KEY_RESPONDER,
211 
213  FlKeyResponder* responder,
217  gpointer user_data);
218 
220  FlKeyResponderInterface* iface) {
221  iface->handle_event = fl_key_embedder_responder_handle_event;
222 }
223 
224 // Initializes the FlKeyEmbedderResponder class methods.
226  FlKeyEmbedderResponderClass* klass) {
227  G_OBJECT_CLASS(klass)->dispose = fl_key_embedder_responder_dispose;
228 }
229 
230 // Initializes an FlKeyEmbedderResponder instance.
231 static void fl_key_embedder_responder_init(FlKeyEmbedderResponder* self) {}
232 
233 // Disposes of an FlKeyEmbedderResponder instance.
234 static void fl_key_embedder_responder_dispose(GObject* object) {
235  FlKeyEmbedderResponder* self = FL_KEY_EMBEDDER_RESPONDER(object);
236 
237  g_clear_pointer(&self->pressing_records, g_hash_table_unref);
238  g_clear_pointer(&self->mapping_records, g_hash_table_unref);
239  g_clear_pointer(&self->modifier_bit_to_checked_keys, g_hash_table_unref);
240  g_clear_pointer(&self->lock_bit_to_checked_keys, g_hash_table_unref);
241  g_clear_pointer(&self->logical_key_to_lock_bit, g_hash_table_unref);
242 
243  G_OBJECT_CLASS(fl_key_embedder_responder_parent_class)->dispose(object);
244 }
245 
246 // Fill in #logical_key_to_lock_bit by associating a logical key with
247 // its corresponding modifier bit.
248 //
249 // This is used as the body of a loop over #lock_bit_to_checked_keys.
250 static void initialize_logical_key_to_lock_bit_loop_body(gpointer lock_bit,
251  gpointer value,
252  gpointer user_data) {
253  FlKeyEmbedderCheckedKey* checked_key =
254  reinterpret_cast<FlKeyEmbedderCheckedKey*>(value);
255  GHashTable* table = reinterpret_cast<GHashTable*>(user_data);
256  g_hash_table_insert(table,
258  GUINT_TO_POINTER(lock_bit));
259 }
260 
261 // Creates a new FlKeyEmbedderResponder instance.
262 FlKeyEmbedderResponder* fl_key_embedder_responder_new(
264  FlKeyEmbedderResponder* self = FL_KEY_EMBEDDER_RESPONDER(
265  g_object_new(FL_TYPE_EMBEDDER_RESPONDER_USER_DATA, nullptr));
266 
267  self->send_key_event = std::move(send_key_event);
268 
269  self->pressing_records = g_hash_table_new(g_direct_hash, g_direct_equal);
270  self->mapping_records = g_hash_table_new(g_direct_hash, g_direct_equal);
271  self->lock_records = 0;
272  self->caps_lock_state_logic_inferrence = kStateLogicUndecided;
273 
274  self->modifier_bit_to_checked_keys =
275  g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL, g_free);
276  initialize_modifier_bit_to_checked_keys(self->modifier_bit_to_checked_keys);
277 
278  self->lock_bit_to_checked_keys =
279  g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL, g_free);
280  initialize_lock_bit_to_checked_keys(self->lock_bit_to_checked_keys);
281 
282  self->logical_key_to_lock_bit =
283  g_hash_table_new(g_direct_hash, g_direct_equal);
284  g_hash_table_foreach(self->lock_bit_to_checked_keys,
286  self->logical_key_to_lock_bit);
287 
288  return self;
289 }
290 
291 /* Implement FlKeyEmbedderUserData */
292 
293 static uint64_t apply_id_plane(uint64_t logical_id, uint64_t plane) {
294  return (logical_id & kValueMask) | plane;
295 }
296 
297 static uint64_t event_to_physical_key(const FlKeyEvent* event) {
298  auto found = xkb_to_physical_key_map.find(event->keycode);
299  if (found != xkb_to_physical_key_map.end()) {
300  return found->second;
301  }
303 }
304 
305 static uint64_t event_to_logical_key(const FlKeyEvent* event) {
306  guint keyval = event->keyval;
307  auto found = gtk_keyval_to_logical_key_map.find(keyval);
308  if (found != gtk_keyval_to_logical_key_map.end()) {
309  return found->second;
310  }
311  // EASCII range
312  if (keyval < 256) {
313  return apply_id_plane(to_lower(keyval), kUnicodePlane);
314  }
315  // Auto-generate key
316  return apply_id_plane(keyval, kGtkPlane);
317 }
318 
319 static uint64_t event_to_timestamp(const FlKeyEvent* event) {
320  return kMicrosecondsPerMillisecond * static_cast<double>(event->time);
321 }
322 
323 // Returns a newly accocated UTF-8 string from event->keyval that must be
324 // freed later with g_free().
