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/***** BEGIN LICENSE BLOCK *****
* Version: EPL 2.0/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Eclipse Public
* License Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.eclipse.org/legal/epl-v20.html
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* Copyright (C) 2006 MenTaLguY <mental@rydia.net>
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the EPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the EPL, the GPL or the LGPL.
***** END LICENSE BLOCK *****/
package org.jruby.ext.thread;
import java.util.concurrent.locks.ReentrantLock;
import org.jruby.Ruby;
import org.jruby.RubyBoolean;
import org.jruby.RubyClass;
import org.jruby.RubyObject;
import org.jruby.RubyThread;
import org.jruby.RubyTime;
import org.jruby.anno.JRubyClass;
import org.jruby.anno.JRubyMethod;
import org.jruby.runtime.Block;
import org.jruby.runtime.Helpers;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.builtin.IRubyObject;
import org.jruby.runtime.marshal.DataType;
import static org.jruby.api.Convert.asBoolean;
import static org.jruby.api.Convert.asFixnum;
/**
* The "Mutex" class from the 'thread' library.
*/
@JRubyClass(name = "Mutex")
public class Mutex extends RubyObject implements DataType {
final ReentrantLock lock = new ReentrantLock();
/**
* The non-fiber thread that currently holds the lock; this will be the same for all fibers associated with that
* thread.
*/
volatile RubyThread lockingThread;
@JRubyMethod(name = "new", rest = true, meta = true)
public static Mutex newInstance(ThreadContext context, IRubyObject recv, IRubyObject[] args, Block block) {
Mutex result = new Mutex(context.runtime, (RubyClass) recv);
result.callInit(context, args, block);
return result;
}
public Mutex(Ruby runtime, RubyClass type) {
super(runtime, type);
}
public static RubyClass setup(ThreadContext context, RubyClass Thread, RubyClass Object) {
return (RubyClass) Object.setConstant(context, "Mutex",
Thread.defineClassUnder(context, "Mutex", Object, Mutex::new).reifiedClass(Mutex.class).defineMethods(context, Mutex.class));
}
@JRubyMethod(name = "locked?")
public RubyBoolean locked_p(ThreadContext context) {
return asBoolean(context, isLocked());
}
public boolean isLocked() {
return lock.isLocked();
}
@JRubyMethod
public RubyBoolean try_lock(ThreadContext context) {
return asBoolean(context, tryLock(context));
}
public boolean tryLock(ThreadContext context) {
if (lock.isHeldByCurrentThread()) {
return false;
}
boolean locked = context.getThread().tryLock(lock);
if (locked) this.lockingThread = context.getThread();
return locked;
}
@JRubyMethod
public IRubyObject lock(ThreadContext context) {
RubyThread thread = context.getThread();
RubyThread parentThread = context.getFiberCurrentThread();
checkRelocking(context);
RubyThread lockingThread = this.lockingThread;
if (lockingThread == parentThread && context.getFiber() != lockingThread.getContext().getFiber()) {
throw context.runtime.newThreadError("deadlock; lock already owned by another fiber belonging to the same thread");
}
// try locking without sleep status to avoid looking like blocking
if (!thread.tryLock(lock)) {
for (;;) {
try {
context.getThread().lockInterruptibly(lock);
break;
} catch (InterruptedException ex) {
//github.com/ ignore, check thread events and try again!
context.pollThreadEvents();
}
}
}
// always check for thread interrupts after acquiring lock
try {
thread.pollThreadEvents(context);
} catch (Throwable t) {
// Thread poll triggered an exception event, release locked locks before propagating
if (lock.isHeldByCurrentThread()) {
thread.unlock(lock);
}
Helpers.throwException(t);
}
// set locking thread once successfully locked with no interrupts
this.lockingThread = parentThread;
return this;
}
@JRubyMethod
public IRubyObject unlock(ThreadContext context) {
if (!isLocked()) {
throw context.runtime.newThreadError("Mutex is not locked");
}
if (!lock.isHeldByCurrentThread()) {
throw context.runtime.newThreadError("Mutex is not owned by calling thread");
}
boolean hasQueued = lock.hasQueuedThreads();
this.lockingThread = null;
context.getThread().unlock(lock);
return hasQueued ? context.nil : this;
}
@JRubyMethod
public IRubyObject sleep(ThreadContext context) {
return sleep(context, context.nil);
}
@JRubyMethod
public IRubyObject sleep(ThreadContext context, IRubyObject timeout) {
final long beg = System.currentTimeMillis();
try {
RubyThread thread = context.getThread();
if (timeout.isNil()) {
thread.sleep(lock);
} else {
double t = RubyTime.convertTimeInterval(context, timeout);
long millis = (long) (t * 1000);
if (Double.compare(t, 0.0d) == 0 || millis == 0) {
// wait time is zero or smaller than 1ms, so we just proceed
} else {
thread.sleep(lock, millis);
}
}
} catch (IllegalMonitorStateException imse) {
throw context.runtime.newThreadError("Attempt to unlock a mutex which is not locked");
} catch (InterruptedException ex) {
context.pollThreadEvents();
}
return asFixnum(context, (System.currentTimeMillis() - beg) / 1000);
}
@JRubyMethod
public IRubyObject synchronize(ThreadContext context, Block block) {
lock(context);
try {
return block.yieldSpecific(context);
} finally {
unlock(context);
}
}
@JRubyMethod(name = "owned?")
public IRubyObject owned_p(ThreadContext context) {
return asBoolean(context, lock.isHeldByCurrentThread());
}
private void checkRelocking(ThreadContext context) {
if (lock.isHeldByCurrentThread()) {
throw context.runtime.newThreadError("deadlock; recursive locking");
}
}
}