/*
    Copyright 2005-2015 Intel Corporation.  All Rights Reserved.

    This file is part of Threading Building Blocks. Threading Building Blocks is free software;
    you can redistribute it and/or modify it under the terms of the GNU General Public License
    version 2  as  published  by  the  Free Software Foundation.  Threading Building Blocks is
    distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the
    implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
    See  the GNU General Public License for more details.   You should have received a copy of
    the  GNU General Public License along with Threading Building Blocks; if not, write to the
    Free Software Foundation, Inc.,  51 Franklin St,  Fifth Floor,  Boston,  MA 02110-1301 USA

    As a special exception,  you may use this file  as part of a free software library without
    restriction.  Specifically,  if other files instantiate templates  or use macros or inline
    functions from this file, or you compile this file and link it with other files to produce
    an executable,  this file does not by itself cause the resulting executable to be covered
    by the GNU General Public License. This exception does not however invalidate any other
    reasons why the executable file might be covered by the GNU General Public License.
*/

#include "tbb/tbb_config.h"
#include "tbb/compat/condition_variable"
#include "tbb/atomic.h"
#include "tbb_misc.h"
#include "dynamic_link.h"
#include "itt_notify.h"

namespace tbb {

namespace internal {

//condition_variable
#if _WIN32||_WIN64
using tbb::interface5::internal::condition_variable_using_event;

static atomic<do_once_state> condvar_api_state;

void WINAPI init_condvar_using_event( condition_variable_using_event* cv_event )
{
    // TODO: For Metro port, we can always use the API for condition variables, without dynamic_link etc.
    cv_event->event = CreateEventEx(NULL, NULL, 0x1 /*CREATE_EVENT_MANUAL_RESET*/, EVENT_ALL_ACCESS );
    InitializeCriticalSectionEx( &cv_event->mutex, 4000, 0 );
    cv_event->n_waiters = 0;
    cv_event->release_count = 0;
    cv_event->epoch = 0;
}

BOOL WINAPI sleep_condition_variable_cs_using_event( condition_variable_using_event* cv_event, LPCRITICAL_SECTION cs, DWORD dwMilliseconds )
{
    EnterCriticalSection( &cv_event->mutex );
    ++cv_event->n_waiters;
    unsigned my_generation = cv_event->epoch;
    LeaveCriticalSection( &cv_event->mutex );
    LeaveCriticalSection( cs );
    for (;;) {
        // should come here at least once
        DWORD rc = WaitForSingleObjectEx( cv_event->event, dwMilliseconds, FALSE );
        EnterCriticalSection( &cv_event->mutex );
        if( rc!=WAIT_OBJECT_0 ) {
            --cv_event->n_waiters;
            LeaveCriticalSection( &cv_event->mutex );
            if( rc==WAIT_TIMEOUT ) {
                SetLastError( WAIT_TIMEOUT );
                EnterCriticalSection( cs );
            }
            return false;
        }
        __TBB_ASSERT( rc==WAIT_OBJECT_0, NULL );
        if( cv_event->release_count>0 && cv_event->epoch!=my_generation )
            break;
        LeaveCriticalSection( &cv_event->mutex );
    }

    // still in the critical section
    --cv_event->n_waiters;
    int count = --cv_event->release_count;
    LeaveCriticalSection( &cv_event->mutex );

    if( count==0 ) {
        __TBB_ASSERT( cv_event->event, "Premature destruction of condition variable?" );
        ResetEvent( cv_event->event );
    }
    EnterCriticalSection( cs );
    return true;
}

void WINAPI wake_condition_variable_using_event( condition_variable_using_event* cv_event )
{
    EnterCriticalSection( &cv_event->mutex );
    if( cv_event->n_waiters>cv_event->release_count ) {
        SetEvent( cv_event->event ); // Signal the manual-reset event.
        ++cv_event->release_count;
        ++cv_event->epoch;
    }
    LeaveCriticalSection( &cv_event->mutex );
}

void WINAPI wake_all_condition_variable_using_event( condition_variable_using_event* cv_event )
{
    EnterCriticalSection( &cv_event->mutex );
    if( cv_event->n_waiters>0 ) {
        SetEvent( cv_event->event );
        cv_event->release_count = cv_event->n_waiters;
        ++cv_event->epoch;
    }
    LeaveCriticalSection( &cv_event->mutex );
}

