ozone: evdev: Fix possibility of stuck keys with libevdev

Same as previous unplug fix, but for the libevdev/gestures path. This
applies to hybrid keyboards with attached mouse/touchpad.

The SYN_DROPPED part is N/A because that is handled by libevdev.

BUG=463002
TEST=Tested unplug by unplugging devices with shift held.
  Shift gets properly released rather than being stuck.
  (NB: Could not reproduce without adding a delay to expose the race).

Review URL: https://codereview.chromium.org/990483002

Cr-Commit-Position: refs/heads/master@{#319673}

ui/events/ozone/evdev/libgestures_glue/event_reader_libevdev_cros.cc

@@ -98,6 +98,10 @@ void EventReaderLibevdevCros::AllowAllKeys() {
   delegate_->AllowAllKeys();
 }
 
+void EventReaderLibevdevCros::OnStopped() {
+  delegate_->OnLibEvdevCrosStopped(&evdev_, &evstate_);
+}
+
 // static
 void EventReaderLibevdevCros::OnSynReport(void* data,
                                           EventStateRec* evstate,

ui/events/ozone/evdev/libgestures_glue/event_reader_libevdev_cros.h

@@ -35,6 +35,9 @@ class EventReaderLibevdevCros : public EventConverterEvdev {
                                      EventStateRec* state,
                                      const timeval& time) = 0;
 
+    // Notifier for stop. This is called with the final event state.
+    virtual void OnLibEvdevCrosStopped(Evdev* evdev, EventStateRec* state) = 0;
+
     // Sets which keyboard keys should be processed.
     virtual void SetAllowedKeys(scoped_ptr<std::set<DomCode>> allowed_keys) = 0;
 
@@ -58,6 +61,7 @@ class EventReaderLibevdevCros : public EventConverterEvdev {
   bool HasCapsLockLed() const override;
   void SetAllowedKeys(scoped_ptr<std::set<DomCode>> allowed_keys) override;
   void AllowAllKeys() override;
+  void OnStopped() override;
 
  private:
   static void OnSynReport(void* data,

ui/events/ozone/evdev/libgestures_glue/gesture_interpreter_libevdev_cros.cc

@@ -79,10 +79,6 @@ base::TimeDelta StimeToTimedelta(stime_t timestamp) {
                                            base::Time::kMicrosecondsPerSecond);
 }
 
-base::TimeDelta TimeValToTimeDelta(const timeval& tv) {
-  return base::TimeDelta::FromMicroseconds(tv.tv_sec * 1000000 + tv.tv_usec);
-}
-
 // Number of fingers for scroll gestures.
 const int kGestureScrollFingerCount = 2;
 
@@ -160,12 +156,14 @@ void GestureInterpreterLibevdevCros::OnLibEvdevCrosOpen(
 void GestureInterpreterLibevdevCros::OnLibEvdevCrosEvent(Evdev* evdev,
                                                          EventStateRec* evstate,
                                                          const timeval& time) {
-  // If the device has keys no it, dispatch any presses/release.
-  DispatchChangedKeys(evdev, time);
+  stime_t timestamp = StimeFromTimeval(&time);
+
+  // If the device has keys on it, dispatch any presses/release.
+  DispatchChangedKeys(evdev->key_state_bitmask, timestamp);
 
   HardwareState hwstate;
   memset(&hwstate, 0, sizeof(hwstate));
-  hwstate.timestamp = StimeFromTimeval(&time);
+  hwstate.timestamp = timestamp;
 
   // Mouse.
   hwstate.rel_x = evstate->rel_x;
@@ -207,6 +205,12 @@ void GestureInterpreterLibevdevCros::OnLibEvdevCrosEvent(Evdev* evdev,
   GestureInterpreterPushHardwareState(interpreter_, &hwstate);
 }
 
+void GestureInterpreterLibevdevCros::OnLibEvdevCrosStopped(
+    Evdev* evdev,
+    EventStateRec* state) {
+  ReleaseKeys();
+}
+
 void GestureInterpreterLibevdevCros::SetAllowedKeys(
     scoped_ptr<std::set<DomCode>> allowed_keys) {
   if (!allowed_keys) {
@@ -421,18 +425,19 @@ void GestureInterpreterLibevdevCros::DispatchMouseButton(unsigned int button,
                              allow_remap, StimeToTimedelta(time)));
 }
 
-void GestureInterpreterLibevdevCros::DispatchChangedKeys(Evdev* evdev,
-                                                         const timeval& time) {
+void GestureInterpreterLibevdevCros::DispatchChangedKeys(
+    unsigned long* new_key_state,
+    stime_t timestamp) {
   unsigned long key_state_diff[EVDEV_BITS_TO_LONGS(KEY_CNT)];
 