325 static char* event_to_character(const FlKeyEvent* event) {
326  gunichar unicodeChar = gdk_keyval_to_unicode(event->keyval);
327  glong items_written;
328  gchar* result = g_ucs4_to_utf8(&unicodeChar, 1, NULL, &items_written, NULL);
329  if (items_written == 0) {
330  if (result != NULL) {
331  g_free(result);
332  }
333  return nullptr;
334  }
335  return result;
336 }
337 
338 // Handles a response from the embedder API to a key event sent to the framework
339 // earlier.
340 static void handle_response(bool handled, gpointer user_data) {
341  g_autoptr(FlKeyEmbedderUserData) data = FL_KEY_EMBEDDER_USER_DATA(user_data);
342 
343  g_return_if_fail(data->callback != nullptr);
344 
345  data->callback(handled, data->user_data);
346 }
347 
348 // Sends a synthesized event to the framework with no demand for callback.
349 static void synthesize_simple_event(FlKeyEmbedderResponder* self,
350  FlutterKeyEventType type,
351  uint64_t physical,
352  uint64_t logical,
353  double timestamp) {
354  FlutterKeyEvent out_event;
355  out_event.struct_size = sizeof(out_event);
356  out_event.timestamp = timestamp;
357  out_event.type = type;
358  out_event.physical = physical;
359  out_event.logical = logical;
360  out_event.character = nullptr;
361  out_event.synthesized = true;
362  self->sent_any_events = true;
363  self->send_key_event(&out_event, nullptr, nullptr);
364 }
365 
366 namespace {
367 
368 // Context variables for the foreach call used to synchronize pressing states
369 // and lock states.
370 typedef struct {
371  FlKeyEmbedderResponder* self;
372  guint state;
373  uint64_t event_logical_key;
374  bool is_down;
375  double timestamp;
376 } SyncStateLoopContext;
377 
378 // Context variables for the foreach call used to find the physical key from
379 // a modifier logical key.
380 typedef struct {
381  bool known_modifier_physical_key;
382  uint64_t logical_key;
383  uint64_t physical_key_from_event;
384  uint64_t corrected_physical_key;
385 } ModifierLogicalToPhysicalContext;
386 
387 } // namespace
388 
389 // Update the pressing record.
390 //
391 // If `logical_key` is 0, the record will be set as "released". Otherwise, the
392 // record will be set as "pressed" with this logical key. This function asserts
393 // that the key is pressed if the caller asked to release, and vice versa.
394 static void update_pressing_state(FlKeyEmbedderResponder* self,
395  uint64_t physical_key,
396  uint64_t logical_key) {
397  if (logical_key != 0) {
398  g_return_if_fail(lookup_hash_table(self->pressing_records, physical_key) ==
399  0);
400  g_hash_table_insert(self->pressing_records,
401  uint64_to_gpointer(physical_key),
402  uint64_to_gpointer(logical_key));
403  } else {
404  g_return_if_fail(lookup_hash_table(self->pressing_records, physical_key) !=
405  0);
406  g_hash_table_remove(self->pressing_records,
407  uint64_to_gpointer(physical_key));
408  }
409 }
410 
411 // Update the lock record.
