Move clipboard processing to a separate thread to avoid blocking the main thread during pastes

app/streaming/input/clipboard.cpp

@@ -2,6 +2,34 @@
 
 #include <QString>
 
+int SdlInputHandler::clipboardThreadProc(void *ptr)
+{
+    auto me = (SdlInputHandler*)ptr;
+
+    while (!SDL_AtomicGet(&me->m_ShutdownClipboardThread)) {
+        QString clipboardData;
+
+        SDL_LockMutex(me->m_ClipboardLock);
+        for (;;) {
+            clipboardData = me->m_ClipboardData;
+            me->m_ClipboardData.clear();
+            if (!clipboardData.isEmpty() || SDL_AtomicGet(&me->m_ShutdownClipboardThread)) {
+                break;
+            }
+            SDL_CondWait(me->m_ClipboardHasData, me->m_ClipboardLock);
+        }
+        SDL_UnlockMutex(me->m_ClipboardLock);
+
+        // We might get here on shutdown, so don't send text if there's
+        // nothing to send.
+        if (!clipboardData.isEmpty()) {
+            me->sendText(clipboardData);
+        }
+    }
+
+    return 0;
+}
+
 #define MAP_KEY(c, sc) \
     case c: \
         event.key.keysym.scancode = sc; \
@@ -13,14 +41,18 @@
         event.key.keysym.mod = KMOD_SHIFT; \
         break
 
-void SdlInputHandler::sendText(const char* text)
+void SdlInputHandler::sendText(QString& string)
 {
-    QString string = QString::fromUtf8(text);
-
     for (int i = 0; i < string.size(); i++) {
         char16_t c = string[i].unicode();
         SDL_Event event = {};
 
+        // If we're sending a very long string, we might get a termination request
+        // while we're in the middle of sending a string. In that case, just bail.
+        if (SDL_AtomicGet(&m_ShutdownClipboardThread)) {
+            return;
+        }
+
         if (c >= 'A' && c <= 'Z') {
             event.key.keysym.scancode = (SDL_Scancode)((c - 'A') + SDL_SCANCODE_A);
             event.key.keysym.mod = KMOD_SHIFT;
@@ -125,6 +157,16 @@ void SdlInputHandler::sendText(const char* text)
             }
         }
 
+        if (event.key.keysym.mod & KMOD_SHIFT) {
+            SDL_Event modifierEvent = {};
+            modifierEvent.type = SDL_KEYDOWN;
+            modifierEvent.key.state = SDL_PRESSED;
+            modifierEvent.key.keysym.scancode = SDL_SCANCODE_LSHIFT;
+            handleKeyEvent(&modifierEvent.key);
+
+            SDL_Delay(10);
+        }
+
         event.type = SDL_KEYDOWN;
         event.key.state = SDL_PRESSED;
         handleKeyEvent(&event.key);
@@ -134,5 +176,15 @@ void SdlInputHandler::sendText(const char* text)
         event.type = SDL_KEYUP;
         event.key.state = SDL_RELEASED;
         handleKeyEvent(&event.key);
+
+        if (event.key.keysym.mod & KMOD_SHIFT) {
+            SDL_Event modifierEvent = {};
+            modifierEvent.type = SDL_KEYUP;
+            modifierEvent.key.state = SDL_RELEASED;
+            modifierEvent.key.keysym.scancode = SDL_SCANCODE_LSHIFT;
+            handleKeyEvent(&modifierEvent.key);
+
+            SDL_Delay(10);
+        }
     }
 }

app/streaming/input/input.cpp

@@ -34,7 +34,8 @@ SdlInputHandler::SdlInputHandler(StreamingPreferences& prefs, NvComputer*, int s
       m_RightButtonReleaseTimer(0),
       m_DragTimer(0),
       m_DragButton(0),
-      m_NumFingersDown(0)
+      m_NumFingersDown(0),
+      m_ClipboardData()
 {
     // Allow gamepad input when the app doesn't have focus if requested
     SDL_SetHint(SDL_HINT_JOYSTICK_ALLOW_BACKGROUND_EVENTS, prefs.backgroundGamepad ? "1" : "0");
@@ -196,6 +197,13 @@ SdlInputHandler::SdlInputHandler(StreamingPreferences& prefs, NvComputer*, int s
     }
 
     m_MouseMoveTimer = SDL_AddTimer(pollingInterval, SdlInputHandler::mouseMoveTimerCallback, this);
+
+    // Initialize state used by the clipboard thread before we start it
+    SDL_AtomicSet(&m_ShutdownClipboardThread, 0);
+    m_ClipboardHasData = SDL_CreateCond();
+    m_ClipboardLock = SDL_CreateMutex();
+
+    m_ClipboardThread = SDL_CreateThread(SdlInputHandler::clipboardThreadProc, "Clipboard Sender", this);
 }
 
 SdlInputHandler::~SdlInputHandler()
@@ -221,6 +229,17 @@ SdlInputHandler::~SdlInputHandler()
     SDL_RemoveTimer(m_RightButtonReleaseTimer);
     SDL_RemoveTimer(m_DragTimer);
 
