/*
    Copyright 2005-2012 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/concurrent_monitor.h"
#include "tbb/atomic.h"
#include "tbb/task_scheduler_init.h"
#include "tbb/parallel_for.h"
#include "tbb/blocked_range.h"
#include "harness.h"
#if _WIN32||_WIN64
#include "tbb/dynamic_link.cpp"
#endif

#include "tbb/semaphore.cpp"
#include "tbb/concurrent_monitor.cpp"

#if _MSC_VER && !defined(__INTEL_COMPILER)
    // Workaround for overzealous compiler warnings
    // Suppress compiler warning about constant conditional expression
    #pragma warning (disable: 4127)
#endif

using namespace tbb;

//! Queuing lock with concurrent_monitor; to test concurrent_monitor::notify( Predicate p )
class QueuingMutex {
public:
    //! Construct unacquired mutex.
    QueuingMutex() { q_tail = NULL; }

    //! The scoped locking pattern
    class ScopedLock: internal::no_copy {
        void Initialize() { mutex = NULL; }
    public:
        ScopedLock() {Initialize();}
        ScopedLock( QueuingMutex& m, size_t test_mode ) { Initialize(); Acquire(m,test_mode); }
        ~ScopedLock() { if( mutex ) Release(); }
        void Acquire( QueuingMutex& m, size_t test_mode );
        void Release();
        void SleepPerhaps();

    private:
        QueuingMutex* mutex;
        ScopedLock* next;
        uintptr_t going;
        internal::concurrent_monitor::thread_context thr_ctx;
    };

    friend class ScopedLock;
private:
    //! The last competitor requesting the lock
    atomic<ScopedLock*> q_tail;
    internal::concurrent_monitor waitq;
};

struct PredicateEq {
    uintptr_t p;
    PredicateEq( uintptr_t p_ ) : p(p_) {}
    bool operator() ( uintptr_t v ) const {return p==v;}
};

struct QueuingMutex_Context {
    const QueuingMutex::ScopedLock* lck;
    QueuingMutex_Context( QueuingMutex::ScopedLock* l_ ) : lck(l_) {}
    uintptr_t operator()() { return uintptr_t(lck); }
};

struct QueuingMutex_Until : NoAssign {
    uintptr_t& flag;
    QueuingMutex_Until( uintptr_t& f_ ) : flag(f_) {}
    bool operator()() { return flag!=0ul; }
};

//! A method to acquire QueuingMutex lock
void QueuingMutex::ScopedLock::Acquire( QueuingMutex& m, size_t test_mode )
{
    // Must set all fields before the fetch_and_store, because once the
    // fetch_and_store executes, *this becomes accessible to other threads.
    mutex = &m;
    next  = NULL;
    going = 0;

    // The fetch_and_store must have release semantics, because we are
    // "sending" the fields initialized above to other processors.
    ScopedLock* pred = m.q_tail.fetch_and_store<tbb::release>(this);
    if( pred ) {
#if TBB_USE_ASSERT
        __TBB_control_consistency_helper(); // on "m.q_tail"
        ASSERT( !pred->next, "the predecessor has another successor!");
#endif
        pred->next = this;
        for( int i=0; i<16; ++i ) {
            if( going!=0ul ) break;
            __TBB_Yield();
        }
        int x = int( test_mode%3 );
        switch( x ) {
        case 0:
            mutex->waitq.wait( QueuingMutex_Until(going), QueuingMutex_Context(this) );
            break;
#if __TBB_LAMBDAS_PRESENT
        case 1:
            mutex->waitq.wait( [&](){ return going!=0ul; }, [=]() { return (uintptr_t)this; } );
            break;
#endif
        default:
            SleepPerhaps();
            break;
        }
    }

    // Acquire critical section indirectly from previous owner or directly from predecessor.
    __TBB_control_consistency_helper(); // on either "m.q_tail" or "going"
}

