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comparison dwt/internal/Lock.d @ 0:380af2bdd8e5

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author Jacob Carlborg <doob@me.com> <jacob.carlborg@gmail.com>
date Sat, 09 Aug 2008 17:00:02 +0200
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-1:000000000000 0:380af2bdd8e5
1 /*******************************************************************************
2 * Copyright (c) 2000, 2005 IBM Corporation and others.
3 * All rights reserved. This program and the accompanying materials
4 * are made available under the terms of the Eclipse Public License v1.0
5 * which accompanies this distribution, and is available at
6 * http://www.eclipse.org/legal/epl-v10.html
7 *
8 * Contributors:
9 * IBM Corporation - initial API and implementation
10 *
11 * Port to the D programming language:
12 * Frank Benoit <benoit@tionex.de>
13 *******************************************************************************/
14 module dwt.internal.Lock;
15
16 import tango.core.Thread;
17 import tango.core.sync.Mutex;
18 import tango.core.sync.Condition;
19 import tango.core.Exception;
20
21 import dwt.dwthelper.utils;
22
23 /**
24 * Instance of this represent a recursive monitor.
25 */
26 public class Lock
27 {
28 int count, waitCount;
29 Thread owner;
30 Mutex mutex;
31 Condition cond;
32
33 public this ()
34 {
35 mutex = new Mutex;
36 cond = new Condition(mutex);
37 }
38
39 /**
40 * Locks the monitor and returns the lock count. If
41 * the lock is owned by another thread, wait until
42 * the lock is released.
43 *
44 * @return the lock count
45 */
46 public int lock ()
47 {
48 synchronized (mutex)
49 {
50 Thread current = Thread.getThis();
51 if (owner !is current)
52 {
53 waitCount++;
54 while (count > 0)
55 {
56 try
57 {
58 cond.wait();
59 }
60 catch (SyncException e)
61 {
62 /* Wait forever, just like synchronized blocks */
63 }
64 }
65 --waitCount;
66 owner = current;
67 }
68 return ++count;
69 }
70 }
71
72 /**
73 * Unlocks the monitor. If the current thread is not
74 * the monitor owner, do nothing.
75 */
76 public void unlock ()
77 {
78 synchronized (mutex)
79 {
80 Thread current = Thread.getThis();
81 if (owner is current)
82 {
83 if (--count is 0)
84 {
85 owner = null;
86 if (waitCount > 0)
87 cond.notifyAll();
88 }
89 }
90 }
91 }
92 }