+    // Wake up the clipboard thread to terminate it
+    SDL_AtomicSet(&m_ShutdownClipboardThread, 1);
+    SDL_CondBroadcast(m_ClipboardHasData);
+
+    // Wait for it to terminate
+    SDL_WaitThread(m_ClipboardThread, nullptr);
+
+    // Now we can safely clean up its resources
+    SDL_DestroyCond(m_ClipboardHasData);
+    SDL_DestroyMutex(m_ClipboardLock);
+
 #if !SDL_VERSION_ATLEAST(2, 0, 9)
     SDL_QuitSubSystem(SDL_INIT_HAPTIC);
     SDL_assert(!SDL_WasInit(SDL_INIT_HAPTIC));

app/streaming/input/input.h

@@ -65,7 +65,7 @@ public:
 
     void handleJoystickArrivalEvent(SDL_JoyDeviceEvent* event);
 
-    void sendText(const char* text);
+    void sendText(QString& string);
 
     void rumble(unsigned short controllerNumber, unsigned short lowFreqMotor, unsigned short highFreqMotor);
 
@@ -136,6 +136,9 @@ private:
     static
     Uint32 dragTimerCallback(Uint32 interval, void* param);
 
+    static
+    int clipboardThreadProc(void *ptr);
+
     SDL_Window* m_Window;
     bool m_MultiController;
     bool m_GamepadMouse;
@@ -187,5 +190,11 @@ private:
     char m_DragButton;
     int m_NumFingersDown;
 
+    SDL_Thread* m_ClipboardThread;
+    SDL_atomic_t m_ShutdownClipboardThread;
+    QString m_ClipboardData;
+    SDL_cond* m_ClipboardHasData;
+    SDL_mutex* m_ClipboardLock;
+
     static const int k_ButtonMap[];
 };

app/streaming/input/keyboard.cpp

@@ -94,12 +94,13 @@ void SdlInputHandler::performPendingSpecialKeyCombo()
                     "Detected paste text combo");
         const char* text;
         if (SDL_HasClipboardText() && (text = SDL_GetClipboardText()) != nullptr) {
-            // Reset pending key combo before pasting,
-            // otherwise it will ignore our keypresses.
-            m_PendingKeyCombo = KeyComboMax;
+            // Append this data to the clipboard data string for the thread to process
+            SDL_LockMutex(m_ClipboardLock);
+            m_ClipboardData.append(text);
+            SDL_CondSignal(m_ClipboardHasData);
+            SDL_UnlockMutex(m_ClipboardLock);
 
-            // Send the text and free it as required by SDL
-            sendText(text);
+            // SDL_GetClipboardText() allocates, so we must free
             SDL_free((void*)text);
         }
         else {
@@ -117,13 +118,17 @@ void SdlInputHandler::performPendingSpecialKeyCombo()
     m_PendingKeyCombo = KeyComboMax;
 }
 
+#define IS_SYNTHETIC_KEY_EVENT(x) ((x)->timestamp == 0)
+
 void SdlInputHandler::handleKeyEvent(SDL_KeyboardEvent* event)
 {
     short keyCode;
     char modifiers;
 
     // Check for our special key combos
-    if ((event->state == SDL_PRESSED) &&
+    // Ignore timestamp == 0 which are sent from our keyboard code.
+    if (!IS_SYNTHETIC_KEY_EVENT(event) &&
+            (event->state == SDL_PRESSED) &&
             (event->keysym.mod & KMOD_CTRL) &&
             (event->keysym.mod & KMOD_ALT) &&
             (event->keysym.mod & KMOD_SHIFT)) {
@@ -157,7 +162,7 @@ void SdlInputHandler::handleKeyEvent(SDL_KeyboardEvent* event)
         }
     }
 
-    if (event->state == SDL_PRESSED && m_PendingKeyCombo != KeyComboMax) {
+    if (!IS_SYNTHETIC_KEY_EVENT(event) && event->state == SDL_PRESSED && m_PendingKeyCombo != KeyComboMax) {
         // Ignore further key presses until the special combo is raised
         return;
     }
@@ -401,12 +406,16 @@ void SdlInputHandler::handleKeyEvent(SDL_KeyboardEvent* event)
         }
     }
 
-    // Track the key state so we always know which keys are down
-    if (event->state == SDL_PRESSED) {
-        m_KeysDown.insert(keyCode);
-    }
-    else {
-        m_KeysDown.remove(keyCode);
+    // If this is a synthetic keypress from the clipboard code,
+    // this will be on a non-main thread, so don't touch m_KeysDown.
+    if (!IS_SYNTHETIC_KEY_EVENT(event)) {
+        // Track the key state so we always know which keys are down
+        if (event->state == SDL_PRESSED) {
+            m_KeysDown.insert(keyCode);
+        }
+        else {
+            m_KeysDown.remove(keyCode);
+        }
     }
 
     LiSendKeyboardEvent(0x8000 | keyCode,
@@ -414,7 +423,7 @@ void SdlInputHandler::handleKeyEvent(SDL_KeyboardEvent* event)
                             KEY_ACTION_DOWN : KEY_ACTION_UP,
                         modifiers);
 
-    if (m_PendingKeyCombo != KeyComboMax && m_KeysDown.isEmpty()) {
+    if (!IS_SYNTHETIC_KEY_EVENT(event) && m_PendingKeyCombo != KeyComboMax && m_KeysDown.isEmpty()) {
         int keys;
         const Uint8 *keyState = SDL_GetKeyboardState(&keys);