412 //
413 // If `is_down` is false, this function is a no-op. Otherwise, this function
414 // finds the lock bit corresponding to `physical_key`, and flips its bit.
415 static void possibly_update_lock_bit(FlKeyEmbedderResponder* self,
416  uint64_t logical_key,
417  bool is_down) {
418  if (!is_down) {
419  return;
420  }
421  const guint mode_bit = GPOINTER_TO_UINT(g_hash_table_lookup(
422  self->logical_key_to_lock_bit, uint64_to_gpointer(logical_key)));
423  if (mode_bit != 0) {
424  self->lock_records ^= mode_bit;
425  }
426 }
427 
428 static void update_mapping_record(FlKeyEmbedderResponder* self,
429  uint64_t physical_key,
430  uint64_t logical_key) {
431  g_hash_table_insert(self->mapping_records, uint64_to_gpointer(logical_key),
432  uint64_to_gpointer(physical_key));
433 }
434 
435 // Synchronizes the pressing state of a key to its state from the event by
436 // synthesizing events.
437 //
438 // This is used as the body of a loop over #modifier_bit_to_checked_keys.
439 static void synchronize_pressed_states_loop_body(gpointer key,
440  gpointer value,
441  gpointer user_data) {
442  SyncStateLoopContext* context =
443  reinterpret_cast<SyncStateLoopContext*>(user_data);
444  FlKeyEmbedderCheckedKey* checked_key =
445  reinterpret_cast<FlKeyEmbedderCheckedKey*>(value);
446 
447  const guint modifier_bit = GPOINTER_TO_INT(key);
448  FlKeyEmbedderResponder* self = context->self;
449  // Each TestKey contains up to two logical keys, typically the left modifier
450  // and the right modifier, that correspond to the same modifier_bit. We'd
451  // like to infer whether to synthesize a down or up event for each key.
452  //
453  // The hard part is that, if we want to synthesize a down event, we don't know
454  // which physical key to use. Here we assume the keyboard layout do not change
455  // frequently and use the last physical-logical relationship, recorded in
456  // #mapping_records.
457  const uint64_t logical_keys[] = {
458  checked_key->primary_logical_key,
459  checked_key->secondary_logical_key,
460  };
461  const guint length = checked_key->secondary_logical_key == 0 ? 1 : 2;
462 
463  const bool any_pressed_by_state = (context->state & modifier_bit) != 0;
464 
465  bool any_pressed_by_record = false;
466 
467  // Traverse each logical key of this modifier bit for 2 purposes:
468  //
469  // 1. Perform the synthesization of release events: If the modifier bit is 0
470  // and the key is pressed, synthesize a release event.
471  // 2. Prepare for the synthesization of press events: If the modifier bit is
472  // 1, and no keys are pressed (discovered here), synthesize a press event
473  // later.
474  for (guint logical_key_idx = 0; logical_key_idx < length; logical_key_idx++) {
475  const uint64_t logical_key = logical_keys[logical_key_idx];
476  g_return_if_fail(logical_key != 0);
477  const uint64_t pressing_physical_key =
478  reverse_lookup_hash_table(self->pressing_records, logical_key);
479  const bool this_key_pressed_before_event = pressing_physical_key != 0;
480 
481  any_pressed_by_record =
482  any_pressed_by_record || this_key_pressed_before_event;
483 
484  if (this_key_pressed_before_event && !any_pressed_by_state) {
485  const uint64_t recorded_physical_key =
486  lookup_hash_table(self->mapping_records, logical_key);
487  // Since this key has been pressed before, there must have been a recorded
488  // physical key.
489  g_return_if_fail(recorded_physical_key != 0);
490  // In rare cases #recorded_logical_key is different from #logical_key.
491  const uint64_t recorded_logical_key =
492  lookup_hash_table(self->pressing_records, recorded_physical_key);
493  synthesize_simple_event(self, kFlutterKeyEventTypeUp,
494  recorded_physical_key, recorded_logical_key,
495  context->timestamp);
496  update_pressing_state(self, recorded_physical_key, 0);
497  }
498  }
499  // If the modifier should be pressed, synthesize a down event for its primary
500  // key.
