api/joy: refresh only manually on certain events

Refresh joylist when new listener arrives, and when the joy singleton
just gets created. Enumerating joys all the time causes high CPU usage
for some of the users.

Issue: #279
Backtrace-by: @exulant
Reported-by: @aka2k

3 files changed, 10 insertions, 24 deletions

diff --git a/opentrack/keybinding-worker.cpp b/opentrack/keybinding-worker.cpp
index b0cef22d..39693a7c 100644
--- a/opentrack/keybinding-worker.cpp
+++ b/opentrack/keybinding-worker.cpp
@@ -164,6 +164,7 @@ KeybindingWorker::fun* KeybindingWorker::_add_receiver(fun& receiver)
     receivers.push_back(std::unique_ptr<fun>(new fun(receiver)));
     fun* f = receivers[receivers.size() - 1].get();
     qDebug() << "add receiver" << (long) f;
+    joy_ctx.refresh();
     return f;
 }
 
diff --git a/opentrack/win32-joystick.cpp b/opentrack/win32-joystick.cpp
index 728e2f68..5e6f2011 100644
--- a/opentrack/win32-joystick.cpp
+++ b/opentrack/win32-joystick.cpp
@@ -6,7 +6,7 @@
 
 void win32_joy_ctx::poll(fn f)
 {
-    refresh(false);
+    //refresh(false);
     
     QMutexLocker l(&mtx);
     
@@ -94,7 +94,7 @@ win32_joy_ctx::win32_joy_ctx()
         qDebug() << "setup DirectInput8 Creation failed!" << GetLastError();
         assert(!"direct input handle can't be created");
     }
-    refresh(true);
+    refresh();
 }
 
 void win32_joy_ctx::release()
@@ -104,18 +104,12 @@ void win32_joy_ctx::release()
     di = nullptr;
 }
 
-void win32_joy_ctx::refresh(bool first)
+void win32_joy_ctx::refresh()
 {
-    if (!first)
-    {
-        // accessing struct Timer without a lock. worst can happen is seconds
-        // and nanoseconds getting out of sync. no big deal.
-        if (timer_joylist.elapsed_ms() < joylist_refresh_ms)
-            return;
-        timer_joylist.start();
-    }
+    QMutexLocker l(&mtx);
     
-    enum_state st(joys, mtx, fake_main_window, di);
+    qDebug() << "joy list refresh";
+    enum_state st(joys, fake_main_window, di);
 }
 
 QString win32_joy_ctx::guid_to_string(const GUID guid)
@@ -184,16 +178,12 @@ bool win32_joy_ctx::joy::poll(fn f)
 }
 
 win32_joy_ctx::enum_state::enum_state(std::unordered_map<QString, std::shared_ptr<joy>> &joys,
-                                      QMutex& mtx,
                                       QMainWindow &fake_main_window,
                                       LPDIRECTINPUT8 di) :
     fake_main_window(fake_main_window),
     di(di)
 {
-    {
-        QMutexLocker l(&mtx);
-        this->joys = joys;
-    }
+    this->joys = joys;
     
     HRESULT hr;
 
@@ -216,7 +206,6 @@ win32_joy_ctx::enum_state::enum_state(std::unordered_map<QString, std::shared_pt
             it++;
     }
     
-    QMutexLocker l(&mtx);
     joys = this->joys;
 }
 
diff --git a/opentrack/win32-joystick.hpp b/opentrack/win32-joystick.hpp
index 6d5e1074..9c888326 100644
--- a/opentrack/win32-joystick.hpp
+++ b/opentrack/win32-joystick.hpp
@@ -57,18 +57,14 @@ struct OPENTRACK_EXPORT win32_joy_ctx
     
     win32_joy_ctx();
     ~win32_joy_ctx();
-    
+    void refresh();
 private:
-    enum { joylist_refresh_ms = 100 };
-    
     QMutex mtx;
-    Timer timer_joylist;
     QMainWindow fake_main_window;
     LPDIRECTINPUT8 di;
     
     static QString guid_to_string(const GUID guid);
     void release();
-    void refresh(bool first);
     
     struct joy
     {
@@ -97,7 +93,7 @@ private:
         static BOOL CALLBACK EnumJoysticksCallback(const DIDEVICEINSTANCE* pdidInstance, VOID* pContext);
         static BOOL CALLBACK EnumObjectsCallback(const DIDEVICEOBJECTINSTANCE* pdidoi, VOID* ctx);
     public:
-        enum_state(std::unordered_map<QString, std::shared_ptr<joy>>& joys, QMutex &mtx, QMainWindow& fake_main_window, LPDIRECTINPUT8 di);
+        enum_state(std::unordered_map<QString, std::shared_ptr<joy>>& joys, QMainWindow& fake_main_window, LPDIRECTINPUT8 di);
     };
 };