X11: Add support for XIM callbacks

This adds support for the XIM instantiate and destroy callbacks, letting
GLFW detect both when the current input method disappears and when a new
one is started.

Tested with ibus.

README.md

@@ -171,6 +171,8 @@ information on what to include when reporting a bug.
  - [X11] Bugfix: `glfwFocusWindow` could terminate on older WMs or without a WM
  - [X11] Bugfix: Querying a disconnected monitor could segfault (#1602)
  - [X11] Bugfix: IME input of CJK was broken for "C" locale (#1587,#1636)
+ - [X11] Bugfix: Termination would segfault if the IM had been destroyed
+ - [X11] Bugfix: Any IM started after initialization would not be detected
  - [Wayland] Removed support for `wl_shell` (#1443)
  - [Wayland] Bugfix: The `GLFW_HAND_CURSOR` shape used the wrong image (#1432)
  - [Wayland] Bugfix: `CLOCK_MONOTONIC` was not correctly enabled

src/x11_init.c

@@ -349,6 +349,40 @@ static GLFWbool hasUsableInputMethodStyle(void)
     return found;
 }
 
+static void inputMethodDestroyCallback(XIM im, XPointer clientData, XPointer callData)
+{
+    _glfw.x11.im = NULL;
+}
+
+static void inputMethodInstantiateCallback(Display* display,
+                                           XPointer clientData,
+                                           XPointer callData)
+{
+    if (_glfw.x11.im)
+        return;
+
+    _glfw.x11.im = XOpenIM(_glfw.x11.display, 0, NULL, NULL);
+    if (_glfw.x11.im)
+    {
+        if (!hasUsableInputMethodStyle())
+        {
+            XCloseIM(_glfw.x11.im);
+            _glfw.x11.im = NULL;
+        }
+    }
+
+    if (_glfw.x11.im)
+    {
+        XIMCallback callback;
+        callback.callback = (XIMProc) inputMethodDestroyCallback;
+        callback.client_data = NULL;
+        XSetIMValues(_glfw.x11.im, XNDestroyCallback, &callback, NULL);
+
+        for (_GLFWwindow* window = _glfw.windowListHead;  window;  window = window->next)
+            _glfwCreateInputContextX11(window);
+    }
+}
+
 // Check whether the specified atom is supported
 //
 static Atom getSupportedAtom(Atom* supportedAtoms,
@@ -1066,6 +1100,8 @@ int _glfwPlatformInit(void)
         _glfw_dlsym(_glfw.x11.xlib.handle, "XQueryPointer");
     _glfw.x11.xlib.RaiseWindow = (PFN_XRaiseWindow)
         _glfw_dlsym(_glfw.x11.xlib.handle, "XRaiseWindow");
+    _glfw.x11.xlib.RegisterIMInstantiateCallback = (PFN_XRegisterIMInstantiateCallback)
+        _glfw_dlsym(_glfw.x11.xlib.handle, "XRegisterIMInstantiateCallback");
     _glfw.x11.xlib.ResizeWindow = (PFN_XResizeWindow)
         _glfw_dlsym(_glfw.x11.xlib.handle, "XResizeWindow");
     _glfw.x11.xlib.ResourceManagerString = (PFN_XResourceManagerString)
@@ -1082,6 +1118,8 @@ int _glfwPlatformInit(void)
         _glfw_dlsym(_glfw.x11.xlib.handle, "XSetErrorHandler");
     _glfw.x11.xlib.SetICFocus = (PFN_XSetICFocus)
         _glfw_dlsym(_glfw.x11.xlib.handle, "XSetICFocus");
+    _glfw.x11.xlib.SetIMValues = (PFN_XSetIMValues)
+        _glfw_dlsym(_glfw.x11.xlib.handle, "XSetIMValues");
     _glfw.x11.xlib.SetInputFocus = (PFN_XSetInputFocus)
         _glfw_dlsym(_glfw.x11.xlib.handle, "XSetInputFocus");
     _glfw.x11.xlib.SetLocaleModifiers = (PFN_XSetLocaleModifiers)
@@ -1142,6 +1180,8 @@ int _glfwPlatformInit(void)
         _glfw_dlsym(_glfw.x11.xlib.handle, "XrmInitialize");
     _glfw.x11.xrm.UniqueQuark = (PFN_XrmUniqueQuark)
         _glfw_dlsym(_glfw.x11.xlib.handle, "XrmUniqueQuark");
+    _glfw.x11.xlib.UnregisterIMInstantiateCallback = (PFN_XUnregisterIMInstantiateCallback)
+        _glfw_dlsym(_glfw.x11.xlib.handle, "XUnregisterIMInstantiateCallback");
     _glfw.x11.xlib.utf8LookupString = (PFN_Xutf8LookupString)
         _glfw_dlsym(_glfw.x11.xlib.handle, "Xutf8LookupString");
     _glfw.x11.xlib.utf8SetWMProperties = (PFN_Xutf8SetWMProperties)
@@ -1184,15 +1224,11 @@ int _glfwPlatformInit(void)
     {
         XSetLocaleModifiers("");
 