//! A method to release QueuingMutex lock
void QueuingMutex::ScopedLock::Release( )
{
    if( !next ) {
        if( this == mutex->q_tail.compare_and_swap<tbb::release>(NULL, this) ) {
            // this was the only item in the queue, and the queue is now empty.
            goto done;
        }
        // Someone in the queue
        spin_wait_while_eq( next, (ScopedLock*)0 );
    }
    __TBB_store_with_release(next->going, 1);
    mutex->waitq.notify( PredicateEq(uintptr_t(next)) );
done:
    Initialize();
}

//! Yield and block; go to sleep
void QueuingMutex::ScopedLock::SleepPerhaps()
{
    bool slept = false;
    internal::concurrent_monitor& mq = mutex->waitq;
    mq.prepare_wait( thr_ctx, uintptr_t(this) );
    while( going==0ul ) {
        if( (slept=mq.commit_wait( thr_ctx ))==true && going!=0ul )
            break;
        slept = false;
        mq.prepare_wait( thr_ctx, uintptr_t(this) );
    }
    if( !slept )
        mq.cancel_wait( thr_ctx );
}

// Spin lock with concurrent_monitor; to test concurrent_monitor::notify_all() and concurrent_monitor::notify()
class SpinMutex {
public:
    //! Construct unacquired mutex.
    SpinMutex() : toggle(false) { flag = 0; }

    //! The scoped locking pattern
    class ScopedLock: internal::no_copy {
        void Initialize() { mutex = NULL; }
    public:
        ScopedLock() {Initialize();}
        ScopedLock( SpinMutex& m, size_t test_mode ) { Initialize(); Acquire(m,test_mode); }
        ~ScopedLock() { if( mutex ) Release(); }
        void Acquire( SpinMutex& m, size_t test_mode );
        void Release();
        void SleepPerhaps();

    private:
        SpinMutex* mutex;
        internal::concurrent_monitor::thread_context thr_ctx;
    };

    friend class ScopedLock;
    friend struct SpinMutex_Until;
private:
    tbb::atomic<unsigned> flag;
    bool toggle;
    internal::concurrent_monitor waitq;
};

struct SpinMutex_Context {
    const SpinMutex::ScopedLock* lck;
    SpinMutex_Context( SpinMutex::ScopedLock* l_ ) : lck(l_) {}
    uintptr_t operator()() { return uintptr_t(lck); }
};

struct SpinMutex_Until {
    const SpinMutex* mtx;
    SpinMutex_Until( SpinMutex* m_ ) : mtx(m_) {}
    bool operator()() { return mtx->flag==0; }
};

//! A method to acquire SpinMutex lock
void SpinMutex::ScopedLock::Acquire( SpinMutex& m, size_t test_mode )
{
    mutex = &m;
retry:
    if( m.flag.compare_and_swap( 1, 0 )!=0 ) {
        int x = int( test_mode%3 );
        switch( x ) {
        case 0:
            mutex->waitq.wait( SpinMutex_Until(mutex), SpinMutex_Context(this) );
            break;
#if __TBB_LAMBDAS_PRESENT
        case 1:
            mutex->waitq.wait( [&](){ return mutex->flag==0; }, [=]() { return (uintptr_t)this; } );
            break;
#endif
        default:
            SleepPerhaps();
            break;
        }
        goto retry;
    }
}

//! A method to release SpinMutex lock
void SpinMutex::ScopedLock::Release()
{
    bool old_toggle = mutex->toggle;
    mutex->toggle = !mutex->toggle;
    mutex->flag = 0;
    if( old_toggle )
        mutex->waitq.notify_one();
    else
        mutex->waitq.notify_all();
}

//! Yield and block; go to sleep
void SpinMutex::ScopedLock::SleepPerhaps()
{
    bool slept = false;
    internal::concurrent_monitor& mq = mutex->waitq;
    mq.prepare_wait( thr_ctx, uintptr_t(this) );
    while( mutex->flag ) {
        if( (slept=mq.commit_wait( thr_ctx ))==true )
            break;
        mq.prepare_wait( thr_ctx, uintptr_t(this) );
    }
    if( !slept )
        mq.cancel_wait( thr_ctx );
}

//! A value protected by a mutex.
template<typename M>
struct Counter {
    typedef M mutex_type;
    M mutex;
    long value;
};

