Merge pull request #9033 from leoetlino/scan-thread

IOS/USB: Move scan thread logic into a separate class

Source/Core/Core/IOS/USB/Host.cpp

@@ -31,19 +31,16 @@ USBHost::USBHost(Kernel& ios, const std::string& device_name) : Device(ios, devi
 {
 }
 
-USBHost::~USBHost()
+USBHost::~USBHost() = default;
-{
-  StopThreads();
-}
 
 IPCCommandResult USBHost::Open(const OpenRequest& request)
 {
   if (!m_has_initialised && !Core::WantsDeterminism())
   {
-    StartThreads();
+    GetScanThread().Start();
     // Force a device scan to complete, because some games (including Your Shape) only care
     // about the initial device list (in the first GETDEVICECHANGE reply).
-    m_first_scan_complete_event.Wait();
+    GetScanThread().WaitForFirstScan();
     m_has_initialised = true;
   }
   return GetDefaultReply(IPC_SUCCESS);
@@ -52,9 +49,9 @@ IPCCommandResult USBHost::Open(const OpenRequest& request)
 void USBHost::UpdateWantDeterminism(const bool new_want_determinism)
 {
   if (new_want_determinism)
-    StopThreads();
+    GetScanThread().Stop();
   else if (IsOpened())
-    StartThreads();
+    GetScanThread().Start();
 }
 
 void USBHost::DoState(PointerWrap& p)
@@ -112,7 +109,6 @@ bool USBHost::UpdateDevices(const bool always_add_hooks)
     return false;
   DetectRemovedDevices(plugged_devices, hooks);
   DispatchHooks(hooks);
-  m_first_scan_complete_event.Set();
   return true;
 }
 
@@ -177,33 +173,44 @@ void USBHost::DispatchHooks(const DeviceChangeHooks& hooks)
     OnDeviceChangeEnd();
 }
 
-void USBHost::StartThreads()
+USBHost::ScanThread::~ScanThread()
+{
+  Stop();
+}
+
+void USBHost::ScanThread::WaitForFirstScan()
+{
+  m_first_scan_complete_event.Wait();
+}
+
+void USBHost::ScanThread::Start()
 {
   if (Core::WantsDeterminism())
     return;
 
-  if (m_scan_thread_running.TestAndSet())
+  if (m_thread_running.TestAndSet())
   {
-    m_scan_thread = std::thread([this] {
+    m_thread = std::thread([this] {
       Common::SetCurrentThreadName("USB Scan Thread");
-      while (m_scan_thread_running.IsSet())
+      while (m_thread_running.IsSet())
       {
-        UpdateDevices();
+        if (m_host->UpdateDevices())
+          m_first_scan_complete_event.Set();
         Common::SleepCurrentThread(50);
       }
     });
   }
 }
 
-void USBHost::StopThreads()
+void USBHost::ScanThread::Stop()
 {
-  if (m_scan_thread_running.TestAndClear())
+  if (m_thread_running.TestAndClear())
-    m_scan_thread.join();
+    m_thread.join();
 
   // Clear all devices and dispatch removal hooks.
   DeviceChangeHooks hooks;
-  DetectRemovedDevices(std::set<u64>(), hooks);
+  m_host->DetectRemovedDevices(std::set<u64>(), hooks);
-  DispatchHooks(hooks);
+  m_host->DispatchHooks(hooks);
 }
 
 IPCCommandResult USBHost::HandleTransfer(std::shared_ptr<USB::Device> device, u32 request,

Source/Core/Core/IOS/USB/Host.h

@@ -46,6 +46,23 @@ protected:
   };
   using DeviceChangeHooks = std::map<std::shared_ptr<USB::Device>, ChangeEvent>;
 
+  class ScanThread final
+  {
+  public:
+    explicit ScanThread(USBHost* host) : m_host(host) {}
+    ~ScanThread();
+    void Start();
+    void Stop();
+    void WaitForFirstScan();
+
+  private:
+    USBHost* m_host = nullptr;
+    Common::Flag m_thread_running;
+    std::thread m_thread;
+    Common::Event m_first_scan_complete_event;
+    Common::Flag m_is_initialized;
+  };
+
   std::map<u64, std::shared_ptr<USB::Device>> m_devices;
   mutable std::mutex m_devices_mutex;
 
@@ -53,25 +70,18 @@ protected:
   virtual void OnDeviceChange(ChangeEvent event, std::shared_ptr<USB::Device> changed_device);
   virtual void OnDeviceChangeEnd();
   virtual bool ShouldAddDevice(const USB::Device& device) const;
+  virtual ScanThread& GetScanThread() = 0;
 
   IPCCommandResult HandleTransfer(std::shared_ptr<USB::Device> device, u32 request,
                                   std::function<s32()> submit) const;
 
 private:
-  void StartThreads();
-  void StopThreads();
-
   bool AddDevice(std::unique_ptr<USB::Device> device);
   bool UpdateDevices(bool always_add_hooks = false);
-
   bool AddNewDevices(std::set<u64>& new_devices, DeviceChangeHooks& hooks, bool always_add_hooks);
   void DetectRemovedDevices(const std::set<u64>& plugged_devices, DeviceChangeHooks& hooks);
   void DispatchHooks(const DeviceChangeHooks& hooks);
 