-        _glfw.x11.im = XOpenIM(_glfw.x11.display, 0, NULL, NULL);
+        // If an IM is already present our callback will be called right away
-        if (_glfw.x11.im)
+        XRegisterIMInstantiateCallback(_glfw.x11.display,
-        {
+                                       NULL, NULL, NULL,
-            if (!hasUsableInputMethodStyle())
+                                       inputMethodInstantiateCallback,
-            {
+                                       NULL);
-                XCloseIM(_glfw.x11.im);
-                _glfw.x11.im = NULL;
-            }
-        }
     }
 
 #if defined(__linux__)
@@ -1229,6 +1265,11 @@ void _glfwPlatformTerminate(void)
     free(_glfw.x11.primarySelectionString);
     free(_glfw.x11.clipboardString);
 
+    XUnregisterIMInstantiateCallback(_glfw.x11.display,
+                                     NULL, NULL, NULL,
+                                     inputMethodInstantiateCallback,
+                                     NULL);
+
     if (_glfw.x11.im)
     {
         XCloseIM(_glfw.x11.im);

src/x11_platform.h

@@ -104,6 +104,7 @@ typedef int (* PFN_XPending)(Display*);
 typedef Bool (* PFN_XQueryExtension)(Display*,const char*,int*,int*,int*);
 typedef Bool (* PFN_XQueryPointer)(Display*,Window,Window*,Window*,int*,int*,int*,int*,unsigned int*);
 typedef int (* PFN_XRaiseWindow)(Display*,Window);
+typedef Bool (* PFN_XRegisterIMInstantiateCallback)(Display*,void*,char*,char*,XIDProc,XPointer);
 typedef int (* PFN_XResizeWindow)(Display*,Window,unsigned int,unsigned int);
 typedef char* (* PFN_XResourceManagerString)(Display*);
 typedef int (* PFN_XSaveContext)(Display*,XID,XContext,const char*);
@@ -112,6 +113,7 @@ typedef Status (* PFN_XSendEvent)(Display*,Window,Bool,long,XEvent*);
 typedef int (* PFN_XSetClassHint)(Display*,Window,XClassHint*);
 typedef XErrorHandler (* PFN_XSetErrorHandler)(XErrorHandler);
 typedef void (* PFN_XSetICFocus)(XIC);
+typedef char* (* PFN_XSetIMValues)(XIM,...);
 typedef int (* PFN_XSetInputFocus)(Display*,Window,int,Time);
 typedef char* (* PFN_XSetLocaleModifiers)(const char*);
 typedef int (* PFN_XSetScreenSaver)(Display*,int,int,int,int);
@@ -142,6 +144,7 @@ typedef Bool (* PFN_XrmGetResource)(XrmDatabase,const char*,const char*,char**,X
 typedef XrmDatabase (* PFN_XrmGetStringDatabase)(const char*);
 typedef void (* PFN_XrmInitialize)(void);
 typedef XrmQuark (* PFN_XrmUniqueQuark)(void);
+typedef Bool (* PFN_XUnregisterIMInstantiateCallback)(Display*,void*,char*,char*,XIDProc,XPointer);
 typedef int (* PFN_Xutf8LookupString)(XIC,XKeyPressedEvent*,char*,int,KeySym*,Status*);
 typedef void (* PFN_Xutf8SetWMProperties)(Display*,Window,const char*,const char*,char**,int,XSizeHints*,XWMHints*,XClassHint*);
