1 /*
   2  * Copyright (c) 2005, 2012, 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 
  26 package sun.java2d.opengl;
  27 
  28 import sun.awt.util.ThreadGroupUtils;
  29 import sun.java2d.pipe.RenderBuffer;
  30 import sun.java2d.pipe.RenderQueue;
  31 import static sun.java2d.pipe.BufferedOpCodes.*;
  32 import java.security.AccessController;
  33 import java.security.PrivilegedAction;
  34 
  35 /**
  36  * OGL-specific implementation of RenderQueue.  This class provides a
  37  * single (daemon) thread that is responsible for periodically flushing
  38  * the queue, thus ensuring that only one thread communicates with the native
  39  * OpenGL libraries for the entire process.
  40  */
  41 public class OGLRenderQueue extends RenderQueue {
  42 
  43     private static OGLRenderQueue theInstance;
  44     private final QueueFlusher flusher;
  45 
  46     private OGLRenderQueue() {
  47         /*
  48          * The thread must be a member of a thread group
  49          * which will not get GCed before VM exit.
  50          */
  51         flusher = AccessController.doPrivileged((PrivilegedAction<QueueFlusher>) () -> {
  52             return new QueueFlusher(ThreadGroupUtils.getRootThreadGroup());
  53         });
  54     }
  55 
  56     /**
  57      * Returns the single OGLRenderQueue instance.  If it has not yet been
  58      * initialized, this method will first construct the single instance
  59      * before returning it.
  60      */
  61     public static synchronized OGLRenderQueue getInstance() {
  62         if (theInstance == null) {
  63             theInstance = new OGLRenderQueue();
  64         }
  65         return theInstance;
  66     }
  67 
  68     /**
  69      * Flushes the single OGLRenderQueue instance synchronously.  If an
  70      * OGLRenderQueue has not yet been instantiated, this method is a no-op.
  71      * This method is useful in the case of Toolkit.sync(), in which we want
  72      * to flush the OGL pipeline, but only if the OGL pipeline is currently
  73      * enabled.  Since this class has few external dependencies, callers need
  74      * not be concerned that calling this method will trigger initialization
  75      * of the OGL pipeline and related classes.
  76      */
  77     public static void sync() {
  78         if (theInstance != null) {
  79             theInstance.lock();
  80             try {
  81                 theInstance.ensureCapacity(4);
  82                 theInstance.getBuffer().putInt(SYNC);
  83                 theInstance.flushNow();
  84             } finally {
  85                 theInstance.unlock();
  86             }
  87         }
  88     }
  89 
  90     /**
  91      * Disposes the native memory associated with the given native
  92      * graphics config info pointer on the single queue flushing thread.
  93      */
  94     public static void disposeGraphicsConfig(long pConfigInfo) {
  95         OGLRenderQueue rq = getInstance();
  96         rq.lock();
  97         try {
  98             // make sure we make the context associated with the given
  99             // GraphicsConfig current before disposing the native resources
 100             OGLContext.setScratchSurface(pConfigInfo);
 101 
 102             RenderBuffer buf = rq.getBuffer();
 103             rq.ensureCapacityAndAlignment(12, 4);
 104             buf.putInt(DISPOSE_CONFIG);
 105             buf.putLong(pConfigInfo);
 106 
 107             // this call is expected to complete synchronously, so flush now
 108             rq.flushNow();
 109         } finally {
 110             rq.unlock();
 111         }
 112     }
 113 
 114     /**
 115      * Returns true if the current thread is the OGL QueueFlusher thread.
 116      */
 117     public static boolean isQueueFlusherThread() {
 118         return (Thread.currentThread() == getInstance().flusher);
 119     }
 120 
 121     public void flushNow() {
 122         // assert lock.isHeldByCurrentThread();
 123         try {
 124             flusher.flushNow();
 125         } catch (Exception e) {
 126             System.err.println("exception in flushNow:");
 127             e.printStackTrace();
 128         }
 129     }
 130 
 131     public void flushAndInvokeNow(Runnable r) {
 132         // assert lock.isHeldByCurrentThread();
 133         try {
 134             flusher.flushAndInvokeNow(r);
 135         } catch (Exception e) {
 136             System.err.println("exception in flushAndInvokeNow:");
 137             e.printStackTrace();
 138         }
 139     }
 140 
 141     private native void flushBuffer(long buf, int limit);
 142 
 143     private void flushBuffer() {
 144         // assert lock.isHeldByCurrentThread();
 145         int limit = buf.position();
 146         if (limit > 0) {
 147             // process the queue
 148             flushBuffer(buf.getAddress(), limit);
 149         }
 150         // reset the buffer position
 151         buf.clear();
 152         // clear the set of references, since we no longer need them
 153         refSet.clear();
 154     }
 155 
 156     private class QueueFlusher extends Thread {
 157         private boolean needsFlush;
 158         private Runnable task;
 159         private Error error;
 160 
 161         public QueueFlusher(ThreadGroup threadGroup) {
 162             super(threadGroup, "Java2D Queue Flusher");
 163             setDaemon(true);
 164             setPriority(Thread.MAX_PRIORITY);
 165             start();
 166         }
 167 
 168         public synchronized void flushNow() {
 169             // wake up the flusher
 170             needsFlush = true;
 171             notify();
 172 
 173             // wait for flush to complete
 174             while (needsFlush) {
 175                 try {
 176                     wait();
 177                 } catch (InterruptedException e) {
 178                 }
 179             }
 180 
 181             // re-throw any error that may have occurred during the flush
 182             if (error != null) {
 183                 throw error;
 184             }
 185         }
 186 
 187         public synchronized void flushAndInvokeNow(Runnable task) {
 188             this.task = task;
 189             flushNow();
 190         }
 191 
 192         public synchronized void run() {
 193             boolean timedOut = false;
 194             while (true) {
 195                 while (!needsFlush) {
 196                     try {
 197                         timedOut = false;
 198                         /*
 199                          * Wait until we're woken up with a flushNow() call,
 200                          * or the timeout period elapses (so that we can
 201                          * flush the queue periodically).
 202                          */
 203                         wait(100);
 204                         /*
 205                          * We will automatically flush the queue if the
 206                          * following conditions apply:
 207                          *   - the wait() timed out
 208                          *   - we can lock the queue (without blocking)
 209                          *   - there is something in the queue to flush
 210                          * Otherwise, just continue (we'll flush eventually).
 211                          */
 212                         if (!needsFlush && (timedOut = tryLock())) {
 213                             if (buf.position() > 0) {
 214                                 needsFlush = true;
 215                             } else {
 216                                 unlock();
 217                             }
 218                         }
 219                     } catch (InterruptedException e) {
 220                     }
 221                 }
 222                 try {
 223                     // reset the throwable state
 224                     error = null;
 225                     // flush the buffer now
 226                     flushBuffer();
 227                     // if there's a task, invoke that now as well
 228                     if (task != null) {
 229                         task.run();
 230                     }
 231                 } catch (Error e) {
 232                     error = e;
 233                 } catch (Exception x) {
 234                     System.err.println("exception in QueueFlusher:");
 235                     x.printStackTrace();
 236                 } finally {
 237                     if (timedOut) {
 238                         unlock();
 239                     }
 240                     task = null;
 241                     // allow the waiting thread to continue
 242                     needsFlush = false;
 243                     notify();
 244                 }
 245             }
 246         }
 247     }
 248 }