501  if (any_pressed_by_state && !any_pressed_by_record) {
502  const uint64_t logical_key = checked_key->primary_logical_key;
503  const uint64_t recorded_physical_key =
504  lookup_hash_table(self->mapping_records, logical_key);
505  // The physical key is derived from past mapping record if possible.
506  //
507  // The event to be synthesized is a key down event. There might not have
508  // been a mapping record, in which case the hard-coded #primary_physical_key
509  // is used.
510  const uint64_t physical_key = recorded_physical_key != 0
511  ? recorded_physical_key
512  : checked_key->primary_physical_key;
513  if (recorded_physical_key == 0) {
514  update_mapping_record(self, physical_key, logical_key);
515  }
516  synthesize_simple_event(self, kFlutterKeyEventTypeDown, physical_key,
517  logical_key, context->timestamp);
518  update_pressing_state(self, physical_key, logical_key);
519  }
520 }
521 
522 // Find the stage # by the current record, which should be the recorded stage
523 // before the event.
524 static int find_stage_by_record(bool is_down, bool is_enabled) {
525  constexpr int stage_by_record_index[] = {
526  0, // is_down: 0, is_enabled: 0
527  2, // 0 1
528  3, // 1 0
529  1 // 1 1
530  };
531  return stage_by_record_index[(is_down << 1) + is_enabled];
532 }
533 
534 // Find the stage # by an event for the target key, which should be inferred
535 // stage before the event.
536 static int find_stage_by_self_event(int stage_by_record,
537  bool is_down_event,
538  bool is_state_on,
539  bool reverse_state_logic) {
540  if (!is_state_on) {
541  return reverse_state_logic ? 2 : 0;
542  }
543  if (is_down_event) {
544  return reverse_state_logic ? 0 : 2;
545  }
546  return stage_by_record;
547 }
548 
549 // Find the stage # by an event for a non-target key, which should be inferred
550 // stage during the event.
551 static int find_stage_by_others_event(int stage_by_record, bool is_state_on) {
552  g_return_val_if_fail(stage_by_record >= 0 && stage_by_record < 4,
553  stage_by_record);
554  if (!is_state_on) {
555  return 0;
556  }
557  if (stage_by_record == 0) {
558  return 1;
559  }
560  return stage_by_record;
561 }
562 
563 // Infer the logic type of CapsLock on the current platform if applicable.
564 //
565 // In most cases, when a lock key is pressed or released, its event has the
566 // key's state as 0-1-1-1 for the 4 stages (as documented in
567 // #synchronize_lock_states_loop_body) respectively. But in very rare cases it
568 // produces 1-1-0-1, which we call "reversed state logic". This is observed
569 // when using Chrome Remote Desktop on macOS (likely a bug).
570 //
571 // To detect whether the current platform behaves normally or reversed, this
572 // function is called on the first down event of CapsLock before calculating
573 // stages. This function then store the inferred mode as
574 // self->caps_lock_state_logic_inferrence.
575 //
576 // This does not help if the same app session is used alternatively between a
577 // reversed platform and a normal platform. But this is the best we can do.
579  FlKeyEmbedderResponder* self,
580  bool is_down_event,
581  bool enabled_by_state,
582  int stage_by_record) {
583  if (self->caps_lock_state_logic_inferrence != kStateLogicUndecided) {
584  return;
585  }
586  if (!is_down_event) {
587  return;
588  }
589  const int stage_by_event = find_stage_by_self_event(
590  stage_by_record, is_down_event, enabled_by_state, false);
591  if ((stage_by_event == 0 && stage_by_record == 2) ||
592  (stage_by_event == 2 && stage_by_record == 0)) {
593  self->caps_lock_state_logic_inferrence = kStateLogicReversed;
594  } else {
595  self->caps_lock_state_logic_inferrence = kStateLogicNormal;
596  }
597 }
598 
599 // Synchronizes the lock state of a key to its state from the event by
600 // synthesizing events.
