[BUG] Fixes issue with haptice device destructor

Previously the instance of the haptic device might have been in the middle of processing
a callback as the destructor gets exectued, calling hdUnschedule should prevent this

Also defers posting of the button events to the update call to prevent another process
from holding up the callback

Source/Devices/imstkHapticDeviceClient.cpp

@@ -71,6 +71,7 @@ HapticDeviceClient::initialize()
     hdEnable(HD_FORCE_OUTPUT);
     hdEnable(HD_FORCE_RAMPING);
 
+    m_schedulerHandle = hdScheduleAsynchronous(hapticCallback, this, HD_MAX_SCHEDULER_PRIORITY); // Call sometime later
     // Success
     LOG(INFO) << "\"" << this->getDeviceName() << "\" successfully initialized.";
 }
@@ -78,13 +79,25 @@ HapticDeviceClient::initialize()
 void
 HapticDeviceClient::update()
 {
-    //hdScheduleSynchronous(hapticCallback, this, HD_MAX_SCHEDULER_PRIORITY);
-    hdScheduleAsynchronous(hapticCallback, this, HD_MAX_SCHEDULER_PRIORITY); // Call sometime later
+    std::vector<std::pair<int, int>> localEvents;
+    m_dataLock.lock();
+    std::swap(m_events, localEvents);
+    m_dataLock.unlock();
+
+    for (const auto& item : localEvents)
+    {
+        postEvent(ButtonEvent(HapticDeviceClient::buttonStateChanged(), item.first, item.second));
+    }
 }
 
 void
 HapticDeviceClient::disable()
 {
+    // HS 2021-oct-07 There is no documentation on whether hdUnschedule is synchronous
+    // or asynchronous, but as all the examples set the sequence to shutdown an HD device
+    // with hdStopScheduler, hdUnschedule, hdDisableDevice i'm assuming an hdWaitForCompletion
+    // is unnecessary here
+    hdUnschedule(m_schedulerHandle);
     hdDisableDevice(m_handle);
 }
 
@@ -125,23 +138,26 @@ HapticDeviceClient::hapticCallback(void* pData)
     client->m_orientation = orientation;
     client->m_transformLock.unlock();
 
+    client->m_dataLock.lock();
     for (int i = 0; i < 4; i++)
     {
         // If button down and not previously down
         if ((state.buttons & (1 << i)) && !client->m_buttons[i])
         {
             client->m_buttons[i] = true;
-            client->postEvent(ButtonEvent(HapticDeviceClient::buttonStateChanged(), i, BUTTON_PRESSED));
+            client->m_events.push_back({ i, BUTTON_PRESSED });
         }
         // If button not down, and previously down
         else if (!(state.buttons & (1 << i)) && client->m_buttons[i])
         {
             client->m_buttons[i] = false;
-            client->postEvent(ButtonEvent(HapticDeviceClient::buttonStateChanged(), i, BUTTON_RELEASED));
+            client->m_events.push_back({ i, BUTTON_RELEASED });
         }
     }
+    client->m_dataLock.unlock();
+
     client->m_trackingEnabled = true;
 
-    return HD_CALLBACK_DONE;
+    return HD_CALLBACK_CONTINUE;
 }
 } // imstk

Source/Devices/imstkHapticDeviceClient.h

@@ -26,6 +26,8 @@
 
 #include <HD/hd.h>
 
+#include <array>
+
 namespace imstk
 {
 struct HDstate
@@ -51,7 +53,6 @@ friend class HapticDeviceManager;
 public:
     virtual ~HapticDeviceClient() = default;
 
-public:
     ///
     /// \brief Use callback to get tracking data from phantom omni
     ///
@@ -86,5 +87,7 @@ private:
 
     HHD     m_handle; ///< device handle
     HDstate m_state;  ///< device reading state
+    HDSchedulerHandle m_schedulerHandle = 0;
+    std::vector<std::pair<int, int>> m_events;
 };
 }