diff options
Diffstat (limited to 'src/java/jogamp/common')
| -rw-r--r-- | src/java/jogamp/common/util/locks/RecursiveLockImpl01Unfairish.java | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/src/java/jogamp/common/util/locks/RecursiveLockImpl01Unfairish.java b/src/java/jogamp/common/util/locks/RecursiveLockImpl01Unfairish.java new file mode 100644 index 0000000..ad29f78 --- /dev/null +++ b/src/java/jogamp/common/util/locks/RecursiveLockImpl01Unfairish.java @@ -0,0 +1,245 @@ +/** + * 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.locks; + +import jogamp.common.Debug; +import java.security.AccessController; + +import java.util.LinkedList; + +/** + * Reentrance locking toolkit, impl a complete fair FIFO scheduler + */ +public class RecursiveLock implements LockExt { + + static class SyncData { + // owner of the lock + Thread owner = null; + // lock recursion + int recursionCount = 0; + // stack trace of the lock, only used if DEBUG + Throwable lockedStack = null; + // waiting thread queue + LinkedList threadQueue = new LinkedList(); + // flag signaling unlock has woken up a waiting thread + boolean signaled = false; + } + private final SyncData sdata = new SyncData(); // synchronized (flow/mem) mutable access + + private static final boolean TRACE_LOCK = Debug.isPropertyDefined("jogamp.debug.Lock.TraceLock", true, AccessController.getContext()); + + public RecursiveLock() { + } + + /** + * Returns the Throwable instance generated when this lock was taken the 1st time + * and if {@link com.jogamp.common.util.locks.Lock#DEBUG} is turned on, otherwise it returns always <code>null</code>. + * @see com.jogamp.common.util.locks.Lock#DEBUG + */ + public final Throwable 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 ) { + if(null!=sdata.lockedStack) { + sdata.lockedStack.printStackTrace(); + } + throw new RuntimeException(Thread.currentThread()+": Not owner, owner is "+sdata.owner); + } + } + } + + public final void lock() { + synchronized(sdata) { + if(!tryLock(TIMEOUT)) { + if(null!=sdata.lockedStack) { + sdata.lockedStack.printStackTrace(); + } + throw new RuntimeException("Waited "+TIMEOUT+"ms for: "+sdata.owner+" - "+Thread.currentThread()+", with recursionCount "+sdata.recursionCount+", lock: "+this+", qsz "+sdata.threadQueue.size()); + } + } + } + + public boolean tryLock(long maxwait) { + synchronized(sdata) { + Thread cur = Thread.currentThread(); + if(TRACE_LOCK) { + String msg = "LOCK 0 ["+this+"], recursions "+sdata.recursionCount+", cur "+cur+", owner "+sdata.owner; + System.err.println(msg); + //Throwable tt = new Throwable(msg); + //tt.printStackTrace(); + } + if (sdata.owner == cur) { + ++sdata.recursionCount; + if(TRACE_LOCK) { + System.err.println("+++ LOCK 2 ["+this+"], recursions "+sdata.recursionCount+", "+cur); + } + return true; + } + + if ( sdata.owner != null || + 0 < maxwait && ( sdata.signaled || sdata.threadQueue.size() > 0 ) ) { + + if ( 0 >= maxwait ) { + // implies 'sdata.owner != null': locked by other thread + // no waiting requested, bail out right away + return false; + } + + boolean timedOut = false; + do { + sdata.threadQueue.addFirst(cur); // should only happen once + try { + sdata.wait(maxwait); + 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) { + return false; + } + + 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; + if(DEBUG) { + sdata.lockedStack = new Throwable("Previously locked by "+sdata.owner+", lock: "+this); + } + return true; + } + } + + + public final void unlock() { + unlock(null); + } + + 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()); + } + } + } + + public int getWaitingThreadQueueSize() { + synchronized(sdata) { + return sdata.threadQueue.size(); + } + } +} + |