ControllerInterface: Add RemoveDevice()

This adds RemoveDevice() to ControllerInterface, fixes ExpressionParser
and some other code to support device removals without crashing,
and adds an IsValid() method to Device, to prepare for hotplugging.

1 files changed, 11 insertions, 0 deletions

diff --git a/Source/Core/InputCommon/ControllerEmu.cpp b/Source/Core/InputCommon/ControllerEmu.cpp
index 117184c8db..b3b13b796a 100644
--- a/Source/Core/InputCommon/ControllerEmu.cpp
+++ b/Source/Core/InputCommon/ControllerEmu.cpp
@@ -6,8 +6,19 @@
 #include <memory>
 #include "Common/Common.h"
 
+// This should be called before calling GetState() or State() on a control reference
+// to prevent a race condition.
+// This is a recursive mutex because UpdateReferences is recursive.
+static std::recursive_mutex s_get_state_mutex;
+std::unique_lock<std::recursive_mutex> ControllerEmu::GetStateLock()
+{
+  std::unique_lock<std::recursive_mutex> lock(s_get_state_mutex);
+  return lock;
+}
+
 void ControllerEmu::UpdateReferences(ControllerInterface& devi)
 {
+  auto lock = ControllerEmu::GetStateLock();
   for (auto& ctrlGroup : groups)
   {
     for (auto& control : ctrlGroup->controls)