Make Applet accesses to the data queues lock

Avoids potential races when the guest access the same applet from more than one thread.

app/src/main/cpp/skyline/applet/controller_applet.cpp

@@ -21,12 +21,12 @@ namespace skyline::applet {
         // Generic macro due to both versions of arguments sharing the same fields but having different layouts
         auto handle{[&](auto controllerSupportModeArg) {
             Logger::InfoNoPrefix("Controller Support: "
-                         "Player Count: {} - {}, "
+                                 "Player Count: {} - {}, "
-                         "Take Over Connection: {}, Left Justify: {}, Dual Joy-Con Allowed: {}, Single Mode Enabled: {}, "
+                                 "Take Over Connection: {}, Left Justify: {}, Dual Joy-Con Allowed: {}, Single Mode Enabled: {}, "
-                         "Identification Color Enabled: {}, Explain Text Enabled: {}",
+                                 "Identification Color Enabled: {}, Explain Text Enabled: {}",
-                         controllerSupportModeArg.playerCountMin, controllerSupportModeArg.playerCountMax,
+                                 controllerSupportModeArg.playerCountMin, controllerSupportModeArg.playerCountMax,
-                         controllerSupportModeArg.enableTakeOverConnection, controllerSupportModeArg.enableLeftJustify, controllerSupportModeArg.enablePermitJoyDual, controllerSupportModeArg.enableSingleMode,
+                                 controllerSupportModeArg.enableTakeOverConnection, controllerSupportModeArg.enableLeftJustify, controllerSupportModeArg.enablePermitJoyDual, controllerSupportModeArg.enableSingleMode,
-                         controllerSupportModeArg.enableIdentificationColor, controllerSupportModeArg.enableExplainText);
+                                 controllerSupportModeArg.enableIdentificationColor, controllerSupportModeArg.enableExplainText);
 
             // Here is where we would trigger the applet UI
 
@@ -62,6 +62,7 @@ namespace skyline::applet {
                 break;
         }
     }
+
     Result ControllerApplet::Start() {
         auto commonArg{PopNormalInput<service::applet::CommonArguments>()};
         ControllerAppletVersion appletVersion{commonArg.apiVersion};
@@ -81,6 +82,7 @@ namespace skyline::applet {
             }
         }
 
+        std::scoped_lock lock{inputDataMutex};
         switch (argPrivate.mode) {
             case ControllerSupportMode::ShowControllerSupport:
                 HandleShowControllerSupport(argPrivate.styleSet, appletVersion, normalInputData.front()->GetSpan());
@@ -105,6 +107,7 @@ namespace skyline::applet {
     }
 
     void ControllerApplet::PushNormalDataToApplet(std::shared_ptr<service::am::IStorage> data) {
+        std::scoped_lock lock{inputDataMutex};
         normalInputData.emplace(std::move(data));
     }
 

app/src/main/cpp/skyline/applet/controller_applet.h

@@ -98,10 +98,12 @@ namespace skyline::applet {
         };
         static_assert(sizeof(ControllerSupportResultInfo) == 0xC);
 
+        std::mutex inputDataMutex;
         std::queue<std::shared_ptr<service::am::IStorage>> normalInputData;
 
         template<typename T>
         T PopNormalInput() {
+            std::scoped_lock lock{inputDataMutex};
             auto data{normalInputData.front()->GetSpan().as<T>()};
             normalInputData.pop();
             return static_cast<T>(data);

app/src/main/cpp/skyline/services/am/applet/IApplet.cpp

@@ -13,16 +13,19 @@ namespace skyline::service::am {
     IApplet::~IApplet() = default;
 
     void IApplet::PushNormalDataAndSignal(std::shared_ptr<IStorage> data) {
+        std::scoped_lock lock{outputDataMutex};
         normalOutputData.emplace(std::move(data));
         onNormalDataPushFromApplet->Signal();
     }
 
     void IApplet::PushInteractiveDataAndSignal(std::shared_ptr<IStorage> data) {
+        std::scoped_lock lock{interactiveOutputDataMutex};
         interactiveOutputData.emplace(std::move(data));
         onInteractiveDataPushFromApplet->Signal();
     }
 
     std::shared_ptr<IStorage> IApplet::PopNormalAndClear() {
+        std::scoped_lock lock{outputDataMutex};
         if (normalOutputData.empty())
             return {};
         std::shared_ptr<IStorage> data(normalOutputData.front());
@@ -32,6 +35,7 @@ namespace skyline::service::am {
     }
 
     std::shared_ptr<IStorage> IApplet::PopInteractiveAndClear() {
+        std::scoped_lock lock{interactiveOutputDataMutex};
         if (interactiveOutputData.empty())
             return {};
         std::shared_ptr<IStorage> data(interactiveOutputData.front());

app/src/main/cpp/skyline/services/am/applet/IApplet.h

@@ -17,11 +17,13 @@ namespace skyline::service::am {
       private:
         std::shared_ptr<kernel::type::KEvent> onNormalDataPushFromApplet;
         std::shared_ptr<kernel::type::KEvent> onInteractiveDataPushFromApplet;
+        std::mutex outputDataMutex;
+        std::queue<std::shared_ptr<IStorage>> normalOutputData; //!< Stores data sent by the applet so the guest can read it when it needs to
+        std::mutex interactiveOutputDataMutex;
+        std::queue<std::shared_ptr<IStorage>> interactiveOutputData; //!< Stores interactive data sent by the applet so the guest can read it when it needs to
 
       protected:
         std::shared_ptr<kernel::type::KEvent> onAppletStateChanged;
-        std::queue<std::shared_ptr<IStorage>> normalOutputData; //!< Stores data sent by the applet so the guest can read it when it needs to
-        std::queue<std::shared_ptr<IStorage>> interactiveOutputData; //!< Stores interactive data sent by the applet so the guest can read it when it needs to
 
         /**
          * @brief Utility to send data to the guest and trigger the onNormalDataPushFromApplet event