1 /*
2  * Copyright 2006-2008 The FLWOR Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 #pragma once
17 #ifndef ZORBA_STORE_LOCK_H
18 #define ZORBA_STORE_LOCK_H
19 
20 #include <zorba/config.h>
21 #include <vector>
22 
23 #include "zorbamisc/config/platform.h"
24 
25 #include "zorbautils/runnable.h"
26 #include "zorbautils/mutex.h"
27 #include "zorbautils/condition.h"
28 
29 namespace zorba {
30 
31 
32 /*******************************************************************************
33 
34 ********************************************************************************/
35 
36 class ZORBA_DLL_PUBLIC Lock
37 {
38 public:
39   enum Mode { NOLOCK, READ, WRITE };
40 
41 protected:
42   class LockRequest
43   {
44     friend class Lock;
45 
46     Lock::Mode    theMode;
47     ulong         theCount;
48     bool          theUpgrade;
49     ThreadId      theThread;
50 
LockRequest(Mode m,ThreadId t)51     LockRequest(Mode m, ThreadId t)
52       :
53       theMode(m),
54       theCount(1),
55       theUpgrade(false),
56       theThread(t)
57     {
58     }
59   };
60 
61 protected:
62   Mutex                     theMutex;
63   Condition                 theCondition;
64 
65   Mode                      theMode;
66   bool                      theHaveUpgradeReq;
67   ulong                     theNumWaiters;
68   std::vector<LockRequest>  theHolders;
69 
70 public:
71   Lock();
72   ~Lock();
73 
74   void rlock();
75   void wlock();
76   void unlock();
77 
78  private:
79   Lock(const Lock &);
80   void operator=(const Lock &);
81 };
82 
83 
84 
85 /*******************************************************************************
86 
87 ********************************************************************************/
88 class ZORBA_DLL_PUBLIC AutoLock
89 {
90 private:
91   Lock & theLock;
92 
93 public:
AutoLock(Lock & l,Lock::Mode m)94   AutoLock(Lock& l, Lock::Mode m) : theLock(l)
95   {
96     if (m == Lock::READ)
97       theLock.rlock();
98     else
99       theLock.wlock();
100   }
101 
~AutoLock()102   ~AutoLock()
103   {
104     theLock.unlock();
105   }
106 };
107 
108 
109 }
110 
111 #endif
112 /* vim:set et sw=2 ts=2: */
113