1 files changed, 215 insertions, 0 deletions
diff --git a/src/java/com/jogamp/common/util/RecursiveToolkitLock.java b/src/java/com/jogamp/common/util/RecursiveToolkitLock.java
new file mode 100644
index 0000000..e02ff94
--- /dev/null
+++ b/src/java/com/jogamp/common/util/RecursiveToolkitLock.java
@@ -0,0 +1,215 @@
+/**
+ * Copyright 2010 JogAmp Community. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ *
+ *    1. Redistributions of source code must retain the above copyright notice, this list of
+ *       conditions and the following disclaimer.
+ *
+ *    2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *       of conditions and the following disclaimer in the documentation and/or other materials
+ *       provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * The views and conclusions contained in the software and documentation are those of the
+ * authors and should not be interpreted as representing official policies, either expressed
+ * or implied, of JogAmp Community.
+ */
+
+package com.jogamp.common.util;
+
+import com.jogamp.common.impl.Debug;
+
+import java.util.LinkedList;
+
+/**
+ * Reentrance locking toolkit, impl a complete fair FIFO scheduler
+ */
+public class RecursiveToolkitLock {
+    static class SyncData {
+        // owner of the lock
+        Thread owner = null; 
+        // lock recursion
+        int recursionCount = 0; 
+        // stack trace of the lock
+        Exception lockedStack = null; 
+        // waiting thread queue
+        LinkedList threadQueue = new LinkedList(); 
+        // flag signaling unlock has woken up a waiting thread
+        boolean signaled = false; 
+    }
+    private SyncData sdata = new SyncData(); // synchronized (flow/mem)  mutable access
+
+    private long timeout;
+    private static final long defaultTimeout = 5000;  // default maximum wait 5s
+    // private static final long defaultTimeout = 300000;  // default maximum wait 300s / 5min
+    private static final boolean TRACE_LOCK = Debug.debug("TraceLock");
+
+    public RecursiveToolkitLock() {
+        this.timeout = defaultTimeout;
+    }
+
+    public RecursiveToolkitLock(long timeout) {
+        this.timeout = timeout;
+    }
+
+    public final Exception getLockedStack() {
+        synchronized(sdata) {
+            return sdata.lockedStack;
+        }
+    }
+
+    public final Thread getOwner() {
+        synchronized(sdata) {
+            return sdata.owner;
+        }
+    }
+
+    public final boolean isOwner() {
+        return isOwner(Thread.currentThread());
+    }
+
+    public final boolean isOwner(Thread thread) {
+        synchronized(sdata) {
+            return sdata.owner == thread ;
+        }
+    }
+
+    public final boolean isLocked() {
+        synchronized(sdata) {
+            return null != sdata.owner;
+        }
+    }
+
+    public final boolean isLockedByOtherThread() {
+        synchronized(sdata) {
+            return null != sdata.owner && Thread.currentThread() != sdata.owner ;
+        }
+    }
+
+    public final int getRecursionCount() {
+        synchronized(sdata) {
+            return sdata.recursionCount;
+        }
+    }
+
+    public final void validateLocked() {
+        synchronized(sdata) {
+            if ( null == sdata.owner ) {
+                throw new RuntimeException(Thread.currentThread()+": Not locked");
+            }
+            if ( Thread.currentThread() != sdata.owner ) {
+                getLockedStack().printStackTrace();
+                throw new RuntimeException(Thread.currentThread()+": Not owner, owner is "+sdata.owner);
+            }
+        }
+    }
+
+    /** Recursive and blocking lockSurface() implementation */
+    public final void lock() {
+        synchronized(sdata) {
+            Thread cur = Thread.currentThread();
+            if (sdata.owner == cur) {
+                ++sdata.recursionCount;
+                if(TRACE_LOCK) {
+                    System.err.println("+++ LOCK 2 ["+this+"], recursions "+sdata.recursionCount+", "+cur);
+                }
+                return;
+            }
+
+            if (sdata.owner != null || sdata.signaled || sdata.threadQueue.size() > 0) {
+                // enqueue due to locked resource or already waiting or signaled threads (be fair)
+                boolean timedOut = false;
+                do {
+                    sdata.threadQueue.addFirst(cur); // should only happen once 
+                    try {
+                        sdata.wait(timeout);
+                        timedOut = sdata.threadQueue.remove(cur); // timeout if not already removed by unlock
+                    } catch (InterruptedException e) {
+                        if(!sdata.signaled) {
+                            // theoretically we could stay in the loop,
+                            // in case the interrupt wasn't issued by unlock, 
+                            // hence the re-enqueue
+                            sdata.threadQueue.remove(cur);
+                            if(TRACE_LOCK) {
+                                System.err.println("XXX LOCK - ["+this+"], recursions "+sdata.recursionCount+", "+cur);
+                            }
+                        }
+                    }
+                } while (null != sdata.owner && !timedOut) ;
+
+                sdata.signaled = false;
+
+                if(timedOut || null != sdata.owner) {
+                    sdata.lockedStack.printStackTrace();
+                    throw new RuntimeException("Waited "+timeout+"ms for: "+sdata.owner+" - "+cur+", with recursionCount "+sdata.recursionCount+", lock: "+this+", qsz "+sdata.threadQueue.size());
+                }
+
+                if(TRACE_LOCK) {
+                    System.err.println("+++ LOCK 3 ["+this+"], recursions "+sdata.recursionCount+", qsz "+sdata.threadQueue.size()+", "+cur);
+                }
+            } else if(TRACE_LOCK) {
+                System.err.println("+++ LOCK 1 ["+this+"], recursions "+sdata.recursionCount+", qsz "+sdata.threadQueue.size()+", "+cur);
+            }
+
+            sdata.owner = cur;
+            sdata.lockedStack = new Exception("Previously locked by "+sdata.owner+", lock: "+this);
+        }
+    }
+    
+
+    /** Recursive and unblocking unlockSurface() implementation */
+    public final void unlock() {
+        unlock(null);
+    }
+
+    /** Recursive and unblocking unlockSurface() implementation */
+    public final void unlock(Runnable taskAfterUnlockBeforeNotify) {
+        synchronized(sdata) {
+            validateLocked();
+
+            if (sdata.recursionCount > 0) {
+                --sdata.recursionCount;
+                if(TRACE_LOCK) {
+                    System.err.println("--- LOCK 1 ["+this+"], recursions "+sdata.recursionCount+", "+Thread.currentThread());
+                }
+                return;
+            }
+            sdata.owner = null;
+            sdata.lockedStack = null;
+            if(null!=taskAfterUnlockBeforeNotify) {
+                taskAfterUnlockBeforeNotify.run();
+            }
+
+            int qsz = sdata.threadQueue.size();
+            if(qsz > 0) {
+                Thread parkedThread = (Thread) sdata.threadQueue.removeLast();
+                if(TRACE_LOCK) {
+                    System.err.println("--- LOCK X ["+this+"], recursions "+sdata.recursionCount+
+                                       ", "+Thread.currentThread()+", irq "+(qsz-1)+": "+parkedThread);
+                }
+                sdata.signaled = true;
+                if(qsz==1) {
+                    // fast path, just one waiting thread
+                    sdata.notify();
+                } else {
+                    // signal the oldest one ..
+                    parkedThread.interrupt(); // Propagate SecurityException if it happens
+                }
+            } else if(TRACE_LOCK) {
+                System.err.println("--- LOCK X ["+this+"], recursions "+sdata.recursionCount+", "+Thread.currentThread());
+            }
+        }
+    }
+}
+