601 //
602 // This is used as the body of a loop over #lock_bit_to_checked_keys.
603 //
604 // This function might modify #caps_lock_state_logic_inferrence.
605 static void synchronize_lock_states_loop_body(gpointer key,
606  gpointer value,
607  gpointer user_data) {
608  SyncStateLoopContext* context =
609  reinterpret_cast<SyncStateLoopContext*>(user_data);
610  FlKeyEmbedderCheckedKey* checked_key =
611  reinterpret_cast<FlKeyEmbedderCheckedKey*>(value);
612 
613  guint modifier_bit = GPOINTER_TO_INT(key);
614  FlKeyEmbedderResponder* self = context->self;
615 
616  const uint64_t logical_key = checked_key->primary_logical_key;
617  const uint64_t recorded_physical_key =
618  lookup_hash_table(self->mapping_records, logical_key);
619  // The physical key is derived from past mapping record if possible.
620  //
621  // If the event to be synthesized is a key up event, then there must have
622  // been a key down event before, which has updated the mapping record.
623  // If the event to be synthesized is a key down event, then there might
624  // not have been a mapping record, in which case the hard-coded
625  // #primary_physical_key is used.
626  const uint64_t physical_key = recorded_physical_key != 0
627  ? recorded_physical_key
628  : checked_key->primary_physical_key;
629 
630  // A lock mode key can be at any of a 4-stage cycle, depending on whether it's
631  // pressed and enabled. The following table lists the definition of each
632  // stage (TruePressed and TrueEnabled), the event of the lock key between
633  // every 2 stages (SelfType and SelfState), and the event of other keys at
634  // each stage (OthersState). On certain platforms SelfState uses a reversed
635  // rule for certain keys (SelfState(rvsd), as documented in
636  // #update_caps_lock_state_logic_inferrence).
637  //
638  // # [0] [1] [2] [3]
639  // TruePressed: Released Pressed Released Pressed
640  // TrueEnabled: Disabled Enabled Enabled Disabled
641  // SelfType: Down Up Down Up
642  // SelfState: 0 1 1 1
643  // SelfState(rvsd): 1 1 0 1
644  // OthersState: 0 1 1 1
645  //
646  // When the exact stage can't be derived, choose the stage that requires the
647  // minimal synthesization.
648 
649  const uint64_t pressed_logical_key =
650  recorded_physical_key == 0
651  ? 0
652  : lookup_hash_table(self->pressing_records, recorded_physical_key);
653 
654  g_return_if_fail(pressed_logical_key == 0 ||
655  pressed_logical_key == logical_key);
656  const int stage_by_record = find_stage_by_record(
657  pressed_logical_key != 0, (self->lock_records & modifier_bit) != 0);
658 
659  const bool enabled_by_state = (context->state & modifier_bit) != 0;
660  const bool this_key_is_event_key = logical_key == context->event_logical_key;
661  if (this_key_is_event_key && checked_key->is_caps_lock) {
662  update_caps_lock_state_logic_inferrence(self, context->is_down,
663  enabled_by_state, stage_by_record);
664  g_return_if_fail(self->caps_lock_state_logic_inferrence !=
665  kStateLogicUndecided);
666  }
667  const bool reverse_state_logic =
668  checked_key->is_caps_lock &&
669  self->caps_lock_state_logic_inferrence == kStateLogicReversed;
670  const int stage_by_event =
671  this_key_is_event_key
672  ? find_stage_by_self_event(stage_by_record, context->is_down,
673  enabled_by_state, reverse_state_logic)
674  : find_stage_by_others_event(stage_by_record, enabled_by_state);
675 
676  // The destination stage is equal to stage_by_event but shifted cyclically to
677  // be no less than stage_by_record.
