Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: //
Chris@16: // (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
Chris@16: // Software License, Version 1.0. (See accompanying file
Chris@16: // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // See http://www.boost.org/libs/interprocess for documentation.
Chris@16: //
Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: #ifndef BOOST_INTERPROCESS_FILE_LOCK_HPP
Chris@16: #define BOOST_INTERPROCESS_FILE_LOCK_HPP
Chris@16: 
Chris@101: #ifndef BOOST_CONFIG_HPP
Chris@101: #  include <boost/config.hpp>
Chris@101: #endif
Chris@101: #
Chris@101: #if defined(BOOST_HAS_PRAGMA_ONCE)
Chris@16: #  pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/interprocess/detail/config_begin.hpp>
Chris@16: #include <boost/interprocess/detail/workaround.hpp>
Chris@16: #include <boost/interprocess/exceptions.hpp>
Chris@16: #include <boost/interprocess/detail/os_file_functions.hpp>
Chris@16: #include <boost/interprocess/detail/os_thread_functions.hpp>
Chris@16: #include <boost/interprocess/detail/posix_time_types_wrk.hpp>
Chris@101: #include <boost/interprocess/sync/detail/common_algorithms.hpp>
Chris@101: #include <boost/interprocess/sync/detail/locks.hpp>
Chris@101: #include <boost/move/utility_core.hpp>
Chris@16: 
Chris@16: //!\file
Chris@16: //!Describes a class that wraps file locking capabilities.
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace interprocess {
Chris@16: 
Chris@16: 
Chris@16: //!A file lock, is a mutual exclusion utility similar to a mutex using a
Chris@16: //!file. A file lock has sharable and exclusive locking capabilities and
Chris@16: //!can be used with scoped_lock and sharable_lock classes.
Chris@16: //!A file lock can't guarantee synchronization between threads of the same
Chris@16: //!process so just use file locks to synchronize threads from different processes.
Chris@16: class file_lock
Chris@16: {
Chris@101:    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
Chris@16:    //Non-copyable
Chris@16:    BOOST_MOVABLE_BUT_NOT_COPYABLE(file_lock)
Chris@101:    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@16: 
Chris@16:    public:
Chris@16:    //!Constructs an empty file mapping.
Chris@16:    //!Does not throw
Chris@16:    file_lock()
Chris@16:       :  m_file_hnd(file_handle_t(ipcdetail::invalid_file()))
Chris@16:    {}
Chris@16: 
Chris@16:    //!Opens a file lock. Throws interprocess_exception if the file does not
Chris@16:    //!exist or there are no operating system resources.
Chris@16:    file_lock(const char *name);
Chris@16: 
Chris@16:    //!Moves the ownership of "moved"'s file mapping object to *this.
Chris@16:    //!After the call, "moved" does not represent any file mapping object.
Chris@16:    //!Does not throw
Chris@16:    file_lock(BOOST_RV_REF(file_lock) moved)
Chris@16:       :  m_file_hnd(file_handle_t(ipcdetail::invalid_file()))
Chris@16:    {  this->swap(moved);   }
Chris@16: 
Chris@16:    //!Moves the ownership of "moved"'s file mapping to *this.
Chris@16:    //!After the call, "moved" does not represent any file mapping.
Chris@16:    //!Does not throw
Chris@16:    file_lock &operator=(BOOST_RV_REF(file_lock) moved)
Chris@16:    {
Chris@16:       file_lock tmp(boost::move(moved));
Chris@16:       this->swap(tmp);
Chris@16:       return *this;
Chris@16:    }
Chris@16: 
Chris@16:    //!Closes a file lock. Does not throw.
Chris@16:    ~file_lock();
Chris@16: 
Chris@16:    //!Swaps two file_locks.
Chris@16:    //!Does not throw.
Chris@16:    void swap(file_lock &other)
Chris@16:    {
Chris@16:       file_handle_t tmp = m_file_hnd;
Chris@16:       m_file_hnd = other.m_file_hnd;
Chris@16:       other.m_file_hnd = tmp;
Chris@16:    }
Chris@16: 
Chris@16:    //Exclusive locking
Chris@16: 
Chris@16:    //!Effects: The calling thread tries to obtain exclusive ownership of the mutex,
Chris@16:    //!   and if another thread has exclusive, or sharable ownership of
Chris@16:    //!   the mutex, it waits until it can obtain the ownership.
Chris@16:    //!Throws: interprocess_exception on error.
Chris@16:    void lock();
Chris@16: 
Chris@16:    //!Effects: The calling thread tries to acquire exclusive ownership of the mutex
Chris@16:    //!   without waiting. If no other thread has exclusive, or sharable
Chris@16:    //!   ownership of the mutex this succeeds.
Chris@16:    //!Returns: If it can acquire exclusive ownership immediately returns true.
Chris@16:    //!   If it has to wait, returns false.
Chris@16:    //!Throws: interprocess_exception on error.
Chris@16:    bool try_lock();
Chris@16: 
Chris@16:    //!Effects: The calling thread tries to acquire exclusive ownership of the mutex
Chris@16:    //!   waiting if necessary until no other thread has exclusive, or sharable
Chris@16:    //!   ownership of the mutex or abs_time is reached.
Chris@16:    //!Returns: If acquires exclusive ownership, returns true. Otherwise returns false.
Chris@16:    //!Throws: interprocess_exception on error.
Chris@16:    bool timed_lock(const boost::posix_time::ptime &abs_time);
Chris@16: 
Chris@16:    //!Precondition: The thread must have exclusive ownership of the mutex.
