ceph/src/boost/boost/interprocess/sync/named_semaphore.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 #ifndef BOOST_INTERPROCESS_NAMED_SEMAPHORE_HPP
  12 #define BOOST_INTERPROCESS_NAMED_SEMAPHORE_HPP
  13
  14 #ifndef BOOST_CONFIG_HPP
  15 #  include <boost/config.hpp>
  16 #endif
  17 #
  18 #if defined(BOOST_HAS_PRAGMA_ONCE)
  19 #  pragma once
  20 #endif
  21
  22 #include <boost/interprocess/detail/config_begin.hpp>
  23 #include <boost/interprocess/detail/workaround.hpp>
  24 #include <boost/interprocess/creation_tags.hpp>
  25 #include <boost/interprocess/exceptions.hpp>
  26 #include <boost/interprocess/permissions.hpp>
  27 #include <boost/interprocess/detail/interprocess_tester.hpp>
  28
  29 #if defined(BOOST_INTERPROCESS_NAMED_SEMAPHORE_USES_POSIX_SEMAPHORES)
  30 #include <boost/interprocess/sync/posix/named_semaphore.hpp>
  31 //Experimental...
  32 #elif !defined(BOOST_INTERPROCESS_FORCE_GENERIC_EMULATION) && defined (BOOST_INTERPROCESS_WINDOWS)
  33    #include <boost/interprocess/sync/windows/named_semaphore.hpp>
  34    #define BOOST_INTERPROCESS_NAMED_SEMAPHORE_USE_WINAPI
  35 #else
  36    #include <boost/interprocess/sync/shm/named_semaphore.hpp>
  37 #endif
  38
  39 //!\file
  40 //!Describes a named semaphore class for inter-process synchronization
  41
  42 namespace boost {
  43 namespace interprocess {
  44
  45 //!A semaphore with a global name, so it can be found from different
  46 //!processes. Allows several resource sharing patterns and efficient
  47 //!acknowledgment mechanisms.
  48 class named_semaphore
  49 {
  50    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
  51
  52    //Non-copyable
  53    named_semaphore();
  54    named_semaphore(const named_semaphore &);
  55    named_semaphore &operator=(const named_semaphore &);
  56    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
  57
  58    public:
  59    //!Creates a global semaphore with a name, and an initial count.
  60    //!If the semaphore can't be created throws interprocess_exception
  61    named_semaphore(create_only_t, const char *name, unsigned int initialCount, const permissions &perm = permissions());
  62
  63    //!Opens or creates a global semaphore with a name, and an initial count.
  64    //!If the semaphore is created, this call is equivalent to
  65    //!named_semaphore(create_only_t, ...)
  66    //!If the semaphore is already created, this call is equivalent to
  67    //!named_semaphore(open_only_t, ... )
  68    //!and initialCount is ignored.
  69    named_semaphore(open_or_create_t, const char *name, unsigned int initialCount, const permissions &perm = permissions());
  70
  71    //!Opens a global semaphore with a name if that semaphore is previously.
  72    //!created. If it is not previously created this function throws
  73    //!interprocess_exception.
  74    named_semaphore(open_only_t, const char *name);
  75
  76    #if defined(BOOST_INTERPROCESS_WCHAR_NAMED_RESOURCES) || defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
  77
  78    //!Creates a global semaphore with a name, and an initial count.
  79    //!If the semaphore can't be created throws interprocess_exception
  80    //!
  81    //!Note: This function is only available on operating systems with
  82    //!      native wchar_t APIs (e.g. Windows).
  83    named_semaphore(create_only_t, const wchar_t *name, unsigned int initialCount, const permissions &perm = permissions());
  84
  85    //!Opens or creates a global semaphore with a name, and an initial count.
  86    //!If the semaphore is created, this call is equivalent to
  87    //!named_semaphore(create_only_t, ...)
  88    //!If the semaphore is already created, this call is equivalent to
  89    //!named_semaphore(open_only_t, ... )
  90    //!and initialCount is ignored.
  91    //!
  92    //!Note: This function is only available on operating systems with
  93    //!      native wchar_t APIs (e.g. Windows).
  94    named_semaphore(open_or_create_t, const wchar_t *name, unsigned int initialCount, const permissions &perm = permissions());
  95
  96    //!Opens a global semaphore with a name if that semaphore is previously.
  97    //!created. If it is not previously created this function throws
  98    //!interprocess_exception.
  99    //!
 100    //!Note: This function is only available on operating systems with
 101    //!      native wchar_t APIs (e.g. Windows).
 102    named_semaphore(open_only_t, const wchar_t *name);
 103
 104    #endif //defined(BOOST_INTERPROCESS_WCHAR_NAMED_RESOURCES) || defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
 105
 106    //!Destroys *this and indicates that the calling process is finished using
 107    //!the resource. The destructor function will deallocate
 108    //!any system resources allocated by the system for use by this process for
 109    //!this resource. The resource can still be opened again calling
 110    //!the open constructor overload. To erase the resource from the system
 111    //!use remove().
 112    ~named_semaphore();
 113
 114    //!Increments the semaphore count. If there are processes/threads blocked waiting
 115    //!for the semaphore, then one of these processes will return successfully from
 116    //!its wait function. If there is an error an interprocess_exception exception is thrown.