void WINAPI destroy_condvar_using_event( condition_variable_using_event* cv_event )
{
    HANDLE my_event = cv_event->event;
    EnterCriticalSection( &cv_event->mutex );
    // NULL is an invalid HANDLE value
    cv_event->event = NULL;
    if( cv_event->n_waiters>0 ) {
        LeaveCriticalSection( &cv_event->mutex );
        spin_wait_until_eq( cv_event->n_waiters, 0 );
        // make sure the last thread completes its access to cv
        EnterCriticalSection( &cv_event->mutex );
    }
    LeaveCriticalSection( &cv_event->mutex );
    CloseHandle( my_event );
}

void WINAPI destroy_condvar_noop( CONDITION_VARIABLE* /*cv*/ ) { /*no op*/ }

static void (WINAPI *__TBB_init_condvar)( PCONDITION_VARIABLE ) = (void (WINAPI *)(PCONDITION_VARIABLE))&init_condvar_using_event;
static BOOL (WINAPI *__TBB_condvar_wait)( PCONDITION_VARIABLE, LPCRITICAL_SECTION, DWORD ) = (BOOL (WINAPI *)(PCONDITION_VARIABLE,LPCRITICAL_SECTION, DWORD))&sleep_condition_variable_cs_using_event;
static void (WINAPI *__TBB_condvar_notify_one)( PCONDITION_VARIABLE ) = (void (WINAPI *)(PCONDITION_VARIABLE))&wake_condition_variable_using_event;
static void (WINAPI *__TBB_condvar_notify_all)( PCONDITION_VARIABLE ) = (void (WINAPI *)(PCONDITION_VARIABLE))&wake_all_condition_variable_using_event;
static void (WINAPI *__TBB_destroy_condvar)( PCONDITION_VARIABLE ) = (void (WINAPI *)(PCONDITION_VARIABLE))&destroy_condvar_using_event;

//! Table describing how to link the handlers.
static const dynamic_link_descriptor CondVarLinkTable[] = {
    DLD(InitializeConditionVariable, __TBB_init_condvar),
    DLD(SleepConditionVariableCS,    __TBB_condvar_wait),
    DLD(WakeConditionVariable,       __TBB_condvar_notify_one),
    DLD(WakeAllConditionVariable,    __TBB_condvar_notify_all)
};

void init_condvar_module()
{
    __TBB_ASSERT( (uintptr_t)__TBB_init_condvar==(uintptr_t)&init_condvar_using_event, NULL );
    if( dynamic_link( "Kernel32.dll", CondVarLinkTable, 4 ) )
        __TBB_destroy_condvar = (void (WINAPI *)(PCONDITION_VARIABLE))&destroy_condvar_noop;
}
#endif /* _WIN32||_WIN64 */

} // namespace internal

#if _WIN32||_WIN64

namespace interface5 {
namespace internal {

using tbb::internal::condvar_api_state;
using tbb::internal::__TBB_init_condvar;
using tbb::internal::__TBB_condvar_wait;
using tbb::internal::__TBB_condvar_notify_one;
using tbb::internal::__TBB_condvar_notify_all;
using tbb::internal::__TBB_destroy_condvar;
using tbb::internal::init_condvar_module;

void internal_initialize_condition_variable( condvar_impl_t& cv )
{
    atomic_do_once( &init_condvar_module, condvar_api_state );
    __TBB_init_condvar( &cv.cv_native );
}

void internal_destroy_condition_variable( condvar_impl_t& cv )
{
    __TBB_destroy_condvar( &cv.cv_native );
}

void internal_condition_variable_notify_one( condvar_impl_t& cv )
{
    __TBB_condvar_notify_one ( &cv.cv_native );
}

void internal_condition_variable_notify_all( condvar_impl_t& cv )
{
    __TBB_condvar_notify_all( &cv.cv_native );
}

bool internal_condition_variable_wait( condvar_impl_t& cv, mutex* mtx, const tick_count::interval_t* i )
{
    DWORD duration = i ? DWORD((i->seconds()*1000)) : INFINITE;
    mtx->set_state( mutex::INITIALIZED );
    BOOL res = __TBB_condvar_wait( &cv.cv_native, mtx->native_handle(), duration );
    mtx->set_state( mutex::HELD );
    return res?true:false;
}

} // namespace internal
} // nameespace interface5

#endif /* _WIN32||_WIN64 */

} // namespace tbb