Chris@16:    //!Effects: The calling thread releases the exclusive ownership of the mutex.
Chris@16:    //!Throws: An exception derived from interprocess_exception on error.
Chris@16:    void unlock();
Chris@16: 
Chris@16:    //Sharable locking
Chris@16: 
Chris@16:    //!Effects: The calling thread tries to obtain sharable ownership of the mutex,
Chris@16:    //!   and if another thread has exclusive ownership of the mutex, waits until
Chris@16:    //!   it can obtain the ownership.
Chris@16:    //!Throws: interprocess_exception on error.
Chris@16:    void lock_sharable();
Chris@16: 
Chris@16:    //!Effects: The calling thread tries to acquire sharable ownership of the mutex
Chris@16:    //!   without waiting. If no other thread has exclusive ownership of the
Chris@16:    //!   mutex this succeeds.
Chris@16:    //!Returns: If it can acquire sharable ownership immediately returns true. If it
Chris@16:    //!   has to wait, returns false.
Chris@16:    //!Throws: interprocess_exception on error.
Chris@16:    bool try_lock_sharable();
Chris@16: 
Chris@16:    //!Effects: The calling thread tries to acquire sharable ownership of the mutex
Chris@16:    //!   waiting if necessary until no other thread has exclusive ownership of
Chris@16:    //!   the mutex or abs_time is reached.
Chris@16:    //!Returns: If acquires sharable ownership, returns true. Otherwise returns false.
Chris@16:    //!Throws: interprocess_exception on error.
Chris@16:    bool timed_lock_sharable(const boost::posix_time::ptime &abs_time);
Chris@16: 
Chris@16:    //!Precondition: The thread must have sharable ownership of the mutex.
Chris@16:    //!Effects: The calling thread releases the sharable ownership of the mutex.
Chris@16:    //!Throws: An exception derived from interprocess_exception on error.
Chris@16:    void unlock_sharable();
Chris@101:    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
Chris@16:    private:
Chris@16:    file_handle_t m_file_hnd;
Chris@16: 
Chris@101:    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@16: };
Chris@16: 
Chris@16: inline file_lock::file_lock(const char *name)
Chris@16: {
Chris@16:    m_file_hnd = ipcdetail::open_existing_file(name, read_write);
Chris@16: 
Chris@16:    if(m_file_hnd == ipcdetail::invalid_file()){
Chris@16:       error_info err(system_error_code());
Chris@16:       throw interprocess_exception(err);
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: inline file_lock::~file_lock()
Chris@16: {
Chris@16:    if(m_file_hnd != ipcdetail::invalid_file()){
Chris@16:       ipcdetail::close_file(m_file_hnd);
Chris@16:       m_file_hnd = ipcdetail::invalid_file();
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: inline void file_lock::lock()
Chris@16: {
Chris@16:    if(!ipcdetail::acquire_file_lock(m_file_hnd)){
Chris@16:       error_info err(system_error_code());
Chris@16:       throw interprocess_exception(err);
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: inline bool file_lock::try_lock()
Chris@16: {
Chris@16:    bool result;
Chris@16:    if(!ipcdetail::try_acquire_file_lock(m_file_hnd, result)){
Chris@16:       error_info err(system_error_code());
Chris@16:       throw interprocess_exception(err);
Chris@16:    }
Chris@16:    return result;
Chris@16: }
Chris@16: 
Chris@16: inline bool file_lock::timed_lock(const boost::posix_time::ptime &abs_time)
Chris@101: {  return ipcdetail::try_based_timed_lock(*this, abs_time);   }
Chris@16: 
Chris@16: inline void file_lock::unlock()
Chris@16: {
Chris@16:    if(!ipcdetail::release_file_lock(m_file_hnd)){
Chris@16:       error_info err(system_error_code());
Chris@16:       throw interprocess_exception(err);
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: inline void file_lock::lock_sharable()
Chris@16: {
Chris@16:    if(!ipcdetail::acquire_file_lock_sharable(m_file_hnd)){
Chris@16:       error_info err(system_error_code());
Chris@16:       throw interprocess_exception(err);
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: inline bool file_lock::try_lock_sharable()
Chris@16: {
Chris@16:    bool result;
Chris@16:    if(!ipcdetail::try_acquire_file_lock_sharable(m_file_hnd, result)){
Chris@16:       error_info err(system_error_code());
Chris@16:       throw interprocess_exception(err);
Chris@16:    }
Chris@16:    return result;
Chris@16: }
Chris@16: 
Chris@16: inline bool file_lock::timed_lock_sharable(const boost::posix_time::ptime &abs_time)
Chris@16: {
Chris@101:    ipcdetail::lock_to_sharable<file_lock> lsh(*this);
Chris@101:    return ipcdetail::try_based_timed_lock(lsh, abs_time);
Chris@16: }
Chris@16: 
Chris@16: inline void file_lock::unlock_sharable()
Chris@16: {
Chris@16:    if(!ipcdetail::release_file_lock_sharable(m_file_hnd)){
Chris@16:       error_info err(system_error_code());
Chris@16:       throw interprocess_exception(err);
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: }  //namespace interprocess {
Chris@16: }  //namespace boost {
Chris@16: 
Chris@16: #include <boost/interprocess/detail/config_end.hpp>
Chris@16: 
Chris@16: #endif   //BOOST_INTERPROCESS_FILE_LOCK_HPP