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 
13 // C Includes
14 #include <stdint.h>
15 #include <time.h>
16 
17 // C++ Includes
18 // Other libraries and framework includes
19 // Project includes
20 #include "lldb/lldb-defines.h"
21 
22 //----------------------------------------------------------------------
23 /// Enumerations for broadcasting.
24 //----------------------------------------------------------------------
25 namespace lldb_private {
26 
27 //----------------------------------------------------------------------
28 /// @class ProcessRunLock ProcessRunLock.h "lldb/Host/ProcessRunLock.h"
29 /// @brief A class used to prevent the process from starting while other
30 /// threads are accessing its data, and prevent access to its data while
31 /// it is running.
32 //----------------------------------------------------------------------
33 
34 class ProcessRunLock {
35 public:
36   ProcessRunLock();
37   ~ProcessRunLock();
38 
39   bool ReadTryLock();
40   bool ReadUnlock();
41   bool SetRunning();
42   bool TrySetRunning();
43   bool SetStopped();
44 
45   class ProcessRunLocker {
46   public:
47     ProcessRunLocker() : m_lock(nullptr) {}
48 
49     ~ProcessRunLocker() { Unlock(); }
50 
51     // Try to lock the read lock, but only do so if there are no writers.
52     bool TryLock(ProcessRunLock *lock) {
53       if (m_lock) {
54         if (m_lock == lock)
55           return true; // We already have this lock locked
56         else
57           Unlock();
58       }
59       if (lock) {
60         if (lock->ReadTryLock()) {
61           m_lock = lock;
62           return true;
63         }
64       }
65       return false;
66     }
67 
68   protected:
69     void Unlock() {
70       if (m_lock) {
71         m_lock->ReadUnlock();
72         m_lock = nullptr;
73       }
74     }
75 
76     ProcessRunLock *m_lock;
77 
78   private:
79     DISALLOW_COPY_AND_ASSIGN(ProcessRunLocker);
80   };
81 
82 protected:
83   lldb::rwlock_t m_rwlock;
84   bool m_running;
85 
86 private:
87   DISALLOW_COPY_AND_ASSIGN(ProcessRunLock);
88 };
89 
90 } // namespace lldb_private
91 
92 #endif // liblldb_ProcessRunLock_h_
93