fix: gate leave() with canLeave(), allowing cleanup

ChangeLog

@@ -5,6 +5,7 @@ Bug fixes:
 - #7522 Fix broken CI caused by renaming project to Deskflow
 - #7524 Restore protocol compatibility with Synergy
 - #7525 Remove Google Drive upload from CI
+- #7520 Fix stuck keys on leave by separating check/leave logic
 
 Enhancements:
 

src/lib/deskflow/IPlatformScreen.h

@@ -67,12 +67,19 @@ public:
 
   //! Leave screen
   /*!
-  Called when the user navigates off the screen.  Returns true on
-  success, false on failure.  A typical reason for failure is being
+  Called when the user navigates off the screen.  Returns true if
+  the leave can proceed.  A typical reason for failure is being
   unable to install the keyboard and mouse snoopers on a primary
   screen.  Secondary screens should not fail.
   */
-  virtual bool leave() = 0;
+  virtual bool canLeave() = 0;
+
+  //! Leave screen
+  /*!
+  Called when the user navigates off the screen.  Should be gated
+  by canLeave().
+  */
+  virtual void leave() = 0;
 
   //! Set clipboard
   /*!

src/lib/deskflow/PlatformScreen.h

@@ -88,7 +88,8 @@ public:
   virtual void enable() = 0;
   virtual void disable() = 0;
   virtual void enter() = 0;
-  virtual bool leave() = 0;
+  virtual bool canLeave() = 0;
+  virtual void leave() = 0;
   virtual bool setClipboard(ClipboardID, const IClipboard *) = 0;
   virtual void checkClipboards() = 0;
   virtual void openScreensaver(bool notify) = 0;

src/lib/deskflow/Screen.cpp

@@ -137,15 +137,18 @@ bool Screen::leave() {
   assert(m_entered == true);
   LOG((CLOG_INFO "leaving screen"));
 
-  if (!m_screen->leave()) {
+  if (!m_screen->canLeave()) {
     return false;
   }
+
   if (m_isPrimary) {
     leavePrimary();
   } else {
     leaveSecondary();
   }
 
+  m_screen->leave();
+
   // make sure our idea of clipboard ownership is correct
   m_screen->checkClipboards();
 

src/lib/platform/EiScreen.cpp

@@ -345,7 +345,9 @@ void EiScreen::enter() {
 #endif
 }
 
-bool EiScreen::leave() {
+bool EiScreen::canLeave() { return true; }
+
+void EiScreen::leave() {
   if (!is_primary_) {
     if (ei_pointer_) {
       ei_device_stop_emulating(ei_pointer_);
@@ -359,7 +361,6 @@ bool EiScreen::leave() {
   }
 
   is_on_screen_ = false;
-  return true;
 }
 
 bool EiScreen::setClipboard(ClipboardID id, const IClipboard *clipboard) {

src/lib/platform/EiScreen.h

@@ -77,7 +77,8 @@ public:
   void enable() override;
   void disable() override;
   void enter() override;
-  bool leave() override;
+  bool canLeave() override;
+  void leave() override;
   bool setClipboard(ClipboardID, const IClipboard *) override;
   void checkClipboards() override;
   void openScreensaver(bool notify) override;

src/lib/platform/MSWindowsScreen.cpp

@@ -308,7 +308,7 @@ void MSWindowsScreen::enter() {
   forceShowCursor();
 }
 
-bool MSWindowsScreen::leave() {
+bool MSWindowsScreen::canLeave() {
   POINT pos;
   if (!getThisCursorPos(&pos)) {
     LOG((CLOG_DEBUG "unable to leave screen as windows security has disabled "
@@ -317,6 +317,11 @@ bool MSWindowsScreen::leave() {
     // leaves the screen
     return false;
   }
+
+  return true;
+}
+
+void MSWindowsScreen::leave() {
   // get keyboard layout of foreground window.  we'll use this
   // keyboard layout for translating keys sent to clients.
   m_keyLayout = AppUtilWindows::instance().getCurrentKeyboardLayout();
@@ -367,8 +372,6 @@ bool MSWindowsScreen::leave() {
     m_sendDragThread = new Thread(new TMethodJob<MSWindowsScreen>(
         this, &MSWindowsScreen::sendDragThread));
   }
-
-  return true;
 }
 
 void MSWindowsScreen::sendDragThread(void *) {

src/lib/platform/MSWindowsScreen.h

@@ -128,7 +128,8 @@ public:
   virtual void enable();
   virtual void disable();
   virtual void enter();
-  virtual bool leave();
+  virtual bool canLeave();
+  virtual void leave();
   virtual bool setClipboard(ClipboardID, const IClipboard *);
   virtual void checkClipboards();
   virtual void openScreensaver(bool notify);

src/lib/platform/OSXScreen.h

@@ -91,7 +91,8 @@ public:
   void enable() override;
   void disable() override;
   void enter() override;
-  bool leave() override;
+  bool canLeave() override;
+  void leave() override;
   bool setClipboard(ClipboardID, const IClipboard *) override;
   void checkClipboards() override;
   void openScreensaver(bool notify) override;

src/lib/platform/OSXScreen.mm

@@ -883,6 +883,12 @@ OSXScreen::enter()
 }
 
 bool
+OSXScreen::canLeave()
+{
+	return true;
+}
+
+void
 OSXScreen::leave()
 {
     hideCursor();
@@ -920,8 +926,6 @@ OSXScreen::leave()
 
 	// now off screen
 	m_isOnScreen = false;
-
-	return true;
 }
 
 bool

src/lib/platform/XWindowsScreen.cpp

@@ -326,7 +326,15 @@ void XWindowsScreen::enter() {
   m_isOnScreen = true;
 }
 
-bool XWindowsScreen::leave() {
+bool XWindowsScreen::canLeave() {
+  // raise and show the window, required to grab mouse and keyboard
+  XMapRaised(m_display, m_window);
+
+  // see if grabbing the mouse and keyboard, if primary, is possible
+  return !(m_isPrimary && !grabMouseAndKeyboard());
+}
+
+void XWindowsScreen::leave() {
   if (!m_isPrimary) {
     // restore the previous keyboard auto-repeat state.  if the user
     // changed the auto-repeat configuration while on the client then
@@ -347,7 +355,6 @@ bool XWindowsScreen::leave() {
   // grab the mouse and keyboard, if primary and possible
   if (m_isPrimary && !grabMouseAndKeyboard()) {
     XUnmapWindow(m_display, m_window);
-    return false;
   }
 
   // save current focus
@@ -376,8 +383,6 @@ bool XWindowsScreen::leave() {
 
   // now off screen
   m_isOnScreen = false;
-
-  return true;
 }
 
 bool XWindowsScreen::setClipboard(ClipboardID id, const IClipboard *clipboard) {

src/lib/platform/XWindowsScreen.h

@@ -79,7 +79,8 @@ public:
   void enable() override;
   void disable() override;
   void enter() override;
-  bool leave() override;
+  bool canLeave() override;
+  void leave() override;
   bool setClipboard(ClipboardID, const IClipboard *) override;
   void checkClipboards() override;
   void openScreensaver(bool notify) override;