-  // Device scanning thread
-  Common::Flag m_scan_thread_running;
-  std::thread m_scan_thread;
-  Common::Event m_first_scan_complete_event;
   bool m_has_initialised = false;
   LibusbUtils::Context m_context;
 };

Source/Core/Core/IOS/USB/OH0/OH0.cpp

@@ -24,6 +24,8 @@ namespace IOS::HLE::Device
 {
 OH0::OH0(Kernel& ios, const std::string& device_name) : USBHost(ios, device_name)
 {
+  static_assert(offsetof(OH0, m_scan_thread) == sizeof(OH0) - sizeof(ScanThread),
+                "ScanThread must be the last data member");
 }
 
 IPCCommandResult OH0::Open(const OpenRequest& request)

Source/Core/Core/IOS/USB/OH0/OH0.h

@@ -66,6 +66,8 @@ private:
   template <typename T>
   void TriggerHook(std::map<T, u32>& hooks, T value, ReturnCode return_value);
 
+  ScanThread& GetScanThread() override { return m_scan_thread; }
+
   struct DeviceEntry
   {
     u32 unknown;
@@ -79,6 +81,8 @@ private:
   std::map<u64, u32> m_removal_hooks;
   std::set<u64> m_opened_devices;
   std::mutex m_hooks_mutex;
+
+  ScanThread m_scan_thread{this};
 };
 }  // namespace Device
 }  // namespace IOS::HLE

Source/Core/Core/IOS/USB/USB_HID/HIDv4.cpp

@@ -24,6 +24,8 @@ namespace IOS::HLE::Device
 {
 USB_HIDv4::USB_HIDv4(Kernel& ios, const std::string& device_name) : USBHost(ios, device_name)
 {
+  static_assert(offsetof(USB_HIDv4, m_scan_thread) == sizeof(USB_HIDv4) - sizeof(ScanThread),
+                "ScanThread must be the last data member");
 }
 
 IPCCommandResult USB_HIDv4::IOCtl(const IOCtlRequest& request)

Source/Core/Core/IOS/USB/USB_HID/HIDv4.h

@@ -39,6 +39,7 @@ private:
   std::vector<u8> GetDeviceEntry(const USB::Device& device) const;
   void OnDeviceChange(ChangeEvent, std::shared_ptr<USB::Device>) override;
   bool ShouldAddDevice(const USB::Device& device) const override;
+  ScanThread& GetScanThread() override { return m_scan_thread; }
 
   static constexpr u32 VERSION = 0x40001;
   static constexpr u8 HID_CLASS = 0x03;
@@ -51,5 +52,7 @@ private:
   // IOS device IDs <=> USB device IDs
   std::map<s32, u64> m_ios_ids;
   std::map<u64, s32> m_device_ids;
+
+  ScanThread m_scan_thread{this};
 };
 }  // namespace IOS::HLE::Device

Source/Core/Core/IOS/USB/USB_HID/HIDv5.cpp

@@ -22,6 +22,9 @@ USB_HIDv5::~USB_HIDv5() = default;
 
 IPCCommandResult USB_HIDv5::IOCtl(const IOCtlRequest& request)
 {
+  static_assert(offsetof(USB_HIDv5, m_scan_thread) == sizeof(USB_HIDv5) - sizeof(ScanThread),
+                "ScanThread must be the last data member");
+
   request.Log(GetDeviceName(), Common::Log::IOS_USB);
   switch (request.request)
   {

Source/Core/Core/IOS/USB/USB_HID/HIDv5.h

@@ -27,11 +27,16 @@ private:
 
   bool ShouldAddDevice(const USB::Device& device) const override;
   bool HasInterfaceNumberInIDs() const override { return true; }
+
+  ScanThread& GetScanThread() override { return m_scan_thread; }
+
   struct AdditionalDeviceData
   {
     u8 interrupt_in_endpoint = 0;
     u8 interrupt_out_endpoint = 0;
   };
   std::array<AdditionalDeviceData, 32> m_additional_device_data{};
+
+  ScanThread m_scan_thread{this};
 };
 }  // namespace IOS::HLE::Device

Source/Core/Core/IOS/USB/USB_VEN/VEN.cpp

@@ -22,6 +22,9 @@ USB_VEN::~USB_VEN() = default;
 
 IPCCommandResult USB_VEN::IOCtl(const IOCtlRequest& request)
 {
+  static_assert(offsetof(USB_VEN, m_scan_thread) == sizeof(USB_VEN) - sizeof(ScanThread),
+                "ScanThread must be the last data member");
+
   request.Log(GetDeviceName(), Common::Log::IOS_USB);
   switch (request.request)
   {

Source/Core/Core/IOS/USB/USB_VEN/VEN.h

@@ -26,5 +26,9 @@ private:
 
   s32 SubmitTransfer(USB::Device& device, const IOCtlVRequest& ioctlv);
   bool HasInterfaceNumberInIDs() const override { return false; }
+
+  ScanThread& GetScanThread() override { return m_scan_thread; }
+
+  ScanThread m_scan_thread{this};
 };
 }  // namespace IOS::HLE::Device