 #define XAllocClassHint _glfw.x11.xlib.AllocClassHint
@@ -200,6 +203,7 @@ typedef void (* PFN_Xutf8SetWMProperties)(Display*,Window,const char*,const char
 #define XQueryExtension _glfw.x11.xlib.QueryExtension
 #define XQueryPointer _glfw.x11.xlib.QueryPointer
 #define XRaiseWindow _glfw.x11.xlib.RaiseWindow
+#define XRegisterIMInstantiateCallback _glfw.x11.xlib.RegisterIMInstantiateCallback
 #define XResizeWindow _glfw.x11.xlib.ResizeWindow
 #define XResourceManagerString _glfw.x11.xlib.ResourceManagerString
 #define XSaveContext _glfw.x11.xlib.SaveContext
@@ -208,6 +212,7 @@ typedef void (* PFN_Xutf8SetWMProperties)(Display*,Window,const char*,const char
 #define XSetClassHint _glfw.x11.xlib.SetClassHint
 #define XSetErrorHandler _glfw.x11.xlib.SetErrorHandler
 #define XSetICFocus _glfw.x11.xlib.SetICFocus
+#define XSetIMValues _glfw.x11.xlib.SetIMValues
 #define XSetInputFocus _glfw.x11.xlib.SetInputFocus
 #define XSetLocaleModifiers _glfw.x11.xlib.SetLocaleModifiers
 #define XSetScreenSaver _glfw.x11.xlib.SetScreenSaver
@@ -238,6 +243,7 @@ typedef void (* PFN_Xutf8SetWMProperties)(Display*,Window,const char*,const char
 #define XrmGetStringDatabase _glfw.x11.xrm.GetStringDatabase
 #define XrmInitialize _glfw.x11.xrm.Initialize
 #define XrmUniqueQuark _glfw.x11.xrm.UniqueQuark
+#define XUnregisterIMInstantiateCallback _glfw.x11.xlib.UnregisterIMInstantiateCallback
 #define Xutf8LookupString _glfw.x11.xlib.utf8LookupString
 #define Xutf8SetWMProperties _glfw.x11.xlib.utf8SetWMProperties
 
@@ -553,6 +559,7 @@ typedef struct _GLFWlibraryX11
         PFN_XQueryExtension QueryExtension;
         PFN_XQueryPointer QueryPointer;
         PFN_XRaiseWindow RaiseWindow;
+        PFN_XRegisterIMInstantiateCallback RegisterIMInstantiateCallback;
         PFN_XResizeWindow ResizeWindow;
         PFN_XResourceManagerString ResourceManagerString;
         PFN_XSaveContext SaveContext;
@@ -561,6 +568,7 @@ typedef struct _GLFWlibraryX11
         PFN_XSetClassHint SetClassHint;
         PFN_XSetErrorHandler SetErrorHandler;
         PFN_XSetICFocus SetICFocus;
+        PFN_XSetIMValues SetIMValues;
         PFN_XSetInputFocus SetInputFocus;
         PFN_XSetLocaleModifiers SetLocaleModifiers;
         PFN_XSetScreenSaver SetScreenSaver;
@@ -577,6 +585,7 @@ typedef struct _GLFWlibraryX11
         PFN_XUnsetICFocus UnsetICFocus;
         PFN_XVisualIDFromVisual VisualIDFromVisual;
         PFN_XWarpPointer WarpPointer;
+        PFN_XUnregisterIMInstantiateCallback UnregisterIMInstantiateCallback;
         PFN_Xutf8LookupString utf8LookupString;
         PFN_Xutf8SetWMProperties utf8SetWMProperties;
     } xlib;
@@ -753,4 +762,5 @@ void _glfwReleaseErrorHandlerX11(void);
 void _glfwInputErrorX11(int error, const char* message);
 