678  constexpr int kNumStages = 4;
679  const int destination_stage = stage_by_event >= stage_by_record
680  ? stage_by_event
681  : stage_by_event + kNumStages;
682 
683  g_return_if_fail(stage_by_record <= destination_stage);
684  if (stage_by_record == destination_stage) {
685  return;
686  }
687  for (int current_stage = stage_by_record; current_stage < destination_stage;
688  current_stage += 1) {
689  if (current_stage == 9) {
690  return;
691  }
692 
693  const int standard_current_stage = current_stage % kNumStages;
694  const bool is_down_event =
695  standard_current_stage == 0 || standard_current_stage == 2;
696  if (is_down_event && recorded_physical_key == 0) {
697  update_mapping_record(self, physical_key, logical_key);
698  }
699  FlutterKeyEventType type =
700  is_down_event ? kFlutterKeyEventTypeDown : kFlutterKeyEventTypeUp;
701  update_pressing_state(self, physical_key, is_down_event ? logical_key : 0);
702  possibly_update_lock_bit(self, logical_key, is_down_event);
703  synthesize_simple_event(self, type, physical_key, logical_key,
704  context->timestamp);
705  }
706 }
707 
708 // Find if a given physical key is the primary physical of one of the known
709 // modifier keys.
710 //
711 // This is used as the body of a loop over #modifier_bit_to_checked_keys.
713  gpointer value,
714  gpointer user_data) {
715  ModifierLogicalToPhysicalContext* context =
716  reinterpret_cast<ModifierLogicalToPhysicalContext*>(user_data);
717  FlKeyEmbedderCheckedKey* checked_key =
718  reinterpret_cast<FlKeyEmbedderCheckedKey*>(value);
719 
720  if (checked_key->primary_physical_key == context->physical_key_from_event) {
721  context->known_modifier_physical_key = true;
722  }
723 }
724 
725 // Return the primary physical key of a known modifier key which matches the
726 // given logical key.
727 //
728 // This is used as the body of a loop over #modifier_bit_to_checked_keys.
729 static void find_physical_from_logical_loop_body(gpointer key,
730  gpointer value,
731  gpointer user_data) {
732  ModifierLogicalToPhysicalContext* context =
733  reinterpret_cast<ModifierLogicalToPhysicalContext*>(user_data);
734  FlKeyEmbedderCheckedKey* checked_key =
735  reinterpret_cast<FlKeyEmbedderCheckedKey*>(value);
736 
737  if (checked_key->primary_logical_key == context->logical_key ||
738  checked_key->secondary_logical_key == context->logical_key) {
739  context->corrected_physical_key = checked_key->primary_physical_key;
740  }
741 }
742 
744  GHashTable* modifier_bit_to_checked_keys,
745  uint64_t physical_key_from_event,
746  uint64_t logical_key) {
747  ModifierLogicalToPhysicalContext logical_to_physical_context;
748  logical_to_physical_context.known_modifier_physical_key = false;
749  logical_to_physical_context.physical_key_from_event = physical_key_from_event;
750  logical_to_physical_context.logical_key = logical_key;
751  // If no match is found, defaults to the physical key retrieved from the
752  // event.
753  logical_to_physical_context.corrected_physical_key = physical_key_from_event;
754 
755  // Check if the physical key is one of the known modifier physical key.
756  g_hash_table_foreach(modifier_bit_to_checked_keys,
758  &logical_to_physical_context);
759 
760  // If the physical key matches a known modifier key, find the modifier
761  // physical key from the logical key.
