1 /*
   2  * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package sun.awt.X11;
  26 
  27 import java.security.AccessController;
  28 import sun.awt.SunToolkit;
  29 import sun.security.action.GetBooleanAction;
  30 import sun.util.logging.PlatformLogger;
  31 
  32 /**
  33  * This class contains code of the global toolkit error handler, exposes static
  34  * methods which allow to set and unset synthetic error handlers.
  35  */
  36 public final class XErrorHandlerUtil {
  37     private static final PlatformLogger log = PlatformLogger.getLogger("sun.awt.X11.XErrorHandlerUtil");
  38 
  39     /**
  40      * The connection to X11 window server.
  41      */
  42     private static long display;
  43 
  44     /**
  45      * Error handler at the moment of {@code XErrorHandlerUtil} initialization.
  46      */
  47     private static long saved_error_handler;
  48 
  49     /**
  50      * XErrorEvent being handled.
  51      */
  52     static volatile XErrorEvent saved_error;
  53 
  54     /**
  55      * Current error handler or null if no error handler is set.
  56      */
  57     private static XErrorHandler current_error_handler;
  58 
  59     /**
  60      * Value of sun.awt.noisyerrorhandler system property.
  61      */
  62     private static boolean noisyAwtHandler = AccessController.doPrivileged(
  63         new GetBooleanAction("sun.awt.noisyerrorhandler"));
  64 
  65     /**
  66      * The flag indicating that {@code init} was called already.
  67      */
  68     private static boolean initPassed;
  69 
  70     /**
  71      * Guarantees that no instance of this class can be created.
  72      */
  73     private XErrorHandlerUtil() {}
  74 
  75     /**
  76      * Sets the toolkit global error handler, stores the connection to X11 server,
  77      * which will be used during an error handling process. This method is called
  78      * once from {@code awt_init_Display} function defined in {@code awt_GraphicsEnv.c}
  79      * file immediately after the connection to X11 window server is opened.
  80      * @param display the connection to X11 server which should be stored
  81      */
  82     private static void init(long display) {
  83         SunToolkit.awtLock();
  84         try {
  85             if (!initPassed) {
  86                 XErrorHandlerUtil.display = display;
  87                 saved_error_handler = XlibWrapper.SetToolkitErrorHandler();
  88                 initPassed = true;
  89             }
  90         } finally {
  91             SunToolkit.awtUnlock();
  92         }
  93     }
  94 
  95     /**
  96      * Sets a synthetic error handler. Must be called with the acquired AWT lock.
  97      * @param handler the synthetic error handler to set
  98      */
  99     public static void WITH_XERROR_HANDLER(XErrorHandler handler) {
 100         saved_error = null;
 101         current_error_handler = handler;
 102     }
 103 
 104     /**
 105      * Unsets a current synthetic error handler. Must be called with the acquired AWT lock.
 106      */
 107     public static void RESTORE_XERROR_HANDLER() {
 108         RESTORE_XERROR_HANDLER(true);
 109     }
 110 
 111     private static void RESTORE_XERROR_HANDLER(boolean doXSync) {
 112         if (doXSync) {
 113             // Wait until all requests are processed by the X server
 114             // and only then uninstall the error handler.
 115             XSync();
 116         }
 117         current_error_handler = null;
 118     }
 119 
 120     /**
 121      * Should be called under LOCK.
 122      */
 123     public static int SAVED_XERROR_HANDLER(long display, XErrorEvent error) {
 124         if (saved_error_handler != 0) {
 125             // Default XErrorHandler may just terminate the process. Don't call it.
 126             // return XlibWrapper.CallErrorHandler(saved_error_handler, display, error.pData);
 127         }
 128         if (log.isLoggable(PlatformLogger.FINE)) {
 129             log.fine("Unhandled XErrorEvent: " +
 130                 "id=" + error.get_resourceid() + ", " +
 131                 "serial=" + error.get_serial() + ", " +
 132                 "ec=" + error.get_error_code() + ", " +
 133                 "rc=" + error.get_request_code() + ", " +
 134                 "mc=" + error.get_minor_code());
 135         }
 136         return 0;
 137     }
 138 
 139     /**
 140      * Called from the native code when an error occurs.
 141      */
 142     private static int globalErrorHandler(long display, long event_ptr) {
 143         if (noisyAwtHandler) {
 144             XlibWrapper.PrintXErrorEvent(display, event_ptr);
 145         }
 146         XErrorEvent event = new XErrorEvent(event_ptr);
 147         saved_error = event;
 148         try {
 149             if (current_error_handler != null) {
 150                 return current_error_handler.handleError(display, event);
 151             } else {
 152                 return SAVED_XERROR_HANDLER(display, event);
 153             }
 154         } catch (Throwable z) {
 155             log.fine("Error in GlobalErrorHandler", z);
 156         }
 157         return 0;
 158     }
 159 
 160     private static void XSync() {
 161         SunToolkit.awtLock();
 162         try {
 163             XlibWrapper.XSync(display, 0);
 164         } finally {
 165             SunToolkit.awtUnlock();
 166         }
 167     }
 168 }