Linux/XInput2: Fix keys being stuck pressed on focus loss.

1 files changed, 50 insertions, 29 deletions

diff --git a/Source/Core/InputCommon/ControllerInterface/Xlib/XInput2.cpp b/Source/Core/InputCommon/ControllerInterface/Xlib/XInput2.cpp
index 9ec1c2be35..dac0c085fa 100644
--- a/Source/Core/InputCommon/ControllerInterface/Xlib/XInput2.cpp
+++ b/Source/Core/InputCommon/ControllerInterface/Xlib/XInput2.cpp
@@ -97,11 +97,11 @@ void PopulateDevices(void* const hwnd)
 // Apply the event mask to the device and all its slaves. Only used in the
 // constructor. Remember, each KeyboardMouse has its own copy of the event
 // stream, which is how multiple event masks can "coexist."
-void KeyboardMouse::SelectEventsForDevice(Window window, XIEventMask* mask, int deviceid)
+void KeyboardMouse::SelectEventsForDevice(XIEventMask* mask, int deviceid)
 {
   // Set the event mask for the master device.
   mask->deviceid = deviceid;
-  XISelectEvents(m_display, window, mask, 1);
+  XISelectEvents(m_display, DefaultRootWindow(m_display), mask, 1);
 
   // Query all the master device's slaves and set the same event mask for
   // those too. There are two reasons we want to do this. For mouse devices,
@@ -109,20 +109,19 @@ void KeyboardMouse::SelectEventsForDevice(Window window, XIEventMask* mask, int
   // devices) emit those. For keyboard devices, selecting slaves avoids
   // dealing with key focus.
 
-  XIDeviceInfo* all_slaves;
-  XIDeviceInfo* current_slave;
   int num_slaves;
-
-  all_slaves = XIQueryDevice(m_display, XIAllDevices, &num_slaves);
+  XIDeviceInfo* const all_slaves = XIQueryDevice(m_display, XIAllDevices, &num_slaves);
 
   for (int i = 0; i < num_slaves; i++)
   {
-    current_slave = &all_slaves[i];
-    if ((current_slave->use != XISlavePointer && current_slave->use != XISlaveKeyboard) ||
-        current_slave->attachment != deviceid)
+    XIDeviceInfo* const slave = &all_slaves[i];
+    if ((slave->use != XISlavePointer && slave->use != XISlaveKeyboard) ||
+        slave->attachment != deviceid)
+    {
       continue;
-    mask->deviceid = current_slave->deviceid;
-    XISelectEvents(m_display, window, mask, 1);
+    }
+    mask->deviceid = slave->deviceid;
+    XISelectEvents(m_display, DefaultRootWindow(m_display), mask, 1);
   }
 
   XIFreeDeviceInfo(all_slaves);
@@ -138,34 +137,44 @@ KeyboardMouse::KeyboardMouse(Window window, int opcode, int pointer, int keyboar
   // "context."
   m_display = XOpenDisplay(nullptr);
 
-  int min_keycode, max_keycode;
-  XDisplayKeycodes(m_display, &min_keycode, &max_keycode);
-
-  int unused;  // should always be 1
-  XIDeviceInfo* pointer_device = XIQueryDevice(m_display, pointer_deviceid, &unused);
+  // should always be 1
+  int unused;
+  XIDeviceInfo* const pointer_device = XIQueryDevice(m_display, pointer_deviceid, &unused);
   name = std::string(pointer_device->name);
   XIFreeDeviceInfo(pointer_device);
 
-  XIEventMask mask;
-  unsigned char mask_buf[(XI_LASTEVENT + 7) / 8];
+  {
+    unsigned char mask_buf[(XI_LASTEVENT + 7) / 8] = {};
+    XISetMask(mask_buf, XI_ButtonPress);
+    XISetMask(mask_buf, XI_ButtonRelease);
+    XISetMask(mask_buf, XI_RawMotion);
+
+    XIEventMask mask;
+    mask.mask = mask_buf;
+    mask.mask_len = sizeof(mask_buf);
 
-  mask.mask_len = sizeof(mask_buf);
-  mask.mask = mask_buf;
-  memset(mask_buf, 0, sizeof(mask_buf));
+    SelectEventsForDevice(&mask, pointer_deviceid);
+  }
+
+  {
+    unsigned char mask_buf[(XI_LASTEVENT + 7) / 8] = {};
+    XISetMask(mask_buf, XI_KeyPress);
+    XISetMask(mask_buf, XI_KeyRelease);
+    XISetMask(mask_buf, XI_FocusOut);
 
-  XISetMask(mask_buf, XI_ButtonPress);
-  XISetMask(mask_buf, XI_ButtonRelease);
-  XISetMask(mask_buf, XI_RawMotion);
-  XISetMask(mask_buf, XI_KeyPress);
-  XISetMask(mask_buf, XI_KeyRelease);
+    XIEventMask mask;
+    mask.mask = mask_buf;
+    mask.mask_len = sizeof(mask_buf);
 
-  SelectEventsForDevice(DefaultRootWindow(m_display), &mask, pointer_deviceid);
-  SelectEventsForDevice(DefaultRootWindow(m_display), &mask, keyboard_deviceid);
+    SelectEventsForDevice(&mask, keyboard_deviceid);
+  }
 
   // Keyboard Keys
+  int min_keycode, max_keycode;
+  XDisplayKeycodes(m_display, &min_keycode, &max_keycode);
   for (int i = min_keycode; i <= max_keycode; ++i)
   {
-    Key* temp_key = new Key(m_display, i, m_state.keyboard);
+    Key* const temp_key = new Key(m_display, i, m_state.keyboard.data());
     if (temp_key->m_keyname.length())
       AddInput(temp_key);
     else
@@ -284,6 +293,10 @@ void KeyboardMouse::UpdateInput()
           delta_y += delta_delta;
       }
       break;
+    case XI_FocusOut:
+      // Clear keyboard state on FocusOut as we will not be receiving KeyRelease events.
+      m_state.keyboard.fill(0);
+      break;
     }
 
     XFreeEventData(m_display, &event.xcookie);
@@ -300,6 +313,14 @@ void KeyboardMouse::UpdateInput()
   // Get the absolute position of the mouse pointer
   if (mouse_moved)
     UpdateCursor();
+
+  // KeyRelease and FocusOut events are sometimes not received.
+  // Cycling Alt-Tab and landing on the same window results in a stuck "Alt" key.
+  // Unpressed keys are released here.
+  std::array<char, 32> keyboard;
+  XQueryKeymap(m_display, keyboard.data());
+  for (size_t i = 0; i != keyboard.size(); ++i)
+    m_state.keyboard[i] &= keyboard[i];
 }
 
 std::string KeyboardMouse::GetName() const