X11: fix XIM input method support

src/SFML/Window/Unix/Display.cpp

@@ -40,6 +40,8 @@ namespace
     // The shared display and its reference counter
     Display* sharedDisplay = NULL;
     unsigned int referenceCount = 0;
+    XIM sharedXIM = NULL;
+    unsigned int referenceCountXIM = 0;
     sf::Mutex mutex;
 
     typedef std::map<std::string, Atom> AtomMap;
@@ -85,6 +87,56 @@ void CloseDisplay(Display* display)
         XCloseDisplay(display);
 }
 
+////////////////////////////////////////////////////////////
+XIM OpenXIM()
+{
+    Lock lock(mutex);
+
+    assert(sharedDisplay != NULL);
+
+    if (referenceCountXIM == 0)
+    {
+        // Create a new XIM instance
+
+        // We need the default (environment) locale and X locale for opening
+        // the IM and properly receiving text
+        // First save the previous ones (this might be able to be written more elegantly?)
+        const char* p;
+        std::string prevLoc((p = setlocale(LC_ALL, NULL)) ? p : "");
+        std::string prevXLoc((p = XSetLocaleModifiers(NULL)) ? p : "");
+
+        // Set the locales from environment
+        setlocale(LC_ALL, "");
+        XSetLocaleModifiers("");
+
+        // Create the input context
+        sharedXIM = XOpenIM(sharedDisplay, NULL, NULL, NULL);
+
+        // Restore the previous locale
+        if (prevLoc.length() != 0)
+            setlocale(LC_ALL, prevLoc.c_str());
+
+        if (prevXLoc.length() != 0)
+            XSetLocaleModifiers(prevXLoc.c_str());
+    }
+
+    referenceCountXIM++;
+
+    return sharedXIM;
+}
+
+////////////////////////////////////////////////////////////
+void CloseXIM(XIM xim)
+{
+    Lock lock(mutex);
+
+    assert(xim == sharedXIM);
+
+    referenceCountXIM--;
+
+    if ((referenceCountXIM == 0) && (xim != NULL))
+        XCloseIM(xim);
+}
 
 ////////////////////////////////////////////////////////////
 Atom getAtom(const std::string& name, bool onlyIfExists)

src/SFML/Window/Unix/Display.hpp

@@ -55,6 +55,27 @@ Display* OpenDisplay();
 ////////////////////////////////////////////////////////////
 void CloseDisplay(Display* display);
 
+////////////////////////////////////////////////////////////
+/// \brief Get the shared XIM context for the Display
+///
+/// This function increments the reference count of the XIM context,
+/// it must be matched with a call to CloseXIM.
+///
+/// It must be called with a display already opened.
+///
+/// \return XIM handle (a pointer) of the context
+///
+////////////////////////////////////////////////////////////
+XIM OpenXIM();
+
+////////////////////////////////////////////////////////////
+/// \brief Release a reference to the shared XIM context
+///
+/// \param xim XIM context to release
+///
+////////////////////////////////////////////////////////////
+void CloseXIM(XIM xim);
+
 ////////////////////////////////////////////////////////////
 /// \brief Get the atom with the specified name
 ///

src/SFML/Window/Unix/WindowImplX11.cpp

@@ -101,7 +101,9 @@ namespace
         Bool checkEvent(::Display*, XEvent* event, XPointer userData)
         {
             // Just check if the event matches the window
-            return event->xany.window == reinterpret_cast< ::Window >(userData);
+            // The input method sometimes sends ClientMessages with a different window ID,
+            // our event loop has to process them for the IM to work
+            return (event->xany.window == reinterpret_cast< ::Window >(userData)) || (event->type == ClientMessage);
         }
 
         // Find the name of the current executable
@@ -803,7 +805,7 @@ WindowImplX11::~WindowImplX11()
 
     // Close the input method
     if (m_inputMethod)
-        XCloseIM(m_inputMethod);
+        CloseXIM(m_inputMethod);
 
     // Close the connection with the X server
     CloseDisplay(m_display);
@@ -1607,7 +1609,7 @@ void WindowImplX11::initialize()
     using namespace WindowsImplX11Impl;
 
     // Create the input context
-    m_inputMethod = XOpenIM(m_display, NULL, NULL, NULL);
+    m_inputMethod = OpenXIM();
 
     if (m_inputMethod)
     {
@@ -1844,6 +1846,9 @@ bool WindowImplX11::processEvent(XEvent& windowEvent)
 
         // Close event
         case ClientMessage:
+        {
+            // Input methods might want random ClientMessage events
+            if (!XFilterEvent(&windowEvent, None))
             {
                 static Atom wmProtocols = getAtom("WM_PROTOCOLS");
 
@@ -1868,6 +1873,7 @@ bool WindowImplX11::processEvent(XEvent& windowEvent)
                         XSendEvent(m_display, DefaultRootWindow(m_display), False, SubstructureNotifyMask | SubstructureRedirectMask, &windowEvent);
                     }
                 }
+            }
             break;
         }
 
@@ -1904,7 +1910,7 @@ bool WindowImplX11::processEvent(XEvent& windowEvent)
                 if (m_inputContext)
                 {
                     Status status;
-                    Uint8  keyBuffer[16];
+                    Uint8  keyBuffer[64];
 
                     int length = Xutf8LookupString(
                         m_inputContext,
@@ -1915,10 +1921,19 @@ bool WindowImplX11::processEvent(XEvent& windowEvent)
                         &status
                     );
 
-                    if (length > 0)
+                    if (status == XBufferOverflow)
+                        err() << "A TextEntered event has more than 64 bytes of UTF-8 input, and "
+                                 "has been discarded\nThis means either you have typed a very long string "
+                                 "(more than 20 chars), or your input method is broken in obscure ways." << std::endl;
+                    else if (status == XLookupChars)
                     {
+                        // There might be more than 1 characters in this event,
+                        // so we must iterate it
                         Uint32 unicode = 0;
-                        Utf8::decode(keyBuffer, keyBuffer + length, unicode, 0);
+                        Uint8* iter = keyBuffer;
+                        while (iter < keyBuffer + length)
+                        {
+                            iter = Utf8::decode(iter, keyBuffer + length, unicode, 0);
                             if (unicode != 0)
                             {
                                 Event textEvent;
@@ -1928,6 +1943,7 @@ bool WindowImplX11::processEvent(XEvent& windowEvent)
                             }
                         }
                     }
+                }
                 else
                 #endif
                 {