/*
    This file is a part of libcds - Concurrent Data Structures library

    (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2017

    Source code repo: http://github.com/khizmax/libcds/
    Download: http://sourceforge.net/projects/libcds/files/

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright notice, this
      list of conditions and the following disclaimer.

    * Redistributions in binary form must reproduce the above copyright notice,
      this list of conditions and the following disclaimer in the documentation
      and/or other materials provided with the distribution.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
    SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
    OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#ifndef CDSLIB_THREADING_DETAILS_PTHREAD_MANAGER_H
#define CDSLIB_THREADING_DETAILS_PTHREAD_MANAGER_H

#include <system_error>
#include <stdio.h>
#include <pthread.h>
#include <cds/threading/details/_common.h>
#include <cds/details/throw_exception.h>

//@cond
namespace cds { namespace threading {

    /// cds::threading::Manager implementation based on pthread thread-specific data functions
    CDS_CXX11_INLINE_NAMESPACE namespace pthread {

        /// Thread-specific data manager based on pthread thread-specific data functions
        /**
            Manager throws an exception of Manager::pthread_exception class if an error occurs
        */
        class Manager {
        private :
            /// pthread error code type
            typedef int pthread_error_code;

            /// pthread exception
            class pthread_exception: public std::system_error
            {
            public:
                /// Exception constructor
                pthread_exception( int nCode, const char * pszFunction )
                    : std::system_error( nCode, std::system_category(), pszFunction )
                {}
            };

            /// pthread TLS key holder
            struct Holder {
            //@cond
                static pthread_key_t   m_key;

                static void key_destructor(void * p)
                {
                    if ( p ) {
                        reinterpret_cast<ThreadData *>(p)->fini();
                        delete reinterpret_cast<ThreadData *>(p);
                    }
                }

                static void init()
                {
                    pthread_error_code  nErr;
                    if ( ( nErr = pthread_key_create( &m_key, key_destructor ) ) != 0 )
                        CDS_THROW_EXCEPTION( pthread_exception( nErr, "pthread_key_create" ));
                }

                static void fini()
                {
                    pthread_error_code  nErr;
                    if ( ( nErr = pthread_key_delete( m_key ) ) != 0 )
                        CDS_THROW_EXCEPTION( pthread_exception( nErr, "pthread_key_delete" ));
                }

                static ThreadData *    get()
                {
                    return reinterpret_cast<ThreadData *>( pthread_getspecific( m_key ));
                }

                static void alloc()
                {
                    pthread_error_code  nErr;
                    ThreadData * pData = new ThreadData;
                    if ( ( nErr = pthread_setspecific( m_key, pData ) ) != 0 )
                        CDS_THROW_EXCEPTION( pthread_exception( nErr, "pthread_setspecific" ));
                }
                static void free()
                {
                    ThreadData * p = get();
                    pthread_setspecific( m_key, nullptr );
                    if ( p )
                        delete p;
                }
            //@endcond
            };

            //@cond
            enum EThreadAction {
                do_getData,
                do_attachThread,
                do_detachThread,
                do_checkData,
                init_holder,
                fini_holder
            };
            //@endcond

            //@cond
            static ThreadData * _threadData( EThreadAction nAction )
            {
                switch ( nAction ) {
                    case do_getData:
                        return Holder::get();
                    case do_checkData:
                        return Holder::get();
                    case do_attachThread:
                        if ( Holder::get() == nullptr )
                            Holder::alloc();
                        return Holder::get();
                    case do_detachThread:
                        Holder::free();
                        return nullptr;
                    case init_holder:
                    case fini_holder:
                        break;
                    default:
                        assert( false ) ;   // anything forgotten?..
                }
                assert(false)   ;   // how did we get here?
                return nullptr;
            }
            //@endcond

        public:
            /// Initialize manager
            /**
                This function is automatically called by cds::Initialize
            */
            static void init()
            {
                Holder::init();
            }

            /// Terminate manager
            /**
                This function is automatically called by cds::Terminate
            */
            static void fini()
            {
                Holder::fini();
            }

            /// Checks whether current thread is attached to \p libcds feature or not.
            static bool isThreadAttached()
            {
                return _threadData( do_checkData ) != nullptr;
            }

            /// This method must be called in beginning of thread execution
            /**
                If TLS pointer to manager's data is \p nullptr, pthread_exception is thrown
                with code = -1.
                If an error occurs in call of pthread API function, pthread_exception is thrown
                with pthread error code.
            */
            static void attachThread()
            {
                ThreadData * pData = _threadData( do_attachThread );
                assert( pData );

                if ( pData ) {
                    pData->init();
                }
                else
                    CDS_THROW_EXCEPTION( pthread_exception( -1, "cds::threading::pthread::Manager::attachThread" ));
            }

            /// This method must be called in end of thread execution
            /**
                If TLS pointer to manager's data is \p nullptr, pthread_exception is thrown
                with code = -1.
                If an error occurs in call of pthread API function, pthread_exception is thrown
                with pthread error code.
            */
            static void detachThread()
            {
                ThreadData * pData = _threadData( do_getData );
                assert( pData );

                if ( pData ) {
                    if ( pData->fini() )
                        _threadData( do_detachThread );
                }
                else
                    CDS_THROW_EXCEPTION( pthread_exception( -1, "cds::threading::pthread::Manager::detachThread" ));
            }

            /// Returns ThreadData pointer for the current thread
            static ThreadData * thread_data()
            {
                return _threadData( do_getData );
            }

            //@cond
            static size_t fake_current_processor()
            {
                return _threadData( do_getData )->fake_current_processor();
            }
            //@endcond

        };

    } // namespace pthread
}} // namespace cds::threading
//@endcond

#endif // #ifndef CDSLIB_THREADING_DETAILS_PTHREAD_MANAGER_H