   // Find changed keys.
   for (unsigned long i = 0; i < arraysize(key_state_diff); ++i)
-    key_state_diff[i] = evdev->key_state_bitmask[i] ^ prev_key_state_[i];
+    key_state_diff[i] = new_key_state[i] ^ prev_key_state_[i];
 
   // Dispatch events for changed keys.
   for (unsigned long key = 0; key < KEY_CNT; ++key) {
     if (EvdevBitIsSet(key_state_diff, key)) {
-      bool value = EvdevBitIsSet(evdev->key_state_bitmask, key);
+      bool value = EvdevBitIsSet(new_key_state, key);
 
       // Mouse buttons are handled by DispatchMouseButton.
       if (key >= BTN_MOUSE && key < BTN_JOYSTICK)
@@ -447,13 +452,20 @@ void GestureInterpreterLibevdevCros::DispatchChangedKeys(Evdev* evdev,
 
       // Dispatch key press or release to keyboard.
       dispatcher_->DispatchKeyEvent(
-          KeyEventParams(id_, key, value, TimeValToTimeDelta(time)));
+          KeyEventParams(id_, key, value, StimeToTimedelta(timestamp)));
     }
   }
 
   // Update internal key state.
   for (unsigned long i = 0; i < EVDEV_BITS_TO_LONGS(KEY_CNT); ++i)
-    prev_key_state_[i] = evdev->key_state_bitmask[i];
+    prev_key_state_[i] = new_key_state[i];
+}
+
+void GestureInterpreterLibevdevCros::ReleaseKeys() {
+  unsigned long new_key_state[EVDEV_BITS_TO_LONGS(KEY_CNT)];
+  memset(&new_key_state, 0, sizeof(new_key_state));
+
+  DispatchChangedKeys(new_key_state, StimeNow());
 }
 
 }  // namespace ui

ui/events/ozone/evdev/libgestures_glue/gesture_interpreter_libevdev_cros.h

@@ -51,6 +51,7 @@ class EVENTS_OZONE_EVDEV_EXPORT GestureInterpreterLibevdevCros
   void OnLibEvdevCrosEvent(Evdev* evdev,
                            EventStateRec* evstate,
                            const timeval& time) override;
+  void OnLibEvdevCrosStopped(Evdev* evdev, EventStateRec* state) override;
   void SetAllowedKeys(
       scoped_ptr<std::set<DomCode>> allowed_keys) override;
   void AllowAllKeys() override;
@@ -79,7 +80,8 @@ class EVENTS_OZONE_EVDEV_EXPORT GestureInterpreterLibevdevCros
   void DispatchMouseButton(unsigned int modifier,
                            bool down,
                            stime_t time);
-  void DispatchChangedKeys(Evdev* evdev, const timeval& time);
+  void DispatchChangedKeys(unsigned long* changed_keys, stime_t timestamp);
+  void ReleaseKeys();
 
   // The unique device id.
   int id_;

ui/events/ozone/evdev/libgestures_glue/gesture_timer_provider.cc

@@ -28,12 +28,8 @@ struct GesturesTimer {
 
  private:
   void OnTimerExpired() {
-    struct timespec ts;
-    int fail = clock_gettime(CLOCK_MONOTONIC, &ts);
-    DCHECK(!fail);
-
     // Run the callback and reschedule the next run if requested.
-    stime_t next_delay = callback_(StimeFromTimespec(&ts), callback_data_);
+    stime_t next_delay = callback_(ui::StimeNow(), callback_data_);
     if (next_delay >= 0) {
       timer_.Start(FROM_HERE,
                    base::TimeDelta::FromMicroseconds(
@@ -68,6 +64,15 @@ void GesturesTimerFree(void* data, GesturesTimer* timer) { delete timer; }
 
 }  // namespace
 
+stime_t StimeNow() {
+  struct timespec ts;
+
+  if (clock_gettime(CLOCK_MONOTONIC, &ts))
+    PLOG(FATAL) << "clock_gettime";
+
+  return StimeFromTimespec(&ts);
+}
+
 const GesturesTimerProvider kGestureTimerProvider = {
     GesturesTimerCreate, GesturesTimerSet, GesturesTimerCancel,
     GesturesTimerFree};

ui/events/ozone/evdev/libgestures_glue/gesture_timer_provider.h

@@ -9,6 +9,8 @@
 
 namespace ui {
 
+stime_t StimeNow();
+
 extern const GesturesTimerProvider kGestureTimerProvider;
 
 }  // namspace ui