ProcessRunLock.h revision 263363 
1//===-- ProcessRunLock.h ----------------------------------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef liblldb_ProcessRunLock_h_
11#define liblldb_ProcessRunLock_h_
12#if defined(__cplusplus)
13
14#include "lldb/lldb-defines.h"
15#include "lldb/Host/Mutex.h"
16#include "lldb/Host/Condition.h"
17#include <stdint.h>
18#include <time.h>
19
20//----------------------------------------------------------------------
21/// Enumerations for broadcasting.
22//----------------------------------------------------------------------
23namespace lldb_private {
24
25//----------------------------------------------------------------------
26/// @class ProcessRunLock ProcessRunLock.h "lldb/Host/ProcessRunLock.h"
27/// @brief A class used to prevent the process from starting while other
28/// threads are accessing its data, and prevent access to its data while
29/// it is running.
30//----------------------------------------------------------------------
31
32class ProcessRunLock
33{
34public:
35    ProcessRunLock();
36    ~ProcessRunLock();
37    bool ReadTryLock ();
38    bool ReadUnlock ();
39    bool SetRunning ();
40    bool TrySetRunning ();
41    bool SetStopped ();
42public:
43    class ProcessRunLocker
44    {
45    public:
46        ProcessRunLocker () :
47            m_lock (NULL)
48        {
49        }
50
51        ~ProcessRunLocker()
52        {
53            Unlock();
54        }
55
56        // Try to lock the read lock, but only do so if there are no writers.
57        bool
58        TryLock (ProcessRunLock *lock)
59        {
60            if (m_lock)
61            {
62                if (m_lock == lock)
63                    return true; // We already have this lock locked
64                else
65                    Unlock();
66            }
67            if (lock)
68            {
69                if (lock->ReadTryLock())
70                {
71                    m_lock = lock;
72                    return true;
73                }
74            }
75            return false;
76        }
77
78    protected:
79        void
80        Unlock ()
81        {
82            if (m_lock)
83            {
84                m_lock->ReadUnlock();
85                m_lock = NULL;
86            }
87        }
88
89        ProcessRunLock *m_lock;
90    private:
91        DISALLOW_COPY_AND_ASSIGN(ProcessRunLocker);
92    };
93
94protected:
95    lldb::rwlock_t m_rwlock;
96    bool m_running;
97private:
98    DISALLOW_COPY_AND_ASSIGN(ProcessRunLock);
99};
100
101} // namespace lldb_private
102
103#endif  // #if defined(__cplusplus)
104#endif // #ifndef liblldb_ProcessRunLock_h_
105