1 /*
2    Copyright (C) 2007, 2008 MySQL AB
3     All rights reserved. Use is subject to license terms.
4 
5    This program is free software; you can redistribute it and/or modify
6    it under the terms of the GNU General Public License, version 2.0,
7    as published by the Free Software Foundation.
8 
9    This program is also distributed with certain software (including
10    but not limited to OpenSSL) that is licensed under separate terms,
11    as designated in a particular file or component or in included license
12    documentation.  The authors of MySQL hereby grant you an additional
13    permission to link the program and your derivative works with the
14    separately licensed software that they have included with MySQL.
15 
16    This program is distributed in the hope that it will be useful,
17    but WITHOUT ANY WARRANTY; without even the implied warranty of
18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19    GNU General Public License, version 2.0, for more details.
20 
21    You should have received a copy of the GNU General Public License
22    along with this program; if not, write to the Free Software
23    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
24 */
25 
26 #ifndef BLOCK_MUTEX_IMPL_HPP
27 #define BLOCK_MUTEX_IMPL_HPP
28 
29 #include "ArrayPool.hpp"
30 #include "DLFifoList.hpp"
31 #include "KeyTable.hpp"
32 #include <signaldata/UtilLock.hpp>
33 
34 class LockQueue
35 {
36 public:
LockQueue()37   LockQueue() {}
38 
39   /**
40    * A lock queue element
41    */
42   struct LockQueueElement
43   {
LockQueueElementLockQueue::LockQueueElement44     LockQueueElement() {}
45 
46     UtilLockReq m_req;
47     union {
48       Uint32 nextPool;
49       Uint32 nextList;
50     };
51     Uint32 prevList;
52   };
53 
54   typedef ArrayPool<LockQueueElement> Pool;
55 
56   Uint32 lock(SimulatedBlock*,
57               Pool&, const UtilLockReq*, const UtilLockReq** = 0);
58   Uint32 unlock(SimulatedBlock*,
59                 Pool&, const UtilUnlockReq* req);
60 
61   /**
62    * After unlock
63    */
64   struct Iterator
65   {
66     SimulatedBlock* m_block;
67     Pool * thePool;
68     Ptr<LockQueueElement> m_prev;
69     Ptr<LockQueueElement> m_curr;
70   };
71 
72   bool first(SimulatedBlock*, Pool& pool, Iterator&);
73   bool next(Iterator&);
74 
75   /**
76    * 0 - done
77    * 1 - already granted
78    * 2 - needs conf
79    */
80   int checkLockGrant(Iterator &, UtilLockReq * req);
81 
82   /**
83    * Clear lock queue
84    */
85   void clear (Pool&);
86 
87   /**
88    * Dump
89    */
90   void dump_queue(Pool&, SimulatedBlock* block);
91 
92 private:
93   /**
94    * The actual lock queue
95    */
96   DLFifoList<LockQueueElement>::Head m_queue;
97 };
98 
99 #endif
100