boost/interprocess/sync/interprocess_mutex.hpp

   1 //////////////////////////////////////////////////////////////////////////////
   2 //
   3 // (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
   4 // Software License, Version 1.0. (See accompanying file
   5 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // See http://www.boost.org/libs/interprocess for documentation.
   8 //
   9 //////////////////////////////////////////////////////////////////////////////
  10 //
  11 // Parts of the pthread code come from Boost Threads code.
  12 //
  13 //////////////////////////////////////////////////////////////////////////////
  14
  15 #ifndef BOOST_INTERPROCESS_MUTEX_HPP
  16 #define BOOST_INTERPROCESS_MUTEX_HPP
  17
  18 #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
  19
  20 #if defined(_MSC_VER)
  21 #  pragma once
  22 #endif
  23
  24 #include <boost/interprocess/detail/config_begin.hpp>
  25 #include <boost/interprocess/exceptions.hpp>
  26 #include <boost/interprocess/detail/workaround.hpp>
  27 #include <boost/interprocess/detail/posix_time_types_wrk.hpp>
  28 #include <boost/assert.hpp>
  29
  30 #if !defined(BOOST_INTERPROCESS_FORCE_GENERIC_EMULATION) && defined (BOOST_INTERPROCESS_POSIX_PROCESS_SHARED)
  31    #include <boost/interprocess/sync/posix/mutex.hpp>
  32    #define BOOST_INTERPROCESS_USE_POSIX
  33 //Experimental...
  34 #elif !defined(BOOST_INTERPROCESS_FORCE_GENERIC_EMULATION) && defined (BOOST_INTERPROCESS_WINDOWS)
  35    #include <boost/interprocess/sync/windows/mutex.hpp>
  36    #define BOOST_INTERPROCESS_USE_WINDOWS
  37 #elif !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
  38    #include <boost/interprocess/sync/spin/mutex.hpp>
  39    #define BOOST_INTERPROCESS_USE_GENERIC_EMULATION
  40
  41 namespace boost {
  42 namespace interprocess {
  43 namespace ipcdetail{
  44 namespace robust_emulation_helpers {
  45
  46 template<class T>
  47 class mutex_traits;
  48
  49 }}}}
  50
  51 #endif
  52
  53 #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
  54
  55 //!\file
  56 //!Describes a mutex class that can be placed in memory shared by
  57 //!several processes.
  58
  59 namespace boost {
  60 namespace interprocess {
  61
  62 class interprocess_condition;
  63
  64 //!Wraps a interprocess_mutex that can be placed in shared memory and can be
  65 //!shared between processes. Allows timed lock tries
  66 class interprocess_mutex
  67 {
  68    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
  69    //Non-copyable
  70    interprocess_mutex(const interprocess_mutex &);
  71    interprocess_mutex &operator=(const interprocess_mutex &);
  72    friend class interprocess_condition;
  73
  74    public:
  75    #if defined(BOOST_INTERPROCESS_USE_GENERIC_EMULATION)
  76       #undef BOOST_INTERPROCESS_USE_GENERIC_EMULATION
  77       typedef ipcdetail::spin_mutex internal_mutex_type;
  78       private:
  79       friend class ipcdetail::robust_emulation_helpers::mutex_traits<interprocess_mutex>;
  80       void take_ownership(){ m_mutex.take_ownership(); }
  81       public:
  82    #elif defined(BOOST_INTERPROCESS_USE_POSIX)
  83       #undef BOOST_INTERPROCESS_USE_POSIX
  84       typedef ipcdetail::posix_mutex internal_mutex_type;
  85    #elif defined(BOOST_INTERPROCESS_USE_WINDOWS)
  86       #undef BOOST_INTERPROCESS_USE_WINDOWS
  87       typedef ipcdetail::windows_mutex internal_mutex_type;
  88    #else
  89       #error "Unknown platform for interprocess_mutex"
  90    #endif
  91
  92    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
  93    public:
  94
  95    //!Constructor.
  96    //!Throws interprocess_exception on error.
  97    interprocess_mutex();
  98
  99    //!Destructor. If any process uses the mutex after the destructor is called
 100    //!the result is undefined. Does not throw.
 101    ~interprocess_mutex();
 102
 103    //!Effects: The calling thread tries to obtain ownership of the mutex, and
 104    //!   if another thread has ownership of the mutex, it waits until it can
 105    //!   obtain the ownership. If a thread takes ownership of the mutex the
 106    //!   mutex must be unlocked by the same mutex.
 107    //!Throws: interprocess_exception on error.
 108    void lock();
 109
 110    //!Effects: The calling thread tries to obtain ownership of the mutex, and
 111    //!   if another thread has ownership of the mutex returns immediately.
 112    //!Returns: If the thread acquires ownership of the mutex, returns true, if
 113    //!   the another thread has ownership of the mutex, returns false.
 114    //!Throws: interprocess_exception on error.
 115    bool try_lock();
 116
 117    //!Effects: The calling thread will try to obtain exclusive ownership of the
 118    //!   mutex if it can do so in until the specified time is reached. If the
 119    //!   mutex supports recursive locking, the mutex must be unlocked the same
 120    //!   number of times it is locked.
 121    //!Returns: If the thread acquires ownership of the mutex, returns true, if
 122    //!   the timeout expires returns false.
 123    //!Throws: interprocess_exception on error.
 124    bool timed_lock(const boost::posix_time::ptime &abs_time);
 125
 126    //!Effects: The calling thread releases the exclusive ownership of the mutex.
 127    //!Throws: interprocess_exception on error.
 128    void unlock();
 129
 130    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
 131    internal_mutex_type &internal_mutex()
 132    {  return m_mutex;   }
 133
 134    const internal_mutex_type &internal_mutex() const
 135    {  return m_mutex;   }
 136
 137    private:
 138    internal_mutex_type m_mutex;
 139    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
 140 };
 141
 142 }  //namespace interprocess {
 143 }  //namespace boost {
 144
 145
 146 namespace boost {
 147 namespace interprocess {
 148
 149 inline interprocess_mutex::interprocess_mutex(){}
 150
 151 inline interprocess_mutex::~interprocess_mutex(){}
 152
 153 inline void interprocess_mutex::lock()
 154 {
 155    #ifdef BOOST_INTERPROCESS_ENABLE_TIMEOUT_WHEN_LOCKING
 156       boost::posix_time::ptime wait_time
 157          = boost::posix_time::microsec_clock::universal_time()
 158          + boost::posix_time::milliseconds(BOOST_INTERPROCESS_TIMEOUT_WHEN_LOCKING_DURATION_MS);
 159       if (!m_mutex.timed_lock(wait_time))
 160       {
 161          throw interprocess_exception(timeout_when_locking_error
 162                                      , "Interprocess mutex timeout when locking. Possible deadlock: "
 163                                        "owner died without unlocking?");
 164       }
 165    #else
 166       m_mutex.lock();
 167    #endif
 168 }
 169
 170 inline bool interprocess_mutex::try_lock()
 171 { return m_mutex.try_lock(); }
 172
 173 inline bool interprocess_mutex::timed_lock(const boost::posix_time::ptime &abs_time)
 174 { return m_mutex.timed_lock(abs_time); }
 175
 176 inline void interprocess_mutex::unlock()
 177 { m_mutex.unlock(); }
 178
 179 }  //namespace interprocess {
 180 }  //namespace boost {
 181
 182 #include <boost/interprocess/detail/config_end.hpp>
 183
 184 #endif   //BOOST_INTERPROCESS_MUTEX_HPP