contrib/llvm/tools/lldb/include/lldb/Host/ProcessRunLock.h

   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 //----------------------------------------------------------------------
  23 namespace 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
  32 class ProcessRunLock
  33 {
  34 public:
  35     ProcessRunLock();
  36     ~ProcessRunLock();
  37     bool ReadTryLock ();
  38     bool ReadUnlock ();
  39     bool SetRunning ();
  40     bool TrySetRunning ();
  41     bool SetStopped ();
  42 public:
  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
  94 protected:
  95     lldb::rwlock_t m_rwlock;
  96     bool m_running;
  97 private:
  98     DISALLOW_COPY_AND_ASSIGN(ProcessRunLock);
  99 };
 100
 101 } // namespace lldb_private
 102
 103 #endif  // #if defined(__cplusplus)
 104 #endif // #ifndef liblldb_ProcessRunLock_h_