Import Tk 8.6.6 (as of svn r86089)

unix/tkUnixFocus.c

@@ -0,0 +1,149 @@
+/*
+ * tkUnixFocus.c --
+ *
+ *	This file contains platform specific functions that manage focus for
+ *	Tk.
+ *
+ * Copyright (c) 1997 Sun Microsystems, Inc.
+ *
+ * See the file "license.terms" for information on usage and redistribution
+ * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ */
+
+#include "tkUnixInt.h"
+
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkpChangeFocus --
+ *
+ *	This function is invoked to move the official X focus from one window
+ *	to another.
+ *
+ * Results:
+ *	The return value is the serial number of the command that changed the
+ *	focus. It may be needed by the caller to filter out focus change
+ *	events that were queued before the command. If the function doesn't
+ *	actually change the focus then it returns 0.
+ *
+ * Side effects:
+ *	The official X focus window changes; the application's focus window
+ *	isn't changed by this function.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TkpChangeFocus(
+    TkWindow *winPtr,		/* Window that is to receive the X focus. */
+    int force)			/* Non-zero means claim the focus even if it
+				 * didn't originally belong to topLevelPtr's
+				 * application. */
+{
+    TkDisplay *dispPtr = winPtr->dispPtr;
+    Tk_ErrorHandler errHandler;
+    Window window, root, parent, *children;
+    unsigned int numChildren, serial;
+    TkWindow *winPtr2;
+    int dummy;
+
+    /*
+     * Don't set the X focus to a window that's marked override-redirect.
+     * This is a hack to avoid problems with menus under olvwm: if we move
+     * the focus then the focus can get lost during keyboard traversal.
+     * Fortunately, we don't really need to move the focus for menus: events
+     * will still find their way to the focus window, and menus aren't
+     * decorated anyway so the window manager doesn't need to hear about the
+     * focus change in order to redecorate the menu.
+     */
+
+    serial = 0;
+    if (winPtr->atts.override_redirect) {
+	return serial;
+    }
+
+    /*
+     * Check to make sure that the focus is still in one of the windows of
+     * this application or one of their descendants. Furthermore, grab the
+     * server to make sure that the focus doesn't change in the middle of this
+     * operation.
+     */
+
+    XGrabServer(dispPtr->display);
+    if (!force) {
+	/*
+	 * Find the focus window, then see if it or one of its ancestors is a
+	 * window in our application (it's possible that the focus window is
+	 * in an embedded application, which may or may not be in the same
+	 * process.
+	 */
+
+	XGetInputFocus(dispPtr->display, &window, &dummy);
+	while (1) {
+	    winPtr2 = (TkWindow *) Tk_IdToWindow(dispPtr->display, window);
+	    if ((winPtr2 != NULL) && (winPtr2->mainPtr == winPtr->mainPtr)) {
+		break;
+	    }
+	    if ((window == PointerRoot) || (window == None)) {
+		goto done;
+	    }
+	    XQueryTree(dispPtr->display, window, &root, &parent, &children,
+		    &numChildren);
+	    if (children != NULL) {
+		XFree((void *) children);
+	    }
+	    if (parent == root) {
+		goto done;
+	    }
+	    window = parent;
+	}
+    }
+
+    /*
+     * Tell X to change the focus. Ignore errors that occur when changing the
+     * focus: it is still possible that the window we're focussing to could
+     * have gotten unmapped, which will generate an error.
+     */
+
+    errHandler = Tk_CreateErrorHandler(dispPtr->display, -1,-1,-1, NULL,NULL);
+    if (winPtr->window == None) {
+	Tcl_Panic("ChangeXFocus got null X window");
+    }
+    XSetInputFocus(dispPtr->display, winPtr->window, RevertToParent,
+	    CurrentTime);
+    Tk_DeleteErrorHandler(errHandler);
+
+    /*
+     * Remember the current serial number for the X server and issue a dummy
+     * server request. This marks the position at which we changed the focus,
+     * so we can distinguish FocusIn and FocusOut events on either side of the
+     * mark.
+     */
+
+    serial = NextRequest(winPtr->display);
+    XNoOp(winPtr->display);
+
+  done:
+    XUngrabServer(dispPtr->display);
+
+    /*
+     * After ungrabbing the server, it's important to flush the output
+     * immediately so that the server sees the ungrab command. Otherwise we
+     * might do something else that needs to communicate with the server (such
+     * as invoking a subprocess that needs to do I/O to the screen); if the
+     * ungrab command is still sitting in our output buffer, we could
+     * deadlock.
+     */
+
+    XFlush(dispPtr->display);
+    return serial;
+}
+
+/*
+ * Local Variables:
+ * mode: c
+ * c-basic-offset: 4
+ * fill-column: 78
+ * End:
+ */