 117    void post();
 118
 119    //!Decrements the semaphore. If the semaphore value is not greater than zero,
 120    //!then the calling process/thread blocks until it can decrement the counter.
 121    //!If there is an error an interprocess_exception exception is thrown.
 122    void wait();
 123
 124    //!Decrements the semaphore if the semaphore's value is greater than zero
 125    //!and returns true. If the value is not greater than zero returns false.
 126    //!If there is an error an interprocess_exception exception is thrown.
 127    bool try_wait();
 128
 129    //!Decrements the semaphore if the semaphore's value is greater
 130    //!than zero and returns true. Otherwise, waits for the semaphore
 131    //!to the posted or the timeout expires. If the timeout expires, the
 132    //!function returns false. If the semaphore is posted the function
 133    //!returns true. If there is an error throws sem_exception
 134    template<class TimePoint>
 135    bool timed_wait(const TimePoint &abs_time);
 136
 137    //!Erases a named semaphore from the system.
 138    //!Returns false on error. Never throws.
 139    static bool remove(const char *name);
 140
 141    #if defined(BOOST_INTERPROCESS_WCHAR_NAMED_RESOURCES) || defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
 142
 143    //!Erases a named semaphore from the system.
 144    //!Returns false on error. Never throws.
 145    //!
 146    //!Note: This function is only available on operating systems with
 147    //!      native wchar_t APIs (e.g. Windows).
 148    static bool remove(const wchar_t *name);
 149
 150    #endif //defined(BOOST_INTERPROCESS_WCHAR_NAMED_RESOURCES) || defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
 151
 152    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
 153    private:
 154    friend class ipcdetail::interprocess_tester;
 155    void dont_close_on_destruction();
 156
 157    #if defined(BOOST_INTERPROCESS_NAMED_SEMAPHORE_USES_POSIX_SEMAPHORES)
 158       typedef ipcdetail::posix_named_semaphore   impl_t;
 159    #elif defined(BOOST_INTERPROCESS_NAMED_SEMAPHORE_USE_WINAPI)
 160       typedef ipcdetail::winapi_named_semaphore impl_t;
 161    #else
 162       typedef ipcdetail::shm_named_semaphore     impl_t;
 163    #endif
 164    impl_t m_sem;
 165    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
 166 };
 167
 168 #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
 169
 170 inline named_semaphore::named_semaphore
 171    (create_only_t, const char *name, unsigned int initialCount, const permissions &perm)
 172    :  m_sem(create_only, name, initialCount, perm)
 173 {}
 174
 175 inline named_semaphore::named_semaphore
 176    (open_or_create_t, const char *name, unsigned int initialCount, const permissions &perm)
 177    :  m_sem(open_or_create, name, initialCount, perm)
 178 {}
 179
 180 inline named_semaphore::named_semaphore(open_only_t, const char *name)
 181    :  m_sem(open_only, name)
 182 {}
 183
 184 #if defined(BOOST_INTERPROCESS_WCHAR_NAMED_RESOURCES) || defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
 185
 186 inline named_semaphore::named_semaphore
 187    (create_only_t, const wchar_t *name, unsigned int initialCount, const permissions &perm)
 188    :  m_sem(create_only, name, initialCount, perm)
 189 {}
 190
 191 inline named_semaphore::named_semaphore
 192    (open_or_create_t, const wchar_t *name, unsigned int initialCount, const permissions &perm)
 193    :  m_sem(open_or_create, name, initialCount, perm)
 194 {}
 195
 196 inline named_semaphore::named_semaphore(open_only_t, const wchar_t *name)
 197    :  m_sem(open_only, name)
 198 {}
 199
 200 #endif //defined(BOOST_INTERPROCESS_WCHAR_NAMED_RESOURCES) || defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
 201
 202 inline named_semaphore::~named_semaphore()
 203 {}
 204
 205 inline void named_semaphore::dont_close_on_destruction()
 206 {  ipcdetail::interprocess_tester::dont_close_on_destruction(m_sem);  }
 207
 208 inline void named_semaphore::wait()
 209 {  m_sem.wait();  }
 210
 211 inline void named_semaphore::post()
 212 {  m_sem.post();  }
 213
 214 inline bool named_semaphore::try_wait()
 215 {  return m_sem.try_wait();  }
 216
 217 template<class TimePoint>
 218 inline bool named_semaphore::timed_wait(const TimePoint &abs_time)
 219 {  return m_sem.timed_wait(abs_time);  }
 220
 221 inline bool named_semaphore::remove(const char *name)
 222 {  return impl_t::remove(name);   }
 223
 224 #if defined(BOOST_INTERPROCESS_WCHAR_NAMED_RESOURCES) || defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
 225
 226 inline bool named_semaphore::remove(const wchar_t *name)
 227 {  return impl_t::remove(name);   }
 228
 229 #endif
 230
 231 #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
 232
 233 }  //namespace interprocess {
 234 }  //namespace boost {
 235
 236
 237 #include <boost/interprocess/detail/config_end.hpp>
 238
 239 #endif   //BOOST_INTERPROCESS_NAMED_SEMAPHORE_HPP