762  if (logical_to_physical_context.known_modifier_physical_key) {
763  g_hash_table_foreach(modifier_bit_to_checked_keys,
765  &logical_to_physical_context);
766  }
767 
768  return logical_to_physical_context.corrected_physical_key;
769 }
770 
772  FlKeyResponder* responder,
773  FlKeyEvent* event,
774  uint64_t specified_logical_key,
776  gpointer user_data) {
777  FlKeyEmbedderResponder* self = FL_KEY_EMBEDDER_RESPONDER(responder);
778 
779  g_return_if_fail(event != nullptr);
780  g_return_if_fail(callback != nullptr);
781 
782  const uint64_t logical_key = specified_logical_key != 0
785  const uint64_t physical_key_from_event = event_to_physical_key(event);
786  const uint64_t physical_key = corrected_modifier_physical_key(
787  self->modifier_bit_to_checked_keys, physical_key_from_event, logical_key);
788  const double timestamp = event_to_timestamp(event);
789  const bool is_down_event = event->is_press;
790 
791  SyncStateLoopContext sync_state_context;
792  sync_state_context.self = self;
793  sync_state_context.state = event->state;
794  sync_state_context.timestamp = timestamp;
795  sync_state_context.is_down = is_down_event;
796  sync_state_context.event_logical_key = logical_key;
797 
798  // Update lock mode states
799  g_hash_table_foreach(self->lock_bit_to_checked_keys,
800  synchronize_lock_states_loop_body, &sync_state_context);
801 
802  // Update pressing states
803  g_hash_table_foreach(self->modifier_bit_to_checked_keys,
805  &sync_state_context);
806 
807  // Construct the real event
808  const uint64_t last_logical_record =
809  lookup_hash_table(self->pressing_records, physical_key);
810 
811  FlutterKeyEvent out_event;
812  out_event.struct_size = sizeof(out_event);
813  out_event.timestamp = timestamp;
814  out_event.physical = physical_key;
815  out_event.logical =
816  last_logical_record != 0 ? last_logical_record : logical_key;
817  out_event.character = nullptr;
818  out_event.synthesized = false;
819 
820  g_autofree char* character_to_free = nullptr;
821  if (is_down_event) {
822  if (last_logical_record) {
823  // A key has been pressed that has the exact physical key as a currently
824  // pressed one. This can happen during repeated events.
825  out_event.type = kFlutterKeyEventTypeRepeat;
826  } else {
827  out_event.type = kFlutterKeyEventTypeDown;
828  }
829  character_to_free = event_to_character(event); // Might be null
830  out_event.character = character_to_free;
831  } else { // is_down_event false
832  if (!last_logical_record) {
833  // The physical key has been released before. It might indicate a missed
834  // event due to loss of focus, or multiple keyboards pressed keys with the
835  // same physical key. Ignore the up event.
836  callback(true, user_data);
837  return;
838  } else {
839  out_event.type = kFlutterKeyEventTypeUp;
840  }
841  }
842 
843  if (out_event.type != kFlutterKeyEventTypeRepeat) {
844  update_pressing_state(self, physical_key, is_down_event ? logical_key : 0);
845  }
846  possibly_update_lock_bit(self, logical_key, is_down_event);
847  if (is_down_event) {
848  update_mapping_record(self, physical_key, logical_key);
849  }
850  FlKeyEmbedderUserData* response_data =
852  self->sent_any_events = true;
853  self->send_key_event(&out_event, handle_response, response_data);
854 }
855 
856 // Sends a key event to the framework.
858  FlKeyResponder* responder,
859  FlKeyEvent* event,
860  uint64_t specified_logical_key,
862  gpointer user_data) {
863  FlKeyEmbedderResponder* self = FL_KEY_EMBEDDER_RESPONDER(responder);
864  self->sent_any_events = false;
867  if (!self->sent_any_events) {
868  self->send_key_event(&kEmptyEvent, nullptr, nullptr);
869  }
870 }
871 
873  FlKeyEmbedderResponder* responder,
874  guint state,
875  double event_time) {
876  const double timestamp = event_time * kMicrosecondsPerMillisecond;
877 
878  SyncStateLoopContext sync_state_context;
879  sync_state_context.self = responder;
880  sync_state_context.state = state;
881  sync_state_context.timestamp = timestamp;
882 
883  // Update pressing states.
884  g_hash_table_foreach(responder->modifier_bit_to_checked_keys,
886  &sync_state_context);
887 }
888 
890  FlKeyEmbedderResponder* self) {
891  return self->pressing_records;
892 }
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Definition: fl_key_embedder_responder.cc:106
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