 void _glfwPushSelectionToManagerX11(void);
+void _glfwCreateInputContextX11(_GLFWwindow* window);
 

src/x11_window.c

@@ -590,6 +590,14 @@ static void enableCursor(_GLFWwindow* window)
     updateCursorImage(window);
 }
 
+// Clear its handle when the input context has been destroyed
+//
+static void inputContextDestroyCallback(XIC ic, XPointer clientData, XPointer callData)
+{
+    _GLFWwindow* window = (_GLFWwindow*) clientData;
+    window->x11.ic = NULL;
+}
+
 // Create the X11 window (and its colormap)
 //
 static GLFWbool createNativeWindow(_GLFWwindow* window,
@@ -768,27 +776,10 @@ static GLFWbool createNativeWindow(_GLFWwindow* window,
                         PropModeReplace, (unsigned char*) &version, 1);
     }
 
-    _glfwPlatformSetWindowTitle(window, wndconfig->title);
-
     if (_glfw.x11.im)
-    {
+        _glfwCreateInputContextX11(window);
-        window->x11.ic = XCreateIC(_glfw.x11.im,
-                                   XNInputStyle,
-                                   XIMPreeditNothing | XIMStatusNothing,
-                                   XNClientWindow,
-                                   window->x11.handle,
-                                   XNFocusWindow,
-                                   window->x11.handle,
-                                   NULL);
-    }
-
-    if (window->x11.ic)
-    {
-        unsigned long filter = 0;
-        if (XGetICValues(window->x11.ic, XNFilterEvents, &filter, NULL) == NULL)
-            XSelectInput(_glfw.x11.display, window->x11.handle, wa.event_mask | filter);
-    }
 
+    _glfwPlatformSetWindowTitle(window, wndconfig->title);
     _glfwPlatformGetWindowPos(window, &window->x11.xpos, &window->x11.ypos);
     _glfwPlatformGetWindowSize(window, &window->x11.width, &window->x11.height);
 
@@ -1173,7 +1164,6 @@ static void processEvent(XEvent *event)
     if (event->type == KeyPress || event->type == KeyRelease)
         keycode = event->xkey.keycode;
 
-    if (_glfw.x11.im)
     filtered = XFilterEvent(event, None);
 
     if (_glfw.x11.randr.available)
@@ -1961,6 +1951,38 @@ void _glfwPushSelectionToManagerX11(void)
     }
 }
 
+void _glfwCreateInputContextX11(_GLFWwindow* window)
+{
+    XIMCallback callback;
+    callback.callback = (XIMProc) inputContextDestroyCallback;
+    callback.client_data = (XPointer) window;
+
+    window->x11.ic = XCreateIC(_glfw.x11.im,
+                               XNInputStyle,
+                               XIMPreeditNothing | XIMStatusNothing,
+                               XNClientWindow,
+                               window->x11.handle,
+                               XNFocusWindow,
+                               window->x11.handle,
+                               XNDestroyCallback,
+                               &callback,
+                               NULL);
+
+    if (window->x11.ic)
+    {
+        XWindowAttributes attribs;
+        XGetWindowAttributes(_glfw.x11.display, window->x11.handle, &attribs);
+
+        unsigned long filter = 0;
+        if (XGetICValues(window->x11.ic, XNFilterEvents, &filter, NULL) == NULL)
+        {
+            XSelectInput(_glfw.x11.display,
+                         window->x11.handle,
+                         attribs.your_event_mask | filter);
+        }
+    }
+}
+
 
 //////////////////////////////////////////////////////////////////////////
 //////                       GLFW platform API                      //////