//! Function object for use with parallel_for.h.
template<typename C, int D>
struct AddOne: NoAssign {
    C& counter;
    /** Increments counter once for each iteration in the iteration space. */
    void operator()( tbb::blocked_range<size_t>& range ) const {
        for( size_t i=range.begin(); i!=range.end(); ++i ) {
            typename C::mutex_type::ScopedLock lock(counter.mutex, i);
            counter.value = counter.value+1;
            if( D>0 )
                for( int j=0; j<D; ++j ) __TBB_Yield();
        }
    }
    AddOne( C& counter_ ) : counter(counter_) {}
};

//! Generic test with TBB mutex type M, max range R, and delay D.
template<typename M,int R, int D>
void Test( int p ) {
    Counter<M> counter;
    counter.value = 0;
    const int n = R;
    tbb::task_scheduler_init init(p);
    tbb::parallel_for(tbb::blocked_range<size_t>(0,n,n/10),AddOne<Counter<M>,D>(counter));
    if( counter.value!=n )
        REPORT("ERROR : counter.value=%ld (instead of %ld)\n",counter.value,n);
}

#if TBB_USE_EXCEPTIONS
#define NTHRS_USED_IN_DESTRUCTOR_TEST 8

atomic<size_t> n_sleepers;

#if defined(_MSC_VER) && defined(_Wp64)
    // Workaround for overzealous compiler warnings in /Wp64 mode
    #pragma warning (disable: 4244 4267)
#endif

struct AllButOneSleep : NoAssign {
    internal::concurrent_monitor*& mon;
    static const size_t VLN = 1024*1024;
    void operator()( int i ) const {
        internal::concurrent_monitor::thread_context thr_ctx;

        if( i==0 ) {
            size_t n_expected_sleepers = NTHRS_USED_IN_DESTRUCTOR_TEST-1;
            while( n_sleepers<n_expected_sleepers )
                __TBB_Yield();
            while( n_sleepers.compare_and_swap( VLN+NTHRS_USED_IN_DESTRUCTOR_TEST, n_expected_sleepers )!=n_expected_sleepers )
                __TBB_Yield();

            for( int j=0; j<100; ++j )
                Harness::Sleep( 1 );
            delete mon;
            mon = NULL;
        } else {
            mon->prepare_wait( thr_ctx, uintptr_t(this) );
            while( n_sleepers<VLN ) {
                try {
                    ++n_sleepers;
                    mon->commit_wait( thr_ctx );
                    if( --n_sleepers>VLN ) 
                        break;
                } catch( tbb::user_abort& ) {
                    // can no longer access 'mon'
                    break;
                }
                mon->prepare_wait( thr_ctx, uintptr_t(this) );
            }
        }
    }
    AllButOneSleep( internal::concurrent_monitor*& m_ ) : mon(m_) {}
};
#endif /* TBB_USE_EXCEPTIONS */

void TestDestructor() {
#if TBB_USE_EXCEPTIONS
    tbb::task_scheduler_init init(NTHRS_USED_IN_DESTRUCTOR_TEST);
    internal::concurrent_monitor* my_mon = new internal::concurrent_monitor;
    REMARK( "testing the destructor\n" );
    n_sleepers = 0;
    NativeParallelFor(NTHRS_USED_IN_DESTRUCTOR_TEST,AllButOneSleep(my_mon));
    ASSERT( my_mon==NULL, "" );
#endif /* TBB_USE_EXCEPTIONS */
}

int TestMain () {
    for( int p=MinThread; p<=MaxThread; ++p ) {
        REMARK( "testing with %d workers\n", static_cast<int>(p) );
        // test the predicated notify
        Test<QueuingMutex,100000,0>( p );
        Test<QueuingMutex,1000,10000>( p );
        // test the notify_all method
        Test<SpinMutex,100000,0>( p );
        Test<SpinMutex,1000,10000>( p );
        REMARK( "calling destructor for task_scheduler_init\n" );
    }
    TestDestructor();
    return Harness::Done;
}
